Re: [PATCH v1] media: rkisp1: Add support for CAC

Laurent Pinchart
2026-03-31T13:39:49Z

On Tue, Mar 31, 2026 at 02:42:33PM +0200, Jacopo Mondi wrote:
> On Mon, Mar 30, 2026 at 04:40:18PM +0200, Barnabás Pőcze wrote:
> > 2026. 03. 25. 16:21 keltezéssel, Jacopo Mondi írta:
> > > On Mon, Mar 23, 2026 at 03:02:16PM +0100, Barnabás Pőcze wrote:
> > > > The CAC block implements chromatic aberration correction. Expose it to
> > > > userspace using the extensible parameters format. This was tested on the
> > > > i.MX8MP platform, but based on available documentation it is also present
> > > > in the RK3399 variant (V10). Thus presumably also in later versions,
> > > > so no feature flag is introduced.
> > > >
> > > > Signed-off-by: Barnabás Pőcze <barnabas.pocze@ideasonboard.com>
> > >
> > > Only minors..
> > >
> > > > ---
> > > > .../platform/rockchip/rkisp1/rkisp1-params.c | 69 ++++++++++++
> > > > .../platform/rockchip/rkisp1/rkisp1-regs.h | 21 +++-
> > > > include/uapi/linux/rkisp1-config.h | 106 +++++++++++++++++-
> > > > 3 files changed, 193 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > > > index 6442436a5e428..b889af9dcee45 100644
> > > > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > > > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-params.c
> > > > @@ -64,6 +64,7 @@ union rkisp1_ext_params_config {
> > > > struct rkisp1_ext_params_compand_bls_config compand_bls;
> > > > struct rkisp1_ext_params_compand_curve_config compand_curve;
> > > > struct rkisp1_ext_params_wdr_config wdr;
> > > > + struct rkisp1_ext_params_cac_config cac;
> > > > };
> > > >
> > > > enum rkisp1_params_formats {
> > > > @@ -1413,6 +1414,48 @@ static void rkisp1_wdr_config(struct rkisp1_params *params,
> > > > RKISP1_CIF_ISP_WDR_TONE_CURVE_YM_MASK);
> > > > }
> > > >
> > > > +static void
> > > > +rkisp1_cac_config(struct rkisp1_params *params,
> > > > + const struct rkisp1_cif_isp_cac_config *arg)
> > >
> > > Fits in one line without going over 80 cols
> >
> > This is what the other functions looks like, so went this this.
>
> It seems to me not all of them are broken, but only the ones that go
> over 80 cols
>
> in example:
>
> static void rkisp1_dpf_config(struct rkisp1_params *params,
> const struct rkisp1_cif_isp_dpf_config *arg)
>
> A detail anyway, up to you
>
> > > > +{
> > > > + u32 regval;

All other functions in this file name similar variables "val", "value"
or "reg_val". Let's not introduce a fourth one. I have a small
preference for "val", but that's not mandatory.

