[PATCH v2 00/12] drm/bridge: tc358768: Fixes and timings improvements

[PATCH v2 00/12] drm/bridge: tc358768: Fixes and timings improvements

[Tomi Valkeinen]

This series contains various fixes and cleanups for TC358768. The target
of this work is to get TC358768 working on Toradex's AM62 based board,
which has the following display pipeline:

AM62 DPI -> TC358768 -> LT8912B -> HDMI connector

The main thing the series does is to improve the DSI HSW, HFP and VSDly
calculations.

 Tomi

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
Changes in v2:
- Add "drm/tegra: rgb: Parameterize V- and H-sync polarities" so that
  Tegra can configure the polarities correctly.
- Add "drm/bridge: tc358768: Default to positive h/v syncs" as we don't
  (necessarily) have the polarities set in the mode.
- Drop "drm/bridge: tc358768: Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
  support" as it's not needed for DRM_BRIDGE_ATTACH_NO_CONNECTOR
  support.
- Link to v1: https://lore.kernel.org/r/20230804-tc358768-v1-0-1afd44b7826b@ideasonboard.com

---
Thierry Reding (1):
      drm/tegra: rgb: Parameterize V- and H-sync polarities

Tomi Valkeinen (11):
      drm/bridge: tc358768: Fix use of uninitialized variable
      drm/bridge: tc358768: Fix bit updates
      drm/bridge: tc358768: Cleanup PLL calculations
      drm/bridge: tc358768: Use struct videomode
      drm/bridge: tc358768: Print logical values, not raw register values
      drm/bridge: tc358768: Use dev for dbg prints, not priv->dev
      drm/bridge: tc358768: Rename dsibclk to hsbyteclk
      drm/bridge: tc358768: Clean up clock period code
      drm/bridge: tc358768: Fix tc358768_ns_to_cnt()
      drm/bridge: tc358768: Attempt to fix DSI horizontal timings
      drm/bridge: tc358768: Default to positive h/v syncs

 drivers/gpu/drm/bridge/tc358768.c | 381 ++++++++++++++++++++++++++++----------
 drivers/gpu/drm/tegra/rgb.c       |  16 +-
 2 files changed, 295 insertions(+), 102 deletions(-)
---
base-commit: 4d49d87b3606369c6e29b9d051892ee1a6fc4e75
change-id: 20230804-tc358768-1b6949ef2e3d

Best regards,
-- 
Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>

[PATCH v2 01/12] drm/tegra: rgb: Parameterize V- and H-sync polarities

[Tomi Valkeinen]

From: Thierry Reding <treding@nvidia.com>

The polarities of the V- and H-sync signals are encoded as flags in the
display mode, so use the existing information to setup the signals for
the RGB interface.

Signed-off-by: Thierry Reding <treding@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
[tomi.valkeinen@ideasonboard.com: default to positive sync]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/tegra/rgb.c | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/tegra/rgb.c b/drivers/gpu/drm/tegra/rgb.c
index 79566c9ea8ff..fc66bbd913b2 100644
--- a/drivers/gpu/drm/tegra/rgb.c
+++ b/drivers/gpu/drm/tegra/rgb.c
@@ -99,6 +99,7 @@ static void tegra_rgb_encoder_disable(struct drm_encoder *encoder)
 
 static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
 {
+	struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
 	struct tegra_output *output = encoder_to_output(encoder);
 	struct tegra_rgb *rgb = to_rgb(output);
 	u32 value;
@@ -108,10 +109,19 @@ static void tegra_rgb_encoder_enable(struct drm_encoder *encoder)
 	value = DE_SELECT_ACTIVE | DE_CONTROL_NORMAL;
 	tegra_dc_writel(rgb->dc, value, DC_DISP_DATA_ENABLE_OPTIONS);
 
-	/* XXX: parameterize? */
+	/* configure H- and V-sync signal polarities */
 	value = tegra_dc_readl(rgb->dc, DC_COM_PIN_OUTPUT_POLARITY(1));
-	value &= ~LVS_OUTPUT_POLARITY_LOW;
-	value &= ~LHS_OUTPUT_POLARITY_LOW;
+
+	if (mode->flags & DRM_MODE_FLAG_NHSYNC)
+		value |= LHS_OUTPUT_POLARITY_LOW;
+	else
+		value &= ~LHS_OUTPUT_POLARITY_LOW;
+
+	if (mode->flags & DRM_MODE_FLAG_NVSYNC)
+		value |= LVS_OUTPUT_POLARITY_LOW;
+	else
+		value &= ~LVS_OUTPUT_POLARITY_LOW;
+
 	tegra_dc_writel(rgb->dc, value, DC_COM_PIN_OUTPUT_POLARITY(1));
 
 	/* XXX: parameterize? */

-- 
2.34.1

[PATCH v2 02/12] drm/bridge: tc358768: Fix use of uninitialized variable

[Tomi Valkeinen]

smatch reports:

drivers/gpu/drm/bridge/tc358768.c:223 tc358768_update_bits() error: uninitialized symbol 'orig'.

Fix this by bailing out from tc358768_update_bits() if the
tc358768_read() produces an error.

Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 819a4b6ec2a0..bc97a837955b 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -216,6 +216,10 @@ static void tc358768_update_bits(struct tc358768_priv *priv, u32 reg, u32 mask,
 	u32 tmp, orig;
 
 	tc358768_read(priv, reg, &orig);
+
+	if (priv->error)
+		return;
+
 	tmp = orig & ~mask;
 	tmp |= val & mask;
 	if (tmp != orig)

-- 
2.34.1

[PATCH v2 03/12] drm/bridge: tc358768: Fix bit updates

[Tomi Valkeinen]

The driver has a few places where it does:

if (thing_is_enabled_in_config)
	update_thing_bit_in_hw()

This means that if the thing is _not_ enabled, the bit never gets
cleared. This affects the h/vsyncs and continuous DSI clock bits.

Fix the driver to always update the bit.

Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index bc97a837955b..b668f77673c3 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -794,8 +794,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		val |= BIT(i + 1);
 	tc358768_write(priv, TC358768_HSTXVREGEN, val);
 
-	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
-		tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
+	tc358768_write(priv, TC358768_TXOPTIONCNTRL,
+		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
 
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
 	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
@@ -861,11 +861,12 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	tc358768_write(priv, TC358768_DSI_HACT, hact);
 
 	/* VSYNC polarity */
-	if (!(mode->flags & DRM_MODE_FLAG_NVSYNC))
-		tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5), BIT(5));
+	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5),
+			     (mode->flags & DRM_MODE_FLAG_PVSYNC) ? BIT(5) : 0);
+
 	/* HSYNC polarity */
-	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
-		tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0), BIT(0));
+	tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0),
+			     (mode->flags & DRM_MODE_FLAG_PHSYNC) ? BIT(0) : 0);
 
 	/* Start DSI Tx */
 	tc358768_write(priv, TC358768_DSI_START, 0x1);

-- 
2.34.1

[PATCH v2 04/12] drm/bridge: tc358768: Cleanup PLL calculations

[Tomi Valkeinen]

As is quite common, some of TC358768's PLL register fields are to be
programmed with (value - 1). Specifically, the FBD and PRD, multiplier
and divider, are such fields.

However, what the driver currently does is that it considers that the
formula used for PLL rate calculation is:

RefClk * [(FBD + 1)/ (PRD + 1)] * [1 / (2^FRS)]

where FBD and PRD are values directly from the registers, while a more
sensible way to look at it is:

RefClk * FBD / PRD * (1 / (2^FRS))

and when the FBD and PRD values are written to the registers, they will
be subtracted by one.

