[PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Balamanikandan Gunasundar]

Hi,

This patch series has a set of enhancements to the Microchip Image Sensor
Controller driver. The objective is to expand its image processing
capabilities and to improve the colors.

This series also introduces a new stats driver that exposes the histogram
data to userspace via v4l2 controls. This allows applications such as
libcamera to access real time image statistics for advanced image
processing like automatic exposure, white balance adjustments etc.

Balakrishnan Sambath (11):
  media: microchip-isc: Enable GDC and CBC module flags for RGB formats
  media: microchip-isc: Improve histogram calculation with outlier
    rejection
  media: microchip-isc: Use channel averages for Grey World AWB
  media: microchip-isc: Add range based black level correction
  media: platform: microchip: Extend gamma table and control range
  media: platform: microchip: Add new histogram submodule
  media: microchip-isc: Register and unregister statistics device
  media: microchip-isc: Always enable histogram for all RAW formats
  media: microchip-isc: fix histogram state initialization order
  media: microchip-isc: decouple histogram cycling from AWB mode
  media: microchip-isc: enable userspace histogram statistics export

Balamanikandan Gunasundar (7):
  media: platform: microchip: set maximum resolution for sam9x7
  media: platform: microchip: Include DPC modules flags in pipeline
  media: microchip-isc: expose hue and saturation as v4l2 controls
  media: microchip-isc: Rename CBC to CBHS
  media: microchip-isc: Store histogram data of all channels
  media: videodev2.h, v4l2-ioctl: Add microchip statistics format
  media: microchip-isc: expose color correction registers as v4l2
    controls

 drivers/media/platform/microchip/Kconfig      |   2 +
 drivers/media/platform/microchip/Makefile     |   2 +-
 .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
 .../platform/microchip/microchip-isc-regs.h   |   3 +
 .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
 .../media/platform/microchip/microchip-isc.h  |  44 +-
 .../microchip/microchip-sama5d2-isc.c         |   2 +-
 .../microchip/microchip-sama7g5-isc.c         |  73 ++-
 drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
 include/linux/atmel-isc-media.h               |  13 +
 include/uapi/linux/videodev2.h                |   3 +
 11 files changed, 1001 insertions(+), 64 deletions(-)
 create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c

-- 
2.34.1

[PATCH 01/18] media: platform: microchip: set maximum resolution for sam9x7

[Balamanikandan Gunasundar]

The maximum resolution for sam9x7 is 2560x1920. And its is 3264x2464 for
sama7g5.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 .../media/platform/microchip/microchip-sama7g5-isc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index b0302dfc3278..36c3f4ba1962 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -55,6 +55,9 @@
 #define ISC_SAMA7G5_MAX_SUPPORT_WIDTH   3264
 #define ISC_SAMA7G5_MAX_SUPPORT_HEIGHT  2464
 
+#define ISC_SAM9X7_MAX_SUPPORT_WIDTH    2560
+#define ISC_SAM9X7_MAX_SUPPORT_HEIGHT   1920
+
 #define ISC_SAMA7G5_PIPELINE \
 	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
 	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
@@ -432,8 +435,13 @@ static int microchip_xisc_probe(struct platform_device *pdev)
 	isc->gamma_table = isc_sama7g5_gamma_table;
 	isc->gamma_max = 0;
 
-	isc->max_width = ISC_SAMA7G5_MAX_SUPPORT_WIDTH;
-	isc->max_height = ISC_SAMA7G5_MAX_SUPPORT_HEIGHT;
+	if ((of_machine_is_compatible("microchip,sam9x7"))) {
+		isc->max_width = ISC_SAM9X7_MAX_SUPPORT_WIDTH;
+		isc->max_height = ISC_SAM9X7_MAX_SUPPORT_HEIGHT;
+	} else {
+		isc->max_width = ISC_SAMA7G5_MAX_SUPPORT_WIDTH;
+		isc->max_height = ISC_SAMA7G5_MAX_SUPPORT_HEIGHT;
+	}
 
 	isc->config_dpc = isc_sama7g5_config_dpc;
 	isc->config_csc = isc_sama7g5_config_csc;
-- 
2.34.1

[PATCH 02/18] media: platform: microchip: Include DPC modules flags in pipeline

[Balamanikandan Gunasundar]

Add DPC_DPCENABLE, DPC_GDCENABLE, and DPC_BLCENABLE enable bits to
ISC_SAMA7G5_PIPELINE macro to prevent isc_sama7g5_adapt_pipeline() from
masking out DPC modules during pipeline configuration

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/platform/microchip/microchip-sama7g5-isc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 36c3f4ba1962..03f7a46acd47 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -59,7 +59,8 @@
 #define ISC_SAM9X7_MAX_SUPPORT_HEIGHT   1920
 
 #define ISC_SAMA7G5_PIPELINE \
-	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
+	(DPC_DPCENABLE | DPC_GDCENABLE | DPC_BLCENABLE | \
+	WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
 	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */
-- 
2.34.1

[PATCH 03/18] media: microchip-isc: Enable GDC and CBC module flags for RGB formats

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Include DPC_GDCENABLE and CBC_ENABLE flags in pipeline configuration for
RGB raw formats to enable green disparity correction and
contrast/brightness control.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index a7cdc743fda7..c138e92a1aca 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -787,7 +787,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				WB_ENABLE | GAM_ENABLES | DPC_BLCENABLE |
-				CC_ENABLE;
+				DPC_GDCENABLE | CBC_ENABLE | CC_ENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
-- 
2.34.1

[PATCH 04/18] media: microchip-isc: Improve histogram calculation with outlier rejection

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Replace simple min/max detection with smart outlier rejection that skips
bottom/top 2% of histogram to avoid noise and saturation. Add channel
average calculation using weighted pixel intensity instead of simple
pixel counting for more accurate color analysis.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c   | 83 ++++++++++++++++---
 .../media/platform/microchip/microchip-isc.h  |  2 +
 2 files changed, 75 insertions(+), 10 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index c138e92a1aca..956bdea830e3 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -262,6 +262,10 @@ static void isc_set_histogram(struct isc_device *isc, bool enable)
 	struct isc_ctrls *ctrls = &isc->ctrls;
 
 	if (enable) {
+		/* Initialize histogram data storage for clean start */
+		memset(ctrls->total_pixels, 0, sizeof(ctrls->total_pixels));
+		memset(ctrls->hist_minmax, 0, sizeof(ctrls->hist_minmax));
+
 		regmap_write(regmap, ISC_HIS_CFG + isc->offsets.his,
 			     ISC_HIS_CFG_MODE_GR |
 			     (isc->config.sd_format->cfa_baycfg
@@ -1231,24 +1235,83 @@ static void isc_hist_count(struct isc_device *isc, u32 *min, u32 *max)
 	regmap_bulk_read(regmap, ISC_HIS_ENTRY + isc->offsets.his_entry,
 			 hist_entry, HIST_ENTRIES);
 
-	*hist_count = 0;
-	/*
-	 * we deliberately ignore the end of the histogram,
-	 * the most white pixels
-	 */
+	/* Calculate total pixels */
+	u32 total_pixels = 0;
+
+	for (i = 0; i < HIST_ENTRIES; i++)
+		total_pixels += hist_entry[i];
+
+	/* Handle empty histogram case */
+	if (total_pixels == 0) {
+		*hist_count = 0;
+		ctrls->channel_avg[ctrls->hist_id] = 256; /* Default middle value */
+		ctrls->total_pixels[ctrls->hist_id] = 0;
+		*min = 1;
+		*max = HIST_ENTRIES - 1;
+		dev_dbg(isc->dev, "isc wb: no pixels in histogram for channel %u", ctrls->hist_id);
+		return;
+	}
+
+	/* Smart outlier rejection - skip bottom/top 2% */
+	u32 dark_threshold = total_pixels / 50;   /* Bottom 2% */
+	u32 bright_threshold = total_pixels / 50; /* Top 2% */
+	u32 cumulative = 0;
+
+	/* Find effective minimum (skip dark noise) */
+	*min = 1;
 	for (i = 1; i < HIST_ENTRIES; i++) {
-		if (*hist_entry && !*min)
+		cumulative += hist_entry[i];
+		if (cumulative > dark_threshold) {
 			*min = i;
-		if (*hist_entry)
+			break;
+		}
+	}
+
+	/* Find effective maximum (skip bright saturation) */
+	cumulative = 0;
+	*max = HIST_ENTRIES - 1;
+	for (i = HIST_ENTRIES - 1; i > *min; i--) {
+		cumulative += hist_entry[i];
+		if (cumulative > bright_threshold) {
 			*max = i;
-		*hist_count += i * (*hist_entry++);
+			break;
+		}
 	}
 
+	/* Ensure reasonable range */
+	if (*max <= *min) {
+		*min = HIST_ENTRIES / 4;
+		*max = (HIST_ENTRIES * 3) / 4;
+	}
+
+	/* Calculate both pixel count and weighted average for useful range */
+	*hist_count = 0;
+	u64 weighted_sum = 0;
+
+	for (i = *min; i <= *max; i++) {
+		u32 pixel_count = hist_entry[i];
+		*hist_count += pixel_count;
+		weighted_sum += (u64)i * pixel_count;
+	}
+
+	/* Store total useful pixels for this channel */
+	ctrls->total_pixels[ctrls->hist_id] = *hist_count;
+
+	/* Calculate channel average */
+	if (*hist_count > 0)
+		ctrls->channel_avg[ctrls->hist_id] =
+			div64_u64(weighted_sum, *hist_count);
+	else
+		/* Default middle value */
+		ctrls->channel_avg[ctrls->hist_id] = 256;
+
 	if (!*min)
 		*min = 1;
 
-	dev_dbg(isc->dev, "isc wb: hist_id %u, hist_count %u",
-		ctrls->hist_id, *hist_count);
+	dev_dbg(isc->dev,
+		"isc wb: hist_id %u, avg %u, count %u, range [%u,%u], total %u",
+		ctrls->hist_id, ctrls->channel_avg[ctrls->hist_id],
+		*hist_count, *min, *max, total_pixels);
 }
 
 static void isc_wb_update(struct isc_ctrls *ctrls)
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index ad4e98a1dd8f..bd75ff4f109b 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -156,6 +156,8 @@ struct isc_ctrls {
 #define HIST_MIN_INDEX		0
 #define HIST_MAX_INDEX		1
 	u32 hist_minmax[HIST_BAYER][2];
+	u32 channel_avg[HIST_BAYER];      /* Average pixel intensity per channel */
+	u32 total_pixels[HIST_BAYER];     /* Total pixels per channel */
 };
 
 #define ISC_PIPE_LINE_NODE_NUM	15
-- 
2.34.1

[PATCH 05/18] media: microchip-isc: Use channel averages for Grey World AWB

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Replace pixel counting with actual pixel intensity averages in Grey
World algorithm for more accurate white balance calculation.This
provides better color correction especially in mixed lighting
conditions.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c   | 35 ++++++++++---------
 1 file changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 956bdea830e3..bb2dd69a83f0 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1317,7 +1317,6 @@ static void isc_hist_count(struct isc_device *isc, u32 *min, u32 *max)
 static void isc_wb_update(struct isc_ctrls *ctrls)
 {
 	struct isc_device *isc = container_of(ctrls, struct isc_device, ctrls);
-	u32 *hist_count = &ctrls->hist_count[0];
 	u32 c, offset[4];
 	u64 avg = 0;
 	/* We compute two gains, stretch gain and grey world gain */
@@ -1328,10 +1327,10 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 	 * them towards the green channel.
 	 * Thus we want to keep Green as fixed and adjust only Red/Blue
 	 * Compute the average of the both green channels first
+	 * Use channel averages for Grey World algorithm
 	 */
-	avg = (u64)hist_count[ISC_HIS_CFG_MODE_GR] +
-		(u64)hist_count[ISC_HIS_CFG_MODE_GB];
-	avg >>= 1;
+	avg = (ctrls->channel_avg[ISC_HIS_CFG_MODE_GR] +
+			ctrls->channel_avg[ISC_HIS_CFG_MODE_GB]) >> 1;
 
 	dev_dbg(isc->dev, "isc wb: green components average %llu\n", avg);
 
@@ -1340,6 +1339,11 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		return;
 
 	for (c = ISC_HIS_CFG_MODE_GR; c <= ISC_HIS_CFG_MODE_B; c++) {
+		u32 hist_min = ctrls->hist_minmax[c][HIST_MIN_INDEX];
+		u32 hist_max = ctrls->hist_minmax[c][HIST_MAX_INDEX];
+		u32 channel_avg = ctrls->channel_avg[c];
+		u32 total_pixels = ctrls->total_pixels[c];
+
 		/*
 		 * the color offset is the minimum value of the histogram.
 		 * we stretch this color to the full range by substracting
@@ -1373,23 +1377,21 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		 * decimals
 		 */
 		s_gain[c] = (HIST_ENTRIES << 9) /
-			(ctrls->hist_minmax[c][HIST_MAX_INDEX] -
-			ctrls->hist_minmax[c][HIST_MIN_INDEX] + 1);
+			(hist_max - hist_min + 1);
 
 		/*
-		 * Now we have to compute the gain w.r.t. the average.
-		 * Add/lose gain to the component towards the average.
-		 * If it happens that the component is zero, use the
-		 * fixed point value : 1.0 gain.
+		 * Grey World gain using channel averages
+		 * This is much more accurate than using hist_count
 		 */
-		if (hist_count[c])
-			gw_gain[c] = div_u64(avg << 9, hist_count[c]);
+		if (channel_avg > 0 && total_pixels > 1000)
+			gw_gain[c] = div64_u64((avg << 9), channel_avg);
 		else
 			gw_gain[c] = 1 << 9;
 
 		dev_dbg(isc->dev,
-			"isc wb: component %d, s_gain %u, gw_gain %u\n",
-			c, s_gain[c], gw_gain[c]);
+			"isc wb: component %d, black_level=%u, avg=%u, s_gain=%u, gw_gain=%u",
+			c, hist_min, channel_avg, s_gain[c], gw_gain[c]);
+
 		/* multiply both gains and adjust for decimals */
 		ctrls->gain[c] = s_gain[c] * gw_gain[c];
 		ctrls->gain[c] >>= 9;
@@ -1397,8 +1399,9 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		/* make sure we are not out of range */
 		ctrls->gain[c] = clamp_val(ctrls->gain[c], 0, GENMASK(12, 0));
 
-		dev_dbg(isc->dev, "isc wb: component %d, final gain %u\n",
-			c, ctrls->gain[c]);
+		dev_dbg(isc->dev,
+			"isc wb: component %d, final gain %u, offset %d\n",
+			c, ctrls->gain[c], ctrls->offset[c]);
 	}
 }
 
-- 
2.34.1

[PATCH 06/18] media: microchip-isc: Add range based black level correction

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Add adaptive black level offset based on histogram minimum and pixel
statistics. Apply conservative correction for high black levels and
gentle correction for low levels to prevent overcorrection and improve
dynamic range.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c   | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index bb2dd69a83f0..2706a27a2506 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1349,7 +1349,27 @@ static void isc_wb_update(struct isc_ctrls *ctrls)
 		 * we stretch this color to the full range by substracting
 		 * this value from the color component.
 		 */
-		offset[c] = ctrls->hist_minmax[c][HIST_MIN_INDEX];
+		if (hist_min > 5 && hist_min < 60 && total_pixels > 1000) {
+			/*
+			 * Basic adaptive black level offset correction
+			 * (Simplified version for kernel fallback)
+			 */
+			if (hist_min > 20)
+				/* Conservative for high levels */
+				offset[c] = hist_min - 4;
+			else if (hist_min > 10)
+				/* Moderate correction */
+				offset[c] = hist_min - 2;
+			else
+				/* Gentle correction */
+				offset[c] = hist_min - 1;
+
+			offset[c] = max(1U, offset[c]);  /* Ensure minimum of 1 */
+		} else {
+			/* Use default behavior for edge cases */
+			offset[c] = hist_min;
+		}
+
 		/*
 		 * The offset is always at least 1. If the offset is 1, we do
 		 * not need to adjust it, so our result must be zero.
-- 
2.34.1

[PATCH 07/18] media: platform: microchip: Extend gamma table and control range

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Add support for multiple levels of gamma correction options (1/2.4,
1/2.2, 1/1.8) which can be modified through V4L2 controls(with range
0-2), with a default of 1/2.2(index 1).

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c   |  3 +-
 .../microchip/microchip-sama7g5-isc.c         | 54 ++++++++++++++-----
 2 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 2706a27a2506..cd379f95fc1c 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1715,8 +1715,7 @@ static int isc_ctrl_init(struct isc_device *isc)
 	ctrls->brightness = 0;
 
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS, -1024, 1023, 1, 0);
-	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1,
-			  isc->gamma_max);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1, 1);
 	isc->awb_ctrl = v4l2_ctrl_new_std(hdl, &isc_awb_ops,
 					  V4L2_CID_AUTO_WHITE_BALANCE,
 					  0, 1, 1, 1);
diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index 03f7a46acd47..d3ed9cfe6686 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -320,21 +320,47 @@ static void isc_sama7g5_adapt_pipeline(struct isc_device *isc)
 	isc->try_config.bits_pipeline &= ISC_SAMA7G5_PIPELINE;
 }
 
