[PATCH 7/8] media: atomisp: allow opt-in raw Bayer capture

[Maurizio Casciano <mauriziocasciano7@gmail.com>]

AtomISP currently rejects all raw formats and silently substitutes
YUV420. This prevents userspace camera processing stacks from obtaining
unprocessed sensor frames.

Add an allow_raw_output module parameter, disabled by default. When it is
enabled, enumerate only the raw format matching the sensor media-bus code
and reconcile raw format requests with the code selected by the sensor.

Also apply the per-sensor padding discovered by the CSI-2 bridge when
enumerating and negotiating frame sizes. Existing systems retain the
global padding and raw-output defaults.

Tested on a Lenovo Yoga Book YB1-X91L with raw capture from its OV2740
and OV8858 sensors.

Signed-off-by: Maurizio Casciano <mauriziocasciano7@gmail.com>
Assisted-by: Codex:gpt-5.6-sol sparse
---
 .../staging/media/atomisp/pci/atomisp_cmd.c   | 24 ++++++++++++++-----
 .../media/atomisp/pci/atomisp_internal.h      |  6 +++++
 .../staging/media/atomisp/pci/atomisp_ioctl.c | 13 ++++++----
 .../staging/media/atomisp/pci/atomisp_v4l2.c  | 15 ++++++++++++
 4 files changed, 48 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_cmd.c b/drivers/staging/media/atomisp/pci/atomisp_cmd.c
index 6cd500d9fd26..9e6387b662bc 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_cmd.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_cmd.c
@@ -3572,10 +3572,14 @@ void atomisp_get_padding(struct atomisp_device *isp, u32 width, u32 height,
 	u32 min_pad_w = ISP2400_MIN_PAD_W;
 	u32 min_pad_h = ISP2400_MIN_PAD_H;
 	struct v4l2_mbus_framefmt *sink;
+	u32 input_padding_w = input->padding_override ?
+			      input->padding_w : pad_w;
+	u32 input_padding_h = input->padding_override ?
+			      input->padding_h : pad_h;
 
 	if (!input->crop_support) {
-		*padding_w = pad_w;
-		*padding_h = pad_h;
+		*padding_w = input_padding_w;
+		*padding_h = input_padding_h;
 		return;
 	}
 
@@ -3588,8 +3592,10 @@ void atomisp_get_padding(struct atomisp_device *isp, u32 width, u32 height,
 		native_rect.height /= 2;
 	}
 
-	*padding_w = min_t(u32, (native_rect.width - width) & ~1, pad_w);
-	*padding_h = min_t(u32, (native_rect.height - height) & ~1, pad_h);
+	*padding_w = min_t(u32, (native_rect.width - width) & ~1,
+			   input_padding_w);
+	*padding_h = min_t(u32, (native_rect.height - height) & ~1,
+			   input_padding_h);
 
 	/* The below minimum padding requirements are for BYT / ISP2400 only */
 	if (IS_ISP2401)
@@ -3804,8 +3810,9 @@ int atomisp_try_fmt(struct atomisp_device *isp, struct v4l2_pix_format *f,
 	int ret;
 
 	fmt = atomisp_get_format_bridge(f->pixelformat);
-	/* Currently, raw formats are broken!!! */
-	if (!fmt || fmt->sh_fmt == IA_CSS_FRAME_FORMAT_RAW) {
+	/* Raw output remains opt-in while the legacy CSS path is validated. */
+	if (!fmt || (fmt->sh_fmt == IA_CSS_FRAME_FORMAT_RAW &&
+		     !atomisp_allow_raw_output)) {
 		f->pixelformat = V4L2_PIX_FMT_YUV420;
 
 		fmt = atomisp_get_format_bridge(f->pixelformat);
@@ -3846,6 +3853,11 @@ int atomisp_try_fmt(struct atomisp_device *isp, struct v4l2_pix_format *f,
 			ffmt.code);
 		return -EINVAL;
 	}
+	if (fmt->sh_fmt == IA_CSS_FRAME_FORMAT_RAW &&
+	    fmt->mbus_code != snr_fmt->mbus_code) {
+		fmt = snr_fmt;
+		f->pixelformat = fmt->pixelformat;
+	}
 
 	f->width = ffmt.width - padding_w;
 	f->height = ffmt.height - padding_h;
diff --git a/drivers/staging/media/atomisp/pci/atomisp_internal.h b/drivers/staging/media/atomisp/pci/atomisp_internal.h
index 5a69580b8251..99a55297033e 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_internal.h
+++ b/drivers/staging/media/atomisp/pci/atomisp_internal.h
@@ -98,6 +98,9 @@
 #define ATOMISP_CSS_SUPPORT_YUVPP     1
 