Change the driver accordingly, as it simplifies the PLL code.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index b668f77673c3..d5831a1236e9 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -316,7 +316,7 @@ static int tc358768_calc_pll(struct tc358768_priv *priv,
 
 	target_pll = tc358768_pclk_to_pll(priv, mode->clock * 1000);
 
-	/* pll_clk = RefClk * [(FBD + 1)/ (PRD + 1)] * [1 / (2^FRS)] */
+	/* pll_clk = RefClk * FBD / PRD * (1 / (2^FRS)) */
 
 	for (i = 0; i < ARRAY_SIZE(frs_limits); i++)
 		if (target_pll >= frs_limits[i])
@@ -336,19 +336,19 @@ static int tc358768_calc_pll(struct tc358768_priv *priv,
 	best_prd = 0;
 	best_fbd = 0;
 
-	for (prd = 0; prd < 16; ++prd) {
-		u32 divisor = (prd + 1) * (1 << frs);
+	for (prd = 1; prd <= 16; ++prd) {
+		u32 divisor = prd * (1 << frs);
 		u32 fbd;
 
-		for (fbd = 0; fbd < 512; ++fbd) {
+		for (fbd = 1; fbd <= 512; ++fbd) {
 			u32 pll, diff, pll_in;
 
-			pll = (u32)div_u64((u64)refclk * (fbd + 1), divisor);
+			pll = (u32)div_u64((u64)refclk * fbd, divisor);
 
 			if (pll >= max_pll || pll < min_pll)
 				continue;
 
-			pll_in = (u32)div_u64((u64)refclk, prd + 1);
+			pll_in = (u32)div_u64((u64)refclk, prd);
 			if (pll_in < 4000000)
 				continue;
 
@@ -611,7 +611,7 @@ static int tc358768_setup_pll(struct tc358768_priv *priv,
 		mode->clock * 1000);
 
 	/* PRD[15:12] FBD[8:0] */
-	tc358768_write(priv, TC358768_PLLCTL0, (prd << 12) | fbd);
+	tc358768_write(priv, TC358768_PLLCTL0, ((prd - 1) << 12) | (fbd - 1));
 
 	/* FRS[11:10] LBWS[9:8] CKEN[4] RESETB[1] EN[0] */
 	tc358768_write(priv, TC358768_PLLCTL1,

-- 
2.34.1

[PATCH v2 05/12] drm/bridge: tc358768: Use struct videomode

[Tomi Valkeinen]

The TC358768 documentation uses HFP, HBP, etc. values to deal with the
video mode, while the driver currently uses the DRM display mode
(htotal, hsync_start, etc).

Change the driver to convert the DRM display mode to struct videomode,
which then allows us to use the same units the documentation uses. This
makes it much easier to work on the code when using the TC358768
documentation as a reference.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 45 +++++++++++++++++++++------------------
 1 file changed, 24 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index d5831a1236e9..9b633038af33 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -650,6 +650,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	u32 dsiclk, dsibclk, video_start;
 	const u32 internal_delay = 40;
 	int ret, i;
+	struct videomode vm;
 
 	if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
 		dev_warn_once(priv->dev, "Non-continuous mode unimplemented, falling back to continuous\n");
@@ -673,6 +674,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		return;
 	}
 
+	drm_display_mode_to_videomode(mode, &vm);
+
 	dsiclk = priv->dsiclk;
 	dsibclk = dsiclk / 4;
 
@@ -681,28 +684,28 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	switch (dsi_dev->format) {
 	case MIPI_DSI_FMT_RGB888:
 		val |= (0x3 << 4);
-		hact = mode->hdisplay * 3;
-		video_start = (mode->htotal - mode->hsync_start) * 3;
+		hact = vm.hactive * 3;
+		video_start = (vm.hsync_len + vm.hback_porch) * 3;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_24;
 		break;
 	case MIPI_DSI_FMT_RGB666:
 		val |= (0x4 << 4);
-		hact = mode->hdisplay * 3;
-		video_start = (mode->htotal - mode->hsync_start) * 3;
+		hact = vm.hactive * 3;
+		video_start = (vm.hsync_len + vm.hback_porch) * 3;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_18;
 		break;
 
 	case MIPI_DSI_FMT_RGB666_PACKED:
 		val |= (0x4 << 4) | BIT(3);
-		hact = mode->hdisplay * 18 / 8;
-		video_start = (mode->htotal - mode->hsync_start) * 18 / 8;
+		hact = vm.hactive * 18 / 8;
+		video_start = (vm.hsync_len + vm.hback_porch) * 18 / 8;
 		data_type = MIPI_DSI_PIXEL_STREAM_3BYTE_18;
 		break;
 
 	case MIPI_DSI_FMT_RGB565:
 		val |= (0x5 << 4);
-		hact = mode->hdisplay * 2;
-		video_start = (mode->htotal - mode->hsync_start) * 2;
+		hact = vm.hactive * 2;
+		video_start = (vm.hsync_len + vm.hback_porch) * 2;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_16;
 		break;
 	default:
@@ -814,43 +817,43 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		tc358768_write(priv, TC358768_DSI_EVENT, 0);
 
 		/* vact */
-		tc358768_write(priv, TC358768_DSI_VACT, mode->vdisplay);
+		tc358768_write(priv, TC358768_DSI_VACT, vm.vactive);
 
 		/* vsw */
-		tc358768_write(priv, TC358768_DSI_VSW,
-			       mode->vsync_end - mode->vsync_start);
+		tc358768_write(priv, TC358768_DSI_VSW, vm.vsync_len);
+
 		/* vbp */
-		tc358768_write(priv, TC358768_DSI_VBPR,
-			       mode->vtotal - mode->vsync_end);
+		tc358768_write(priv, TC358768_DSI_VBPR, vm.vback_porch);
 
 		/* hsw * byteclk * ndl / pclk */
-		val = (u32)div_u64((mode->hsync_end - mode->hsync_start) *
+		val = (u32)div_u64(vm.hsync_len *
 				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
-				   mode->clock * 1000);
+				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HSW, val);
 
 		/* hbp * byteclk * ndl / pclk */
-		val = (u32)div_u64((mode->htotal - mode->hsync_end) *
+		val = (u32)div_u64(vm.hback_porch *
 				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
-				   mode->clock * 1000);
+				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HBPR, val);
 	} else {
 		/* Set event mode */
 		tc358768_write(priv, TC358768_DSI_EVENT, 1);
 
 		/* vact */
-		tc358768_write(priv, TC358768_DSI_VACT, mode->vdisplay);
+		tc358768_write(priv, TC358768_DSI_VACT, vm.vactive);
 
 		/* vsw (+ vbp) */
 		tc358768_write(priv, TC358768_DSI_VSW,
-			       mode->vtotal - mode->vsync_start);
+			       vm.vsync_len + vm.vback_porch);
+
 		/* vbp (not used in event mode) */
 		tc358768_write(priv, TC358768_DSI_VBPR, 0);
 
 		/* (hsw + hbp) * byteclk * ndl / pclk */
-		val = (u32)div_u64((mode->htotal - mode->hsync_start) *
+		val = (u32)div_u64((vm.hsync_len + vm.hback_porch) *
 				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
-				   mode->clock * 1000);
+				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HSW, val);
 
 		/* hbp (not used in event mode) */

-- 
2.34.1

[PATCH v2 06/12] drm/bridge: tc358768: Print logical values, not raw register values

[Tomi Valkeinen]

The driver debug prints DSI related timings as raw register values in
hex. It is much more useful to see the "logical" value of the timing,
not the register value.

Change the prints to print the values separately, in case a single
register contains multiple values, and use %u to have it in a more human
consumable form.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 9b633038af33..0ef51d04bb21 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -739,57 +739,59 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 	/* LP11 > 100us for D-PHY Rx Init */
 	val = tc358768_ns_to_cnt(100 * 1000, dsibclk_nsk) - 1;
-	dev_dbg(priv->dev, "LINEINITCNT: 0x%x\n", val);
+	dev_dbg(priv->dev, "LINEINITCNT: %u\n", val);
 	tc358768_write(priv, TC358768_LINEINITCNT, val);
 
 	/* LPTimeCnt > 50ns */
 	val = tc358768_ns_to_cnt(50, dsibclk_nsk) - 1;
 	lptxcnt = val;
-	dev_dbg(priv->dev, "LPTXTIMECNT: 0x%x\n", val);
+	dev_dbg(priv->dev, "LPTXTIMECNT: %u\n", val);
 	tc358768_write(priv, TC358768_LPTXTIMECNT, val);
 
 	/* 38ns < TCLK_PREPARE < 95ns */
 	val = tc358768_ns_to_cnt(65, dsibclk_nsk) - 1;
+	dev_dbg(priv->dev, "TCLK_PREPARECNT %u\n", val);
 	/* TCLK_PREPARE + TCLK_ZERO > 300ns */
 	val2 = tc358768_ns_to_cnt(300 - tc358768_to_ns(2 * ui_nsk),
 				  dsibclk_nsk) - 2;
+	dev_dbg(priv->dev, "TCLK_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
-	dev_dbg(priv->dev, "TCLK_HEADERCNT: 0x%x\n", val);
 	tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
 
 	/* TCLK_TRAIL > 60ns AND TEOT <= 105 ns + 12*UI */
 	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), dsibclk_nsk) - 5;
 	val = clamp(raw_val, 0, 127);
-	dev_dbg(priv->dev, "TCLK_TRAILCNT: 0x%x\n", val);
+	dev_dbg(priv->dev, "TCLK_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);
 
 	/* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */
 	val = 50 + tc358768_to_ns(4 * ui_nsk);
 	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
+	dev_dbg(priv->dev, "THS_PREPARECNT %u\n", val);
 	/* THS_PREPARE + THS_ZERO > 145ns + 10*UI */
 	raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), dsibclk_nsk) - 10;
 	val2 = clamp(raw_val, 0, 127);
+	dev_dbg(priv->dev, "THS_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
-	dev_dbg(priv->dev, "THS_HEADERCNT: 0x%x\n", val);
 	tc358768_write(priv, TC358768_THS_HEADERCNT, val);
 