> > > > +
> > > > + /*
> > > > + * The enable bit is in the same register (RKISP1_CIF_ISP_CAC_CTRL),
> > > > + * so only set the clipping mode, and do not modify the other bits.
> > > > + */
> > > > + regval = rkisp1_read(params->rkisp1, RKISP1_CIF_ISP_CAC_CTRL);
> > > > + regval &= ~(RKISP1_CIF_ISP_CAC_CTRL_H_CLIP_MODE |
> > > > + RKISP1_CIF_ISP_CAC_CTRL_V_CLIP_MODE);
> > > > + regval |= FIELD_PREP(RKISP1_CIF_ISP_CAC_CTRL_H_CLIP_MODE, arg->h_clip_mode) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_CTRL_V_CLIP_MODE, arg->v_clip_mode);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_CTRL, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_COUNT_START_H_MASK, arg->h_count_start) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_COUNT_START_V_MASK, arg->v_count_start);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_COUNT_START, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_A_RED_MASK, arg->red[0]) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_A_BLUE_MASK, arg->blue[0]);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_A, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_B_RED_MASK, arg->red[1]) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_B_BLUE_MASK, arg->blue[1]);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_B, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_C_RED_MASK, arg->red[2]) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_C_BLUE_MASK, arg->blue[2]);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_C, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_X_NORM_NF_MASK, arg->x_nf) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_X_NORM_NS_MASK, arg->x_ns);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_X_NORM, regval);
> > > > +
> > > > + regval = FIELD_PREP(RKISP1_CIF_ISP_CAC_Y_NORM_NF_MASK, arg->y_nf) |
> > > > + FIELD_PREP(RKISP1_CIF_ISP_CAC_Y_NORM_NS_MASK, arg->y_ns);
> > > > + rkisp1_write(params->rkisp1, RKISP1_CIF_ISP_CAC_Y_NORM, regval);
> > > > +}
> > > > +
> > > > static void
> > > > rkisp1_isp_isr_other_config(struct rkisp1_params *params,
> > > > const struct rkisp1_params_cfg *new_params)
> > > > @@ -2089,6 +2132,25 @@ static void rkisp1_ext_params_wdr(struct rkisp1_params *params,
> > > > RKISP1_CIF_ISP_WDR_CTRL_ENABLE);
> > > > }
> > > >
> > > > +static void rkisp1_ext_params_cac(struct rkisp1_params *params,
> > > > + const union rkisp1_ext_params_config *block)
> > > > +{
> > > > + const struct rkisp1_ext_params_cac_config *cac = &block->cac;
> > > > +
> > > > + if (cac->header.flags & RKISP1_EXT_PARAMS_FL_BLOCK_DISABLE) {
> > > > + rkisp1_param_clear_bits(params, RKISP1_CIF_ISP_CAC_CTRL,
> > > > + RKISP1_CIF_ISP_CAC_CTRL_ENABLE);
> > > > + return;
> > > > + }
> > > > +
> > > > + rkisp1_cac_config(params, &cac->config);
> > > > +
> > > > + if ((cac->header.flags & RKISP1_EXT_PARAMS_FL_BLOCK_ENABLE) &&
> > > > + !(params->enabled_blocks & BIT(cac->header.type)))
> > > > + rkisp1_param_set_bits(params, RKISP1_CIF_ISP_CAC_CTRL,
> > > > + RKISP1_CIF_ISP_CAC_CTRL_ENABLE);
> > > > +}
> > > > +
> > > > typedef void (*rkisp1_block_handler)(struct rkisp1_params *params,
> > > > const union rkisp1_ext_params_config *config);
> > > >
> > > > @@ -2185,6 +2247,10 @@ static const struct rkisp1_ext_params_handler {
> > > > .handler = rkisp1_ext_params_wdr,
> > > > .group = RKISP1_EXT_PARAMS_BLOCK_GROUP_OTHERS,
> > > > },
> > > > + [RKISP1_EXT_PARAMS_BLOCK_TYPE_CAC] = {
> > > > + .handler = rkisp1_ext_params_cac,
> > > > + .group = RKISP1_EXT_PARAMS_BLOCK_GROUP_OTHERS,
> > > > + },
> > > > };
> > > >
> > > > #define RKISP1_PARAMS_BLOCK_INFO(block, data) \
> > > > @@ -2215,6 +2281,7 @@ rkisp1_ext_params_block_types_info[] = {
> > > > RKISP1_PARAMS_BLOCK_INFO(COMPAND_EXPAND, compand_curve),
> > > > RKISP1_PARAMS_BLOCK_INFO(COMPAND_COMPRESS, compand_curve),
> > > > RKISP1_PARAMS_BLOCK_INFO(WDR, wdr),
> > > > + RKISP1_PARAMS_BLOCK_INFO(CAC, cac),
> > > > };
> > > >
> > > > static_assert(ARRAY_SIZE(rkisp1_ext_params_handlers) ==
> > > > @@ -2474,6 +2541,8 @@ void rkisp1_params_disable(struct rkisp1_params *params)
> > > > rkisp1_ie_enable(params, false);
> > > > rkisp1_param_clear_bits(params, RKISP1_CIF_ISP_DPF_MODE,
> > > > RKISP1_CIF_ISP_DPF_MODE_EN);
> > > > + rkisp1_param_clear_bits(params, RKISP1_CIF_ISP_CAC_CTRL,
> > > > + RKISP1_CIF_ISP_CAC_CTRL_ENABLE);
> > > > }
> > > >
> > > > static const struct rkisp1_params_ops rkisp1_v10_params_ops = {
> > > > diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-regs.h b/drivers/media/platform/rockchip/rkisp1/rkisp1-regs.h
> > > > index fbeb186cde0d5..8e25537459bbd 100644
> > > > --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-regs.h
> > > > +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-regs.h
> > > > @@ -724,6 +724,23 @@
> > > > #define RKISP1_CIF_ISP_WDR_DMIN_STRENGTH_MASK GENMASK(20, 16)
> > > > #define RKISP1_CIF_ISP_WDR_DMIN_STRENGTH_MAX 16U
> > > >
> > > > +/* CAC */
> > > > +#define RKISP1_CIF_ISP_CAC_CTRL_ENABLE BIT(0)
> > > > +#define RKISP1_CIF_ISP_CAC_CTRL_V_CLIP_MODE GENMASK(2, 1)
> > > > +#define RKISP1_CIF_ISP_CAC_CTRL_H_CLIP_MODE GENMASK(3, 3)

I'd go for BIT(3) as you use BIT(0) for the enable bit.