-/* Gamma table with gamma 1/2.2 */
+/* Gamma tables with gamma values 0.42, 0.45(Default), 0.56 */
 static const u32 isc_sama7g5_gamma_table[][GAMMA_ENTRIES] = {
-	/* index 0 --> gamma bipartite */
+	/* index 0 --> gamma bipartite 1/2.4(=0.42) */
 	{
-	      0x980,  0x4c0320,  0x650260,  0x7801e0,  0x8701a0,  0x940180,
-	   0xa00160,  0xab0120,  0xb40120,  0xbd0120,  0xc60100,  0xce0100,
-	   0xd600e0,  0xdd00e0,  0xe400e0,  0xeb00c0,  0xf100c0,  0xf700c0,
-	   0xfd00c0, 0x10300a0, 0x10800c0, 0x10e00a0, 0x11300a0, 0x11800a0,
-	  0x11d00a0, 0x12200a0, 0x12700a0, 0x12c0080, 0x13000a0, 0x1350080,
-	  0x13900a0, 0x13e0080, 0x1420076, 0x17d0062, 0x1ae0054, 0x1d8004a,
-	  0x1fd0044, 0x21f003e, 0x23e003a, 0x25b0036, 0x2760032, 0x28f0030,
-	  0x2a7002e, 0x2be002c, 0x2d4002c, 0x2ea0028, 0x2fe0028, 0x3120026,
-	  0x3250024, 0x3370024, 0x3490022, 0x35a0022, 0x36b0020, 0x37b0020,
-	  0x38b0020, 0x39b001e, 0x3aa001e, 0x3b9001c, 0x3c7001c, 0x3d5001c,
-	  0x3e3001c, 0x3f1001c, 0x3ff001a, 0x40c001a },
+	      0x940,  0x4b0310,  0x630250,  0x7601d0,  0x840190,  0x910170,
+	   0x9d0150,  0xa80110,  0xb10110,  0xba0110,  0xc300f0,  0xcb00f0,
+	   0xd300e0,  0xda00e0,  0xe100c0,  0xe800c0,  0xee00c0,  0xf400c0,
+	   0xfa00a0, 0x10000a0, 0x10500a0, 0x10b00a0, 0x11000a0, 0x11500a0,
+	  0x11a0080, 0x11f0080, 0x1240080, 0x1290080, 0x12e0080, 0x1330070,
+	  0x1380070, 0x13c0070, 0x1410070, 0x17a0060, 0x1aa0052, 0x1d40046,
+	  0x1f90042, 0x21b003c, 0x23a0038, 0x2570034, 0x2720030, 0x28b002e,
+	  0x2a3002c, 0x2ba002a, 0x2d0002a, 0x2e60028, 0x2fa0026, 0x30e0026,
+	  0x3210024, 0x3330022, 0x3450022, 0x3560020, 0x3670020, 0x3770020,
+	  0x387001e, 0x396001e, 0x3a5001c, 0x3b3001c, 0x3c1001c, 0x3cf001a,
+	  0x3dd001a, 0x3eb0018, 0x3f90018 },
+	/* index 1 --> gamma bipartite 1/2.2(=0.45) */
+	{
+	     0x980,  0x4c0320,  0x650260,  0x7801e0,  0x8701a0,  0x940180,
+	  0xa00160,  0xab0120,  0xb40120,  0xbd0120,  0xc60100,  0xce0100,
+	  0xd600e0,  0xdd00e0,  0xe400e0,  0xeb00c0,  0xf100c0,  0xf700c0,
+	  0xfd00c0, 0x10300a0, 0x10800c0, 0x10e00a0, 0x11300a0, 0x11800a0,
+	 0x11d00a0, 0x12200a0, 0x12700a0, 0x12c0080, 0x13000a0, 0x1350080,
+	 0x13900a0, 0x13e0080, 0x1420076, 0x17d0062, 0x1ae0054, 0x1d8004a,
+	 0x1fd0044, 0x21f003e, 0x23e003a, 0x25b0036, 0x2760032, 0x28f0030,
+	 0x2a7002e, 0x2be002c, 0x2d4002c, 0x2ea0028, 0x2fe0028, 0x3120026,
+	 0x3250024, 0x3370024, 0x3490022, 0x35a0022, 0x36b0020, 0x37b0020,
+	 0x38b0020, 0x39b001e, 0x3aa001e, 0x3b9001c, 0x3c7001c, 0x3d5001c,
+	 0x3e3001c, 0x3f1001c, 0x3ff001a, 0x40c001a },
+	/* index 2 --> gamma bipartite 1/1.8(=0.56) */
+	{
+	      0xa62,  0x4f0350,  0x680280,  0x7e0200,  0x8d01c0,  0x9a01a0,
+	   0xa50180,  0xb00140,  0xb90140,  0xc20120,  0xcb0120,  0xd30100,
+	   0xdb0100,  0xe300e0,  0xea00e0,  0xf100e0,  0xf700c0,  0xfd00c0,
+	  0x10300c0, 0x10900a0, 0x10e00a0, 0x11400a0, 0x11900a0, 0x11e00a0,
+	  0x12300a0, 0x12800a0, 0x12d0080, 0x1320080, 0x1370080, 0x13c0080,
+	  0x1410080, 0x1460080, 0x14a0070, 0x1830060, 0x1b40052, 0x1df0048,
+	  0x2040042, 0x2250040, 0x2440038, 0x2600036, 0x27b0032, 0x2940030,
+	  0x2ac002e, 0x2c4002c, 0x2da002a, 0x2f0002a, 0x3050028, 0x3190026,
+	  0x32c0026, 0x33e0024, 0x3500024, 0x3610022, 0x3720020, 0x3820020,
+	  0x3920020, 0x3a2001e, 0x3b1001e, 0x3c0001c, 0x3ce001c, 0x3dc001c,
+	  0x3ea001a, 0x3f8001a, 0x4060018, 0x4130018 },
 };
 
 static int xisc_parse_dt(struct device *dev, struct isc_device *isc)
@@ -434,7 +460,7 @@ static int microchip_xisc_probe(struct platform_device *pdev)
 	}
 
 	isc->gamma_table = isc_sama7g5_gamma_table;
-	isc->gamma_max = 0;
+	isc->gamma_max = 2;
 
 	if ((of_machine_is_compatible("microchip,sam9x7"))) {
 		isc->max_width = ISC_SAM9X7_MAX_SUPPORT_WIDTH;
-- 
2.34.1

[PATCH 08/18] media: platform: microchip: Add new histogram submodule

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Add new histogram submodule driver to export raw histogram statistics
and data to userspace.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/Kconfig      |   2 +
 drivers/media/platform/microchip/Makefile     |   2 +-
 .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
 .../media/platform/microchip/microchip-isc.h  |  24 +
 4 files changed, 576 insertions(+), 1 deletion(-)
 create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c

diff --git a/drivers/media/platform/microchip/Kconfig b/drivers/media/platform/microchip/Kconfig
index 4734ecced029..2864a57e2ff4 100644
--- a/drivers/media/platform/microchip/Kconfig
+++ b/drivers/media/platform/microchip/Kconfig
@@ -10,6 +10,7 @@ config VIDEO_MICROCHIP_ISC
 	select MEDIA_CONTROLLER
 	select VIDEO_V4L2_SUBDEV_API
 	select VIDEOBUF2_DMA_CONTIG
+	select VIDEOBUF2_VMALLOC
 	select REGMAP_MMIO
 	select V4L2_FWNODE
 	select VIDEO_MICROCHIP_ISC_BASE
@@ -26,6 +27,7 @@ config VIDEO_MICROCHIP_XISC
 	depends on VIDEO_DEV && COMMON_CLK
 	depends on ARCH_AT91 || COMPILE_TEST
 	select VIDEOBUF2_DMA_CONTIG
+	select VIDEOBUF2_VMALLOC
 	select REGMAP_MMIO
 	select V4L2_FWNODE
 	select VIDEO_MICROCHIP_ISC_BASE
diff --git a/drivers/media/platform/microchip/Makefile b/drivers/media/platform/microchip/Makefile
index bd8d6e779c51..94c64d3d242c 100644
--- a/drivers/media/platform/microchip/Makefile
+++ b/drivers/media/platform/microchip/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 microchip-isc-objs = microchip-sama5d2-isc.o
 microchip-xisc-objs = microchip-sama7g5-isc.o
-microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o
+microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o microchip-isc-stats.o
 
 obj-$(CONFIG_VIDEO_MICROCHIP_ISC_BASE) += microchip-isc-common.o
 obj-$(CONFIG_VIDEO_MICROCHIP_ISC) += microchip-isc.o
diff --git a/drivers/media/platform/microchip/microchip-isc-stats.c b/drivers/media/platform/microchip/microchip-isc-stats.c
new file mode 100644
index 000000000000..d7813c9d95ac
--- /dev/null
+++ b/drivers/media/platform/microchip/microchip-isc-stats.c
@@ -0,0 +1,549 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Microchip ISC Driver - Statistics Subdevice
+ * Raw Histogram Export for Userspace Applications
+ *
+ * Copyright (C) 2025 Microchip Technology Inc.
+ *
+ * Author: Balakrishnan Sambath <balakrishnan.s@microchip.com>
+ */
+
+#include <linux/clk.h>
+#include <media/v4l2-common.h>
+#include <media/v4l2-event.h>
+#include <media/v4l2-ioctl.h>
+#include <media/videobuf2-core.h>
+#include <media/videobuf2-vmalloc.h>
+#include "microchip-isc-regs.h"
+#include "microchip-isc.h"
+
+#define ISC_STATS_DEV_NAME	"microchip-isc_stats"
+#define ISC_STATS_MIN_BUFS	2
+#define ISC_STATS_MAX_BUFS	8
+
+/**
+ * struct isc_stat_buffer - Raw histogram statistics buffer structure
+ * @frame_number: Sequential frame number from capture
+ * @timestamp: Frame capture timestamp in nanoseconds
+ * @meas_type: Bitmask of measurement types available (ISC_CIF_ISP_STAT_*)
+ * @hist: Array of histogram data for each Bayer channel
+ * @hist.hist_bins: Raw 512-bin histogram data from hardware
+ * @hist.hist_min: Minimum pixel value observed in channel
+ * @hist.hist_max: Maximum pixel value observed in channel
+ * @hist.total_pixels: Total number of pixels processed in channel
+ * @valid_channels: Bitmask indicating which Bayer channels contain valid data
+ * @bayer_pattern: Current Bayer pattern configuration (CFA_BAYCFG_*)
+ * @reserved: Padding for future expansion and alignment
+ *
+ * This structure contains raw, unprocessed histogram data from the ISC
+ * hardware for all four Bayer channels (GR, R, GB, B). No algorithmic
+ * processing is performed - data is exported directly from hardware
+ * registers for userspace processing applications.
+ */
+struct isc_stat_buffer {
+	u32 frame_number;
+	u64 timestamp;
+	u32 meas_type;
+
+	struct {
+		u32 hist_bins[HIST_ENTRIES];
+		u32 hist_min;
+		u32 hist_max;
+		u32 total_pixels;
+	} hist[HIST_BAYER];
+
+	u8 valid_channels;
+	u8 bayer_pattern;
+	u16 reserved[2];
+} __packed;
+
+/* Statistics measurement type flags */
+#define ISC_CIF_ISP_STAT_HIST		BIT(0)
+
+static bool isc_stats_in_use(struct isc_stats *stats)
+{
+	struct video_device *vdev;
+
+	if (!stats || !stats->isc)
+		return false;
+
+	vdev = &stats->vnode.vdev;
+	return vdev && video_is_registered(vdev) && !list_empty(&vdev->fh_list);
+}
+
+static bool isc_stats_has_bufs(struct isc_stats *stats)
+{
+	bool has_buffers;
+
+	if (!stats)
+		return false;
+
+	spin_lock(&stats->lock);
+	has_buffers = !list_empty(&stats->stat);
+	spin_unlock(&stats->lock);
+
+	return has_buffers;
+}
+
+/*
+ * V4L2 device operations
+ */
+
+static int isc_stats_enum_fmt_meta_cap(struct file *file, void *priv,
+				       struct v4l2_fmtdesc *f)
+{
+	struct video_device *video = video_devdata(file);
+	struct isc_stats *stats = video_get_drvdata(video);
+
+	if (f->index > 0 || f->type != video->queue->type)
+		return -EINVAL;
+
+	f->pixelformat = stats->vdev_fmt.fmt.meta.dataformat;
+	return 0;
+}
+
+static int isc_stats_g_fmt_meta_cap(struct file *file, void *priv,
+				    struct v4l2_format *f)
+{
+	struct video_device *video = video_devdata(file);
+	struct isc_stats *stats = video_get_drvdata(video);
+	struct v4l2_meta_format *meta = &f->fmt.meta;
+
+	if (f->type != video->queue->type)
+		return -EINVAL;
+
+	memset(meta, 0, sizeof(*meta));
+	meta->dataformat = stats->vdev_fmt.fmt.meta.dataformat;
+	meta->buffersize = stats->vdev_fmt.fmt.meta.buffersize;
+
+	return 0;
+}
+
+static int isc_stats_querycap(struct file *file, void *priv,
+			      struct v4l2_capability *cap)
+{
+	struct video_device *vdev = video_devdata(file);
+
+	strscpy(cap->driver, "microchip-isc", sizeof(cap->driver));
+	strscpy(cap->card, vdev->name, sizeof(cap->card));
+	strscpy(cap->bus_info, "platform:microchip-isc", sizeof(cap->bus_info));
+
+	return 0;
+}
+
+static int isc_stats_open(struct file *file)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct isc_stats *stats = video_get_drvdata(vdev);
+
+	dev_dbg(stats->isc->dev, "Stats device opened by %s (pid %d)\n",
+		current->comm, current->pid);
+
+	return v4l2_fh_open(file);
+}
+
+static int isc_stats_release(struct file *file)
+{
+	struct video_device *vdev = video_devdata(file);
+	struct isc_stats *stats = video_get_drvdata(vdev);
+
+	dev_dbg(stats->isc->dev, "Stats device closed by %s (pid %d)\n",
+		current->comm, current->pid);
+
+	return _vb2_fop_release(file, NULL);
+}
+
+static const struct v4l2_ioctl_ops isc_stats_ioctl_ops = {
+	.vidioc_reqbufs = vb2_ioctl_reqbufs,
+	.vidioc_querybuf = vb2_ioctl_querybuf,
+	.vidioc_create_bufs = vb2_ioctl_create_bufs,
+	.vidioc_qbuf = vb2_ioctl_qbuf,
+	.vidioc_dqbuf = vb2_ioctl_dqbuf,
+	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
+	.vidioc_expbuf = vb2_ioctl_expbuf,
+	.vidioc_streamon = vb2_ioctl_streamon,
+	.vidioc_streamoff = vb2_ioctl_streamoff,
+	.vidioc_enum_fmt_meta_cap = isc_stats_enum_fmt_meta_cap,
+	.vidioc_g_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
+	.vidioc_s_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
+	.vidioc_try_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
+	.vidioc_querycap = isc_stats_querycap,
+	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
+	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
+};
+
+static const struct v4l2_file_operations isc_stats_fops = {
+	.mmap = vb2_fop_mmap,
+	.unlocked_ioctl = video_ioctl2,
+	.poll = vb2_fop_poll,
+	.open = isc_stats_open,
+	.release = isc_stats_release
+};
+
+/*
+ * VB2 queue operations
+ */
+
+static int isc_stats_vb2_queue_setup(struct vb2_queue *vq,
+				     unsigned int *num_buffers,
+				     unsigned int *num_planes,
+				     unsigned int sizes[],
+				     struct device *alloc_devs[])
+{
+	struct isc_stats *stats = vq->drv_priv;
+
+	*num_planes = 1;
+	*num_buffers = clamp_t(u32, *num_buffers, ISC_STATS_MIN_BUFS,
+			       ISC_STATS_MAX_BUFS);
+	sizes[0] = sizeof(struct isc_stat_buffer);
+
+	dev_dbg(stats->isc->dev, "Stats queue: %u buffers, %u bytes each\n",
+		*num_buffers, sizes[0]);
+
+	return 0;
+}
+
+static void isc_stats_vb2_buf_queue(struct vb2_buffer *vb)
+{
+	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
+	struct isc_buffer *stats_buf = container_of(vbuf, struct isc_buffer, vb);
+	struct vb2_queue *vq = vb->vb2_queue;
+	struct isc_stats *stats_dev = vq->drv_priv;
+
+	spin_lock_irq(&stats_dev->lock);
+	list_add_tail(&stats_buf->list, &stats_dev->stat);
+	spin_unlock_irq(&stats_dev->lock);
+
+	dev_dbg(stats_dev->isc->dev, "Stats buffer %d queued\n", vb->index);
+}
+
+static int isc_stats_vb2_buf_prepare(struct vb2_buffer *vb)
+{
+	if (vb2_plane_size(vb, 0) < sizeof(struct isc_stat_buffer))
+		return -EINVAL;
+
+	vb2_set_plane_payload(vb, 0, sizeof(struct isc_stat_buffer));
+	return 0;
+}
+
+static int isc_stats_vb2_start_streaming(struct vb2_queue *vq,
+					 unsigned int count)
+{
+	struct isc_stats *stats = vq->drv_priv;
+
+	dev_dbg(stats->isc->dev, "Stats streaming started\n");
+	return 0;
+}
+
+static void isc_stats_vb2_stop_streaming(struct vb2_queue *vq)
+{
+	struct isc_stats *stats = vq->drv_priv;
+	struct isc_buffer *buf;
+	unsigned int i;
+
+	dev_dbg(stats->isc->dev, "Stats streaming stopped\n");
+
+	spin_lock_irq(&stats->lock);
+	for (i = 0; i < ISC_STATS_MAX_BUFS; i++) {
+		if (list_empty(&stats->stat))
+			break;
+		buf = list_first_entry(&stats->stat, struct isc_buffer, list);
+		list_del(&buf->list);
+		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
+	}
+	spin_unlock_irq(&stats->lock);
+}
+
+static const struct vb2_ops isc_stats_vb2_ops = {
+	.queue_setup = isc_stats_vb2_queue_setup,
+	.buf_queue = isc_stats_vb2_buf_queue,
+	.buf_prepare = isc_stats_vb2_buf_prepare,
+	.start_streaming = isc_stats_vb2_start_streaming,
+	.stop_streaming = isc_stats_vb2_stop_streaming,
+	.wait_prepare = vb2_ops_wait_prepare,
+	.wait_finish = vb2_ops_wait_finish,
+};
+
+static int isc_stats_init_vb2_queue(struct vb2_queue *q,
+				    struct isc_stats *stats)
+{
+	struct isc_vdev_node *node;
+
+	node = container_of(q, struct isc_vdev_node, buf_queue);
+
+	q->type = V4L2_BUF_TYPE_META_CAPTURE;
+	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;
+	q->drv_priv = stats;
+	q->ops = &isc_stats_vb2_ops;
+	q->mem_ops = &vb2_vmalloc_memops;
+	q->buf_struct_size = sizeof(struct isc_buffer);
+	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
+	q->lock = &node->vlock;
+
+	return vb2_queue_init(q);
+}
+
+/*
+ * Histogram data processing
+ */
+
+static void isc_stats_fill_data(struct isc_stats *stats,
+				struct isc_stat_buffer *pbuf)
+{
+	struct isc_device *isc = stats->isc;
+	struct isc_ctrls *ctrls = &isc->ctrls;
+	int c;
+
+	pbuf->meas_type |= ISC_CIF_ISP_STAT_HIST;
+
+	/* Copy existing histogram data from AWB work function */
+	for (c = 0; c < HIST_BAYER; c++) {
+		memcpy(pbuf->hist[c].hist_bins, isc->full_hist_data[c],
+		       sizeof(pbuf->hist[c].hist_bins));
+
+		pbuf->hist[c].hist_min = ctrls->hist_minmax[c][HIST_MIN_INDEX];
+		pbuf->hist[c].hist_max = ctrls->hist_minmax[c][HIST_MAX_INDEX];
+		pbuf->hist[c].total_pixels = ctrls->total_pixels[c];
+	}
+
+	/* Set valid channels - all 4 Bayer channels */
+	pbuf->valid_channels = 0x0F;
+
+	/* Set Bayer pattern */
+	if (isc->config.sd_format)
+		pbuf->bayer_pattern = isc->config.sd_format->cfa_baycfg;
+	else
+		pbuf->bayer_pattern = 0;
+
+	dev_dbg(isc->dev,
+		"Stats data ready: pixels=[%u,%u,%u,%u], valid_channels=0x%x\n",
+		pbuf->hist[0].total_pixels, pbuf->hist[1].total_pixels,
+		pbuf->hist[2].total_pixels, pbuf->hist[3].total_pixels,
+		pbuf->valid_channels);
+}
+
+static void isc_stats_send_buf(struct isc_stats *stats)
+{
+	struct isc_stat_buffer *cur_stat_buf;
+	struct isc_buffer *cur_buf = NULL;
+	struct isc_device *isc = stats->isc;
+	unsigned int frame_sequence = isc->sequence;
+	u64 timestamp = ktime_get_ns();
+
+	/* Get one empty buffer from userspace */
+	spin_lock(&stats->lock);
+	if (!list_empty(&stats->stat)) {
+		cur_buf = list_first_entry(&stats->stat,
+					   struct isc_buffer, list);
+		list_del(&cur_buf->list);
+	}
+	spin_unlock(&stats->lock);
+
+	if (!cur_buf) {
+		dev_dbg(isc->dev, "No stats buffer available\n");
+		return;
+	}
+
+	cur_stat_buf = vb2_plane_vaddr(&cur_buf->vb.vb2_buf, 0);
+	if (!cur_stat_buf) {
+		dev_err(isc->dev, "Failed to get stats buffer vaddr\n");
+		goto error_return_buffer;
+	}
+
+	/* Clear buffer and fill metadata */
+	memset(cur_stat_buf, 0, sizeof(*cur_stat_buf));
+	cur_stat_buf->frame_number = frame_sequence;
+	cur_stat_buf->timestamp = timestamp;
+
+	/* Fill raw histogram data */
+	isc_stats_fill_data(stats, cur_stat_buf);
+
+	/* Send buffer to userspace */
+	vb2_set_plane_payload(&cur_buf->vb.vb2_buf, 0,
+			      sizeof(struct isc_stat_buffer));
+	cur_buf->vb.sequence = frame_sequence;
+	cur_buf->vb.vb2_buf.timestamp = timestamp;
+	vb2_buffer_done(&cur_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
+
+	dev_dbg(isc->dev,
+		"Stats sent: frame=%u, channels=[%u,%u,%u,%u] pixels\n",
+		frame_sequence,
+		cur_stat_buf->hist[0].total_pixels,
+		cur_stat_buf->hist[1].total_pixels,
+		cur_stat_buf->hist[2].total_pixels,
+		cur_stat_buf->hist[3].total_pixels);
+	return;
+
+error_return_buffer:
+	/* Return buffer to queue on error */
+	spin_lock(&stats->lock);
+	list_add(&cur_buf->list, &stats->stat);
+	spin_unlock(&stats->lock);
+}
+
+/*
+ * Public API functions
+ */
+
+/**
+ * isc_stats_isr() - Process statistics in interrupt context
+ * @stats: ISC histogram statistics device
+ *
+ * Called from the ISC interrupt handler when histogram data is ready.
+ * Exports raw histogram data to userspace applications that have
+ * buffers queued on the statistics device.
+ */
+void isc_stats_isr(struct isc_stats *stats)
+{
+	if (!stats) {
+		pr_err("ISC stats: stats is NULL\n");
+		return;
+	}
+
+	if (!stats->isc) {
+		pr_err("ISC stats: stats->isc is NULL\n");
+		return;
+	}
+
+	/* Only send data if userspace is using the device */
+	if (!isc_stats_in_use(stats)) {
+		dev_dbg(stats->isc->dev, "Stats device not in use\n");
+		return;
+	}
+
+	/* Only send data if userspace has queued buffers */
+	if (!isc_stats_has_bufs(stats)) {
+		dev_dbg(stats->isc->dev, "No queued buffers\n");
+		return;
+	}
+
+	/* Send histogram data to userspace */
+	isc_stats_send_buf(stats);
+}
+EXPORT_SYMBOL_GPL(isc_stats_isr);
+
+/**
+ * isc_stats_active() - Check if userspace is actively using stats
+ * @stats: ISC histogram statistics device
+ *
+ * Determines if any userspace application has the statistics device open
+ * and has queued buffers waiting for histogram data.
+ *
+ * Return: true if userspace is ready to receive data, false otherwise
+ */
+bool isc_stats_active(struct isc_stats *stats)
+{
+	return isc_stats_in_use(stats) && isc_stats_has_bufs(stats);
+}
+EXPORT_SYMBOL_GPL(isc_stats_active);
+
+static void isc_stats_init(struct isc_stats *stats)
+{
+	stats->vdev_fmt.fmt.meta.dataformat = V4L2_META_FMT_ISC_STAT_3A;
+	stats->vdev_fmt.fmt.meta.buffersize = sizeof(struct isc_stat_buffer);
+}
+
+/**
+ * isc_stats_register() - Register statistics device
+ * @isc: ISC device
+ *
+ * Creates and registers a V4L2 video device for exporting raw histogram
+ * statistics to userspace.
+ *
+ */
+int isc_stats_register(struct isc_device *isc)
+{
+	struct isc_stats *stats = &isc->stats;
+	struct isc_vdev_node *node = &stats->vnode;
+	struct video_device *vdev = &node->vdev;
+	int ret;
+
+	/* Initialize stats structure */
+	stats->isc = isc;
+	mutex_init(&node->vlock);
+	INIT_LIST_HEAD(&stats->stat);
+	spin_lock_init(&stats->lock);
+
+	/* Configure video device */
+	strscpy(vdev->name, ISC_STATS_DEV_NAME, sizeof(vdev->name));
+	vdev->ioctl_ops = &isc_stats_ioctl_ops;
+	vdev->fops = &isc_stats_fops;
+	vdev->release = video_device_release_empty;
+	vdev->lock = &node->vlock;
+	vdev->v4l2_dev = &isc->v4l2_dev;
+	vdev->queue = &node->buf_queue;
+	vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
+	vdev->vfl_dir = VFL_DIR_RX;
+
+	/* Initialize VB2 queue */
+	ret = isc_stats_init_vb2_queue(vdev->queue, stats);
+	if (ret) {
+		dev_err(isc->dev, "Failed to init stats VB2 queue: %d\n", ret);
+		goto error_cleanup;
+	}
+
+	/* Initialize stats format */
+	isc_stats_init(stats);
+
+	video_set_drvdata(vdev, stats);
+
+	node->pad.flags = MEDIA_PAD_FL_SINK;
+	ret = media_entity_pads_init(&vdev->entity, 1, &node->pad);
+	if (ret) {
+		dev_err(isc->dev, "Failed to init stats media entity: %d\n", ret);
+		goto error_cleanup;
+	}
+
+	/* Register video device */
+	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
+	if (ret) {
+		dev_err(isc->dev, "Failed to register stats device: %d\n", ret);
+		goto error_media_cleanup;
+	}
+
+	dev_info(isc->dev, "Stats device registered as %s\n",
+		 video_device_node_name(vdev));
+
+	return 0;
+
+error_media_cleanup:
+	media_entity_cleanup(&vdev->entity);
+error_cleanup:
+	mutex_destroy(&node->vlock);
+	stats->isc = NULL;
+	return ret;
+}
+EXPORT_SYMBOL_GPL(isc_stats_register);
+
+/**
+ * isc_stats_unregister() - Unregister statistics device
+ * @isc: ISC device
+ *
+ * Unregisters and cleans up the statistics video device.
+ */
+void isc_stats_unregister(struct isc_device *isc)
+{
+	struct isc_stats *stats = &isc->stats;
+	struct isc_vdev_node *node = &stats->vnode;
+	struct video_device *vdev = &node->vdev;
+
+	if (!stats->isc)
+		return;
+
+	dev_dbg(isc->dev, "Unregistering stats device\n");
+
+	/* Unregister video device */
+	vb2_video_unregister_device(vdev);
+
+	media_entity_cleanup(&vdev->entity);
+
+	/* Destroy synchronization primitives */
+	mutex_destroy(&node->vlock);
+
+	stats->isc = NULL;
+}
+EXPORT_SYMBOL_GPL(isc_stats_unregister);
+
+MODULE_AUTHOR("Balakrishnan Sambath <balakrishnan.s@microchip.com>");
+MODULE_DESCRIPTION("Microchip ISC Statistics Driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index bd75ff4f109b..5245e2790268 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -197,6 +197,23 @@ enum isc_scaler_pads {
 	ISC_SCALER_PADS_NUM	= 2,
 };
 