 	/* TWAKEUP > 1ms in lptxcnt steps */
 	val = tc358768_ns_to_cnt(1020000, dsibclk_nsk);
 	val = val / (lptxcnt + 1) - 1;
-	dev_dbg(priv->dev, "TWAKEUP: 0x%x\n", val);
+	dev_dbg(priv->dev, "TWAKEUP: %u\n", val);
 	tc358768_write(priv, TC358768_TWAKEUP, val);
 
 	/* TCLK_POSTCNT > 60ns + 52*UI */
 	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(52 * ui_nsk),
 				 dsibclk_nsk) - 3;
-	dev_dbg(priv->dev, "TCLK_POSTCNT: 0x%x\n", val);
+	dev_dbg(priv->dev, "TCLK_POSTCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_POSTCNT, val);
 
 	/* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */
 	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk),
 				     dsibclk_nsk) - 4;
 	val = clamp(raw_val, 0, 15);
-	dev_dbg(priv->dev, "THS_TRAILCNT: 0x%x\n", val);
+	dev_dbg(priv->dev, "THS_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_THS_TRAILCNT, val);
 
 	val = BIT(0);
@@ -803,10 +805,11 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
 	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
 	val = tc358768_ns_to_cnt(val, dsibclk_nsk) / 4 - 1;
+	dev_dbg(priv->dev, "TXTAGOCNT: %u\n", val);
 	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk),
 				  dsibclk_nsk) - 2;
+	dev_dbg(priv->dev, "RXTASURECNT: %u\n", val2);
 	val = val << 16 | val2;
-	dev_dbg(priv->dev, "BTACNTRL1: 0x%x\n", val);
 	tc358768_write(priv, TC358768_BTACNTRL1, val);
 
 	/* START[0] */

-- 
2.34.1

[PATCH v2 07/12] drm/bridge: tc358768: Use dev for dbg prints, not priv->dev

[Tomi Valkeinen]

Simplify the code by capturing the priv->dev value to dev variable, and
use it.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 41 ++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 0ef51d04bb21..3266c08d9bf1 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -651,9 +651,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	const u32 internal_delay = 40;
 	int ret, i;
 	struct videomode vm;
+	struct device *dev = priv->dev;
 
 	if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
-		dev_warn_once(priv->dev, "Non-continuous mode unimplemented, falling back to continuous\n");
+		dev_warn_once(dev, "Non-continuous mode unimplemented, falling back to continuous\n");
 		mode_flags &= ~MIPI_DSI_CLOCK_NON_CONTINUOUS;
 	}
 
@@ -661,7 +662,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 	ret = tc358768_sw_reset(priv);
 	if (ret) {
-		dev_err(priv->dev, "Software reset failed: %d\n", ret);
+		dev_err(dev, "Software reset failed: %d\n", ret);
 		tc358768_hw_disable(priv);
 		return;
 	}
@@ -669,7 +670,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	mode = &bridge->encoder->crtc->state->adjusted_mode;
 	ret = tc358768_setup_pll(priv, mode);
 	if (ret) {
-		dev_err(priv->dev, "PLL setup failed: %d\n", ret);
+		dev_err(dev, "PLL setup failed: %d\n", ret);
 		tc358768_hw_disable(priv);
 		return;
 	}
@@ -709,7 +710,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_16;
 		break;
 	default:
-		dev_err(priv->dev, "Invalid data format (%u)\n",
+		dev_err(dev, "Invalid data format (%u)\n",
 			dsi_dev->format);
 		tc358768_hw_disable(priv);
 		return;
@@ -733,65 +734,65 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 				  dsibclk);
 	dsiclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION, dsiclk);
 	ui_nsk = dsiclk_nsk / 2;
-	dev_dbg(priv->dev, "dsiclk_nsk: %u\n", dsiclk_nsk);
-	dev_dbg(priv->dev, "ui_nsk: %u\n", ui_nsk);
-	dev_dbg(priv->dev, "dsibclk_nsk: %u\n", dsibclk_nsk);
+	dev_dbg(dev, "dsiclk_nsk: %u\n", dsiclk_nsk);
+	dev_dbg(dev, "ui_nsk: %u\n", ui_nsk);
+	dev_dbg(dev, "dsibclk_nsk: %u\n", dsibclk_nsk);
 
 	/* LP11 > 100us for D-PHY Rx Init */
 	val = tc358768_ns_to_cnt(100 * 1000, dsibclk_nsk) - 1;
-	dev_dbg(priv->dev, "LINEINITCNT: %u\n", val);
+	dev_dbg(dev, "LINEINITCNT: %u\n", val);
 	tc358768_write(priv, TC358768_LINEINITCNT, val);
 
 	/* LPTimeCnt > 50ns */
 	val = tc358768_ns_to_cnt(50, dsibclk_nsk) - 1;
 	lptxcnt = val;
-	dev_dbg(priv->dev, "LPTXTIMECNT: %u\n", val);
+	dev_dbg(dev, "LPTXTIMECNT: %u\n", val);
 	tc358768_write(priv, TC358768_LPTXTIMECNT, val);
 
 	/* 38ns < TCLK_PREPARE < 95ns */
 	val = tc358768_ns_to_cnt(65, dsibclk_nsk) - 1;
-	dev_dbg(priv->dev, "TCLK_PREPARECNT %u\n", val);
+	dev_dbg(dev, "TCLK_PREPARECNT %u\n", val);
 	/* TCLK_PREPARE + TCLK_ZERO > 300ns */
 	val2 = tc358768_ns_to_cnt(300 - tc358768_to_ns(2 * ui_nsk),
 				  dsibclk_nsk) - 2;
-	dev_dbg(priv->dev, "TCLK_ZEROCNT %u\n", val2);
+	dev_dbg(dev, "TCLK_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
 
 	/* TCLK_TRAIL > 60ns AND TEOT <= 105 ns + 12*UI */
 	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), dsibclk_nsk) - 5;
 	val = clamp(raw_val, 0, 127);
-	dev_dbg(priv->dev, "TCLK_TRAILCNT: %u\n", val);
+	dev_dbg(dev, "TCLK_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);
 
 	/* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */
 	val = 50 + tc358768_to_ns(4 * ui_nsk);
 	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
-	dev_dbg(priv->dev, "THS_PREPARECNT %u\n", val);
+	dev_dbg(dev, "THS_PREPARECNT %u\n", val);
 	/* THS_PREPARE + THS_ZERO > 145ns + 10*UI */
 	raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), dsibclk_nsk) - 10;
 	val2 = clamp(raw_val, 0, 127);
-	dev_dbg(priv->dev, "THS_ZEROCNT %u\n", val2);
+	dev_dbg(dev, "THS_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_THS_HEADERCNT, val);
 
 	/* TWAKEUP > 1ms in lptxcnt steps */
 	val = tc358768_ns_to_cnt(1020000, dsibclk_nsk);
 	val = val / (lptxcnt + 1) - 1;
-	dev_dbg(priv->dev, "TWAKEUP: %u\n", val);
+	dev_dbg(dev, "TWAKEUP: %u\n", val);
 	tc358768_write(priv, TC358768_TWAKEUP, val);
 
 	/* TCLK_POSTCNT > 60ns + 52*UI */
 	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(52 * ui_nsk),
 				 dsibclk_nsk) - 3;
-	dev_dbg(priv->dev, "TCLK_POSTCNT: %u\n", val);
+	dev_dbg(dev, "TCLK_POSTCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_POSTCNT, val);
 
 	/* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */
 	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk),
 				     dsibclk_nsk) - 4;
 	val = clamp(raw_val, 0, 15);
-	dev_dbg(priv->dev, "THS_TRAILCNT: %u\n", val);
+	dev_dbg(dev, "THS_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_THS_TRAILCNT, val);
 
 	val = BIT(0);
@@ -805,10 +806,10 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
 	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
 	val = tc358768_ns_to_cnt(val, dsibclk_nsk) / 4 - 1;
-	dev_dbg(priv->dev, "TXTAGOCNT: %u\n", val);
+	dev_dbg(dev, "TXTAGOCNT: %u\n", val);
 	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk),
 				  dsibclk_nsk) - 2;
-	dev_dbg(priv->dev, "RXTASURECNT: %u\n", val2);
+	dev_dbg(dev, "RXTASURECNT: %u\n", val2);
 	val = val << 16 | val2;
 	tc358768_write(priv, TC358768_BTACNTRL1, val);
 
@@ -902,7 +903,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 	ret = tc358768_clear_error(priv);
 	if (ret) {
-		dev_err(priv->dev, "Bridge pre_enable failed: %d\n", ret);
+		dev_err(dev, "Bridge pre_enable failed: %d\n", ret);
 		tc358768_bridge_disable(bridge);
 		tc358768_bridge_post_disable(bridge);
 	}

-- 
2.34.1

[PATCH v2 08/12] drm/bridge: tc358768: Rename dsibclk to hsbyteclk

[Tomi Valkeinen]

The Toshiba documentation talks about HSByteClk when referring to the
DSI HS byte clock, whereas the driver uses 'dsibclk' name. Also, in a
few places the driver calculates the byte clock from the DSI clock, even
if the byte clock is already available in a variable.