> > > > +#define RKISP1_CIF_ISP_CAC_COUNT_START_H_MASK GENMASK(12, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_COUNT_START_V_MASK GENMASK(28, 16)
> > > > +#define RKISP1_CIF_ISP_CAC_A_RED_MASK GENMASK(8, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_A_BLUE_MASK GENMASK(24, 16)
> > > > +#define RKISP1_CIF_ISP_CAC_B_RED_MASK GENMASK(8, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_B_BLUE_MASK GENMASK(24, 16)
> > > > +#define RKISP1_CIF_ISP_CAC_C_RED_MASK GENMASK(8, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_C_BLUE_MASK GENMASK(24, 16)
> > >
> > > All these masks for coefficients 0, 1 and 2 are identical. Maybe
> > > #define RKISP1_CIF_ISP_CAC_RED_MASK GENMASK(8, 0)
> > > #define RKISP1_CIF_ISP_CAC_BLUE_MASK GENMASK(24, 16)
> > >
> > > is enough
> >
> > Adjusted.
> >
> > > > +#define RKISP1_CIF_ISP_CAC_X_NORM_NF_MASK GENMASK(4, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_X_NORM_NS_MASK GENMASK(19, 16)
> > > > +#define RKISP1_CIF_ISP_CAC_Y_NORM_NF_MASK GENMASK(4, 0)
> > > > +#define RKISP1_CIF_ISP_CAC_Y_NORM_NS_MASK GENMASK(19, 16)
> >
> > Did the same with these as well.
>
> Ah thanks!
>
> > > > +
> > > > /* =================================================================== */
> > > > /* CIF Registers */
> > > > /* =================================================================== */
> > > > @@ -1196,8 +1213,8 @@
> > > > #define RKISP1_CIF_ISP_CAC_A (RKISP1_CIF_ISP_CAC_BASE + 0x00000008)
> > > > #define RKISP1_CIF_ISP_CAC_B (RKISP1_CIF_ISP_CAC_BASE + 0x0000000c)
> > > > #define RKISP1_CIF_ISP_CAC_C (RKISP1_CIF_ISP_CAC_BASE + 0x00000010)
> > > > -#define RKISP1_CIF_ISP_X_NORM (RKISP1_CIF_ISP_CAC_BASE + 0x00000014)
> > > > -#define RKISP1_CIF_ISP_Y_NORM (RKISP1_CIF_ISP_CAC_BASE + 0x00000018)
> > > > +#define RKISP1_CIF_ISP_CAC_X_NORM (RKISP1_CIF_ISP_CAC_BASE + 0x00000014)
> > > > +#define RKISP1_CIF_ISP_CAC_Y_NORM (RKISP1_CIF_ISP_CAC_BASE + 0x00000018)
> > > >
> > > > #define RKISP1_CIF_ISP_EXP_BASE 0x00002600
> > > > #define RKISP1_CIF_ISP_EXP_CTRL (RKISP1_CIF_ISP_EXP_BASE + 0x00000000)
> > > > diff --git a/include/uapi/linux/rkisp1-config.h b/include/uapi/linux/rkisp1-config.h
> > > > index b2d2a71f7baff..d8acccaddd0e9 100644
> > > > --- a/include/uapi/linux/rkisp1-config.h
> > > > +++ b/include/uapi/linux/rkisp1-config.h
> > > > @@ -967,6 +967,92 @@ struct rkisp1_cif_isp_wdr_config {
> > > > __u8 use_iref;
> > > > };
> > > >
> > > > +/*
> > > > + * enum rkisp1_cif_isp_cac_h_clip_mode - horizontal clipping mode
> > > > + *
> > > > + * @RKISP1_CIF_ISP_CAC_H_CLIP_MODE_4PX: +/- 4 pixels
> > > > + * @RKISP1_CIF_ISP_CAC_H_CLIP_MODE_4_5PX: +/- 4/5 pixels depending on bayer position
> > > > + */
> > > > +enum rkisp1_cif_isp_cac_h_clip_mode {
> > > > + RKISP1_CIF_ISP_CAC_H_CLIP_MODE_4PX = 0,
> > > > + RKISP1_CIF_ISP_CAC_H_CLIP_MODE_4_5PX = 1,
> > > > +};
> > > > +
> > > > +/**
> > > > + * enum rkisp1_cif_isp_cac_v_clip_mode - vertical clipping mode
> > > > + *
> > > > + * @RKISP1_CIF_ISP_CAC_V_CLIP_MODE_2PX: +/- 2 pixels
> > > > + * @RKISP1_CIF_ISP_CAC_V_CLIP_MODE_3PX: +/- 3 pixels
> > > > + * @RKISP1_CIF_ISP_CAC_V_CLIP_MODE_3_4PX: +/- 3/4 pixels depending on bayer position
> > > > + */
> > > > +enum rkisp1_cif_isp_cac_v_clip_mode {
> > > > + RKISP1_CIF_ISP_CAC_V_CLIP_MODE_2PX = 0,
> > > > + RKISP1_CIF_ISP_CAC_V_CLIP_MODE_3PX = 1,
> > > > + RKISP1_CIF_ISP_CAC_V_CLIP_MODE_3_4PX = 2,
> > > > +};
> > > > +
> > > > +/**
> > > > + * struct rkisp1_cif_isp_cac_config - chromatic aberration correction configuration
> > > > + *
> > > > + * The correction is carried out by shifting the red and blue pixels relative
> > > > + * to the green ones, depending on the distance from the optical center:
> > >
> > > Yes, the distance to the center is one parameter, but the shifting
> > > amount depends on other things. I would drop the last part of the
> > > sentence and move the description of the two below fields after the
> > > text
> >
> > That's true, but within a specific image, the only varying quantity
> > is the distance, so I think it is important to emphasize that.
> >
> > And I also quite like this structure of
> > - description of step
> > - parameters of step
> > - description of step
> > ...
> >
> > so I would love to keep it like this, if that's ok?
>
> Ok!

