Re: [PATCH v2 1/2] media: v4l2-cci: Add support for little-endian encoded registers

Hi Alexander,

Thank you for the patch.

On Wed, Nov 01, 2023 at 01:23:53PM +0100, Alexander Stein wrote:

Some sensors, e.g. Sony, are using little-endian registers. Add support for

I would write Sony IMX290 here, as there are Sony sensors that use big endian.

those by encoding the endianess into Bit 20 of the register address.

Fixes: af73323b97702 ("media: imx290: Convert to new CCI register access helpers") Cc: stable@vger.kernel.org Signed-off-by: Alexander Stein alexander.stein@ew.tq-group.com

---

drivers/media/v4l2-core/v4l2-cci.c | 44 ++++++++++++++++++++++++------ include/media/v4l2-cci.h | 5 ++++ 2 files changed, 41 insertions(+), 8 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-cci.c b/drivers/media/v4l2-core/v4l2-cci.c index bc2dbec019b04..673637b67bf67 100644 --- a/drivers/media/v4l2-core/v4l2-cci.c +++ b/drivers/media/v4l2-core/v4l2-cci.c @@ -18,6 +18,7 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err) {

• bool little_endian; unsigned int len; u8 buf[8]; int ret;

@@ -25,6 +26,7 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err) if (err && *err) return *err;

• little_endian = reg & CCI_REG_LE;

You could initialize the variable when declaring it. Same below.

len = FIELD_GET(CCI_REG_WIDTH_MASK, reg); reg = FIELD_GET(CCI_REG_ADDR_MASK, reg); @@ -40,16 +42,28 @@ int cci_read(struct regmap *map, u32 reg, u64 *val, int *err) *val = buf[0]; break; case 2:

• *val = get_unaligned_be16(buf);
  

• if (little_endian)
  

• 	*val = get_unaligned_le16(buf);
  

• else
  

• 	*val = get_unaligned_be16(buf);
  

Unrelated to this patch, isn't buf aligned to a 4 bytes boundary ?

break;

case 3:

• *val = get_unaligned_be24(buf);
  

• if (little_endian)
  

• 	*val = get_unaligned_le24(buf);
  

• else
  

• 	*val = get_unaligned_be24(buf);
  

  break; case 4:

• *val = get_unaligned_be32(buf);
  

• if (little_endian)
  

• 	*val = get_unaligned_le32(buf);
  

• else
  

• 	*val = get_unaligned_be32(buf);
  

  break; case 8:

• *val = get_unaligned_be64(buf);
  

• if (little_endian)
  

• 	*val = get_unaligned_le64(buf);
  

• else
  

• 	*val = get_unaligned_be64(buf);
  

  break; default: dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",

@@ -68,6 +82,7 @@ EXPORT_SYMBOL_GPL(cci_read); int cci_write(struct regmap *map, u32 reg, u64 val, int *err) {

• bool little_endian; unsigned int len; u8 buf[8]; int ret;

@@ -75,6 +90,7 @@ int cci_write(struct regmap *map, u32 reg, u64 val, int *err) if (err && *err) return *err;

• little_endian = reg & CCI_REG_LE; len = FIELD_GET(CCI_REG_WIDTH_MASK, reg); reg = FIELD_GET(CCI_REG_ADDR_MASK, reg);

@@ -83,16 +99,28 @@ int cci_write(struct regmap *map, u32 reg, u64 val, int *err) buf[0] = val; break; case 2:

• put_unaligned_be16(val, buf);
  

• if (little_endian)
  

• 	put_unaligned_le16(val, buf);
  

• else
  

• 	put_unaligned_be16(val, buf);
  

  break; case 3:

• put_unaligned_be24(val, buf);
  

• if (little_endian)
  

• 	put_unaligned_le24(val, buf);
  

• else
  

• 	put_unaligned_be24(val, buf);
  

  break; case 4:

• put_unaligned_be32(val, buf);
  

• if (little_endian)
  

• 	put_unaligned_le32(val, buf);
  

• else
  

• 	put_unaligned_be32(val, buf);
  

  break; case 8:

• put_unaligned_be64(val, buf);
  

• if (little_endian)
  

• 	put_unaligned_le64(val, buf);
  

• else
  

• 	put_unaligned_be64(val, buf);
  

  break; default: dev_err(regmap_get_device(map), "Error invalid reg-width %u for reg 0x%04x\n",

diff --git a/include/media/v4l2-cci.h b/include/media/v4l2-cci.h index 0f6803e4b17e9..ef3faf0c9d44d 100644 --- a/include/media/v4l2-cci.h +++ b/include/media/v4l2-cci.h @@ -32,12 +32,17 @@ struct cci_reg_sequence { #define CCI_REG_ADDR_MASK GENMASK(15, 0) #define CCI_REG_WIDTH_SHIFT 16 #define CCI_REG_WIDTH_MASK GENMASK(19, 16) +#define CCI_REG_LE BIT(20) #define CCI_REG8(x) ((1 << CCI_REG_WIDTH_SHIFT) | (x)) #define CCI_REG16(x) ((2 << CCI_REG_WIDTH_SHIFT) | (x)) #define CCI_REG24(x) ((3 << CCI_REG_WIDTH_SHIFT) | (x)) #define CCI_REG32(x) ((4 << CCI_REG_WIDTH_SHIFT) | (x)) #define CCI_REG64(x) ((8 << CCI_REG_WIDTH_SHIFT) | (x)) +#define CCI_REG16_LE(x) ((2 << CCI_REG_WIDTH_SHIFT) | (x) | CCI_REG_LE) +#define CCI_REG24_LE(x) ((3 << CCI_REG_WIDTH_SHIFT) | (x) | CCI_REG_LE) +#define CCI_REG32_LE(x) ((4 << CCI_REG_WIDTH_SHIFT) | (x) | CCI_REG_LE) +#define CCI_REG64_LE(x) ((8 << CCI_REG_WIDTH_SHIFT) | (x) | CCI_REG_LE)

I would put CCI_REG_LE first, to match the bits order.

Reviewed-by: Laurent Pinchart laurent.pinchart@ideasonboard.com

/**

• cci_read() - Read a value from a single CCI register