[PATCH AUTOSEL 6.17-6.1] media: i2c: og01a1b: Specify monochrome media bus format instead of Bayer

[Sasha Levin <sashal@kernel.org>]

From: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>

[ Upstream commit bfbd5aa5347fbd11ade188b316b800bfb27d9e22 ]

The OmniVision OG01A1B image sensor is a monochrome sensor, it supports
8-bit and 10-bit RAW output formats only.

That said the planar greyscale Y8/Y10 media formats are more appropriate
for the sensor instead of the originally and arbitrary selected SGRBG one,
since there is no red, green or blue color components.

Signed-off-by: Vladimir Zapolskiy <vladimir.zapolskiy@linaro.org>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

LLM Generated explanations, may be completely bogus:

YES

- Problem fixed: The sensor is monochrome, but the driver advertised a
  Bayer RAW10 bus code. This is incorrect and can cause wrong pipeline
  negotiation and processing (e.g., debayering on a non-CFA stream).
- Precise fix: Three small, contained changes switch the media bus code
  from Bayer to monochrome:
  - Default pad format: `fmt->code = MEDIA_BUS_FMT_Y10_1X10;` in
    `og01a1b_update_pad_format` (drivers/media/i2c/og01a1b.c:685).
  - Advertised code enumeration: `code->code = MEDIA_BUS_FMT_Y10_1X10;`
    in `og01a1b_enum_mbus_code` (drivers/media/i2c/og01a1b.c:827).
  - Frame-size enumeration input check: `fse->code !=
    MEDIA_BUS_FMT_Y10_1X10` (drivers/media/i2c/og01a1b.c:839).
- Scope and risk: The changes are limited to format reporting in this
  sensor subdev; no register programming, timing, or streaming logic is
  touched. The on-wire MIPI CSI-2 data type remains RAW10; this is a
  representational fix, not a hardware/protocol change.
- User impact: Correctly reporting monochrome Y10 avoids erroneous color
  processing and enables proper link validation with components that
  expect grayscale formats. Many bridge/ISP drivers already support
  `MEDIA_BUS_FMT_Y10_1X10`, minimizing regression risk.
- Compatibility: The driver’s single supported mode is 10-bit, and the
  code already reflects 10-bit depth, so Y10 is consistent with current
  capabilities. There’s no API/ABI change visible to V4L2 capture nodes;
  this is subdev pad-format metadata.
- Stable criteria alignment:
  - Important bug fix (wrong format reported for a monochrome sensor).
  - Small, surgical change (three lines).
  - No architectural or cross-subsystem churn.
  - Low regression risk; aligns with established handling of monochrome
    sensors.
  - Confined to one i2c/media driver file
    (`drivers/media/i2c/og01a1b.c`).

Given the correctness improvement, minimal scope, and low risk, this is
a good candidate for stable backport.

 drivers/media/i2c/og01a1b.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/media/i2c/og01a1b.c b/drivers/media/i2c/og01a1b.c
index 78d5d406e4b72..b7d0b677975d5 100644
--- a/drivers/media/i2c/og01a1b.c
+++ b/drivers/media/i2c/og01a1b.c
@@ -682,7 +682,7 @@ static void og01a1b_update_pad_format(const struct og01a1b_mode *mode,
 {
 	fmt->width = mode->width;
 	fmt->height = mode->height;
-	fmt->code = MEDIA_BUS_FMT_SGRBG10_1X10;
+	fmt->code = MEDIA_BUS_FMT_Y10_1X10;
 	fmt->field = V4L2_FIELD_NONE;
 }
 
@@ -828,7 +828,7 @@ static int og01a1b_enum_mbus_code(struct v4l2_subdev *sd,
 	if (code->index > 0)
 		return -EINVAL;
 
-	code->code = MEDIA_BUS_FMT_SGRBG10_1X10;
+	code->code = MEDIA_BUS_FMT_Y10_1X10;
 
 	return 0;
 }
@@ -840,7 +840,7 @@ static int og01a1b_enum_frame_size(struct v4l2_subdev *sd,
 	if (fse->index >= ARRAY_SIZE(supported_modes))
 		return -EINVAL;
 
-	if (fse->code != MEDIA_BUS_FMT_SGRBG10_1X10)
+	if (fse->code != MEDIA_BUS_FMT_Y10_1X10)
 		return -EINVAL;
 
 	fse->min_width = supported_modes[fse->index].width;
-- 
2.51.0