Ack.

> > > > + *
> > > > + * @h_count_start: horizontal coordinate of the optical center (13-bit unsigned integer; [1,8191])
> > > > + * @v_count_start: vertical coordinate of the optical center (13-bit unsigned integer; [1,8191])
> > >
> > > so these could go just before @x_nf
> > >
> > > > + *
> > > > + * For each pixel, the x/y distances from the optical center are calculated and
> > >
> > > I forgot: did we establish that the correction is applied to the
> > > euclidean distance or to x and y separately ?
> >
> > Given that there are two sets of "normalization" parameters, the assumption is that
> > at least the x/y distances are transformed separately. I see two reasonable choices
> > after that: (a) use the two distances separately, (b) use the radial distance. The
> > documentation says (b). However, testing with sensor test patterns suggests that
> > it is not the case (a horizontal/vertical boundary between appropriately colored
> > regions should have a curvature after the transformation with appropriate parameters).
>
> I now recall that you have been able to shift just one plan when using
> the sensor's test pattern

I agree about the normalization, but it sounds really weird that the
hardware would then shift separately in the X and Y directions. Below
you document the radial correction formula, which looks correct to me.

> > > > + * then transformed into the [0,255] range based on the following formula:
> > >
> > > s/transformed/normalized ?
> >
> > To be honest I vastly prefer "transform" / "map" over "normalize" here.
>
> You're right here, the below formula doesn't normalize the
> distance in an interval but just re-scale it
>
> > > > + *
> > > > + * (((d << 4) >> s) * f) >> 5
> > > > + *
> > > > + * where `d` is the distance, `s` and `f` are the normalization parameters:
> > >
> > > Can you use 'ns' and 'nf' to match the below ?
> >
> > Adjusted.
>
> Thanks!
>
> > > > + *
> > > > + * @x_nf: horizontal normalization scale parameter (5-bit unsigned integer; [0,31])
> > > > + * @x_ns: horizontal normalization shift parameter (4-bit unsigned integer; [0,15])
> > > > + *
> > > > + * @y_nf: vertical normalization scale parameter (5-bit unsigned integer; [0,31])
> > > > + * @y_ns: vertical normalization shift parameter (4-bit unsigned integer; [0,15])
> > > > + *
> > > > + * These parameters should be chosen based on the image resolution, the position
> > > > + * of the optical center, and the shape of pixels: so that no normalized distance
> > >
> > > s/pixels:/pixels/
> >
> > Replaced `:` with `,`.
> >
> > > > + * is larger than 255. If the pixels have square shape, the two sets of parameters
> > > > + * should be equal.