+/* Video device node structure */
+struct isc_vdev_node {
+	struct video_device vdev;
+	struct vb2_queue buf_queue;
+	struct mutex vlock; /* lock for video node */
+	struct media_pad pad;
+};
+
+/* Statistics device structure */
+struct isc_stats {
+	struct isc_device *isc;
+	struct isc_vdev_node vnode;
+	struct list_head stat;
+	spinlock_t lock; /* lock for buffers */
+	struct v4l2_format vdev_fmt;
+};
+
 /*
  * struct isc_device - ISC device driver data/config struct
  * @regmap:		Register map
@@ -340,6 +357,9 @@ struct isc_device {
 		struct v4l2_ctrl	*gb_off_ctrl;
 	};
 
+	/* Statistics device */
+	struct isc_stats stats;
+
 #define GAMMA_ENTRIES	64
 	/* pointer to the defined gamma table */
 	const u32	(*gamma_table)[GAMMA_ENTRIES];
@@ -396,6 +416,10 @@ int isc_scaler_link(struct isc_device *isc);
 int isc_scaler_init(struct isc_device *isc);
 int isc_mc_init(struct isc_device *isc, u32 ver);
 void isc_mc_cleanup(struct isc_device *isc);
+int isc_stats_register(struct isc_device *isc);
+void isc_stats_unregister(struct isc_device *isc);
+void isc_stats_isr(struct isc_stats *stats);
+bool isc_stats_active(struct isc_stats *stats);
 
 struct isc_format *isc_find_format_by_code(struct isc_device *isc,
 					   unsigned int code, int *index);
-- 
2.34.1

Re: [PATCH 08/18] media: platform: microchip: Add new histogram submodule

[Hans Verkuil]

Apologies for the late review, but this needs a bit more work:

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:
> From: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> 
> Add new histogram submodule driver to export raw histogram statistics
> and data to userspace.
> 
> Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> ---
>  drivers/media/platform/microchip/Kconfig      |   2 +
>  drivers/media/platform/microchip/Makefile     |   2 +-
>  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>  .../media/platform/microchip/microchip-isc.h  |  24 +
>  4 files changed, 576 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> 
> diff --git a/drivers/media/platform/microchip/Kconfig b/drivers/media/platform/microchip/Kconfig
> index 4734ecced029..2864a57e2ff4 100644
> --- a/drivers/media/platform/microchip/Kconfig
> +++ b/drivers/media/platform/microchip/Kconfig
> @@ -10,6 +10,7 @@ config VIDEO_MICROCHIP_ISC
>  	select MEDIA_CONTROLLER
>  	select VIDEO_V4L2_SUBDEV_API
>  	select VIDEOBUF2_DMA_CONTIG
> +	select VIDEOBUF2_VMALLOC
>  	select REGMAP_MMIO
>  	select V4L2_FWNODE
>  	select VIDEO_MICROCHIP_ISC_BASE
> @@ -26,6 +27,7 @@ config VIDEO_MICROCHIP_XISC
>  	depends on VIDEO_DEV && COMMON_CLK
>  	depends on ARCH_AT91 || COMPILE_TEST
>  	select VIDEOBUF2_DMA_CONTIG
> +	select VIDEOBUF2_VMALLOC
>  	select REGMAP_MMIO
>  	select V4L2_FWNODE
>  	select VIDEO_MICROCHIP_ISC_BASE
> diff --git a/drivers/media/platform/microchip/Makefile b/drivers/media/platform/microchip/Makefile
> index bd8d6e779c51..94c64d3d242c 100644
> --- a/drivers/media/platform/microchip/Makefile
> +++ b/drivers/media/platform/microchip/Makefile
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  microchip-isc-objs = microchip-sama5d2-isc.o
>  microchip-xisc-objs = microchip-sama7g5-isc.o
> -microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o
> +microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o microchip-isc-stats.o
>  
>  obj-$(CONFIG_VIDEO_MICROCHIP_ISC_BASE) += microchip-isc-common.o
>  obj-$(CONFIG_VIDEO_MICROCHIP_ISC) += microchip-isc.o
> diff --git a/drivers/media/platform/microchip/microchip-isc-stats.c b/drivers/media/platform/microchip/microchip-isc-stats.c
> new file mode 100644
> index 000000000000..d7813c9d95ac
> --- /dev/null
> +++ b/drivers/media/platform/microchip/microchip-isc-stats.c
> @@ -0,0 +1,549 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Microchip ISC Driver - Statistics Subdevice
> + * Raw Histogram Export for Userspace Applications
> + *
> + * Copyright (C) 2025 Microchip Technology Inc.
> + *
> + * Author: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-vmalloc.h>
> +#include "microchip-isc-regs.h"
> +#include "microchip-isc.h"
> +
> +#define ISC_STATS_DEV_NAME	"microchip-isc_stats"
> +#define ISC_STATS_MIN_BUFS	2
> +#define ISC_STATS_MAX_BUFS	8
> +
> +/**
> + * struct isc_stat_buffer - Raw histogram statistics buffer structure
> + * @frame_number: Sequential frame number from capture
> + * @timestamp: Frame capture timestamp in nanoseconds
> + * @meas_type: Bitmask of measurement types available (ISC_CIF_ISP_STAT_*)
> + * @hist: Array of histogram data for each Bayer channel
> + * @hist.hist_bins: Raw 512-bin histogram data from hardware
> + * @hist.hist_min: Minimum pixel value observed in channel
> + * @hist.hist_max: Maximum pixel value observed in channel
> + * @hist.total_pixels: Total number of pixels processed in channel
> + * @valid_channels: Bitmask indicating which Bayer channels contain valid data
> + * @bayer_pattern: Current Bayer pattern configuration (CFA_BAYCFG_*)
> + * @reserved: Padding for future expansion and alignment
> + *
> + * This structure contains raw, unprocessed histogram data from the ISC
> + * hardware for all four Bayer channels (GR, R, GB, B). No algorithmic
> + * processing is performed - data is exported directly from hardware
> + * registers for userspace processing applications.
> + */
> +struct isc_stat_buffer {
> +	u32 frame_number;
> +	u64 timestamp;
> +	u32 meas_type;
> +
> +	struct {
> +		u32 hist_bins[HIST_ENTRIES];
> +		u32 hist_min;
> +		u32 hist_max;
> +		u32 total_pixels;
> +	} hist[HIST_BAYER];
> +
> +	u8 valid_channels;
> +	u8 bayer_pattern;
> +	u16 reserved[2];
> +} __packed;
> +
> +/* Statistics measurement type flags */
> +#define ISC_CIF_ISP_STAT_HIST		BIT(0)
> +
> +static bool isc_stats_in_use(struct isc_stats *stats)
> +{
> +	struct video_device *vdev;
> +
> +	if (!stats || !stats->isc)
> +		return false;
> +
> +	vdev = &stats->vnode.vdev;
> +	return vdev && video_is_registered(vdev) && !list_empty(&vdev->fh_list);
> +}
> +
> +static bool isc_stats_has_bufs(struct isc_stats *stats)
> +{
> +	bool has_buffers;
> +
> +	if (!stats)
> +		return false;
> +
> +	spin_lock(&stats->lock);
> +	has_buffers = !list_empty(&stats->stat);
> +	spin_unlock(&stats->lock);
> +
> +	return has_buffers;
> +}
> +
> +/*
> + * V4L2 device operations
> + */
> +
> +static int isc_stats_enum_fmt_meta_cap(struct file *file, void *priv,
> +				       struct v4l2_fmtdesc *f)
> +{
> +	struct video_device *video = video_devdata(file);
> +	struct isc_stats *stats = video_get_drvdata(video);
> +
> +	if (f->index > 0 || f->type != video->queue->type)
> +		return -EINVAL;

No need for the f->type check.

> +
> +	f->pixelformat = stats->vdev_fmt.fmt.meta.dataformat;
> +	return 0;
> +}
> +
> +static int isc_stats_g_fmt_meta_cap(struct file *file, void *priv,
> +				    struct v4l2_format *f)
> +{
> +	struct video_device *video = video_devdata(file);
> +	struct isc_stats *stats = video_get_drvdata(video);
> +	struct v4l2_meta_format *meta = &f->fmt.meta;
> +
> +	if (f->type != video->queue->type)
> +		return -EINVAL;

No need for this, just drop this check.

> +
> +	memset(meta, 0, sizeof(*meta));

No need, it's already zeroed by the V4L2 core.

> +	meta->dataformat = stats->vdev_fmt.fmt.meta.dataformat;
> +	meta->buffersize = stats->vdev_fmt.fmt.meta.buffersize;
> +
> +	return 0;
> +}
> +
> +static int isc_stats_querycap(struct file *file, void *priv,
> +			      struct v4l2_capability *cap)
> +{
> +	struct video_device *vdev = video_devdata(file);
> +
> +	strscpy(cap->driver, "microchip-isc", sizeof(cap->driver));
> +	strscpy(cap->card, vdev->name, sizeof(cap->card));
> +	strscpy(cap->bus_info, "platform:microchip-isc", sizeof(cap->bus_info));

You can drop the last line, it's filled in by the V4L2 core.

> +
> +	return 0;
> +}
> +
> +static int isc_stats_open(struct file *file)
> +{
> +	struct video_device *vdev = video_devdata(file);
> +	struct isc_stats *stats = video_get_drvdata(vdev);
> +
> +	dev_dbg(stats->isc->dev, "Stats device opened by %s (pid %d)\n",
> +		current->comm, current->pid);
> +
> +	return v4l2_fh_open(file);
> +}
> +
> +static int isc_stats_release(struct file *file)
> +{
> +	struct video_device *vdev = video_devdata(file);
> +	struct isc_stats *stats = video_get_drvdata(vdev);
> +
> +	dev_dbg(stats->isc->dev, "Stats device closed by %s (pid %d)\n",
> +		current->comm, current->pid);
> +
> +	return _vb2_fop_release(file, NULL);
> +}

These two functions make no sense. Drop them, see below for what to use instead.

> +
> +static const struct v4l2_ioctl_ops isc_stats_ioctl_ops = {
> +	.vidioc_reqbufs = vb2_ioctl_reqbufs,
> +	.vidioc_querybuf = vb2_ioctl_querybuf,
> +	.vidioc_create_bufs = vb2_ioctl_create_bufs,
> +	.vidioc_qbuf = vb2_ioctl_qbuf,
> +	.vidioc_dqbuf = vb2_ioctl_dqbuf,
> +	.vidioc_prepare_buf = vb2_ioctl_prepare_buf,
> +	.vidioc_expbuf = vb2_ioctl_expbuf,
> +	.vidioc_streamon = vb2_ioctl_streamon,
> +	.vidioc_streamoff = vb2_ioctl_streamoff,
> +	.vidioc_enum_fmt_meta_cap = isc_stats_enum_fmt_meta_cap,
> +	.vidioc_g_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
> +	.vidioc_s_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
> +	.vidioc_try_fmt_meta_cap = isc_stats_g_fmt_meta_cap,
> +	.vidioc_querycap = isc_stats_querycap,
> +	.vidioc_subscribe_event = v4l2_ctrl_subscribe_event,
> +	.vidioc_unsubscribe_event = v4l2_event_unsubscribe,
> +};
> +
> +static const struct v4l2_file_operations isc_stats_fops = {
> +	.mmap = vb2_fop_mmap,
> +	.unlocked_ioctl = video_ioctl2,
> +	.poll = vb2_fop_poll,
> +	.open = isc_stats_open,

Just use v4l2_fh_open.

> +	.release = isc_stats_release

And for this use vb2_fop_release.

> +};
> +
> +/*
> + * VB2 queue operations
> + */
> +
> +static int isc_stats_vb2_queue_setup(struct vb2_queue *vq,
> +				     unsigned int *num_buffers,
> +				     unsigned int *num_planes,
> +				     unsigned int sizes[],
> +				     struct device *alloc_devs[])
> +{
> +	struct isc_stats *stats = vq->drv_priv;
> +

This doesn't handle VIDIOC_CREATEBUFS correctly. See isc_queue_setup
on how to do that correctly.

> +	*num_planes = 1;
> +	*num_buffers = clamp_t(u32, *num_buffers, ISC_STATS_MIN_BUFS,
> +			       ISC_STATS_MAX_BUFS);

Why limit the number of buffers? The default max is 32 (VIDEO_MAX_FRAME),
and unless there are hardware limitations that require adjustments, I'd
just leave *num_buffers alone.