To align the driver with the documentation, change the 'dsibclk'
variable to 'hsbyteclk'. This also make it easier to visually separate
'dsibclk' and 'dsiclk' variables.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 48 +++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 24 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 3266c08d9bf1..db45b4a982c0 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -604,7 +604,7 @@ static int tc358768_setup_pll(struct tc358768_priv *priv,
 
 	dev_dbg(priv->dev, "PLL: refclk %lu, fbd %u, prd %u, frs %u\n",
 		clk_get_rate(priv->refclk), fbd, prd, frs);
-	dev_dbg(priv->dev, "PLL: pll_clk: %u, DSIClk %u, DSIByteClk %u\n",
+	dev_dbg(priv->dev, "PLL: pll_clk: %u, DSIClk %u, HSByteClk %u\n",
 		priv->dsiclk * 2, priv->dsiclk, priv->dsiclk / 4);
 	dev_dbg(priv->dev, "PLL: pclk %u (panel: %u)\n",
 		tc358768_pll_to_pclk(priv, priv->dsiclk * 2),
@@ -646,8 +646,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	u32 val, val2, lptxcnt, hact, data_type;
 	s32 raw_val;
 	const struct drm_display_mode *mode;
-	u32 dsibclk_nsk, dsiclk_nsk, ui_nsk;
-	u32 dsiclk, dsibclk, video_start;
+	u32 hsbyteclk_nsk, dsiclk_nsk, ui_nsk;
+	u32 dsiclk, hsbyteclk, video_start;
 	const u32 internal_delay = 40;
 	int ret, i;
 	struct videomode vm;
@@ -678,7 +678,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	drm_display_mode_to_videomode(mode, &vm);
 
 	dsiclk = priv->dsiclk;
-	dsibclk = dsiclk / 4;
+	hsbyteclk = dsiclk / 4;
 
 	/* Data Format Control Register */
 	val = BIT(2) | BIT(1) | BIT(0); /* rdswap_en | dsitx_en | txdt_en */
@@ -730,67 +730,67 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		tc358768_write(priv, TC358768_D0W_CNTRL + i * 4, 0x0000);
 
 	/* DSI Timings */
-	dsibclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION,
-				  dsibclk);
+	hsbyteclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION,
+				  hsbyteclk);
 	dsiclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION, dsiclk);
 	ui_nsk = dsiclk_nsk / 2;
 	dev_dbg(dev, "dsiclk_nsk: %u\n", dsiclk_nsk);
 	dev_dbg(dev, "ui_nsk: %u\n", ui_nsk);
-	dev_dbg(dev, "dsibclk_nsk: %u\n", dsibclk_nsk);
+	dev_dbg(dev, "hsbyteclk_nsk: %u\n", hsbyteclk_nsk);
 
 	/* LP11 > 100us for D-PHY Rx Init */
-	val = tc358768_ns_to_cnt(100 * 1000, dsibclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(100 * 1000, hsbyteclk_nsk) - 1;
 	dev_dbg(dev, "LINEINITCNT: %u\n", val);
 	tc358768_write(priv, TC358768_LINEINITCNT, val);
 
 	/* LPTimeCnt > 50ns */
-	val = tc358768_ns_to_cnt(50, dsibclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(50, hsbyteclk_nsk) - 1;
 	lptxcnt = val;
 	dev_dbg(dev, "LPTXTIMECNT: %u\n", val);
 	tc358768_write(priv, TC358768_LPTXTIMECNT, val);
 
 	/* 38ns < TCLK_PREPARE < 95ns */
-	val = tc358768_ns_to_cnt(65, dsibclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(65, hsbyteclk_nsk) - 1;
 	dev_dbg(dev, "TCLK_PREPARECNT %u\n", val);
 	/* TCLK_PREPARE + TCLK_ZERO > 300ns */
 	val2 = tc358768_ns_to_cnt(300 - tc358768_to_ns(2 * ui_nsk),
-				  dsibclk_nsk) - 2;
+				  hsbyteclk_nsk) - 2;
 	dev_dbg(dev, "TCLK_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
 
 	/* TCLK_TRAIL > 60ns AND TEOT <= 105 ns + 12*UI */
-	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), dsibclk_nsk) - 5;
+	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), hsbyteclk_nsk) - 5;
 	val = clamp(raw_val, 0, 127);
 	dev_dbg(dev, "TCLK_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);
 
 	/* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */
 	val = 50 + tc358768_to_ns(4 * ui_nsk);
-	val = tc358768_ns_to_cnt(val, dsibclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(val, hsbyteclk_nsk) - 1;
 	dev_dbg(dev, "THS_PREPARECNT %u\n", val);
 	/* THS_PREPARE + THS_ZERO > 145ns + 10*UI */
-	raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), dsibclk_nsk) - 10;
+	raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), hsbyteclk_nsk) - 10;
 	val2 = clamp(raw_val, 0, 127);
 	dev_dbg(dev, "THS_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_THS_HEADERCNT, val);
 
 	/* TWAKEUP > 1ms in lptxcnt steps */
-	val = tc358768_ns_to_cnt(1020000, dsibclk_nsk);
+	val = tc358768_ns_to_cnt(1020000, hsbyteclk_nsk);
 	val = val / (lptxcnt + 1) - 1;
 	dev_dbg(dev, "TWAKEUP: %u\n", val);
 	tc358768_write(priv, TC358768_TWAKEUP, val);
 
 	/* TCLK_POSTCNT > 60ns + 52*UI */
 	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(52 * ui_nsk),
-				 dsibclk_nsk) - 3;
+				 hsbyteclk_nsk) - 3;
 	dev_dbg(dev, "TCLK_POSTCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_POSTCNT, val);
 
 	/* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */
 	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk),
-				     dsibclk_nsk) - 4;
+				     hsbyteclk_nsk) - 4;
 	val = clamp(raw_val, 0, 15);
 	dev_dbg(dev, "THS_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_THS_TRAILCNT, val);
@@ -804,11 +804,11 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
 
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
-	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
-	val = tc358768_ns_to_cnt(val, dsibclk_nsk) / 4 - 1;
+	val = tc358768_to_ns((lptxcnt + 1) * hsbyteclk_nsk * 4);
+	val = tc358768_ns_to_cnt(val, hsbyteclk_nsk) / 4 - 1;
 	dev_dbg(dev, "TXTAGOCNT: %u\n", val);
-	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk),
-				  dsibclk_nsk) - 2;
+	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * hsbyteclk_nsk),
+				  hsbyteclk_nsk) - 2;
 	dev_dbg(dev, "RXTASURECNT: %u\n", val2);
 	val = val << 16 | val2;
 	tc358768_write(priv, TC358768_BTACNTRL1, val);
@@ -831,13 +831,13 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 		/* hsw * byteclk * ndl / pclk */
 		val = (u32)div_u64(vm.hsync_len *
-				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
+				   (u64)hsbyteclk * priv->dsi_lanes,
 				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HSW, val);
 
 		/* hbp * byteclk * ndl / pclk */
 		val = (u32)div_u64(vm.hback_porch *
-				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
+				   (u64)hsbyteclk * priv->dsi_lanes,
 				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HBPR, val);
 	} else {
@@ -856,7 +856,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 		/* (hsw + hbp) * byteclk * ndl / pclk */
 		val = (u32)div_u64((vm.hsync_len + vm.hback_porch) *
-				   ((u64)priv->dsiclk / 4) * priv->dsi_lanes,
+				   (u64)hsbyteclk * priv->dsi_lanes,
 				   vm.pixelclock);
 		tc358768_write(priv, TC358768_DSI_HSW, val);
 

-- 
2.34.1

[PATCH v2 09/12] drm/bridge: tc358768: Clean up clock period code

[Tomi Valkeinen]

The driver defines TC358768_PRECISION as 1000, and uses "nsk" to refer
to clock periods. The original author does not remember where all this
came from. Effectively the driver is using picoseconds as the unit for
clock periods, yet referring to them by "nsk".