I wonder if we could have anisotropic lenses (from the point of view of
chromatic aberrations) with square pixels. We can deal with it later.

> > > > + *
> > > > + * The actual amount of correction is calculated with a third degree polynomial:
> > > > + *
> > > > + * c[0] * r + c[1] * r^2 + c[2] * r^3
> > > > + *
> > > > + * where `c` is the set of coefficients for the given color, and `r` is distance:
> > > > + *
> > > > + * @red: red coefficients (5.4 two's complement; [-16,15.9375])
> > > > + * @blue: blue coefficients (5.4 two's complement; [-16,15.9375])
> > > > + *
> > > > + * Finally, the amount is clipped as requested:
> > > > + *
> > > > + * @h_clip_mode: maximum horizontal shift (from enum rkisp1_cif_isp_cac_h_clip_mode)
> > > > + * @v_clip_mode: maximum vertical shift (from enum rkisp1_cif_isp_cac_v_clip_mode)
> > > > + *
> > > > + * A positive result will shift away from the optical center, while a negative
> > > > + * one will shift towards the optical center. In the latter case, the pixel
> > > > + * values at the edges are duplicated.
> > > > + */
> > > > +struct rkisp1_cif_isp_cac_config {
> > > > + __u8 h_clip_mode;
> > > > + __u8 v_clip_mode;
> > > > +
> > > > + __u16 h_count_start;
> > > > + __u16 v_count_start;
> > > > +
> > > > + __u16 red[3];
> > > > + __u16 blue[3];
> > > > +
> > > > + __u8 x_nf;
> > > > + __u8 x_ns;
> > > > +
> > > > + __u8 y_nf;
> > > > + __u8 y_ns;
> > > > +};
> > > > +
> > > > /*---------- PART2: Measurement Statistics ------------*/
> > > >
> > > > /**
> > > > @@ -1161,6 +1247,7 @@ enum rkisp1_ext_params_block_type {
> > > > RKISP1_EXT_PARAMS_BLOCK_TYPE_COMPAND_EXPAND,
> > > > RKISP1_EXT_PARAMS_BLOCK_TYPE_COMPAND_COMPRESS,
> > > > RKISP1_EXT_PARAMS_BLOCK_TYPE_WDR,
> > > > + RKISP1_EXT_PARAMS_BLOCK_TYPE_CAC,
> > > > };
> > > >
> > > > /* For backward compatibility */
> > > > @@ -1507,6 +1594,22 @@ struct rkisp1_ext_params_wdr_config {
> > > > struct rkisp1_cif_isp_wdr_config config;
> > > > } __attribute__((aligned(8)));
> > > >
> > > > +/**
> > > > + * struct rkisp1_ext_params_cac_config - RkISP1 extensible params CAC config
> > > > + *
> > > > + * RkISP1 extensible parameters CAC block.
> > > > + * Identified by :c:type:`RKISP1_EXT_PARAMS_BLOCK_TYPE_CAC`.
> > > > + *
> > > > + * @header: The RkISP1 extensible parameters header, see
> > > > + * :c:type:`rkisp1_ext_params_block_header`
> > > > + * @config: CAC configuration, see
> > > > + * :c:type:`rkisp1_cif_isp_cac_config`
> > > > + */
> > > > +struct rkisp1_ext_params_cac_config {
> > > > + struct rkisp1_ext_params_block_header header;
> > > > + struct rkisp1_cif_isp_cac_config config;
> > > > +} __attribute__((aligned(8)));
> > > > +
> > > > /*
> > > > * The rkisp1_ext_params_compand_curve_config structure is counted twice as it
> > > > * is used for both the COMPAND_EXPAND and COMPAND_COMPRESS block types.
> > > > @@ -1532,7 +1635,8 @@ struct rkisp1_ext_params_wdr_config {
> > > > sizeof(struct rkisp1_ext_params_compand_bls_config) +\
> > > > sizeof(struct rkisp1_ext_params_compand_curve_config) +\
> > > > sizeof(struct rkisp1_ext_params_compand_curve_config) +\
> > > > - sizeof(struct rkisp1_ext_params_wdr_config))
> > > > + sizeof(struct rkisp1_ext_params_wdr_config) +\
> > > > + sizeof(struct rkisp1_ext_params_cac_config))
> > >
> > > All minors, please add
> > > Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>

and

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

> > > >
> > > > /**
> > > > * enum rksip1_ext_param_buffer_version - RkISP1 extensible parameters version

--
Regards,

Laurent Pinchart