> +	sizes[0] = sizeof(struct isc_stat_buffer);
> +
> +	dev_dbg(stats->isc->dev, "Stats queue: %u buffers, %u bytes each\n",
> +		*num_buffers, sizes[0]);
> +
> +	return 0;
> +}
> +
> +static void isc_stats_vb2_buf_queue(struct vb2_buffer *vb)
> +{
> +	struct vb2_v4l2_buffer *vbuf = to_vb2_v4l2_buffer(vb);
> +	struct isc_buffer *stats_buf = container_of(vbuf, struct isc_buffer, vb);
> +	struct vb2_queue *vq = vb->vb2_queue;
> +	struct isc_stats *stats_dev = vq->drv_priv;
> +
> +	spin_lock_irq(&stats_dev->lock);
> +	list_add_tail(&stats_buf->list, &stats_dev->stat);
> +	spin_unlock_irq(&stats_dev->lock);
> +
> +	dev_dbg(stats_dev->isc->dev, "Stats buffer %d queued\n", vb->index);
> +}
> +
> +static int isc_stats_vb2_buf_prepare(struct vb2_buffer *vb)
> +{
> +	if (vb2_plane_size(vb, 0) < sizeof(struct isc_stat_buffer))
> +		return -EINVAL;
> +
> +	vb2_set_plane_payload(vb, 0, sizeof(struct isc_stat_buffer));
> +	return 0;
> +}
> +
> +static int isc_stats_vb2_start_streaming(struct vb2_queue *vq,
> +					 unsigned int count)
> +{
> +	struct isc_stats *stats = vq->drv_priv;
> +
> +	dev_dbg(stats->isc->dev, "Stats streaming started\n");
> +	return 0;
> +}
> +
> +static void isc_stats_vb2_stop_streaming(struct vb2_queue *vq)
> +{
> +	struct isc_stats *stats = vq->drv_priv;
> +	struct isc_buffer *buf;
> +	unsigned int i;
> +
> +	dev_dbg(stats->isc->dev, "Stats streaming stopped\n");
> +
> +	spin_lock_irq(&stats->lock);
> +	for (i = 0; i < ISC_STATS_MAX_BUFS; i++) {
> +		if (list_empty(&stats->stat))
> +			break;
> +		buf = list_first_entry(&stats->stat, struct isc_buffer, list);
> +		list_del(&buf->list);
> +		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_ERROR);
> +	}
> +	spin_unlock_irq(&stats->lock);
> +}
> +
> +static const struct vb2_ops isc_stats_vb2_ops = {
> +	.queue_setup = isc_stats_vb2_queue_setup,
> +	.buf_queue = isc_stats_vb2_buf_queue,
> +	.buf_prepare = isc_stats_vb2_buf_prepare,
> +	.start_streaming = isc_stats_vb2_start_streaming,
> +	.stop_streaming = isc_stats_vb2_stop_streaming,
> +	.wait_prepare = vb2_ops_wait_prepare,
> +	.wait_finish = vb2_ops_wait_finish,

Drop these last two lines: wait_prepare/finish is deprecated and will hopefully be
removed in 6.20.

> +};
> +
> +static int isc_stats_init_vb2_queue(struct vb2_queue *q,
> +				    struct isc_stats *stats)
> +{
> +	struct isc_vdev_node *node;
> +
> +	node = container_of(q, struct isc_vdev_node, buf_queue);
> +
> +	q->type = V4L2_BUF_TYPE_META_CAPTURE;
> +	q->io_modes = VB2_MMAP | VB2_USERPTR | VB2_DMABUF;

I'm not keen on VB2_USERPTR for new drivers. But I won't block it if you
believe there is a good use case for this.

> +	q->drv_priv = stats;
> +	q->ops = &isc_stats_vb2_ops;
> +	q->mem_ops = &vb2_vmalloc_memops;
> +	q->buf_struct_size = sizeof(struct isc_buffer);
> +	q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC;
> +	q->lock = &node->vlock;
> +
> +	return vb2_queue_init(q);
> +}
> +
> +/*
> + * Histogram data processing
> + */
> +
> +static void isc_stats_fill_data(struct isc_stats *stats,
> +				struct isc_stat_buffer *pbuf)
> +{
> +	struct isc_device *isc = stats->isc;
> +	struct isc_ctrls *ctrls = &isc->ctrls;
> +	int c;
> +
> +	pbuf->meas_type |= ISC_CIF_ISP_STAT_HIST;
> +
> +	/* Copy existing histogram data from AWB work function */
> +	for (c = 0; c < HIST_BAYER; c++) {
> +		memcpy(pbuf->hist[c].hist_bins, isc->full_hist_data[c],
> +		       sizeof(pbuf->hist[c].hist_bins));
> +
> +		pbuf->hist[c].hist_min = ctrls->hist_minmax[c][HIST_MIN_INDEX];
> +		pbuf->hist[c].hist_max = ctrls->hist_minmax[c][HIST_MAX_INDEX];
> +		pbuf->hist[c].total_pixels = ctrls->total_pixels[c];
> +	}
> +
> +	/* Set valid channels - all 4 Bayer channels */
> +	pbuf->valid_channels = 0x0F;
> +
> +	/* Set Bayer pattern */
> +	if (isc->config.sd_format)
> +		pbuf->bayer_pattern = isc->config.sd_format->cfa_baycfg;
> +	else
> +		pbuf->bayer_pattern = 0;
> +
> +	dev_dbg(isc->dev,
> +		"Stats data ready: pixels=[%u,%u,%u,%u], valid_channels=0x%x\n",
> +		pbuf->hist[0].total_pixels, pbuf->hist[1].total_pixels,
> +		pbuf->hist[2].total_pixels, pbuf->hist[3].total_pixels,
> +		pbuf->valid_channels);
> +}
> +
> +static void isc_stats_send_buf(struct isc_stats *stats)
> +{
> +	struct isc_stat_buffer *cur_stat_buf;
> +	struct isc_buffer *cur_buf = NULL;
> +	struct isc_device *isc = stats->isc;
> +	unsigned int frame_sequence = isc->sequence;
> +	u64 timestamp = ktime_get_ns();
> +
> +	/* Get one empty buffer from userspace */
> +	spin_lock(&stats->lock);
> +	if (!list_empty(&stats->stat)) {
> +		cur_buf = list_first_entry(&stats->stat,
> +					   struct isc_buffer, list);
> +		list_del(&cur_buf->list);
> +	}
> +	spin_unlock(&stats->lock);
> +
> +	if (!cur_buf) {
> +		dev_dbg(isc->dev, "No stats buffer available\n");
> +		return;
> +	}
> +
> +	cur_stat_buf = vb2_plane_vaddr(&cur_buf->vb.vb2_buf, 0);
> +	if (!cur_stat_buf) {
> +		dev_err(isc->dev, "Failed to get stats buffer vaddr\n");
> +		goto error_return_buffer;
> +	}
> +
> +	/* Clear buffer and fill metadata */
> +	memset(cur_stat_buf, 0, sizeof(*cur_stat_buf));
> +	cur_stat_buf->frame_number = frame_sequence;
> +	cur_stat_buf->timestamp = timestamp;
> +
> +	/* Fill raw histogram data */
> +	isc_stats_fill_data(stats, cur_stat_buf);
> +
> +	/* Send buffer to userspace */
> +	vb2_set_plane_payload(&cur_buf->vb.vb2_buf, 0,
> +			      sizeof(struct isc_stat_buffer));
> +	cur_buf->vb.sequence = frame_sequence;
> +	cur_buf->vb.vb2_buf.timestamp = timestamp;
> +	vb2_buffer_done(&cur_buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
> +
> +	dev_dbg(isc->dev,
> +		"Stats sent: frame=%u, channels=[%u,%u,%u,%u] pixels\n",
> +		frame_sequence,
> +		cur_stat_buf->hist[0].total_pixels,
> +		cur_stat_buf->hist[1].total_pixels,
> +		cur_stat_buf->hist[2].total_pixels,
> +		cur_stat_buf->hist[3].total_pixels);
> +	return;
> +
> +error_return_buffer:
> +	/* Return buffer to queue on error */
> +	spin_lock(&stats->lock);
> +	list_add(&cur_buf->list, &stats->stat);
> +	spin_unlock(&stats->lock);
> +}
> +
> +/*
> + * Public API functions
> + */
> +
> +/**
> + * isc_stats_isr() - Process statistics in interrupt context
> + * @stats: ISC histogram statistics device
> + *
> + * Called from the ISC interrupt handler when histogram data is ready.
> + * Exports raw histogram data to userspace applications that have
> + * buffers queued on the statistics device.
> + */
> +void isc_stats_isr(struct isc_stats *stats)
> +{
> +	if (!stats) {
> +		pr_err("ISC stats: stats is NULL\n");
> +		return;
> +	}
> +
> +	if (!stats->isc) {
> +		pr_err("ISC stats: stats->isc is NULL\n");
> +		return;
> +	}
> +
> +	/* Only send data if userspace is using the device */
> +	if (!isc_stats_in_use(stats)) {
> +		dev_dbg(stats->isc->dev, "Stats device not in use\n");
> +		return;
> +	}
> +
> +	/* Only send data if userspace has queued buffers */
> +	if (!isc_stats_has_bufs(stats)) {
> +		dev_dbg(stats->isc->dev, "No queued buffers\n");
> +		return;
> +	}
> +
> +	/* Send histogram data to userspace */
> +	isc_stats_send_buf(stats);
> +}
> +EXPORT_SYMBOL_GPL(isc_stats_isr);
> +
> +/**
> + * isc_stats_active() - Check if userspace is actively using stats
> + * @stats: ISC histogram statistics device
> + *
> + * Determines if any userspace application has the statistics device open
> + * and has queued buffers waiting for histogram data.
> + *
> + * Return: true if userspace is ready to receive data, false otherwise
> + */
> +bool isc_stats_active(struct isc_stats *stats)
> +{
> +	return isc_stats_in_use(stats) && isc_stats_has_bufs(stats);
> +}
> +EXPORT_SYMBOL_GPL(isc_stats_active);
> +
> +static void isc_stats_init(struct isc_stats *stats)
> +{
> +	stats->vdev_fmt.fmt.meta.dataformat = V4L2_META_FMT_ISC_STAT_3A;
> +	stats->vdev_fmt.fmt.meta.buffersize = sizeof(struct isc_stat_buffer);

It's a bit overkill to have the vdev_fmt field in stats. Just drop the field and
this function and just set these values directly in g/enum_fmt.

> +}
> +
> +/**
> + * isc_stats_register() - Register statistics device
> + * @isc: ISC device
> + *
> + * Creates and registers a V4L2 video device for exporting raw histogram
> + * statistics to userspace.
> + *
> + */
> +int isc_stats_register(struct isc_device *isc)
> +{
> +	struct isc_stats *stats = &isc->stats;
> +	struct isc_vdev_node *node = &stats->vnode;
> +	struct video_device *vdev = &node->vdev;
> +	int ret;
> +
> +	/* Initialize stats structure */
> +	stats->isc = isc;
> +	mutex_init(&node->vlock);
> +	INIT_LIST_HEAD(&stats->stat);
> +	spin_lock_init(&stats->lock);
> +
> +	/* Configure video device */
> +	strscpy(vdev->name, ISC_STATS_DEV_NAME, sizeof(vdev->name));
> +	vdev->ioctl_ops = &isc_stats_ioctl_ops;
> +	vdev->fops = &isc_stats_fops;
> +	vdev->release = video_device_release_empty;
> +	vdev->lock = &node->vlock;
> +	vdev->v4l2_dev = &isc->v4l2_dev;
> +	vdev->queue = &node->buf_queue;
> +	vdev->device_caps = V4L2_CAP_META_CAPTURE | V4L2_CAP_STREAMING;
> +	vdev->vfl_dir = VFL_DIR_RX;
> +
> +	/* Initialize VB2 queue */
> +	ret = isc_stats_init_vb2_queue(vdev->queue, stats);
> +	if (ret) {
> +		dev_err(isc->dev, "Failed to init stats VB2 queue: %d\n", ret);
> +		goto error_cleanup;
> +	}
> +
> +	/* Initialize stats format */
> +	isc_stats_init(stats);
> +
> +	video_set_drvdata(vdev, stats);
> +
> +	node->pad.flags = MEDIA_PAD_FL_SINK;
> +	ret = media_entity_pads_init(&vdev->entity, 1, &node->pad);
> +	if (ret) {
> +		dev_err(isc->dev, "Failed to init stats media entity: %d\n", ret);
> +		goto error_cleanup;
> +	}
> +
> +	/* Register video device */
> +	ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
> +	if (ret) {
> +		dev_err(isc->dev, "Failed to register stats device: %d\n", ret);
> +		goto error_media_cleanup;
> +	}
> +
> +	dev_info(isc->dev, "Stats device registered as %s\n",
> +		 video_device_node_name(vdev));
> +
> +	return 0;
> +
> +error_media_cleanup:
> +	media_entity_cleanup(&vdev->entity);
> +error_cleanup:
> +	mutex_destroy(&node->vlock);
> +	stats->isc = NULL;
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(isc_stats_register);
> +
> +/**
> + * isc_stats_unregister() - Unregister statistics device
> + * @isc: ISC device
> + *
> + * Unregisters and cleans up the statistics video device.
> + */
> +void isc_stats_unregister(struct isc_device *isc)
> +{
> +	struct isc_stats *stats = &isc->stats;
> +	struct isc_vdev_node *node = &stats->vnode;
> +	struct video_device *vdev = &node->vdev;
> +
> +	if (!stats->isc)
> +		return;
> +
> +	dev_dbg(isc->dev, "Unregistering stats device\n");
> +
> +	/* Unregister video device */
> +	vb2_video_unregister_device(vdev);
> +
> +	media_entity_cleanup(&vdev->entity);
> +
> +	/* Destroy synchronization primitives */
> +	mutex_destroy(&node->vlock);
> +
> +	stats->isc = NULL;
> +}
> +EXPORT_SYMBOL_GPL(isc_stats_unregister);
> +
> +MODULE_AUTHOR("Balakrishnan Sambath <balakrishnan.s@microchip.com>");
> +MODULE_DESCRIPTION("Microchip ISC Statistics Driver");
> +MODULE_LICENSE("GPL");
> diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
> index bd75ff4f109b..5245e2790268 100644
> --- a/drivers/media/platform/microchip/microchip-isc.h
> +++ b/drivers/media/platform/microchip/microchip-isc.h
> @@ -197,6 +197,23 @@ enum isc_scaler_pads {
>  	ISC_SCALER_PADS_NUM	= 2,
>  };
>  
> +/* Video device node structure */
> +struct isc_vdev_node {
> +	struct video_device vdev;
> +	struct vb2_queue buf_queue;
> +	struct mutex vlock; /* lock for video node */
> +	struct media_pad pad;
> +};
> +
> +/* Statistics device structure */
> +struct isc_stats {
> +	struct isc_device *isc;
> +	struct isc_vdev_node vnode;
> +	struct list_head stat;
> +	spinlock_t lock; /* lock for buffers */
> +	struct v4l2_format vdev_fmt;
> +};
> +
>  /*
>   * struct isc_device - ISC device driver data/config struct
>   * @regmap:		Register map
> @@ -340,6 +357,9 @@ struct isc_device {
>  		struct v4l2_ctrl	*gb_off_ctrl;
>  	};
>  
> +	/* Statistics device */
> +	struct isc_stats stats;
> +
>  #define GAMMA_ENTRIES	64
>  	/* pointer to the defined gamma table */
>  	const u32	(*gamma_table)[GAMMA_ENTRIES];
> @@ -396,6 +416,10 @@ int isc_scaler_link(struct isc_device *isc);
>  int isc_scaler_init(struct isc_device *isc);
>  int isc_mc_init(struct isc_device *isc, u32 ver);
>  void isc_mc_cleanup(struct isc_device *isc);
> +int isc_stats_register(struct isc_device *isc);
> +void isc_stats_unregister(struct isc_device *isc);
> +void isc_stats_isr(struct isc_stats *stats);
> +bool isc_stats_active(struct isc_stats *stats);
>  
>  struct isc_format *isc_find_format_by_code(struct isc_device *isc,
>  					   unsigned int code, int *index);

Regards,

	Hans

Re: [PATCH 08/18] media: platform: microchip: Add new histogram submodule

[Hans Verkuil]

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:
> From: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> 
> Add new histogram submodule driver to export raw histogram statistics
> and data to userspace.
> 
> Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> ---
>  drivers/media/platform/microchip/Kconfig      |   2 +
>  drivers/media/platform/microchip/Makefile     |   2 +-
>  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>  .../media/platform/microchip/microchip-isc.h  |  24 +
>  4 files changed, 576 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> 
> diff --git a/drivers/media/platform/microchip/Kconfig b/drivers/media/platform/microchip/Kconfig
> index 4734ecced029..2864a57e2ff4 100644
> --- a/drivers/media/platform/microchip/Kconfig
> +++ b/drivers/media/platform/microchip/Kconfig
> @@ -10,6 +10,7 @@ config VIDEO_MICROCHIP_ISC
>  	select MEDIA_CONTROLLER
>  	select VIDEO_V4L2_SUBDEV_API
>  	select VIDEOBUF2_DMA_CONTIG
> +	select VIDEOBUF2_VMALLOC
>  	select REGMAP_MMIO
>  	select V4L2_FWNODE
>  	select VIDEO_MICROCHIP_ISC_BASE
> @@ -26,6 +27,7 @@ config VIDEO_MICROCHIP_XISC
>  	depends on VIDEO_DEV && COMMON_CLK
>  	depends on ARCH_AT91 || COMPILE_TEST
>  	select VIDEOBUF2_DMA_CONTIG
> +	select VIDEOBUF2_VMALLOC
>  	select REGMAP_MMIO
>  	select V4L2_FWNODE
>  	select VIDEO_MICROCHIP_ISC_BASE
> diff --git a/drivers/media/platform/microchip/Makefile b/drivers/media/platform/microchip/Makefile
> index bd8d6e779c51..94c64d3d242c 100644
> --- a/drivers/media/platform/microchip/Makefile
> +++ b/drivers/media/platform/microchip/Makefile
> @@ -1,7 +1,7 @@
>  # SPDX-License-Identifier: GPL-2.0-only
>  microchip-isc-objs = microchip-sama5d2-isc.o
>  microchip-xisc-objs = microchip-sama7g5-isc.o
> -microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o
> +microchip-isc-common-objs = microchip-isc-base.o microchip-isc-clk.o microchip-isc-scaler.o microchip-isc-stats.o
>  
>  obj-$(CONFIG_VIDEO_MICROCHIP_ISC_BASE) += microchip-isc-common.o
>  obj-$(CONFIG_VIDEO_MICROCHIP_ISC) += microchip-isc.o
> diff --git a/drivers/media/platform/microchip/microchip-isc-stats.c b/drivers/media/platform/microchip/microchip-isc-stats.c
> new file mode 100644
> index 000000000000..d7813c9d95ac
> --- /dev/null
> +++ b/drivers/media/platform/microchip/microchip-isc-stats.c
> @@ -0,0 +1,549 @@
> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
> +/*
> + * Microchip ISC Driver - Statistics Subdevice
> + * Raw Histogram Export for Userspace Applications
> + *
> + * Copyright (C) 2025 Microchip Technology Inc.
> + *
> + * Author: Balakrishnan Sambath <balakrishnan.s@microchip.com>
> + */
> +
> +#include <linux/clk.h>
> +#include <media/v4l2-common.h>
> +#include <media/v4l2-event.h>
> +#include <media/v4l2-ioctl.h>
> +#include <media/videobuf2-core.h>
> +#include <media/videobuf2-vmalloc.h>
> +#include "microchip-isc-regs.h"
> +#include "microchip-isc.h"
> +
> +#define ISC_STATS_DEV_NAME	"microchip-isc_stats"
> +#define ISC_STATS_MIN_BUFS	2
> +#define ISC_STATS_MAX_BUFS	8
> +
> +/**
> + * struct isc_stat_buffer - Raw histogram statistics buffer structure
> + * @frame_number: Sequential frame number from capture
> + * @timestamp: Frame capture timestamp in nanoseconds
> + * @meas_type: Bitmask of measurement types available (ISC_CIF_ISP_STAT_*)
> + * @hist: Array of histogram data for each Bayer channel
> + * @hist.hist_bins: Raw 512-bin histogram data from hardware
> + * @hist.hist_min: Minimum pixel value observed in channel
> + * @hist.hist_max: Maximum pixel value observed in channel
> + * @hist.total_pixels: Total number of pixels processed in channel
> + * @valid_channels: Bitmask indicating which Bayer channels contain valid data
> + * @bayer_pattern: Current Bayer pattern configuration (CFA_BAYCFG_*)
> + * @reserved: Padding for future expansion and alignment
> + *
> + * This structure contains raw, unprocessed histogram data from the ISC
> + * hardware for all four Bayer channels (GR, R, GB, B). No algorithmic
> + * processing is performed - data is exported directly from hardware
> + * registers for userspace processing applications.
> + */
> +struct isc_stat_buffer {
> +	u32 frame_number;
> +	u64 timestamp;

Swap the two fields above to avoid introducing holes due to alignment problems.