Clean this up by just saying the periods are in picoseconds.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 60 +++++++++++++++++++--------------------
 1 file changed, 29 insertions(+), 31 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index db45b4a982c0..9411b0fb471e 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -15,6 +15,7 @@
 #include <linux/regmap.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
+#include <linux/units.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_drv.h>
@@ -627,15 +628,14 @@ static int tc358768_setup_pll(struct tc358768_priv *priv,
 	return tc358768_clear_error(priv);
 }
 
-#define TC358768_PRECISION	1000
-static u32 tc358768_ns_to_cnt(u32 ns, u32 period_nsk)
+static u32 tc358768_ns_to_cnt(u32 ns, u32 period_ps)
 {
-	return (ns * TC358768_PRECISION + period_nsk) / period_nsk;
+	return (ns * 1000 + period_ps) / period_ps;
 }
 
-static u32 tc358768_to_ns(u32 nsk)
+static u32 tc358768_ps_to_ns(u32 ps)
 {
-	return (nsk / TC358768_PRECISION);
+	return ps / 1000;
 }
 
 static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
@@ -646,7 +646,7 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	u32 val, val2, lptxcnt, hact, data_type;
 	s32 raw_val;
 	const struct drm_display_mode *mode;
-	u32 hsbyteclk_nsk, dsiclk_nsk, ui_nsk;
+	u32 hsbyteclk_ps, dsiclk_ps, ui_ps;
 	u32 dsiclk, hsbyteclk, video_start;
 	const u32 internal_delay = 40;
 	int ret, i;
@@ -730,67 +730,65 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		tc358768_write(priv, TC358768_D0W_CNTRL + i * 4, 0x0000);
 
 	/* DSI Timings */
-	hsbyteclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION,
-				  hsbyteclk);
-	dsiclk_nsk = (u32)div_u64((u64)1000000000 * TC358768_PRECISION, dsiclk);
-	ui_nsk = dsiclk_nsk / 2;
-	dev_dbg(dev, "dsiclk_nsk: %u\n", dsiclk_nsk);
-	dev_dbg(dev, "ui_nsk: %u\n", ui_nsk);
-	dev_dbg(dev, "hsbyteclk_nsk: %u\n", hsbyteclk_nsk);
+	hsbyteclk_ps = (u32)div_u64(PICO, hsbyteclk);
+	dsiclk_ps = (u32)div_u64(PICO, dsiclk);
+	ui_ps = dsiclk_ps / 2;
+	dev_dbg(dev, "dsiclk: %u ps, ui %u ps, hsbyteclk %u ps\n", dsiclk_ps,
+		ui_ps, hsbyteclk_ps);
 
 	/* LP11 > 100us for D-PHY Rx Init */
-	val = tc358768_ns_to_cnt(100 * 1000, hsbyteclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(100 * 1000, hsbyteclk_ps) - 1;
 	dev_dbg(dev, "LINEINITCNT: %u\n", val);
 	tc358768_write(priv, TC358768_LINEINITCNT, val);
 
 	/* LPTimeCnt > 50ns */
-	val = tc358768_ns_to_cnt(50, hsbyteclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(50, hsbyteclk_ps) - 1;
 	lptxcnt = val;
 	dev_dbg(dev, "LPTXTIMECNT: %u\n", val);
 	tc358768_write(priv, TC358768_LPTXTIMECNT, val);
 
 	/* 38ns < TCLK_PREPARE < 95ns */
-	val = tc358768_ns_to_cnt(65, hsbyteclk_nsk) - 1;
+	val = tc358768_ns_to_cnt(65, hsbyteclk_ps) - 1;
 	dev_dbg(dev, "TCLK_PREPARECNT %u\n", val);
 	/* TCLK_PREPARE + TCLK_ZERO > 300ns */
-	val2 = tc358768_ns_to_cnt(300 - tc358768_to_ns(2 * ui_nsk),
-				  hsbyteclk_nsk) - 2;
+	val2 = tc358768_ns_to_cnt(300 - tc358768_ps_to_ns(2 * ui_ps),
+				  hsbyteclk_ps) - 2;
 	dev_dbg(dev, "TCLK_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_TCLK_HEADERCNT, val);
 
 	/* TCLK_TRAIL > 60ns AND TEOT <= 105 ns + 12*UI */
-	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(2 * ui_nsk), hsbyteclk_nsk) - 5;
+	raw_val = tc358768_ns_to_cnt(60 + tc358768_ps_to_ns(2 * ui_ps), hsbyteclk_ps) - 5;
 	val = clamp(raw_val, 0, 127);
 	dev_dbg(dev, "TCLK_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_TRAILCNT, val);
 
 	/* 40ns + 4*UI < THS_PREPARE < 85ns + 6*UI */
-	val = 50 + tc358768_to_ns(4 * ui_nsk);
-	val = tc358768_ns_to_cnt(val, hsbyteclk_nsk) - 1;
+	val = 50 + tc358768_ps_to_ns(4 * ui_ps);
+	val = tc358768_ns_to_cnt(val, hsbyteclk_ps) - 1;
 	dev_dbg(dev, "THS_PREPARECNT %u\n", val);
 	/* THS_PREPARE + THS_ZERO > 145ns + 10*UI */
-	raw_val = tc358768_ns_to_cnt(145 - tc358768_to_ns(3 * ui_nsk), hsbyteclk_nsk) - 10;
+	raw_val = tc358768_ns_to_cnt(145 - tc358768_ps_to_ns(3 * ui_ps), hsbyteclk_ps) - 10;
 	val2 = clamp(raw_val, 0, 127);
 	dev_dbg(dev, "THS_ZEROCNT %u\n", val2);
 	val |= val2 << 8;
 	tc358768_write(priv, TC358768_THS_HEADERCNT, val);
 
 	/* TWAKEUP > 1ms in lptxcnt steps */
-	val = tc358768_ns_to_cnt(1020000, hsbyteclk_nsk);
+	val = tc358768_ns_to_cnt(1020000, hsbyteclk_ps);
 	val = val / (lptxcnt + 1) - 1;
 	dev_dbg(dev, "TWAKEUP: %u\n", val);
 	tc358768_write(priv, TC358768_TWAKEUP, val);
 
 	/* TCLK_POSTCNT > 60ns + 52*UI */
-	val = tc358768_ns_to_cnt(60 + tc358768_to_ns(52 * ui_nsk),
-				 hsbyteclk_nsk) - 3;
+	val = tc358768_ns_to_cnt(60 + tc358768_ps_to_ns(52 * ui_ps),
+				 hsbyteclk_ps) - 3;
 	dev_dbg(dev, "TCLK_POSTCNT: %u\n", val);
 	tc358768_write(priv, TC358768_TCLK_POSTCNT, val);
 
 	/* max(60ns + 4*UI, 8*UI) < THS_TRAILCNT < 105ns + 12*UI */
-	raw_val = tc358768_ns_to_cnt(60 + tc358768_to_ns(18 * ui_nsk),
-				     hsbyteclk_nsk) - 4;
+	raw_val = tc358768_ns_to_cnt(60 + tc358768_ps_to_ns(18 * ui_ps),
+				     hsbyteclk_ps) - 4;
 	val = clamp(raw_val, 0, 15);
 	dev_dbg(dev, "THS_TRAILCNT: %u\n", val);
 	tc358768_write(priv, TC358768_THS_TRAILCNT, val);
@@ -804,11 +802,11 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
 
 	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
-	val = tc358768_to_ns((lptxcnt + 1) * hsbyteclk_nsk * 4);
-	val = tc358768_ns_to_cnt(val, hsbyteclk_nsk) / 4 - 1;
+	val = tc358768_ps_to_ns((lptxcnt + 1) * hsbyteclk_ps * 4);
+	val = tc358768_ns_to_cnt(val, hsbyteclk_ps) / 4 - 1;
 	dev_dbg(dev, "TXTAGOCNT: %u\n", val);
-	val2 = tc358768_ns_to_cnt(tc358768_to_ns((lptxcnt + 1) * hsbyteclk_nsk),
-				  hsbyteclk_nsk) - 2;
+	val2 = tc358768_ns_to_cnt(tc358768_ps_to_ns((lptxcnt + 1) * hsbyteclk_ps),
+				  hsbyteclk_ps) - 2;
 	dev_dbg(dev, "RXTASURECNT: %u\n", val2);
 	val = val << 16 | val2;
 	tc358768_write(priv, TC358768_BTACNTRL1, val);

-- 
2.34.1

[PATCH v2 10/12] drm/bridge: tc358768: Fix tc358768_ns_to_cnt()

[Tomi Valkeinen]

The tc358768_ns_to_cnt() is, most likely, supposed to do a div-round-up
operation, but it misses subtracting one from the dividend.

Fix this by just using DIV_ROUND_UP().

Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index 9411b0fb471e..dc2241c18dde 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -630,7 +630,7 @@ static int tc358768_setup_pll(struct tc358768_priv *priv,
 
 static u32 tc358768_ns_to_cnt(u32 ns, u32 period_ps)
 {
-	return (ns * 1000 + period_ps) / period_ps;
+	return DIV_ROUND_UP(ns * 1000, period_ps);
 }
 
 static u32 tc358768_ps_to_ns(u32 ps)

-- 
2.34.1

[PATCH v2 11/12] drm/bridge: tc358768: Attempt to fix DSI horizontal timings

[Tomi Valkeinen]

The DSI horizontal timing calculations done by the driver seem to often
lead to underflows or overflows, depending on the videomode.

There are two main things the current driver doesn't seem to get right:
DSI HSW and HFP, and VSDly. However, even following Toshiba's
documentation it seems we don't always get a working display.

This patch attempts to fix the horizontal timings for DSI event mode, and
on a system with a DSI->HDMI encoder, a lot of standard HDMI modes now
seem to work. The work relies on Toshiba's documentation, but also quite
a bit on empirical testing.

This also adds timing related debug prints to make it easier to improve
on this later.

The DSI pulse mode has only been tested with a fixed-resolution panel,
which limits the testing of different modes on DSI pulse mode. However,
as the VSDly calculation also affects pulse mode, so this might cause a
regression.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 211 +++++++++++++++++++++++++++++++++-----
 1 file changed, 183 insertions(+), 28 deletions(-)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index dc2241c18dde..ea19de5509ed 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -9,6 +9,7 @@
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/kernel.h>
+#include <linux/math64.h>
 #include <linux/media-bus-format.h>
 #include <linux/minmax.h>
 #include <linux/module.h>
@@ -157,6 +158,7 @@ struct tc358768_priv {
 	u32 frs;	/* PLL Freqency range for HSCK (post divider) */
 
 	u32 dsiclk;	/* pll_clk / 2 */
+	u32 pclk;	/* incoming pclk rate */
 };
 
 static inline struct tc358768_priv *dsi_host_to_tc358768(struct mipi_dsi_host
@@ -380,6 +382,7 @@ static int tc358768_calc_pll(struct tc358768_priv *priv,
 	priv->prd = best_prd;
 	priv->frs = frs;
 	priv->dsiclk = best_pll / 2;
+	priv->pclk = mode->clock * 1000;
 
 	return 0;
 }
@@ -638,6 +641,28 @@ static u32 tc358768_ps_to_ns(u32 ps)
 	return ps / 1000;
 }
 
+static u32 tc358768_dpi_to_ns(u32 val, u32 pclk)
+{
+	return (u32)div_u64((u64)val * NANO, pclk);
+}
+
+/* Convert value in DPI pixel clock units to DSI byte count */
+static u32 tc358768_dpi_to_dsi_bytes(struct tc358768_priv *priv, u32 val)
+{
+	u64 m = (u64)val * priv->dsiclk / 4 * priv->dsi_lanes;
+	u64 n = priv->pclk;
+
+	return (u32)div_u64(m + n - 1, n);
+}
+
+static u32 tc358768_dsi_bytes_to_ns(struct tc358768_priv *priv, u32 val)
+{
+	u64 m = (u64)val * NANO;
+	u64 n = priv->dsiclk / 4 * priv->dsi_lanes;
+
+	return (u32)div_u64(m, n);
+}
+
 static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 {
 	struct tc358768_priv *priv = bridge_to_tc358768(bridge);
@@ -647,11 +672,19 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	s32 raw_val;
 	const struct drm_display_mode *mode;
 	u32 hsbyteclk_ps, dsiclk_ps, ui_ps;
-	u32 dsiclk, hsbyteclk, video_start;
-	const u32 internal_delay = 40;
+	u32 dsiclk, hsbyteclk;
 	int ret, i;
 	struct videomode vm;
 	struct device *dev = priv->dev;
+	/* In pixelclock units */
+	u32 dpi_htot, dpi_data_start;
+	/* In byte units */
+	u32 dsi_dpi_htot, dsi_dpi_data_start;
+	u32 dsi_hsw, dsi_hbp, dsi_hact, dsi_hfp;
+	const u32 dsi_hss = 4; /* HSS is a short packet (4 bytes) */
+	/* In hsbyteclk units */
+	u32 dsi_vsdly;
+	const u32 internal_dly = 40;
 
 	if (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) {
 		dev_warn_once(dev, "Non-continuous mode unimplemented, falling back to continuous\n");
@@ -686,27 +719,23 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 	case MIPI_DSI_FMT_RGB888:
 		val |= (0x3 << 4);
 		hact = vm.hactive * 3;
-		video_start = (vm.hsync_len + vm.hback_porch) * 3;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_24;
 		break;
 	case MIPI_DSI_FMT_RGB666:
 		val |= (0x4 << 4);
 		hact = vm.hactive * 3;
-		video_start = (vm.hsync_len + vm.hback_porch) * 3;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_18;
 		break;
 
 	case MIPI_DSI_FMT_RGB666_PACKED:
 		val |= (0x4 << 4) | BIT(3);
 		hact = vm.hactive * 18 / 8;
-		video_start = (vm.hsync_len + vm.hback_porch) * 18 / 8;
 		data_type = MIPI_DSI_PIXEL_STREAM_3BYTE_18;
 		break;
 
 	case MIPI_DSI_FMT_RGB565:
 		val |= (0x5 << 4);
 		hact = vm.hactive * 2;
-		video_start = (vm.hsync_len + vm.hback_porch) * 2;
 		data_type = MIPI_DSI_PACKED_PIXEL_STREAM_16;
 		break;
 	default:
@@ -716,9 +745,150 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 		return;
 	}
 