 #define ATOMISP_CSS_OUTPUT_SECOND_INDEX     1
+
+extern bool atomisp_allow_raw_output;
+
 #define ATOMISP_CSS_OUTPUT_DEFAULT_INDEX    0
 
 /* ISP2401 */
@@ -116,6 +119,9 @@
 struct atomisp_input_subdev {
 	enum atomisp_camera_port port;
 	u32 code; /* MEDIA_BUS_FMT_* */
+	u32 padding_w;
+	u32 padding_h;
+	bool padding_override;
 	bool binning_support;
 	bool crop_support;
 	bool sensor_on;
diff --git a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
index 50366bf10f32..e63b3e99e5fd 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_ioctl.c
@@ -554,8 +554,10 @@ static int atomisp_enum_framesizes(struct file *file, void *priv,
 		return ret;
 
 	fsize->type = V4L2_FRMSIZE_TYPE_DISCRETE;
-	fsize->discrete.width = fse.max_width - pad_w;
-	fsize->discrete.height = fse.max_height - pad_h;
+	fsize->discrete.width = fse.max_width -
+		(input->padding_override ? input->padding_w : pad_w);
+	fsize->discrete.height = fse.max_height -
+		(input->padding_override ? input->padding_h : pad_h);
 
 	return 0;
 }
@@ -629,8 +631,11 @@ static int atomisp_enum_fmt_cap(struct file *file, void *fh,
 		 *
 		 * FIXME: fix the pipeline to allow sensor format too.
 		 */
-		if (format->sh_fmt == IA_CSS_FRAME_FORMAT_RAW)
-			continue;
+		if (format->sh_fmt == IA_CSS_FRAME_FORMAT_RAW) {
+			if (!atomisp_allow_raw_output ||
+			    format->mbus_code != code.code)
+				continue;
+		}
 
 		/* Found a match. Now let's pick f->index'th one. */
 		if (fi < f->index) {
diff --git a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
index 812230397409..d30f69f5a794 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
@@ -25,6 +25,7 @@
 
 #include "atomisp_cmd.h"
 #include "atomisp_common.h"
+#include "atomisp_csi2.h"
 #include "atomisp_fops.h"
 #include "atomisp_ioctl.h"
 #include "atomisp_internal.h"
@@ -72,6 +73,11 @@ int pad_h = 16;
 module_param(pad_h, int, 0644);
 MODULE_PARM_DESC(pad_h, "extra data for ISP processing");
 
+bool atomisp_allow_raw_output;
+module_param_named(allow_raw_output, atomisp_allow_raw_output, bool, 0644);
+MODULE_PARM_DESC(allow_raw_output,
+		 "allow experimental raw Bayer output (default:false)");
+
 /*
  * FIXME: this is a hack to make easier to support ISP2401 variant.
  * As a given system will either be ISP2401 or not, we can just use
@@ -889,6 +895,15 @@ static void atomisp_init_sensor(struct atomisp_input_subdev *input)
 	struct v4l2_subdev_state *try_sd_state, *act_sd_state;
 	int i, err;
 
+	input->padding_override =
+		atomisp_csi2_get_sensor_padding(input->sensor->dev,
+						&input->padding_w,
+						&input->padding_h);
+	if (input->padding_override)
+		dev_info(input->sensor->dev,
+			 "using ISP input padding %ux%u\n",
+			 input->padding_w, input->padding_h);
+
 	/*
 	 * FIXME: Drivers are not supposed to use __v4l2_subdev_state_alloc()
 	 * but atomisp needs this for try_fmt on its /dev/video# node since
-- 
2.53.0