> +	u32 meas_type;
> +
> +	struct {
> +		u32 hist_bins[HIST_ENTRIES];
> +		u32 hist_min;
> +		u32 hist_max;
> +		u32 total_pixels;
> +	} hist[HIST_BAYER];
> +
> +	u8 valid_channels;
> +	u8 bayer_pattern;
> +	u16 reserved[2];
> +} __packed;

After swapping those two fields you probably can drop __packed, but I'm not certain.
It's probably a good idea to check with the pahole utility if there are no holes in
this structure.

This structure must be part of include/uapi/linux/, probably
include/uapi/linux/media/microchip/something.h

Userspace must have access to this, otherwise it can't parse the metadata. Note
that that also means that the HIST_ENTRIES and HIST_BAYER/ISC_HIS_CFG_MODE_B
defines are in that uapi include as well.

> +
> +/* Statistics measurement type flags */
> +#define ISC_CIF_ISP_STAT_HIST		BIT(0)
> +

Regards,

	Hans

[PATCH 09/18] media: microchip-isc: Register and unregister statistics device

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Register the statistics sub-device during async complete and ensure
proper cleanup for the same in isc_mc_cleanup().

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index cd379f95fc1c..5b49b6ff5ae9 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1912,6 +1912,13 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
 		goto isc_async_complete_err;
 	}
 
+	/* Register statistics device */
+	ret = isc_stats_register(isc);
+	if (ret) {
+		dev_err(isc->dev, "Failed to register stats device: %d\n", ret);
+		goto isc_async_complete_unregister_device;
+	}
+
 	ret = isc_scaler_link(isc);
 	if (ret < 0)
 		goto isc_async_complete_unregister_device;
@@ -2036,6 +2043,7 @@ void isc_mc_cleanup(struct isc_device *isc)
 {
 	media_entity_cleanup(&isc->video_dev.entity);
 	media_device_cleanup(&isc->mdev);
+	isc_stats_unregister(isc);
 }
 EXPORT_SYMBOL_GPL(isc_mc_cleanup);
 
-- 
2.34.1

[PATCH 10/18] media: microchip-isc: Always enable histogram for all RAW formats

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Remove AWB dependency to allow histogram collection even when AWB is
handled in userspace.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 5b49b6ff5ae9..e6d7f59893ac 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -318,8 +318,7 @@ static int isc_configure(struct isc_device *isc)
 	 * The current implemented histogram is available for RAW R, B, GB, GR
 	 * channels. We need to check if sensor is outputting RAW BAYER
 	 */
-	if (isc->ctrls.awb &&
-	    ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code))
+	if (ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code))
 		isc_set_histogram(isc, true);
 	else
 		isc_set_histogram(isc, false);
-- 
2.34.1

[PATCH 11/18] media: microchip-isc: expose hue and saturation as v4l2 controls

[Balamanikandan Gunasundar]

Expose hue and saturation as adjustable controls allowing users to modify
it. Write the user specified values to the hardware registers. Additionally
write the brightness and contrast values to the registers that were
missing.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c     | 17 +++++++++++++++++
 .../platform/microchip/microchip-isc-regs.h     |  3 +++
 .../media/platform/microchip/microchip-isc.h    |  2 ++
 3 files changed, 22 insertions(+)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index e6d7f59893ac..ce22b4789ebd 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1520,6 +1520,7 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
 	struct isc_device *isc = container_of(ctrl->handler,
 					     struct isc_device, ctrls.handler);
 	struct isc_ctrls *ctrls = &isc->ctrls;
+	struct regmap *regmap = isc->regmap;
 
 	if (ctrl->flags & V4L2_CTRL_FLAG_INACTIVE)
 		return 0;
@@ -1527,9 +1528,19 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
 	switch (ctrl->id) {
 	case V4L2_CID_BRIGHTNESS:
 		ctrls->brightness = ctrl->val & ISC_CBC_BRIGHT_MASK;
+		regmap_write(regmap, ISC_CBC_BRIGHT + isc->offsets.cbc, ctrls->brightness);
 		break;
 	case V4L2_CID_CONTRAST:
 		ctrls->contrast = ctrl->val & ISC_CBC_CONTRAST_MASK;
+		regmap_write(regmap, ISC_CBC_CONTRAST + isc->offsets.cbc, ctrls->contrast);
+		break;
+	case V4L2_CID_HUE:
+		ctrls->hue = ctrl->val & ISC_CBCHS_HUE_MASK;
+		regmap_write(regmap, ISC_CBCHS_HUE, ctrls->hue);
+		break;
+	case V4L2_CID_SATURATION:
+		ctrls->saturation = ctrl->val & ISC_CBCHS_SAT_MASK;
+		regmap_write(regmap, ISC_CBCHS_SAT, ctrls->saturation);
 		break;
 	case V4L2_CID_GAMMA:
 		ctrls->gamma_index = ctrl->val;
@@ -1538,6 +1549,10 @@ static int isc_s_ctrl(struct v4l2_ctrl *ctrl)
 		return -EINVAL;
 	}
 
+	mutex_lock(&isc->awb_mutex);
+	isc_update_profile(isc);
+	mutex_unlock(&isc->awb_mutex);
+
 	return 0;
 }
 
@@ -1714,6 +1729,8 @@ static int isc_ctrl_init(struct isc_device *isc)
 	ctrls->brightness = 0;
 
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_BRIGHTNESS, -1024, 1023, 1, 0);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_HUE, -180, 180, 1, 0);
+	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_SATURATION, 0, 100, 1, 16);
 	v4l2_ctrl_new_std(hdl, ops, V4L2_CID_GAMMA, 0, isc->gamma_max, 1, 1);
 	isc->awb_ctrl = v4l2_ctrl_new_std(hdl, &isc_awb_ops,
 					  V4L2_CID_AUTO_WHITE_BALANCE,
diff --git a/drivers/media/platform/microchip/microchip-isc-regs.h b/drivers/media/platform/microchip/microchip-isc-regs.h
index e77e1d9a1db8..2593bd533cac 100644
--- a/drivers/media/platform/microchip/microchip-isc-regs.h
+++ b/drivers/media/platform/microchip/microchip-isc-regs.h
@@ -270,8 +270,11 @@
 
 /* Hue Register */
 #define ISC_CBCHS_HUE	0x4e0
+#define ISC_CBCHS_HUE_MASK	GENMASK(8, 0)
+
 /* Saturation Register */
 #define ISC_CBCHS_SAT	0x4e4
+#define ISC_CBCHS_SAT_MASK	GENMASK(11, 0)
 
 /* Offset for SUB422 register specific to sama5d2 product */
 #define ISC_SAMA5D2_SUB422_OFFSET	0
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index 5245e2790268..7afba3c04dfb 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -139,6 +139,8 @@ struct isc_ctrls {
 
 	u32 brightness;
 	u32 contrast;
+	u32 hue;
+	u32 saturation;
 	u8 gamma_index;
 #define ISC_WB_NONE	0
 #define ISC_WB_AUTO	1
-- 
2.34.1

[PATCH 12/18] media: microchip-isc: Rename CBC to CBHS

[Balamanikandan Gunasundar]

As per the datasheet the more relevant name for this enable bit is
"Contrast, Brightness, Hue and Saturation Control Enable"

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c  | 10 +++++-----
 drivers/media/platform/microchip/microchip-isc.h       |  2 +-
 .../media/platform/microchip/microchip-sama5d2-isc.c   |  2 +-
 .../media/platform/microchip/microchip-sama7g5-isc.c   |  2 +-
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index ce22b4789ebd..e9bd191f042b 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -790,7 +790,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				WB_ENABLE | GAM_ENABLES | DPC_BLCENABLE |
-				DPC_GDCENABLE | CBC_ENABLE | CC_ENABLE;
+				DPC_GDCENABLE | CBHS_ENABLE | CC_ENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -800,7 +800,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | GAM_ENABLES | WB_ENABLE |
-				SUB420_ENABLE | SUB422_ENABLE | CBC_ENABLE |
+				SUB420_ENABLE | SUB422_ENABLE | CBHS_ENABLE |
 				DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
@@ -811,7 +811,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				SUB422_ENABLE | CBC_ENABLE | DPC_BLCENABLE;
+				SUB422_ENABLE | CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -823,7 +823,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				SUB422_ENABLE | CBC_ENABLE | DPC_BLCENABLE;
+				SUB422_ENABLE | CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
@@ -834,7 +834,7 @@ static int isc_try_configure_pipeline(struct isc_device *isc)
 		if (ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
 			isc->try_config.bits_pipeline = CFA_ENABLE |
 				CSC_ENABLE | WB_ENABLE | GAM_ENABLES |
-				CBC_ENABLE | DPC_BLCENABLE;
+				CBHS_ENABLE | DPC_BLCENABLE;
 		} else {
 			isc->try_config.bits_pipeline = 0x0;
 		}
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index 7afba3c04dfb..35dfd2501ea2 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -88,7 +88,7 @@ struct isc_format {
 #define GAM_RENABLE	BIT(9)
 #define VHXS_ENABLE	BIT(10)
 #define CSC_ENABLE	BIT(11)
-#define CBC_ENABLE	BIT(12)
+#define CBHS_ENABLE	BIT(12)
 #define SUB422_ENABLE	BIT(13)
 #define SUB420_ENABLE	BIT(14)
 
diff --git a/drivers/media/platform/microchip/microchip-sama5d2-isc.c b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
index 66d3d7891991..239aac170472 100644
--- a/drivers/media/platform/microchip/microchip-sama5d2-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama5d2-isc.c
@@ -54,7 +54,7 @@
 
 #define ISC_SAMA5D2_PIPELINE \
 	(WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
-	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
+	CBHS_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */
 static const struct isc_format sama5d2_controller_formats[] = {
diff --git a/drivers/media/platform/microchip/microchip-sama7g5-isc.c b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
index d3ed9cfe6686..985281c4dc76 100644
--- a/drivers/media/platform/microchip/microchip-sama7g5-isc.c
+++ b/drivers/media/platform/microchip/microchip-sama7g5-isc.c
@@ -61,7 +61,7 @@
 #define ISC_SAMA7G5_PIPELINE \
 	(DPC_DPCENABLE | DPC_GDCENABLE | DPC_BLCENABLE | \
 	WB_ENABLE | CFA_ENABLE | CC_ENABLE | GAM_ENABLES | CSC_ENABLE | \
-	CBC_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
+	CBHS_ENABLE | SUB422_ENABLE | SUB420_ENABLE)
 
 /* This is a list of the formats that the ISC can *output* */
 static const struct isc_format sama7g5_controller_formats[] = {
-- 
2.34.1

[PATCH 13/18] media: microchip-isc: Store histogram data of all channels

[Balamanikandan Gunasundar]

Store the histogram data for all 4 channels(R, B, GR, GB). The data of each
channel is available on one interrupt. We need 4 interrupt cycles to get
all four channels. Store all the channels in a 2D array. This data is later
passed to the application buffer when it requests for a dequeue.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c  | 2 +-
 drivers/media/platform/microchip/microchip-isc-stats.c | 2 +-
 drivers/media/platform/microchip/microchip-isc.h       | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index e9bd191f042b..6651be6fcb57 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1225,7 +1225,7 @@ static void isc_hist_count(struct isc_device *isc, u32 *min, u32 *max)
 	struct regmap *regmap = isc->regmap;
 	struct isc_ctrls *ctrls = &isc->ctrls;
 	u32 *hist_count = &ctrls->hist_count[ctrls->hist_id];
-	u32 *hist_entry = &ctrls->hist_entry[0];
+	u32 *hist_entry = &ctrls->hist_entry[ctrls->hist_id][0];
 	u32 i;
 
 	*min = 0;
diff --git a/drivers/media/platform/microchip/microchip-isc-stats.c b/drivers/media/platform/microchip/microchip-isc-stats.c
index d7813c9d95ac..1f3d1ea75005 100644
--- a/drivers/media/platform/microchip/microchip-isc-stats.c
+++ b/drivers/media/platform/microchip/microchip-isc-stats.c
@@ -298,7 +298,7 @@ static void isc_stats_fill_data(struct isc_stats *stats,
 
 	/* Copy existing histogram data from AWB work function */
 	for (c = 0; c < HIST_BAYER; c++) {
-		memcpy(pbuf->hist[c].hist_bins, isc->full_hist_data[c],
+		memcpy(pbuf->hist[c].hist_bins, &isc->ctrls.hist_entry[0][c],
 		       sizeof(pbuf->hist[c].hist_bins));
 
 		pbuf->hist[c].hist_min = ctrls->hist_minmax[c][HIST_MIN_INDEX];
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index 35dfd2501ea2..fcb20669ef69 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -151,7 +151,7 @@ struct isc_ctrls {
 	u32 gain[HIST_BAYER];
 	s32 offset[HIST_BAYER];
 
-	u32 hist_entry[HIST_ENTRIES];
+	u32 hist_entry[HIST_BAYER][HIST_ENTRIES];
 	u32 hist_count[HIST_BAYER];
 	u8 hist_id;
 	u8 hist_stat;
-- 
2.34.1

[PATCH 14/18] media: microchip-isc: fix histogram state initialization order

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Move hist_stat assignment before profile update to ensure histogram state
is properly set when update_profile triggers register writes. This prevents
race conditions during histogram initialization.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 6651be6fcb57..e9f14de7ae32 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -275,10 +275,10 @@ static void isc_set_histogram(struct isc_device *isc, bool enable)
 			     ISC_HIS_CTRL_EN);
 		regmap_write(regmap, ISC_INTEN, ISC_INT_HISDONE);
 		ctrls->hist_id = ISC_HIS_CFG_MODE_GR;
+		ctrls->hist_stat = HIST_ENABLED;
 		isc_update_profile(isc);
 		regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_HISREQ);
 
-		ctrls->hist_stat = HIST_ENABLED;
 	} else {
 		regmap_write(regmap, ISC_INTDIS, ISC_INT_HISDONE);
 		regmap_write(regmap, ISC_HIS_CTRL + isc->offsets.his,
-- 
2.34.1

[PATCH 15/18] media: microchip-isc: decouple histogram cycling from AWB mode

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Fix histogram cycling stopping after first channel when AWB is disabled.
Now the histogram cycling will continue even when AWB is disabled,
enabling hardware histogram data export to userspace.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index e9f14de7ae32..cafd05244db2 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1509,7 +1509,7 @@ static void isc_awb_work(struct work_struct *w)
 	mutex_unlock(&isc->awb_mutex);
 
 	/* if awb has been disabled, we don't need to start another histogram */
-	if (ctrls->awb)
+	if (ctrls->hist_stat == HIST_ENABLED)
 		regmap_write(regmap, ISC_CTRLEN, ISC_CTRL_HISREQ);
 
 	pm_runtime_put_sync(isc->dev);
-- 
2.34.1

[PATCH 16/18] media: microchip-isc: enable userspace histogram statistics export

[Balamanikandan Gunasundar]

From: Balakrishnan Sambath <balakrishnan.s@microchip.com>

Export raw histogram data to userspace only when all 4 Bayer channels
are ready and userspace has active listeners. Also continue AWB work as
long as userspace listeners are active.

Signed-off-by: Balakrishnan Sambath <balakrishnan.s@microchip.com>
Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/platform/microchip/microchip-isc-base.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index cafd05244db2..6c937a20fce0 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -1450,6 +1450,15 @@ static void isc_awb_work(struct work_struct *w)
 	if (hist_id != ISC_HIS_CFG_MODE_B) {
 		hist_id++;
 	} else {
+		/* All 4 channels processed - notify userspace */
+		if (isc_stats_active(&isc->stats))
+			isc_stats_isr(&isc->stats);
+		else
+			dev_info(isc->dev, "No active userspace listeners\n");
+	}
+
+	/* Continue with AWB processing only if AWB is enabled */
+	if (ctrls->awb != ISC_WB_NONE) {
 		isc_wb_update(ctrls);
 		hist_id = ISC_HIS_CFG_MODE_GR;
 	}
@@ -1499,7 +1508,7 @@ static void isc_awb_work(struct work_struct *w)
 	mutex_lock(&isc->awb_mutex);
 
 	/* streaming is not active anymore */
-	if (isc->stop) {
+	if (isc->stop && !isc_stats_active(&isc->stats)) {
 		mutex_unlock(&isc->awb_mutex);
 		return;
 	}
-- 
2.34.1

[PATCH 17/18] media: videodev2.h, v4l2-ioctl: Add microchip statistics format

[Balamanikandan Gunasundar]

Add microchip ISC specific statistics meta data format. This data consists
of raw histogram statistics that is exported to userspace for further
processing. This fixes the kernel warning "Unknown pixelformat"

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
 include/uapi/linux/videodev2.h       | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index 01cf52c3ea33..a03e8f3ab610 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1467,6 +1467,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
 	case V4L2_META_FMT_RK_ISP1_PARAMS:	descr = "Rockchip ISP1 3A Parameters"; break;
 	case V4L2_META_FMT_RK_ISP1_STAT_3A:	descr = "Rockchip ISP1 3A Statistics"; break;
 	case V4L2_META_FMT_RK_ISP1_EXT_PARAMS:	descr = "Rockchip ISP1 Ext 3A Params"; break;
+	case V4L2_META_FMT_ISC_STAT_3A: descr = "Microchip ISP statistics"; break;
 	case V4L2_META_FMT_C3ISP_PARAMS:	descr = "Amlogic C3 ISP Parameters"; break;
 	case V4L2_META_FMT_C3ISP_STATS:		descr = "Amlogic C3 ISP Statistics"; break;
 	case V4L2_PIX_FMT_NV12_8L128:	descr = "NV12 (8x128 Linear)"; break;
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index becd08fdbddb..ba628f9bb89f 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -875,6 +875,9 @@ struct v4l2_pix_format {
 #define V4L2_META_FMT_RK_ISP1_STAT_3A	v4l2_fourcc('R', 'K', '1', 'S') /* Rockchip ISP1 3A Statistics */
 #define V4L2_META_FMT_RK_ISP1_EXT_PARAMS	v4l2_fourcc('R', 'K', '1', 'E') /* Rockchip ISP1 3a Extensible Parameters */
 
+/* Vendor specific - used for Microchip camera sub-system */
+#define V4L2_META_FMT_ISC_STAT_3A      v4l2_fourcc('I', 'S', 'C', 'S')
+
 /* Vendor specific - used for C3_ISP */
 #define V4L2_META_FMT_C3ISP_PARAMS	v4l2_fourcc('C', '3', 'P', 'M') /* Amlogic C3 ISP Parameters */
 #define V4L2_META_FMT_C3ISP_STATS	v4l2_fourcc('C', '3', 'S', 'T') /* Amlogic C3 ISP Statistics */
-- 
2.34.1

Re: [PATCH 17/18] media: videodev2.h, v4l2-ioctl: Add microchip statistics format

[Hans Verkuil]

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:
> Add microchip ISC specific statistics meta data format. This data consists
> of raw histogram statistics that is exported to userspace for further
> processing. This fixes the kernel warning "Unknown pixelformat"
> 
> Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
> ---
>  drivers/media/v4l2-core/v4l2-ioctl.c | 1 +
>  include/uapi/linux/videodev2.h       | 3 +++
>  2 files changed, 4 insertions(+)
> 
> diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
> index 01cf52c3ea33..a03e8f3ab610 100644
> --- a/drivers/media/v4l2-core/v4l2-ioctl.c
> +++ b/drivers/media/v4l2-core/v4l2-ioctl.c
> @@ -1467,6 +1467,7 @@ static void v4l_fill_fmtdesc(struct v4l2_fmtdesc *fmt)
>  	case V4L2_META_FMT_RK_ISP1_PARAMS:	descr = "Rockchip ISP1 3A Parameters"; break;
>  	case V4L2_META_FMT_RK_ISP1_STAT_3A:	descr = "Rockchip ISP1 3A Statistics"; break;
>  	case V4L2_META_FMT_RK_ISP1_EXT_PARAMS:	descr = "Rockchip ISP1 Ext 3A Params"; break;
> +	case V4L2_META_FMT_ISC_STAT_3A: descr = "Microchip ISP statistics"; break;

statistics -> Statistics

>  	case V4L2_META_FMT_C3ISP_PARAMS:	descr = "Amlogic C3 ISP Parameters"; break;
>  	case V4L2_META_FMT_C3ISP_STATS:		descr = "Amlogic C3 ISP Statistics"; break;
>  	case V4L2_PIX_FMT_NV12_8L128:	descr = "NV12 (8x128 Linear)"; break;
> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
> index becd08fdbddb..ba628f9bb89f 100644
> --- a/include/uapi/linux/videodev2.h
> +++ b/include/uapi/linux/videodev2.h
> @@ -875,6 +875,9 @@ struct v4l2_pix_format {
>  #define V4L2_META_FMT_RK_ISP1_STAT_3A	v4l2_fourcc('R', 'K', '1', 'S') /* Rockchip ISP1 3A Statistics */
>  #define V4L2_META_FMT_RK_ISP1_EXT_PARAMS	v4l2_fourcc('R', 'K', '1', 'E') /* Rockchip ISP1 3a Extensible Parameters */
>  
> +/* Vendor specific - used for Microchip camera sub-system */
> +#define V4L2_META_FMT_ISC_STAT_3A      v4l2_fourcc('I', 'S', 'C', 'S')
> +
>  /* Vendor specific - used for C3_ISP */
>  #define V4L2_META_FMT_C3ISP_PARAMS	v4l2_fourcc('C', '3', 'P', 'M') /* Amlogic C3 ISP Parameters */
>  #define V4L2_META_FMT_C3ISP_STATS	v4l2_fourcc('C', '3', 'S', 'T') /* Amlogic C3 ISP Statistics */

This meta format must be documented just like e.g. V4L2_META_FMT_C3ISP_STATS.