+	/*
+	 * There are three important things to make TC358768 work correctly,
+	 * which are not trivial to manage:
+	 *
+	 * 1. Keep the DPI line-time and the DSI line-time as close to each
+	 *    other as possible.
+	 * 2. TC358768 goes to LP mode after each line's active area. The DSI
+	 *    HFP period has to be long enough for entering and exiting LP mode.
+	 *    But it is not clear how to calculate this.
+	 * 3. VSDly (video start delay) has to be long enough to ensure that the
+	 *    DSI TX does not start transmitting util we have started receiving
+	 *    pixel data from the DPI input. It is not clear how to calculate
+	 *    this either.
+	 */
+
+	dpi_htot = vm.hactive + vm.hfront_porch + vm.hsync_len + vm.hback_porch;
+	dpi_data_start = vm.hsync_len + vm.hback_porch;
+
+	dev_dbg(dev, "dpi horiz timing (pclk): %u + %u + %u + %u = %u\n",
+		vm.hsync_len, vm.hback_porch, vm.hactive, vm.hfront_porch,
+		dpi_htot);
+
+	dev_dbg(dev, "dpi horiz timing (ns): %u + %u + %u + %u = %u\n",
+		tc358768_dpi_to_ns(vm.hsync_len, vm.pixelclock),
+		tc358768_dpi_to_ns(vm.hback_porch, vm.pixelclock),
+		tc358768_dpi_to_ns(vm.hactive, vm.pixelclock),
+		tc358768_dpi_to_ns(vm.hfront_porch, vm.pixelclock),
+		tc358768_dpi_to_ns(dpi_htot, vm.pixelclock));
+
+	dev_dbg(dev, "dpi data start (ns): %u + %u = %u\n",
+		tc358768_dpi_to_ns(vm.hsync_len, vm.pixelclock),
+		tc358768_dpi_to_ns(vm.hback_porch, vm.pixelclock),
+		tc358768_dpi_to_ns(dpi_data_start, vm.pixelclock));
+
+	dsi_dpi_htot = tc358768_dpi_to_dsi_bytes(priv, dpi_htot);
+	dsi_dpi_data_start = tc358768_dpi_to_dsi_bytes(priv, dpi_data_start);
+
+	if (dsi_dev->mode_flags & MIPI_DSI_MODE_VIDEO_SYNC_PULSE) {
+		dsi_hsw = tc358768_dpi_to_dsi_bytes(priv, vm.hsync_len);
+		dsi_hbp = tc358768_dpi_to_dsi_bytes(priv, vm.hback_porch);
+	} else {
+		/* HBP is included in HSW in event mode */
+		dsi_hbp = 0;
+		dsi_hsw = tc358768_dpi_to_dsi_bytes(priv,
+			vm.hsync_len + vm.hback_porch);
+
+		/*
+		 * The pixel packet includes the actual pixel data, and:
+		 * DSI packet header = 4 bytes
+		 * DCS code = 1 byte
+		 * DSI packet footer = 2 bytes
+		 */
+		dsi_hact = hact + 4 + 1 + 2;
+
+		dsi_hfp = dsi_dpi_htot - dsi_hact - dsi_hsw - dsi_hss;
+
+		/*
+		 * Here we should check if HFP is long enough for entering LP
+		 * and exiting LP, but it's not clear how to calculate that.
+		 * Instead, this is a naive algorithm that just adjusts the HFP
+		 * and HSW so that HFP is (at least) roughly 2/3 of the total
+		 * blanking time.
+		 */
+		if (dsi_hfp < (dsi_hfp + dsi_hsw + dsi_hss) * 2 / 3) {
+			u32 old_hfp = dsi_hfp;
+			u32 old_hsw = dsi_hsw;
+			u32 tot = dsi_hfp + dsi_hsw + dsi_hss;
+
+			dsi_hsw = tot / 3;
+
+			/*
+			 * Seems like sometimes HSW has to be divisible by num-lanes, but
+			 * not always...
+			 */
+			dsi_hsw = roundup(dsi_hsw, priv->dsi_lanes);
+
+			dsi_hfp = dsi_dpi_htot - dsi_hact - dsi_hsw - dsi_hss;
+
+			dev_dbg(dev,
+				"hfp too short, adjusting dsi hfp and dsi hsw from %u, %u to %u, %u\n",
+				old_hfp, old_hsw, dsi_hfp, dsi_hsw);
+		}
+
+		dev_dbg(dev,
+			"dsi horiz timing (bytes): %u, %u + %u + %u + %u = %u\n",
+			dsi_hss, dsi_hsw, dsi_hbp, dsi_hact, dsi_hfp,
+			dsi_hss + dsi_hsw + dsi_hbp + dsi_hact + dsi_hfp);
+
+		dev_dbg(dev, "dsi horiz timing (ns): %u + %u + %u + %u + %u = %u\n",
+			tc358768_dsi_bytes_to_ns(priv, dsi_hss),
+			tc358768_dsi_bytes_to_ns(priv, dsi_hsw),
+			tc358768_dsi_bytes_to_ns(priv, dsi_hbp),
+			tc358768_dsi_bytes_to_ns(priv, dsi_hact),
+			tc358768_dsi_bytes_to_ns(priv, dsi_hfp),
+			tc358768_dsi_bytes_to_ns(priv, dsi_hss + dsi_hsw + dsi_hbp + dsi_hact + dsi_hfp));
+	}
+
+	/* VSDly calculation */
+
+	/* Start with the HW internal delay */
+	dsi_vsdly = internal_dly;
+
+	/* Convert to byte units as the other variables are in byte units */
+	dsi_vsdly *= priv->dsi_lanes;
+
+	/* Do we need more delay, in addition to the internal? */
+	if (dsi_dpi_data_start > dsi_vsdly + dsi_hss + dsi_hsw + dsi_hbp) {
+		dsi_vsdly = dsi_dpi_data_start - dsi_hss - dsi_hsw - dsi_hbp;
+		dsi_vsdly = roundup(dsi_vsdly, priv->dsi_lanes);
+	}
+
+	dev_dbg(dev, "dsi data start (bytes) %u + %u + %u + %u = %u\n",
+		dsi_vsdly, dsi_hss, dsi_hsw, dsi_hbp,
+		dsi_vsdly + dsi_hss + dsi_hsw + dsi_hbp);
+
+	dev_dbg(dev, "dsi data start (ns) %u + %u + %u + %u = %u\n",
+		tc358768_dsi_bytes_to_ns(priv, dsi_vsdly),
+		tc358768_dsi_bytes_to_ns(priv, dsi_hss),
+		tc358768_dsi_bytes_to_ns(priv, dsi_hsw),
+		tc358768_dsi_bytes_to_ns(priv, dsi_hbp),
+		tc358768_dsi_bytes_to_ns(priv, dsi_vsdly + dsi_hss + dsi_hsw + dsi_hbp));
+
+	/* Convert back to hsbyteclk */
+	dsi_vsdly /= priv->dsi_lanes;
+
+	/*
+	 * The docs say that there is an internal delay of 40 cycles.
+	 * However, we get underflows if we follow that rule. If we
+	 * instead ignore the internal delay, things work. So either
+	 * the docs are wrong or the calculations are wrong.
+	 *
+	 * As a temporary fix, add the internal delay here, to counter
+	 * the subtraction when writing the register.
+	 */
+	dsi_vsdly += internal_dly;
+
+	/* Clamp to the register max */
+	if (dsi_vsdly - internal_dly > 0x3ff) {
+		dev_warn(dev, "VSDly too high, underflows likely\n");
+		dsi_vsdly = 0x3ff + internal_dly;
+	}
+
 	/* VSDly[9:0] */
-	video_start = max(video_start, internal_delay + 1) - internal_delay;
-	tc358768_write(priv, TC358768_VSDLY, video_start);
+	tc358768_write(priv, TC358768_VSDLY, dsi_vsdly - internal_dly);
 
 	tc358768_write(priv, TC358768_DATAFMT, val);
 	tc358768_write(priv, TC358768_DSITX_DT, data_type);
@@ -826,18 +996,6 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 		/* vbp */
 		tc358768_write(priv, TC358768_DSI_VBPR, vm.vback_porch);
-
-		/* hsw * byteclk * ndl / pclk */
-		val = (u32)div_u64(vm.hsync_len *
-				   (u64)hsbyteclk * priv->dsi_lanes,
-				   vm.pixelclock);
-		tc358768_write(priv, TC358768_DSI_HSW, val);
-
-		/* hbp * byteclk * ndl / pclk */
-		val = (u32)div_u64(vm.hback_porch *
-				   (u64)hsbyteclk * priv->dsi_lanes,
-				   vm.pixelclock);
-		tc358768_write(priv, TC358768_DSI_HBPR, val);
 	} else {
 		/* Set event mode */
 		tc358768_write(priv, TC358768_DSI_EVENT, 1);
@@ -851,16 +1009,13 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
 
 		/* vbp (not used in event mode) */
 		tc358768_write(priv, TC358768_DSI_VBPR, 0);
+	}
 
-		/* (hsw + hbp) * byteclk * ndl / pclk */
-		val = (u32)div_u64((vm.hsync_len + vm.hback_porch) *
-				   (u64)hsbyteclk * priv->dsi_lanes,
-				   vm.pixelclock);
-		tc358768_write(priv, TC358768_DSI_HSW, val);
+	/* hsw (bytes) */
+	tc358768_write(priv, TC358768_DSI_HSW, dsi_hsw);
 
-		/* hbp (not used in event mode) */
-		tc358768_write(priv, TC358768_DSI_HBPR, 0);
-	}
+	/* hbp (bytes) */
+	tc358768_write(priv, TC358768_DSI_HBPR, dsi_hbp);
 
 	/* hact (bytes) */
 	tc358768_write(priv, TC358768_DSI_HACT, hact);

-- 
2.34.1

[PATCH v2 12/12] drm/bridge: tc358768: Default to positive h/v syncs

[Tomi Valkeinen]

As the TC358768 is a DPI to DSI bridge, the DSI side does not need to
define h/v sync polarities. This means that sometimes we have a mode
without defined sync polarities, which does not work on the DPI side.

Add a mode_fixup hook to default to positive sync polarities.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
---
 drivers/gpu/drm/bridge/tc358768.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
index ea19de5509ed..b465e0a31d09 100644
--- a/drivers/gpu/drm/bridge/tc358768.c
+++ b/drivers/gpu/drm/bridge/tc358768.c
@@ -1124,9 +1124,27 @@ tc358768_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
 	return input_fmts;
 }
 
+static bool tc358768_mode_fixup(struct drm_bridge *bridge,
+				const struct drm_display_mode *mode,
+				struct drm_display_mode *adjusted_mode)
+{
+	/* Default to positive sync */
+
+	if (!(adjusted_mode->flags &
+	      (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_NHSYNC)))
+		adjusted_mode->flags |= DRM_MODE_FLAG_PHSYNC;
+
+	if (!(adjusted_mode->flags &
+	      (DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_NVSYNC)))
+		adjusted_mode->flags |= DRM_MODE_FLAG_PVSYNC;
+
+	return true;
+}
+
 static const struct drm_bridge_funcs tc358768_bridge_funcs = {
 	.attach = tc358768_bridge_attach,
 	.mode_valid = tc358768_bridge_mode_valid,
+	.mode_fixup = tc358768_mode_fixup,
 	.pre_enable = tc358768_bridge_pre_enable,
 	.enable = tc358768_bridge_enable,
 	.disable = tc358768_bridge_disable,

-- 
2.34.1

Re: [PATCH v2 00/12] drm/bridge: tc358768: Fixes and timings improvements

[Tomi Valkeinen]

On 16/08/2023 14:25, Tomi Valkeinen wrote:
> This series contains various fixes and cleanups for TC358768. The target
> of this work is to get TC358768 working on Toradex's AM62 based board,
> which has the following display pipeline:
> 
> AM62 DPI -> TC358768 -> LT8912B -> HDMI connector
> 
> The main thing the series does is to improve the DSI HSW, HFP and VSDly
> calculations.
> 
>   Tomi
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> Changes in v2:
> - Add "drm/tegra: rgb: Parameterize V- and H-sync polarities" so that
>    Tegra can configure the polarities correctly.
> - Add "drm/bridge: tc358768: Default to positive h/v syncs" as we don't
>    (necessarily) have the polarities set in the mode.
> - Drop "drm/bridge: tc358768: Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
>    support" as it's not needed for DRM_BRIDGE_ATTACH_NO_CONNECTOR
>    support.
> - Link to v1: https://lore.kernel.org/r/20230804-tc358768-v1-0-1afd44b7826b@ideasonboard.com

Looks like I forgot to add the reviewed-bys from Peter. Sorry about 
that! Will add to v3.

