Am Donnerstag, 2. November 2023, 02:22:17 CET schrieb Laurent Pinchart:
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> 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@xxxxxxxxxxxxxxx
> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> > ---
> >
> > 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.
You mean this order?
CCI_REG8(x)
CCI_REG16_LE(x)
CCI_REG16(x)
CCI_REG24_LE(x)
CCI_REG24(x)
CCI_REG32_LE(x)
CCI_REG32(x)
CCI_REG64_LE(x)
CCI_REG64(x)
I would either keep the _LE variants at the bottom or below to their big-
endian counterpart. I prefer readability thus I would put the _LE at the
bottom, also it aligns nicely with the additional bit set.
Best regards,
Alexander
> Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
>
> > /**
> >
> > * cci_read() - Read a value from a single CCI register
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