Regards,

	Hans

[PATCH 18/18] media: microchip-isc: expose color correction registers as v4l2 controls

[Balamanikandan Gunasundar]

Enable the Color correction registers as v4l2 controls. Applications such
as libcamera can read and write the elements of color correction matrix
through the standard v4l2 control API.

Signed-off-by: Balamanikandan Gunasundar <balamanikandan.gunasundar@microchip.com>
---
 .../platform/microchip/microchip-isc-base.c   | 175 +++++++++++++++++-
 .../media/platform/microchip/microchip-isc.h  |  12 ++
 include/linux/atmel-isc-media.h               |  13 ++
 3 files changed, 199 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/microchip/microchip-isc-base.c b/drivers/media/platform/microchip/microchip-isc-base.c
index 6c937a20fce0..e679dc02dc9f 100644
--- a/drivers/media/platform/microchip/microchip-isc-base.c
+++ b/drivers/media/platform/microchip/microchip-isc-base.c
@@ -32,7 +32,7 @@
 #include "microchip-isc-regs.h"
 #include "microchip-isc.h"
 
-#define ISC_IS_FORMAT_RAW(mbus_code) \
+#define ISC_IS_FORMAT_RAW(mbus_code)		\
 	(((mbus_code) & 0xf000) == 0x3000)
 
 #define ISC_IS_FORMAT_GREY(mbus_code) \
@@ -1677,6 +1677,165 @@ static int isc_g_volatile_awb_ctrl(struct v4l2_ctrl *ctrl)
 	return 0;
 }
 
+static int isc_cc_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct isc_device *isc = container_of(ctrl->handler,
+					     struct isc_device, ctrls.handler);
+	struct regmap *regmap = isc->regmap;
+
+	dev_dbg(isc->dev, "id = 0x%x; val = 0x%x", ctrl->id, ctrl->val);
+
+	switch (ctrl->id) {
+	case ISC_CID_CC_RR:
+		regmap_update_bits(regmap, ISC_CC_RR_RG, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_RG:
+		regmap_update_bits(regmap, ISC_CC_RR_RG, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	case ISC_CID_CC_RB:
+		regmap_update_bits(regmap, ISC_CC_RB_OR, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_OR:
+		regmap_update_bits(regmap, ISC_CC_RB_OR, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	case ISC_CID_CC_GR:
+		regmap_update_bits(regmap, ISC_CC_GR_GG, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_GG:
+		regmap_update_bits(regmap, ISC_CC_GR_GG, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	case ISC_CID_CC_GB:
+		regmap_update_bits(regmap, ISC_CC_GB_OG, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_OG:
+		regmap_update_bits(regmap, ISC_CC_GB_OG, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	case ISC_CID_CC_BR:
+		regmap_update_bits(regmap, ISC_CC_BR_BG, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_BG:
+		regmap_update_bits(regmap, ISC_CC_BR_BG, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	case ISC_CID_CC_BB:
+		regmap_update_bits(regmap, ISC_CC_BB_OB, GENMASK(11, 0), ctrl->val);
+		break;
+	case ISC_CID_CC_OB:
+		regmap_update_bits(regmap, ISC_CC_BB_OB, GENMASK(27, 16),
+				   (ctrl->val & GENMASK(11, 0)) << 16);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int isc_cc_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct isc_device *isc = container_of(ctrl->handler,
+					     struct isc_device, ctrls.handler);
+	struct regmap *regmap = isc->regmap;
+	unsigned int reg;
+
+	switch (ctrl->id) {
+	case ISC_CID_CC_RR:
+		regmap_read(regmap, ISC_CC_RR_RG, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_RG:
+		regmap_read(regmap, ISC_CC_RR_RG, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	case ISC_CID_CC_RB:
+		regmap_read(regmap, ISC_CC_RB_OR, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_OR:
+		regmap_read(regmap, ISC_CC_RB_OR, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	case ISC_CID_CC_GR:
+		regmap_read(regmap, ISC_CC_GR_GG, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_GG:
+		regmap_read(regmap, ISC_CC_GR_GG, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	case ISC_CID_CC_GB:
+		regmap_read(regmap, ISC_CC_GB_OG, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_OG:
+		regmap_read(regmap, ISC_CC_GB_OG, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	case ISC_CID_CC_BR:
+		regmap_read(regmap, ISC_CC_BR_BG, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_BG:
+		regmap_read(regmap, ISC_CC_BR_BG, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	case ISC_CID_CC_BB:
+		regmap_read(regmap, ISC_CC_BB_OB, &reg);
+		ctrl->val = sign_extend32(reg & GENMASK(11, 0), 11);
+		break;
+	case ISC_CID_CC_OB:
+		regmap_read(regmap, ISC_CC_BB_OB, &reg);
+		ctrl->val = sign_extend32((reg & GENMASK(27, 16)) >> 16, 11);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(isc->dev, "id = 0x%x; val = 0x%x", ctrl->id, ctrl->val);
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops isc_cc_ops = {
+	.s_ctrl = isc_cc_s_ctrl,
+	.g_volatile_ctrl = isc_cc_g_volatile_ctrl,
+};
+
+#define ISC_CTRL_CC(_name, _id, _name_str) \
+	static const struct v4l2_ctrl_config _name = { \
+		.ops = &isc_cc_ops, \
+		.id = _id, \
+		.name = _name_str, \
+		.type = V4L2_CTRL_TYPE_INTEGER, \
+		.flags = V4L2_CTRL_FLAG_SLIDER, \
+		.min = -2048, \
+		.max = 2047, \
+		.step = 1, \
+		.def = 0, \
+	}
+
+ISC_CTRL_CC(isc_cc_rr_ctrl, ISC_CID_CC_RR, "CC RR");
+ISC_CTRL_CC(isc_cc_rg_ctrl, ISC_CID_CC_RG, "CC RG");
+
+ISC_CTRL_CC(isc_cc_rb_ctrl, ISC_CID_CC_RB, "CC RB");
+ISC_CTRL_CC(isc_cc_or_ctrl, ISC_CID_CC_OR, "CC OR");
+
+ISC_CTRL_CC(isc_cc_gr_ctrl, ISC_CID_CC_GR, "CC GR");
+ISC_CTRL_CC(isc_cc_gg_ctrl, ISC_CID_CC_GG, "CC GG");
+
+ISC_CTRL_CC(isc_cc_gb_ctrl, ISC_CID_CC_GB, "CC GB");
+ISC_CTRL_CC(isc_cc_og_ctrl, ISC_CID_CC_OG, "CC OG");
+
+ISC_CTRL_CC(isc_cc_br_ctrl, ISC_CID_CC_BR, "CC BR");
+ISC_CTRL_CC(isc_cc_bg_ctrl, ISC_CID_CC_BG, "CC BG");
+
+ISC_CTRL_CC(isc_cc_bb_ctrl, ISC_CID_CC_BB, "CC BB");
+ISC_CTRL_CC(isc_cc_ob_ctrl, ISC_CID_CC_OB, "CC OB");
+
 static const struct v4l2_ctrl_ops isc_awb_ops = {
 	.s_ctrl = isc_s_awb_ctrl,
 	.g_volatile_ctrl = isc_g_volatile_awb_ctrl,
@@ -1767,6 +1926,20 @@ static int isc_ctrl_init(struct isc_device *isc)
 	isc->gr_off_ctrl = v4l2_ctrl_new_custom(hdl, &isc_gr_off_ctrl, NULL);
 	isc->gb_off_ctrl = v4l2_ctrl_new_custom(hdl, &isc_gb_off_ctrl, NULL);
 
+	/* Color correction control */
+	isc->cc_rr = v4l2_ctrl_new_custom(hdl, &isc_cc_rr_ctrl, NULL);
+	isc->cc_rg = v4l2_ctrl_new_custom(hdl, &isc_cc_rg_ctrl, NULL);
+	isc->cc_rb = v4l2_ctrl_new_custom(hdl, &isc_cc_rb_ctrl, NULL);
+	isc->cc_or = v4l2_ctrl_new_custom(hdl, &isc_cc_or_ctrl, NULL);
+	isc->cc_gr = v4l2_ctrl_new_custom(hdl, &isc_cc_gr_ctrl, NULL);
+	isc->cc_gg = v4l2_ctrl_new_custom(hdl, &isc_cc_gg_ctrl, NULL);
+	isc->cc_gb = v4l2_ctrl_new_custom(hdl, &isc_cc_gb_ctrl, NULL);
+	isc->cc_og = v4l2_ctrl_new_custom(hdl, &isc_cc_og_ctrl, NULL);
+	isc->cc_br = v4l2_ctrl_new_custom(hdl, &isc_cc_br_ctrl, NULL);
+	isc->cc_bg = v4l2_ctrl_new_custom(hdl, &isc_cc_bg_ctrl, NULL);
+	isc->cc_bb = v4l2_ctrl_new_custom(hdl, &isc_cc_bb_ctrl, NULL);
+	isc->cc_ob = v4l2_ctrl_new_custom(hdl, &isc_cc_ob_ctrl, NULL);
+
 	/*
 	 * The cluster is in auto mode with autowhitebalance enabled
 	 * and manual mode otherwise.
diff --git a/drivers/media/platform/microchip/microchip-isc.h b/drivers/media/platform/microchip/microchip-isc.h
index fcb20669ef69..aaa6c4b653d4 100644
--- a/drivers/media/platform/microchip/microchip-isc.h
+++ b/drivers/media/platform/microchip/microchip-isc.h
@@ -357,6 +357,18 @@ struct isc_device {
 		struct v4l2_ctrl	*b_off_ctrl;
 		struct v4l2_ctrl	*gr_off_ctrl;
 		struct v4l2_ctrl	*gb_off_ctrl;
+		struct v4l2_ctrl        *cc_rr;
+		struct v4l2_ctrl        *cc_rg;
+		struct v4l2_ctrl        *cc_rb;
+		struct v4l2_ctrl        *cc_or;
+		struct v4l2_ctrl        *cc_gr;
+		struct v4l2_ctrl        *cc_gg;
+		struct v4l2_ctrl        *cc_gb;
+		struct v4l2_ctrl        *cc_og;
+		struct v4l2_ctrl        *cc_br;
+		struct v4l2_ctrl        *cc_bg;
+		struct v4l2_ctrl        *cc_bb;
+		struct v4l2_ctrl        *cc_ob;
 	};
 
 	/* Statistics device */
diff --git a/include/linux/atmel-isc-media.h b/include/linux/atmel-isc-media.h
index 79a320fb724e..028d34c8de81 100644
--- a/include/linux/atmel-isc-media.h
+++ b/include/linux/atmel-isc-media.h
@@ -53,6 +53,19 @@ enum atmel_isc_ctrl_id {
 	ISC_CID_GR_OFFSET,
 	/* Green Blue component offset control */
 	ISC_CID_GB_OFFSET,
+	/* Color correction registers */
+	ISC_CID_CC_RR,
+	ISC_CID_CC_RG,
+	ISC_CID_CC_RB,
+	ISC_CID_CC_OR,
+	ISC_CID_CC_GR,
+	ISC_CID_CC_GG,
+	ISC_CID_CC_GB,
+	ISC_CID_CC_OG,
+	ISC_CID_CC_BR,
+	ISC_CID_CC_BG,
+	ISC_CID_CC_BB,
+	ISC_CID_CC_OB,
 };
 
 #endif
-- 
2.34.1

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Eugen Hristev]

Hi Bala,

On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
> Hi,
> 
> This patch series has a set of enhancements to the Microchip Image Sensor
> Controller driver. The objective is to expand its image processing
> capabilities and to improve the colors.
> 
> This series also introduces a new stats driver that exposes the histogram
> data to userspace via v4l2 controls. This allows applications such as
> libcamera to access real time image statistics for advanced image
> processing like automatic exposure, white balance adjustments etc.
> 
> Balakrishnan Sambath (11):
>   media: microchip-isc: Enable GDC and CBC module flags for RGB formats
>   media: microchip-isc: Improve histogram calculation with outlier
>     rejection
>   media: microchip-isc: Use channel averages for Grey World AWB
>   media: microchip-isc: Add range based black level correction
>   media: platform: microchip: Extend gamma table and control range
>   media: platform: microchip: Add new histogram submodule
>   media: microchip-isc: Register and unregister statistics device
>   media: microchip-isc: Always enable histogram for all RAW formats
>   media: microchip-isc: fix histogram state initialization order
>   media: microchip-isc: decouple histogram cycling from AWB mode
>   media: microchip-isc: enable userspace histogram statistics export
> 
> Balamanikandan Gunasundar (7):
>   media: platform: microchip: set maximum resolution for sam9x7
>   media: platform: microchip: Include DPC modules flags in pipeline
>   media: microchip-isc: expose hue and saturation as v4l2 controls
>   media: microchip-isc: Rename CBC to CBHS
>   media: microchip-isc: Store histogram data of all channels
>   media: videodev2.h, v4l2-ioctl: Add microchip statistics format
>   media: microchip-isc: expose color correction registers as v4l2
>     controls
> 
>  drivers/media/platform/microchip/Kconfig      |   2 +
>  drivers/media/platform/microchip/Makefile     |   2 +-
>  .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
>  .../platform/microchip/microchip-isc-regs.h   |   3 +
>  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>  .../media/platform/microchip/microchip-isc.h  |  44 +-
>  .../microchip/microchip-sama5d2-isc.c         |   2 +-
>  .../microchip/microchip-sama7g5-isc.c         |  73 ++-
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
>  include/linux/atmel-isc-media.h               |  13 +
>  include/uapi/linux/videodev2.h                |   3 +
>  11 files changed, 1001 insertions(+), 64 deletions(-)
>  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> 

This looks interesting.
I would like to see the compliance tool output for more platforms
(sama7g5, sama5d2, and the new sam9x7), also the media-ctl -p , to see
the topology with your new driver.

Thanks,
Eugen

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Kieran Bingham]

Quoting Eugen Hristev (2025-10-09 21:11:17)
> Hi Bala,
> 
> On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
> > Hi,
> > 
> > This patch series has a set of enhancements to the Microchip Image Sensor
> > Controller driver. The objective is to expand its image processing
> > capabilities and to improve the colors.
> > 
> > This series also introduces a new stats driver that exposes the histogram
> > data to userspace via v4l2 controls. This allows applications such as
> > libcamera to access real time image statistics for advanced image
> > processing like automatic exposure, white balance adjustments etc.

How much data do you anticipate to be passing through controls? (What
can the hardware provide in total if we look at the bigger picture to
support the full device?)

For all other ISPs we've been working towards using structured parameter
buffers to pass data - and we've been making that format extensible,
which I think could also be a design that can apply to statistics.

This would greatly reduce the overhead of managing 'one control per
value' ... or things like passing large tables (like a lens shading
table perhaps) through controls.

--
Kieran

> > 
> > Balakrishnan Sambath (11):
> >   media: microchip-isc: Enable GDC and CBC module flags for RGB formats
> >   media: microchip-isc: Improve histogram calculation with outlier
> >     rejection
> >   media: microchip-isc: Use channel averages for Grey World AWB
> >   media: microchip-isc: Add range based black level correction
> >   media: platform: microchip: Extend gamma table and control range
> >   media: platform: microchip: Add new histogram submodule
> >   media: microchip-isc: Register and unregister statistics device
> >   media: microchip-isc: Always enable histogram for all RAW formats
> >   media: microchip-isc: fix histogram state initialization order
> >   media: microchip-isc: decouple histogram cycling from AWB mode
> >   media: microchip-isc: enable userspace histogram statistics export
> > 
> > Balamanikandan Gunasundar (7):
> >   media: platform: microchip: set maximum resolution for sam9x7
> >   media: platform: microchip: Include DPC modules flags in pipeline
> >   media: microchip-isc: expose hue and saturation as v4l2 controls
> >   media: microchip-isc: Rename CBC to CBHS
> >   media: microchip-isc: Store histogram data of all channels
> >   media: videodev2.h, v4l2-ioctl: Add microchip statistics format
> >   media: microchip-isc: expose color correction registers as v4l2
> >     controls
> > 
> >  drivers/media/platform/microchip/Kconfig      |   2 +
> >  drivers/media/platform/microchip/Makefile     |   2 +-
> >  .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
> >  .../platform/microchip/microchip-isc-regs.h   |   3 +
> >  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
> >  .../media/platform/microchip/microchip-isc.h  |  44 +-
> >  .../microchip/microchip-sama5d2-isc.c         |   2 +-
> >  .../microchip/microchip-sama7g5-isc.c         |  73 ++-
> >  drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
> >  include/linux/atmel-isc-media.h               |  13 +
> >  include/uapi/linux/videodev2.h                |   3 +
> >  11 files changed, 1001 insertions(+), 64 deletions(-)
> >  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> > 
> 
> This looks interesting.
> I would like to see the compliance tool output for more platforms
> (sama7g5, sama5d2, and the new sam9x7), also the media-ctl -p , to see
> the topology with your new driver.
> 
> Thanks,
> Eugen

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Laurent Pinchart]

On Fri, Oct 10, 2025 at 09:21:51AM +0100, Kieran Bingham wrote:
> Quoting Eugen Hristev (2025-10-09 21:11:17)
> > On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
> > > Hi,
> > > 
> > > This patch series has a set of enhancements to the Microchip Image Sensor
> > > Controller driver. The objective is to expand its image processing
> > > capabilities and to improve the colors.
> > > 
> > > This series also introduces a new stats driver that exposes the histogram
> > > data to userspace via v4l2 controls. This allows applications such as
> > > libcamera to access real time image statistics for advanced image
> > > processing like automatic exposure, white balance adjustments etc.
> 
> How much data do you anticipate to be passing through controls? (What
> can the hardware provide in total if we look at the bigger picture to
> support the full device?)
> 
> For all other ISPs we've been working towards using structured parameter
> buffers to pass data - and we've been making that format extensible,
> which I think could also be a design that can apply to statistics.
> 
> This would greatly reduce the overhead of managing 'one control per
> value' ... or things like passing large tables (like a lens shading
> table perhaps) through controls.

V4L2 is standardizing on parameter buffers and statistics buffers for
ISPs. Using the same mechanism here will keep the driver in line with
other ISPs, which will help in userspace too.