  Tomi

Re: [PATCH v2 00/12] drm/bridge: tc358768: Fixes and timings improvements

[Péter Ujfalusi]

On 16/08/2023 14:25, Tomi Valkeinen wrote:
> This series contains various fixes and cleanups for TC358768. The target
> of this work is to get TC358768 working on Toradex's AM62 based board,
> which has the following display pipeline:
> 
> AM62 DPI -> TC358768 -> LT8912B -> HDMI connector
> 
> The main thing the series does is to improve the DSI HSW, HFP and VSDly
> calculations.

Thanks Tomi for the updates, I cannot test it or verify against the
datasheet, but codewise the series looks nice:

Reviewed-by: Peter Ujfalusi <peter.ujfalusi@gmail.com>

> 
>  Tomi
> 
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
> Changes in v2:
> - Add "drm/tegra: rgb: Parameterize V- and H-sync polarities" so that
>   Tegra can configure the polarities correctly.
> - Add "drm/bridge: tc358768: Default to positive h/v syncs" as we don't
>   (necessarily) have the polarities set in the mode.
> - Drop "drm/bridge: tc358768: Add DRM_BRIDGE_ATTACH_NO_CONNECTOR
>   support" as it's not needed for DRM_BRIDGE_ATTACH_NO_CONNECTOR
>   support.
> - Link to v1: https://lore.kernel.org/r/20230804-tc358768-v1-0-1afd44b7826b@ideasonboard.com
> 
> ---
> Thierry Reding (1):
>       drm/tegra: rgb: Parameterize V- and H-sync polarities
> 
> Tomi Valkeinen (11):
>       drm/bridge: tc358768: Fix use of uninitialized variable
>       drm/bridge: tc358768: Fix bit updates
>       drm/bridge: tc358768: Cleanup PLL calculations
>       drm/bridge: tc358768: Use struct videomode
>       drm/bridge: tc358768: Print logical values, not raw register values
>       drm/bridge: tc358768: Use dev for dbg prints, not priv->dev
>       drm/bridge: tc358768: Rename dsibclk to hsbyteclk
>       drm/bridge: tc358768: Clean up clock period code
>       drm/bridge: tc358768: Fix tc358768_ns_to_cnt()
>       drm/bridge: tc358768: Attempt to fix DSI horizontal timings
>       drm/bridge: tc358768: Default to positive h/v syncs
> 
>  drivers/gpu/drm/bridge/tc358768.c | 381 ++++++++++++++++++++++++++++----------
>  drivers/gpu/drm/tegra/rgb.c       |  16 +-
>  2 files changed, 295 insertions(+), 102 deletions(-)
> ---
> base-commit: 4d49d87b3606369c6e29b9d051892ee1a6fc4e75
> change-id: 20230804-tc358768-1b6949ef2e3d
> 
> Best regards,

-- 
Péter

Re: [PATCH v2 03/12] drm/bridge: tc358768: Fix bit updates

[Maxim Schwalm]

Hi Tomi,

On 16.08.23 13:25, Tomi Valkeinen wrote:
> The driver has a few places where it does:
> 
> if (thing_is_enabled_in_config)
> 	update_thing_bit_in_hw()
> 
> This means that if the thing is _not_ enabled, the bit never gets
> cleared. This affects the h/vsyncs and continuous DSI clock bits.
> 
> Fix the driver to always update the bit.
> 
> Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
> ---
>  drivers/gpu/drm/bridge/tc358768.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
> index bc97a837955b..b668f77673c3 100644
> --- a/drivers/gpu/drm/bridge/tc358768.c
> +++ b/drivers/gpu/drm/bridge/tc358768.c
> @@ -794,8 +794,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
>  		val |= BIT(i + 1);
>  	tc358768_write(priv, TC358768_HSTXVREGEN, val);
>  
> -	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
> -		tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
> +	tc358768_write(priv, TC358768_TXOPTIONCNTRL,
> +		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
>  
>  	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
>  	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
> @@ -861,11 +861,12 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
>  	tc358768_write(priv, TC358768_DSI_HACT, hact);
>  
>  	/* VSYNC polarity */
> -	if (!(mode->flags & DRM_MODE_FLAG_NVSYNC))
> -		tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5), BIT(5));
> +	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5),
> +			     (mode->flags & DRM_MODE_FLAG_PVSYNC) ? BIT(5) : 0);
> +
>  	/* HSYNC polarity */
> -	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> -		tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0), BIT(0));
> +	tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0),
> +			     (mode->flags & DRM_MODE_FLAG_PHSYNC) ? BIT(0) : 0);
>  
>  	/* Start DSI Tx */
>  	tc358768_write(priv, TC358768_DSI_START, 0x1);
> 

shouldn't the last patch of this series be moved before this one?
Currently, this patch will still lead to a temporary regression until
patch #12 is applied.

Best regards,
Maxim

Re: [PATCH v2 03/12] drm/bridge: tc358768: Fix bit updates

[Tomi Valkeinen]

On 22/08/2023 01:22, Maxim Schwalm wrote:
> Hi Tomi,
> 
> On 16.08.23 13:25, Tomi Valkeinen wrote:
>> The driver has a few places where it does:
>>
>> if (thing_is_enabled_in_config)
>> 	update_thing_bit_in_hw()
>>
>> This means that if the thing is _not_ enabled, the bit never gets
>> cleared. This affects the h/vsyncs and continuous DSI clock bits.
>>
>> Fix the driver to always update the bit.
>>
>> Fixes: ff1ca6397b1d ("drm/bridge: Add tc358768 driver")
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   drivers/gpu/drm/bridge/tc358768.c | 13 +++++++------
>>   1 file changed, 7 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358768.c b/drivers/gpu/drm/bridge/tc358768.c
>> index bc97a837955b..b668f77673c3 100644
>> --- a/drivers/gpu/drm/bridge/tc358768.c
>> +++ b/drivers/gpu/drm/bridge/tc358768.c
>> @@ -794,8 +794,8 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
>>   		val |= BIT(i + 1);
>>   	tc358768_write(priv, TC358768_HSTXVREGEN, val);
>>   
>> -	if (!(mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS))
>> -		tc358768_write(priv, TC358768_TXOPTIONCNTRL, 0x1);
>> +	tc358768_write(priv, TC358768_TXOPTIONCNTRL,
>> +		       (mode_flags & MIPI_DSI_CLOCK_NON_CONTINUOUS) ? 0 : BIT(0));
>>   
>>   	/* TXTAGOCNT[26:16] RXTASURECNT[10:0] */
>>   	val = tc358768_to_ns((lptxcnt + 1) * dsibclk_nsk * 4);
>> @@ -861,11 +861,12 @@ static void tc358768_bridge_pre_enable(struct drm_bridge *bridge)
>>   	tc358768_write(priv, TC358768_DSI_HACT, hact);
>>   
>>   	/* VSYNC polarity */
>> -	if (!(mode->flags & DRM_MODE_FLAG_NVSYNC))
>> -		tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5), BIT(5));
>> +	tc358768_update_bits(priv, TC358768_CONFCTL, BIT(5),
>> +			     (mode->flags & DRM_MODE_FLAG_PVSYNC) ? BIT(5) : 0);
>> +
>>   	/* HSYNC polarity */
>> -	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
>> -		tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0), BIT(0));
>> +	tc358768_update_bits(priv, TC358768_PP_MISC, BIT(0),
>> +			     (mode->flags & DRM_MODE_FLAG_PHSYNC) ? BIT(0) : 0);
>>   
>>   	/* Start DSI Tx */
>>   	tc358768_write(priv, TC358768_DSI_START, 0x1);
>>
> 
> shouldn't the last patch of this series be moved before this one?
> Currently, this patch will still lead to a temporary regression until
> patch #12 is applied.

Indeed, good point. I'll change the patch order.

  Tomi