> > > 
> > > Balakrishnan Sambath (11):
> > >   media: microchip-isc: Enable GDC and CBC module flags for RGB formats
> > >   media: microchip-isc: Improve histogram calculation with outlier
> > >     rejection
> > >   media: microchip-isc: Use channel averages for Grey World AWB
> > >   media: microchip-isc: Add range based black level correction
> > >   media: platform: microchip: Extend gamma table and control range
> > >   media: platform: microchip: Add new histogram submodule
> > >   media: microchip-isc: Register and unregister statistics device
> > >   media: microchip-isc: Always enable histogram for all RAW formats
> > >   media: microchip-isc: fix histogram state initialization order
> > >   media: microchip-isc: decouple histogram cycling from AWB mode
> > >   media: microchip-isc: enable userspace histogram statistics export
> > > 
> > > Balamanikandan Gunasundar (7):
> > >   media: platform: microchip: set maximum resolution for sam9x7
> > >   media: platform: microchip: Include DPC modules flags in pipeline
> > >   media: microchip-isc: expose hue and saturation as v4l2 controls
> > >   media: microchip-isc: Rename CBC to CBHS
> > >   media: microchip-isc: Store histogram data of all channels
> > >   media: videodev2.h, v4l2-ioctl: Add microchip statistics format
> > >   media: microchip-isc: expose color correction registers as v4l2
> > >     controls
> > > 
> > >  drivers/media/platform/microchip/Kconfig      |   2 +
> > >  drivers/media/platform/microchip/Makefile     |   2 +-
> > >  .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
> > >  .../platform/microchip/microchip-isc-regs.h   |   3 +
> > >  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
> > >  .../media/platform/microchip/microchip-isc.h  |  44 +-
> > >  .../microchip/microchip-sama5d2-isc.c         |   2 +-
> > >  .../microchip/microchip-sama7g5-isc.c         |  73 ++-
> > >  drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
> > >  include/linux/atmel-isc-media.h               |  13 +
> > >  include/uapi/linux/videodev2.h                |   3 +
> > >  11 files changed, 1001 insertions(+), 64 deletions(-)
> > >  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> > 
> > This looks interesting.
> > I would like to see the compliance tool output for more platforms
> > (sama7g5, sama5d2, and the new sam9x7), also the media-ctl -p , to see
> > the topology with your new driver.

-- 
Regards,

Laurent Pinchart

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Balamanikandan.Gunasundar]

Hi  Kieran,

On 10/10/25 1:51 pm, Kieran Bingham wrote:
>> Hi Bala,
>>
>> On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
>>> Hi,
>>>
>>> This patch series has a set of enhancements to the Microchip Image Sensor
>>> Controller driver. The objective is to expand its image processing
>>> capabilities and to improve the colors.
>>>
>>> This series also introduces a new stats driver that exposes the histogram
>>> data to userspace via v4l2 controls. This allows applications such as
>>> libcamera to access real time image statistics for advanced image
>>> processing like automatic exposure, white balance adjustments etc.
> How much data do you anticipate to be passing through controls? (What
> can the hardware provide in total if we look at the bigger picture to
> support the full device?)
Thanks for the feedback. Currently the hardware provides histogram data 
with 256 bins per color (R, G, B and Y) each 32 bit wide. So roughly 
around 4 x 256 x 4 = 4K of data per frame. The intent to use  it as v4l2 
controls was to make this data easily accessible to user space without a 
need for a new data interface initially. However I agree that we may 
expand the statistics for future ISP blocks to include region based 
stats (We are already in discussion with the design)
>
> For all other ISPs we've been working towards using structured parameter
> buffers to pass data - and we've been making that format extensible,
> which I think could also be a design that can apply to statistics.

That sounds great and we can certainly explore aligning with the 
structured buffers for histogram data and any other future statistics.

Thanks,

Bala

>
> This would greatly reduce the overhead of managing 'one control per
> value' ... or things like passing large tables (like a lens shading
> table perhaps) through controls.
>
> --
> Kieran

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Balamanikandan.Gunasundar]

Hi Kieran,

On 15/10/25 11:35 am, Balamanikandan Gunasundar - I64410 wrote:
> Hi  Kieran,
>
> On 10/10/25 1:51 pm, Kieran Bingham wrote:
>>> Hi Bala,
>>>
>>> On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
>>>> Hi,
>>>>
>>>> This patch series has a set of enhancements to the Microchip Image Sensor
>>>> Controller driver. The objective is to expand its image processing
>>>> capabilities and to improve the colors.
>>>>
>>>> This series also introduces a new stats driver that exposes the histogram
>>>> data to userspace via v4l2 controls. This allows applications such as
>>>> libcamera to access real time image statistics for advanced image
>>>> processing like automatic exposure, white balance adjustments etc.
>> How much data do you anticipate to be passing through controls? (What
>> can the hardware provide in total if we look at the bigger picture to
>> support the full device?)
> Thanks for the feedback. Currently the hardware provides histogram data
> with 256 bins per color (R, G, B and Y) each 32 bit wide. So roughly
> around 4 x 256 x 4 = 4K of data per frame. The intent to use  it as v4l2
> controls was to make this data easily accessible to user space without a


Correcting my mistake here. The histogram statistics are exported to 
userspace as v4l2 meta data through the new driver.  Not the v4l2 controls.

The controls like brightness, contrast etc are exported as v4l2 controls.

Thanks,

Bala.


> need for a new data interface initially. However I agree that we may
> expand the statistics for future ISP blocks to include region based
> stats (We are already in discussion with the design)
>> For all other ISPs we've been working towards using structured parameter
>> buffers to pass data - and we've been making that format extensible,
>> which I think could also be a design that can apply to statistics.
> That sounds great and we can certainly explore aligning with the
> structured buffers for histogram data and any other future statistics.
>
> Thanks,
>
> Bala
>
>> This would greatly reduce the overhead of managing 'one control per
>> value' ... or things like passing large tables (like a lens shading
>> table perhaps) through controls.
>>
>> --
>> Kieran
>

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Balamanikandan.Gunasundar]

Hi Kieran,

On 10/10/25 1:51 pm, Kieran Bingham wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> Quoting Eugen Hristev (2025-10-09 21:11:17)
>> Hi Bala,
>>
>> On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
>>> Hi,
>>>
>>> This patch series has a set of enhancements to the Microchip Image Sensor
>>> Controller driver. The objective is to expand its image processing
>>> capabilities and to improve the colors.
>>>
>>> This series also introduces a new stats driver that exposes the histogram
>>> data to userspace via v4l2 controls. This allows applications such as


My apologies. I made a mistake clarifying this earlier. The new stats 
driver does not use V4L2 controls, it exports the buffer through the 
v4l2 meta data| (|V4L2_BUF_TYPE_META_CAPTURE)||instead. So I guess this 
is the approach you are suggesting.

The controls like brightness, contrast, hue and saturation are exported 
as V4L2 controls.

root@sam9x75-curiosity-sd:~# v4l2-ctl -l

User Controls

                      brightness 0x00980900 (int)    : min=-1024 
max=1023 step=1 default=0 value=0 flags=slider
                        contrast 0x00980901 (int)    : min=-2048 
max=2047 step=1 default=16 value=16 flags=slider
                      saturation 0x00980902 (int)    : min=0 max=100 
step=1 default=16 value=16 flags=slider
                             hue 0x00980903 (int)    : min=-180 max=180 
step=1 default=0 value=0 flags=slider

<snip>


Thanks,

Bala.


>>> libcamera to access real time image statistics for advanced image
>>> processing like automatic exposure, white balance adjustments etc.
> How much data do you anticipate to be passing through controls? (What
> can the hardware provide in total if we look at the bigger picture to
> support the full device?)
>
> For all other ISPs we've been working towards using structured parameter
> buffers to pass data - and we've been making that format extensible,
> which I think could also be a design that can apply to statistics.
>
> This would greatly reduce the overhead of managing 'one control per
> value' ... or things like passing large tables (like a lens shading
> table perhaps) through controls.
>
> --
> Kieran
>
>>> Balakrishnan Sambath (11):
>>>    media: microchip-isc: Enable GDC and CBC module flags for RGB formats
>>>    media: microchip-isc: Improve histogram calculation with outlier
>>>      rejection
>>>    media: microchip-isc: Use channel averages for Grey World AWB
>>>    media: microchip-isc: Add range based black level correction
>>>    media: platform: microchip: Extend gamma table and control range
>>>    media: platform: microchip: Add new histogram submodule
>>>    media: microchip-isc: Register and unregister statistics device
>>>    media: microchip-isc: Always enable histogram for all RAW formats
>>>    media: microchip-isc: fix histogram state initialization order
>>>    media: microchip-isc: decouple histogram cycling from AWB mode
>>>    media: microchip-isc: enable userspace histogram statistics export
>>>
>>> Balamanikandan Gunasundar (7):
>>>    media: platform: microchip: set maximum resolution for sam9x7
>>>    media: platform: microchip: Include DPC modules flags in pipeline
>>>    media: microchip-isc: expose hue and saturation as v4l2 controls
>>>    media: microchip-isc: Rename CBC to CBHS
>>>    media: microchip-isc: Store histogram data of all channels
>>>    media: videodev2.h, v4l2-ioctl: Add microchip statistics format
>>>    media: microchip-isc: expose color correction registers as v4l2
>>>      controls
>>>
>>>   drivers/media/platform/microchip/Kconfig      |   2 +
>>>   drivers/media/platform/microchip/Makefile     |   2 +-
>>>   .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
>>>   .../platform/microchip/microchip-isc-regs.h   |   3 +
>>>   .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>>>   .../media/platform/microchip/microchip-isc.h  |  44 +-
>>>   .../microchip/microchip-sama5d2-isc.c         |   2 +-
>>>   .../microchip/microchip-sama7g5-isc.c         |  73 ++-
>>>   drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
>>>   include/linux/atmel-isc-media.h               |  13 +
>>>   include/uapi/linux/videodev2.h                |   3 +
>>>   11 files changed, 1001 insertions(+), 64 deletions(-)
>>>   create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
>>>
>> This looks interesting.
>> I would like to see the compliance tool output for more platforms
>> (sama7g5, sama5d2, and the new sam9x7), also the media-ctl -p , to see
>> the topology with your new driver.
>>
>> Thanks,
>> Eugen

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Balamanikandan.Gunasundar]

On 10/10/25 1:41 am, Eugen Hristev wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> Hi Bala,
>
> On 10/9/25 18:52, Balamanikandan Gunasundar wrote:
>> Hi,
>>
>> This patch series has a set of enhancements to the Microchip Image Sensor
>> Controller driver. The objective is to expand its image processing
>> capabilities and to improve the colors.
>>
>> This series also introduces a new stats driver that exposes the histogram
>> data to userspace via v4l2 controls. This allows applications such as
>> libcamera to access real time image statistics for advanced image
>> processing like automatic exposure, white balance adjustments etc.
>>
>> Balakrishnan Sambath (11):
>>    media: microchip-isc: Enable GDC and CBC module flags for RGB formats
>>    media: microchip-isc: Improve histogram calculation with outlier
>>      rejection
>>    media: microchip-isc: Use channel averages for Grey World AWB
>>    media: microchip-isc: Add range based black level correction
>>    media: platform: microchip: Extend gamma table and control range
>>    media: platform: microchip: Add new histogram submodule
>>    media: microchip-isc: Register and unregister statistics device
>>    media: microchip-isc: Always enable histogram for all RAW formats
>>    media: microchip-isc: fix histogram state initialization order
>>    media: microchip-isc: decouple histogram cycling from AWB mode
>>    media: microchip-isc: enable userspace histogram statistics export
>>
>> Balamanikandan Gunasundar (7):
>>    media: platform: microchip: set maximum resolution for sam9x7
>>    media: platform: microchip: Include DPC modules flags in pipeline
>>    media: microchip-isc: expose hue and saturation as v4l2 controls
>>    media: microchip-isc: Rename CBC to CBHS
>>    media: microchip-isc: Store histogram data of all channels
>>    media: videodev2.h, v4l2-ioctl: Add microchip statistics format
>>    media: microchip-isc: expose color correction registers as v4l2
>>      controls
>>
>>   drivers/media/platform/microchip/Kconfig      |   2 +
>>   drivers/media/platform/microchip/Makefile     |   2 +-
>>   .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
>>   .../platform/microchip/microchip-isc-regs.h   |   3 +
>>   .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>>   .../media/platform/microchip/microchip-isc.h  |  44 +-
>>   .../microchip/microchip-sama5d2-isc.c         |   2 +-
>>   .../microchip/microchip-sama7g5-isc.c         |  73 ++-
>>   drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
>>   include/linux/atmel-isc-media.h               |  13 +
>>   include/uapi/linux/videodev2.h                |   3 +
>>   11 files changed, 1001 insertions(+), 64 deletions(-)
>>   create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
>>
> This looks interesting.
> I would like to see the compliance tool output for more platforms
> (sama7g5, sama5d2, and the new sam9x7), also the media-ctl -p , to see
> the topology with your new driver.
>
> Thanks,
> Eugen


Please find the output below,

-------- sama7g5ek --------

root@sama7g5ek-sd:~# v4l2-compliance -d /dev/video0
v4l2-compliance 1.26.1-5142, 32 bits, 64-bit time_t
v4l2-compliance SHA: 4aee01a02792 2023-12-12 21:40:38

Compliance test for microchip-isc device /dev/video0:

Driver Info:
         Driver name      : microchip-isc
         Card type        : Microchip Image Sensor Controll
         Bus info         : platform:e1408000.xisc
         Driver version   : 6.12.48
         Capabilities     : 0xa4200001
                 Video Capture
                 I/O MC
                 Streaming
                 Extended Pix Format
                 Device Capabilities
         Device Caps      : 0x24200001
                 Video Capture
                 I/O MC
                 Streaming
                 Extended Pix Format
Media Driver Info:
         Driver name      : microchip_isc_c
         Model            : microchip,sama7g5-isc
         Serial           :
         Bus info         : platform:e1408000.xisc
         Media version    : 6.12.48
         Hardware revision: 0x00000220 (544)
         Driver version   : 6.12.48
Interface Info:
         ID               : 0x0300001a
         Type             : V4L Video
Entity Info:
         ID               : 0x00000018 (24)
         Name             : microchip_isc_common
         Function         : V4L2 I/O
         Flags            : default
         Pad 0x01000019   : 0: Sink
           Link 0x02000022: from remote pad 0x1000003 of entity 
'microchip_isc_scaler' (Video Scaler): Data, Enabled, Immutable

Required ioctls:
         test MC information (see 'Media Driver Info' above): OK
         test VIDIOC_QUERYCAP: OK
         test invalid ioctls: OK

Allow for multiple opens:
         test second /dev/video0 open: OK
         test VIDIOC_QUERYCAP: OK
         test VIDIOC_G/S_PRIORITY: OK
         test for unlimited opens: OK

Debug ioctls:
         test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
         test VIDIOC_LOG_STATUS: OK

Input ioctls:
         test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
         test VIDIOC_ENUMAUDIO: OK (Not Supported)
         test VIDIOC_G/S/ENUMINPUT: OK
         test VIDIOC_G/S_AUDIO: OK (Not Supported)
         Inputs: 1 Audio Inputs: 0 Tuners: 0

Output ioctls:
         test VIDIOC_G/S_MODULATOR: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_ENUMAUDOUT: OK (Not Supported)
         test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDOUT: OK (Not Supported)
         Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
         test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
         test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
         test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
         test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls (Input 0):
         test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
         test VIDIOC_QUERYCTRL: OK
         test VIDIOC_G/S_CTRL: OK
         test VIDIOC_G/S/TRY_EXT_CTRLS: OK
         test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
         test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
         Standard Controls: 8 Private Controls: 20

Format ioctls (Input 0):
         test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
         test VIDIOC_G/S_PARM: OK (Not Supported)
         test VIDIOC_G_FBUF: OK (Not Supported)
         test VIDIOC_G_FMT: OK
         test VIDIOC_TRY_FMT: OK
         test VIDIOC_S_FMT: OK
         test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
         test Cropping: OK (Not Supported)
         test Composing: OK (Not Supported)
         test Scaling: OK

Codec ioctls (Input 0):
         test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
         test VIDIOC_G_ENC_INDEX: OK (Not Supported)
         test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls (Input 0):
         test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
         test CREATE_BUFS maximum buffers: OK
         test VIDIOC_EXPBUF: OK
         test Requests: OK (Not Supported)
         test TIME32/64: OK

Total for microchip-isc device /dev/video0: 48, Succeeded: 48, Failed: 
0, Warnings: 0
root@sama7g5ek-sd:~# v4l2-compliance -d /dev/video1
v4l2-compliance 1.26.1-5142, 32 bits, 64-bit time_t
v4l2-compliance SHA: 4aee01a02792 2023-12-12 21:40:38

Compliance test for microchip-isc device /dev/video1:

Driver Info:
         Driver name      : microchip-isc
         Card type        : microchip-isc_stats
         Bus info         : platform:microchip-isc
         Driver version   : 6.12.48
         Capabilities     : 0x84a00000
                 Metadata Capture
                 Streaming
                 Extended Pix Format
                 Device Capabilities
         Device Caps      : 0x04a00000
                 Metadata Capture
                 Streaming
                 Extended Pix Format
Media Driver Info:
         Driver name      : microchip_isc_c
         Model            : microchip,sama7g5-isc
         Serial           :
         Bus info         : platform:e1408000.xisc
         Media version    : 6.12.48
         Hardware revision: 0x00000220 (544)
         Driver version   : 6.12.48
Interface Info:
         ID               : 0x0300001e
         Type             : V4L Video
Entity Info:
         ID               : 0x0000001c (28)
         Name             : microchip-isc_stats
         Function         : V4L2 I/O
         Pad 0x0100001d   : 0: Sink

Required ioctls:
         test MC information (see 'Media Driver Info' above): OK
                 warn: v4l2-compliance.cpp(670): media bus_info 
'platform:e1408000.xisc' differs from V4L2 bus_info 'platform:microchip-isc'
         test VIDIOC_QUERYCAP: OK
         test invalid ioctls: OK

Allow for multiple opens:
         test second /dev/video1 open: OK
                 warn: v4l2-compliance.cpp(670): media bus_info 
'platform:e1408000.xisc' differs from V4L2 bus_info 'platform:microchip-isc'
         test VIDIOC_QUERYCAP: OK
         test VIDIOC_G/S_PRIORITY: OK
         test for unlimited opens: OK

Debug ioctls:
         test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
         test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:
         test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
         test VIDIOC_ENUMAUDIO: OK (Not Supported)
         test VIDIOC_G/S/ENUMINPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDIO: OK (Not Supported)
         Inputs: 0 Audio Inputs: 0 Tuners: 0

Output ioctls:
         test VIDIOC_G/S_MODULATOR: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_ENUMAUDOUT: OK (Not Supported)
         test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDOUT: OK (Not Supported)
         Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
         test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
         test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
         test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
         test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls:
         test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK (Not Supported)
         test VIDIOC_QUERYCTRL: OK (Not Supported)
         test VIDIOC_G/S_CTRL: OK (Not Supported)
         test VIDIOC_G/S/TRY_EXT_CTRLS: OK (Not Supported)
         test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK (Not Supported)
         test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
         Standard Controls: 0 Private Controls: 0

Format ioctls:
         test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
         test VIDIOC_G/S_PARM: OK (Not Supported)
         test VIDIOC_G_FBUF: OK (Not Supported)
         test VIDIOC_G_FMT: OK
         test VIDIOC_TRY_FMT: OK
         test VIDIOC_S_FMT: OK
         test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
         test Cropping: OK (Not Supported)
         test Composing: OK (Not Supported)
         test Scaling: OK (Not Supported)

Codec ioctls:
         test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
         test VIDIOC_G_ENC_INDEX: OK (Not Supported)
         test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls:
         test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
         test CREATE_BUFS maximum buffers: OK
         test VIDIOC_EXPBUF: OK
         test Requests: OK (Not Supported)
         test TIME32/64: OK

Total for microchip-isc device /dev/video1: 48, Succeeded: 48, Failed: 
0, Warnings: 2
root@sama7g5ek-sd:~# media-ctl -p
Media controller API version 6.12.48

Media device information
------------------------
driver          microchip_isc_c
model           microchip,sama7g5-isc
serial
bus info        platform:e1408000.xisc
hw revision     0x220
driver version  6.12.48

Device topology
- entity 1: microchip_isc_scaler (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev0
         pad0: Sink
                 [stream:0 fmt:SBGGR8_1X8/3264x2464 field:none 
colorspace:srgb
                  crop.bounds:(0,0)/3264x2464
                  crop:(0,0)/3264x2464]
                 <- "csi2dc":1 [ENABLED,IMMUTABLE]
         pad1: Source
                 [stream:0 fmt:SBGGR8_1X8/3264x2464 field:none 
colorspace:srgb]
                 -> "microchip_isc_common":0 [ENABLED,IMMUTABLE]

- entity 4: csi2dc (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev1
         pad0: Sink
                 [stream:0 fmt:SRGGB8_1X8/640x480 field:none 
colorspace:srgb]
                 <- "dw-csi.0":1 [ENABLED]
         pad1: Source
                 [stream:0 fmt:SRGGB8_1X8/640x480 field:none 
colorspace:srgb]
                 -> "microchip_isc_scaler":0 [ENABLED,IMMUTABLE]

- entity 7: dw-csi.0 (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev2
         pad0: Sink
                 [stream:0 fmt:SBGGR8_1X8/0x0]
                 <- "imx219 1-0010":0 [ENABLED]
         pad1: Source
                 [stream:0 fmt:SBGGR8_1X8/0x0]
                 -> "csi2dc":0 [ENABLED]

- entity 12: imx219 1-0010 (1 pad, 1 link, 0 routes)
              type V4L2 subdev subtype Sensor flags 0
              device node name /dev/v4l-subdev3
         pad0: Source
                 [stream:0 fmt:SRGGB10_1X10/3280x2464 field:none 
colorspace:raw xfer:none ycbcr:601 quantization:full-range
                  crop.bounds:(8,8)/3280x2464
                  crop:(8,8)/3280x2464]
                 -> "dw-csi.0":0 [ENABLED]

- entity 24: microchip_isc_common (1 pad, 1 link)
              type Node subtype V4L flags 1
              device node name /dev/video0
         pad0: Sink
                 <- "microchip_isc_scaler":1 [ENABLED,IMMUTABLE]

- entity 28: microchip-isc_stats (1 pad, 0 link)
              type Node subtype V4L flags 0
              device node name /dev/video1
         pad0: Sink

-------------sam9x75_curiosity------------------

root@sam9x75-curiosity-sd:~# v4l2-compliance -d /dev/video0
v4l2-compliance 1.26.1-5142, 32 bits, 64-bit time_t
v4l2-compliance SHA: 4aee01a02792 2023-12-12 21:40:38

Compliance test for microchip-isc device /dev/video0:

Driver Info:
         Driver name      : microchip-isc
         Card type        : Microchip Image Sensor Controll
         Bus info         : platform:f8048000.xisc
         Driver version   : 6.12.48
         Capabilities     : 0xa4200001
                 Video Capture
                 I/O MC
                 Streaming
                 Extended Pix Format
                 Device Capabilities
         Device Caps      : 0x24200001
                 Video Capture
                 I/O MC
                 Streaming
                 Extended Pix Format
Media Driver Info:
         Driver name      : microchip_isc_c
         Model            : microchip,sama7g5-isc
         Serial           :
         Bus info         : platform:f8048000.xisc
         Media version    : 6.12.48
         Hardware revision: 0x00010260 (66144)
         Driver version   : 6.12.48
Interface Info:
         ID               : 0x0300001a
         Type             : V4L Video
Entity Info:
         ID               : 0x00000018 (24)
         Name             : microchip_isc_common
         Function         : V4L2 I/O
         Flags            : default
         Pad 0x01000019   : 0: Sink
           Link 0x02000022: from remote pad 0x1000003 of entity 
'microchip_isc_scaler' (Video Scaler): Data, Enabled, Immutable

Required ioctls:
         test MC information (see 'Media Driver Info' above): OK
         test VIDIOC_QUERYCAP: OK
         test invalid ioctls: OK

Allow for multiple opens:
         test second /dev/video0 open: OK
         test VIDIOC_QUERYCAP: OK
         test VIDIOC_G/S_PRIORITY: OK
         test for unlimited opens: OK

Debug ioctls:
         test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
         test VIDIOC_LOG_STATUS: OK

Input ioctls:
         test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
         test VIDIOC_ENUMAUDIO: OK (Not Supported)
         test VIDIOC_G/S/ENUMINPUT: OK
         test VIDIOC_G/S_AUDIO: OK (Not Supported)
         Inputs: 1 Audio Inputs: 0 Tuners: 0

Output ioctls:
         test VIDIOC_G/S_MODULATOR: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_ENUMAUDOUT: OK (Not Supported)
         test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDOUT: OK (Not Supported)
         Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
         test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
         test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
         test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
         test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls (Input 0):
         test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK
         test VIDIOC_QUERYCTRL: OK
         test VIDIOC_G/S_CTRL: OK
         test VIDIOC_G/S/TRY_EXT_CTRLS: OK
         test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK
         test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
         Standard Controls: 8 Private Controls: 20

Format ioctls (Input 0):
         test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
         test VIDIOC_G/S_PARM: OK (Not Supported)
         test VIDIOC_G_FBUF: OK (Not Supported)
         test VIDIOC_G_FMT: OK
         test VIDIOC_TRY_FMT: OK
         test VIDIOC_S_FMT: OK
         test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
         test Cropping: OK (Not Supported)
         test Composing: OK (Not Supported)
         test Scaling: OK

Codec ioctls (Input 0):
         test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
         test VIDIOC_G_ENC_INDEX: OK (Not Supported)
         test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls (Input 0):
         test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
         test CREATE_BUFS maximum buffers: OK
         test VIDIOC_EXPBUF: OK
         test Requests: OK (Not Supported)
         test TIME32/64: OK

Total for microchip-isc device /dev/video0: 48, Succeeded: 48, Failed: 
0, Warnings: 0
root@sam9x75-curiosity-sd:~# v4l2-compliance -d /dev/video1
v4l2-compliance 1.26.1-5142, 32 bits, 64-bit time_t
v4l2-compliance SHA: 4aee01a02792 2023-12-12 21:40:38

Compliance test for microchip-isc device /dev/video1:

Driver Info:
         Driver name      : microchip-isc
         Card type        : microchip-isc_stats
         Bus info         : platform:microchip-isc
         Driver version   : 6.12.48
         Capabilities     : 0x84a00000
                 Metadata Capture
                 Streaming
                 Extended Pix Format
                 Device Capabilities
         Device Caps      : 0x04a00000
                 Metadata Capture
                 Streaming
                 Extended Pix Format
Media Driver Info:
         Driver name      : microchip_isc_c
         Model            : microchip,sama7g5-isc
         Serial           :
         Bus info         : platform:f8048000.xisc
         Media version    : 6.12.48
         Hardware revision: 0x00010260 (66144)
         Driver version   : 6.12.48
Interface Info:
         ID               : 0x0300001e
         Type             : V4L Video
Entity Info:
         ID               : 0x0000001c (28)
         Name             : microchip-isc_stats
         Function         : V4L2 I/O
         Pad 0x0100001d   : 0: Sink

Required ioctls:
         test MC information (see 'Media Driver Info' above): OK
                 warn: v4l2-compliance.cpp(670): media bus_info 
'platform:f8048000.xisc' differs from V4L2 bus_info 'platform:microchip-isc'
         test VIDIOC_QUERYCAP: OK
         test invalid ioctls: OK

Allow for multiple opens:
         test second /dev/video1 open: OK
                 warn: v4l2-compliance.cpp(670): media bus_info 
'platform:f8048000.xisc' differs from V4L2 bus_info 'platform:microchip-isc'
         test VIDIOC_QUERYCAP: OK
         test VIDIOC_G/S_PRIORITY: OK
         test for unlimited opens: OK

Debug ioctls:
         test VIDIOC_DBG_G/S_REGISTER: OK (Not Supported)
         test VIDIOC_LOG_STATUS: OK (Not Supported)

Input ioctls:
         test VIDIOC_G/S_TUNER/ENUM_FREQ_BANDS: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_S_HW_FREQ_SEEK: OK (Not Supported)
         test VIDIOC_ENUMAUDIO: OK (Not Supported)
         test VIDIOC_G/S/ENUMINPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDIO: OK (Not Supported)
         Inputs: 0 Audio Inputs: 0 Tuners: 0

Output ioctls:
         test VIDIOC_G/S_MODULATOR: OK (Not Supported)
         test VIDIOC_G/S_FREQUENCY: OK (Not Supported)
         test VIDIOC_ENUMAUDOUT: OK (Not Supported)
         test VIDIOC_G/S/ENUMOUTPUT: OK (Not Supported)
         test VIDIOC_G/S_AUDOUT: OK (Not Supported)
         Outputs: 0 Audio Outputs: 0 Modulators: 0

Input/Output configuration ioctls:
         test VIDIOC_ENUM/G/S/QUERY_STD: OK (Not Supported)
         test VIDIOC_ENUM/G/S/QUERY_DV_TIMINGS: OK (Not Supported)
         test VIDIOC_DV_TIMINGS_CAP: OK (Not Supported)
         test VIDIOC_G/S_EDID: OK (Not Supported)

Control ioctls:
         test VIDIOC_QUERY_EXT_CTRL/QUERYMENU: OK (Not Supported)
         test VIDIOC_QUERYCTRL: OK (Not Supported)
         test VIDIOC_G/S_CTRL: OK (Not Supported)
         test VIDIOC_G/S/TRY_EXT_CTRLS: OK (Not Supported)
         test VIDIOC_(UN)SUBSCRIBE_EVENT/DQEVENT: OK (Not Supported)
         test VIDIOC_G/S_JPEGCOMP: OK (Not Supported)
         Standard Controls: 0 Private Controls: 0

Format ioctls:
         test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: OK
         test VIDIOC_G/S_PARM: OK (Not Supported)
         test VIDIOC_G_FBUF: OK (Not Supported)
         test VIDIOC_G_FMT: OK
         test VIDIOC_TRY_FMT: OK
         test VIDIOC_S_FMT: OK
         test VIDIOC_G_SLICED_VBI_CAP: OK (Not Supported)
         test Cropping: OK (Not Supported)
         test Composing: OK (Not Supported)
         test Scaling: OK (Not Supported)

Codec ioctls:
         test VIDIOC_(TRY_)ENCODER_CMD: OK (Not Supported)
         test VIDIOC_G_ENC_INDEX: OK (Not Supported)
         test VIDIOC_(TRY_)DECODER_CMD: OK (Not Supported)

Buffer ioctls:
         test VIDIOC_REQBUFS/CREATE_BUFS/QUERYBUF: OK
         test CREATE_BUFS maximum buffers: OK
         test VIDIOC_EXPBUF: OK
         test Requests: OK (Not Supported)
         test TIME32/64: OK

Total for microchip-isc device /dev/video1: 48, Succeeded: 48, Failed: 
0, Warnings: 2
root@sam9x75-curiosity-sd:~# media-ctl -p
Media controller API version 6.12.48

Media device information
------------------------
driver          microchip_isc_c
model           microchip,sama7g5-isc
serial
bus info        platform:f8048000.xisc
hw revision     0x10260
driver version  6.12.48

Device topology
- entity 1: microchip_isc_scaler (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev0
         pad0: Sink
                 [stream:0 fmt:SBGGR8_1X8/2560x1920 field:none 
colorspace:srgb
                  crop.bounds:(0,0)/2560x1920
                  crop:(0,0)/2560x1920]
                 <- "csi2dc":1 [ENABLED,IMMUTABLE]
         pad1: Source
                 [stream:0 fmt:SBGGR8_1X8/2560x1920 field:none 
colorspace:srgb]
                 -> "microchip_isc_common":0 [ENABLED,IMMUTABLE]

- entity 4: csi2dc (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev1
         pad0: Sink
                 [stream:0 fmt:SRGGB8_1X8/640x480 field:none 
colorspace:srgb]
                 <- "dw-csi.0":1 [ENABLED]
         pad1: Source
                 [stream:0 fmt:SRGGB8_1X8/640x480 field:none 
colorspace:srgb]
                 -> "microchip_isc_scaler":0 [ENABLED,IMMUTABLE]

- entity 7: dw-csi.0 (2 pads, 2 links, 0 routes)
             type V4L2 subdev subtype Unknown flags 0
             device node name /dev/v4l-subdev2
         pad0: Sink
                 [stream:0 fmt:SBGGR8_1X8/0x0]
                 <- "imx219 0-0010":0 [ENABLED]
         pad1: Source
                 [stream:0 fmt:SBGGR8_1X8/0x0]
                 -> "csi2dc":0 [ENABLED]

- entity 12: imx219 0-0010 (1 pad, 1 link, 0 routes)
              type V4L2 subdev subtype Sensor flags 0
              device node name /dev/v4l-subdev3
         pad0: Source
                 [stream:0 fmt:SRGGB10_1X10/3280x2464 field:none 
colorspace:raw xfer:none ycbcr:601 quantization:full-range
                  crop.bounds:(8,8)/3280x2464
                  crop:(8,8)/3280x2464]
                 -> "dw-csi.0":0 [ENABLED]

- entity 24: microchip_isc_common (1 pad, 1 link)
              type Node subtype V4L flags 1
              device node name /dev/video0
         pad0: Sink
                 <- "microchip_isc_scaler":1 [ENABLED,IMMUTABLE]

- entity 28: microchip-isc_stats (1 pad, 0 link)
              type Node subtype V4L flags 0
              device node name /dev/video1
         pad0: Sink

I will get you the output for sama5d2 shortly.

Thanks,

Bala

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Hans Verkuil]

Hi Balamanikandan,

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:
> Hi,
> 
> This patch series has a set of enhancements to the Microchip Image Sensor
> Controller driver. The objective is to expand its image processing
> capabilities and to improve the colors.
> 
> This series also introduces a new stats driver that exposes the histogram
> data to userspace via v4l2 controls. This allows applications such as
> libcamera to access real time image statistics for advanced image
> processing like automatic exposure, white balance adjustments etc.

Most of this series is fine, but the histogram part needs more work.

I would recommend splitting up this series in two parts: one for the
various fixes and improvements, and one for the histogram feature.

The first series with the fixes I can take easily. In fact, if you
post that this week (no later than Thursday), then I can pick it
up in time for v6.19.

As mentioned the histogram part needs more work. Mostly small stuff,
but the documentation is the major missing part.

I also want to see the output of 'v4l2-compliance -m0 -s' (i.e.
with streaming) in the cover letter of the histogram series to be
certain nothing was forgotten.

Make sure you compile v4l2-compliance straight from the git repo,
don't use a distro version since that's usually out of date.

Regards,

	Hans

> 
> Balakrishnan Sambath (11):
>   media: microchip-isc: Enable GDC and CBC module flags for RGB formats
>   media: microchip-isc: Improve histogram calculation with outlier
>     rejection
>   media: microchip-isc: Use channel averages for Grey World AWB
>   media: microchip-isc: Add range based black level correction
>   media: platform: microchip: Extend gamma table and control range
>   media: platform: microchip: Add new histogram submodule
>   media: microchip-isc: Register and unregister statistics device
>   media: microchip-isc: Always enable histogram for all RAW formats
>   media: microchip-isc: fix histogram state initialization order
>   media: microchip-isc: decouple histogram cycling from AWB mode
>   media: microchip-isc: enable userspace histogram statistics export
> 
> Balamanikandan Gunasundar (7):
>   media: platform: microchip: set maximum resolution for sam9x7
>   media: platform: microchip: Include DPC modules flags in pipeline
>   media: microchip-isc: expose hue and saturation as v4l2 controls
>   media: microchip-isc: Rename CBC to CBHS
>   media: microchip-isc: Store histogram data of all channels
>   media: videodev2.h, v4l2-ioctl: Add microchip statistics format
>   media: microchip-isc: expose color correction registers as v4l2
>     controls
> 
>  drivers/media/platform/microchip/Kconfig      |   2 +
>  drivers/media/platform/microchip/Makefile     |   2 +-
>  .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
>  .../platform/microchip/microchip-isc-regs.h   |   3 +
>  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>  .../media/platform/microchip/microchip-isc.h  |  44 +-
>  .../microchip/microchip-sama5d2-isc.c         |   2 +-
>  .../microchip/microchip-sama7g5-isc.c         |  73 ++-
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
>  include/linux/atmel-isc-media.h               |  13 +
>  include/uapi/linux/videodev2.h                |   3 +
>  11 files changed, 1001 insertions(+), 64 deletions(-)
>  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
> 

Re: [PATCH 00/18] media: microchip-isc: Color correction and histogram stats

[Hans Verkuil]

On 09/10/2025 17:52, Balamanikandan Gunasundar wrote:
> Hi,
> 
> This patch series has a set of enhancements to the Microchip Image Sensor
> Controller driver. The objective is to expand its image processing
> capabilities and to improve the colors.
> 
> This series also introduces a new stats driver that exposes the histogram
> data to userspace via v4l2 controls. This allows applications such as
> libcamera to access real time image statistics for advanced image
> processing like automatic exposure, white balance adjustments etc.

Note that bisect of this series failed: some patches seem to have dependencies
on later patches, which is obviously wrong. Make sure you double check that
for v2.

The documentation also fails to build since there is no documentation for the
new meta format, but I already commented on that.

Regards,

	Hans

> 
> Balakrishnan Sambath (11):
>   media: microchip-isc: Enable GDC and CBC module flags for RGB formats
>   media: microchip-isc: Improve histogram calculation with outlier
>     rejection
>   media: microchip-isc: Use channel averages for Grey World AWB
>   media: microchip-isc: Add range based black level correction
>   media: platform: microchip: Extend gamma table and control range
>   media: platform: microchip: Add new histogram submodule
>   media: microchip-isc: Register and unregister statistics device
>   media: microchip-isc: Always enable histogram for all RAW formats
>   media: microchip-isc: fix histogram state initialization order
>   media: microchip-isc: decouple histogram cycling from AWB mode
>   media: microchip-isc: enable userspace histogram statistics export
> 
> Balamanikandan Gunasundar (7):
>   media: platform: microchip: set maximum resolution for sam9x7
>   media: platform: microchip: Include DPC modules flags in pipeline
>   media: microchip-isc: expose hue and saturation as v4l2 controls
>   media: microchip-isc: Rename CBC to CBHS
>   media: microchip-isc: Store histogram data of all channels
>   media: videodev2.h, v4l2-ioctl: Add microchip statistics format
>   media: microchip-isc: expose color correction registers as v4l2
>     controls
> 
>  drivers/media/platform/microchip/Kconfig      |   2 +
>  drivers/media/platform/microchip/Makefile     |   2 +-
>  .../platform/microchip/microchip-isc-base.c   | 373 ++++++++++--
>  .../platform/microchip/microchip-isc-regs.h   |   3 +
>  .../platform/microchip/microchip-isc-stats.c  | 549 ++++++++++++++++++
>  .../media/platform/microchip/microchip-isc.h  |  44 +-
>  .../microchip/microchip-sama5d2-isc.c         |   2 +-
>  .../microchip/microchip-sama7g5-isc.c         |  73 ++-
>  drivers/media/v4l2-core/v4l2-ioctl.c          |   1 +
>  include/linux/atmel-isc-media.h               |  13 +
>  include/uapi/linux/videodev2.h                |   3 +
>  11 files changed, 1001 insertions(+), 64 deletions(-)
>  create mode 100644 drivers/media/platform/microchip/microchip-isc-stats.c
>