Re: [v8 04/14] media: rppx1: wbmeas: Add support for white balance measurement

[Jacopo Mondi <jacopo.mondi@ideasonboard.com>]

Hi Antoine

On Wed, May 06, 2026 at 03:58:30PM +0200, Antoine Bouyer wrote:
> On 5/4/26 3:05 AM, Niklas Söderlund wrote:
> > Extend the RPPX1 driver to allow setting the white balance measurement
> > configuration and consuming the resulting statistics. It uses the RPPX1
> > framework for parameters and its writer abstraction to allow the user to
> > control how, and when, configuration is applied to the RPPX1.
> >
> > Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> > Co-developed-by: Jai Luthra <jai.luthra+renesas@ideasonboard.com>
> > Signed-off-by: Jai Luthra <jai.luthra+renesas@ideasonboard.com>
> > ---
> >   .../platform/dreamchip/rppx1/rpp_module.h     |   2 +
> >   .../platform/dreamchip/rppx1/rpp_params.c     |   4 +
> >   .../platform/dreamchip/rppx1/rpp_stats.c      |  18 +++
> >   .../platform/dreamchip/rppx1/rppx1_wbmeas.c   | 103 ++++++++++++++++++
> >   .../uapi/linux/media/dreamchip/rppx1-config.h | 101 ++++++++++++++++-
> >   5 files changed, 226 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/media/platform/dreamchip/rppx1/rpp_module.h b/drivers/media/platform/dreamchip/rppx1/rpp_module.h
> > index 742904973e35..85fb23174e57 100644
> > --- a/drivers/media/platform/dreamchip/rppx1/rpp_module.h
> > +++ b/drivers/media/platform/dreamchip/rppx1/rpp_module.h
> > @@ -85,10 +85,12 @@ void rpp_module_clrset(struct rpp_module *mod, u32 offset, u32 mask, u32 value);
> >
> >   union rppx1_params_block {
> >          struct v4l2_isp_params_block_header header;
> > +       struct rppx1_wbmeas_params wbmeas;
> >   };
> >
> >   union rppx1_stats_block {
> >          struct v4l2_isp_params_block_header header;
> > +       struct rppx1_wbmeas_stats wbmeas;
> >   };
> >
> >   struct rpp_module_ops {
> > diff --git a/drivers/media/platform/dreamchip/rppx1/rpp_params.c b/drivers/media/platform/dreamchip/rppx1/rpp_params.c
> > index a5feb18f3bd5..1262350d2190 100644
> > --- a/drivers/media/platform/dreamchip/rppx1/rpp_params.c
> > +++ b/drivers/media/platform/dreamchip/rppx1/rpp_params.c
> > @@ -16,6 +16,7 @@
> >
> >   static const struct v4l2_isp_block_type_info
> >   rppx1_ext_params_blocks_info[] = {
> > +       RPPX1_PARAMS_BLOCK_INFO(WBMEAS_POST, wbmeas),
> >   };
> >
> >   int rppx1_params(struct rppx1 *rpp, struct vb2_buffer *vb, size_t max_size,
> > @@ -50,6 +51,9 @@ int rppx1_params(struct rppx1 *rpp, struct vb2_buffer *vb, size_t max_size,
> >                  block_offset += block->header.size;
> >
> >                  switch (block->header.type) {
> > +               case RPPX1_PARAMS_BLOCK_TYPE_WBMEAS_POST:
> > +                       module = &rpp->post.wbmeas;
> > +                       break;
> >                  default:
> >                          module = NULL;
> >                          break;
> > diff --git a/drivers/media/platform/dreamchip/rppx1/rpp_stats.c b/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
> > index 8f43e56ba361..4c38e657e5f0 100644
> > --- a/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
> > +++ b/drivers/media/platform/dreamchip/rppx1/rpp_stats.c
> > @@ -14,6 +14,11 @@
> >                  .size = sizeof(struct rppx1_ ## block ## _stats), \
> >          }
> >
> > +static const struct v4l2_isp_block_type_info
> > +rppx1_stats_blocks_info[] = {
> > +       RPPX1_STATS_BLOCK_INFO(WBMEAS_POST, wbmeas),
> > +};
> > +
> >   #define rppx1_init_stats_block(rpp, buf, type)                         \
> >          ((union rppx1_stats_block *)                                    \
> >          v4l2_isp_stats_init_block((rpp)->dev, (buf),                    \
> > @@ -23,5 +28,18 @@
> >
> >   void rppx1_stats_fill_isr(struct rppx1 *rpp, u32 isc, void *buf)
> >   {
> > +       struct v4l2_isp_buffer *stats = buf;
> > +       union rppx1_stats_block *block;
> > +
> > +       v4l2_isp_stats_init_buffer(stats);
> > +
> > +       if (isc & RPPX1_IRQ_ID_POST_AWB_MEAS) {
> > +               block = rppx1_init_stats_block(rpp, stats,
> > +                                              RPPX1_STATS_BLOCK_TYPE_WBMEAS_POST);
> > +               if (!block)
>
> Hi Niklas
>
> I assume you need to use IS_ERR() here, instead of null pointer check, since
> v4l2_isp_stats_init_block() does return an error from this series [1].
>
> Same applies to other stats blocks.

Duh, thanks for catching! This is defintely my bad and not Niklas' has
I didn't update these callers when I changed the return value of
v4l2_isp_stats_init_block() ...

>
> BR
> Antoine
>
> [1] https://lore.kernel.org/linux-media/20260505-extensible-stats-v1-6-e16f326b8dad@ideasonboard.com/
>
> > +                       return;
> > +
> > +               rpp_module_call(&rpp->post.wbmeas, fill_stats, block);
> > +       }
> >   }
> >   EXPORT_SYMBOL_GPL(rppx1_stats_fill_isr);
> > diff --git a/drivers/media/platform/dreamchip/rppx1/rppx1_wbmeas.c b/drivers/media/platform/dreamchip/rppx1/rppx1_wbmeas.c
> > index 3d197d914d07..53263bc96280 100644
> > --- a/drivers/media/platform/dreamchip/rppx1/rppx1_wbmeas.c
> > +++ b/drivers/media/platform/dreamchip/rppx1/rppx1_wbmeas.c
> > @@ -56,6 +56,109 @@ static int rppx1_wbmeas_probe(struct rpp_module *mod)
> >          return 0;
> >   }
> >
> > +static int
> > +rppx1_wbmeas_fill_params(struct rpp_module *mod,
> > +                        const union rppx1_params_block *block,
> > +                        rppx1_reg_write write, void *priv)
> > +{
> > +       const struct rppx1_wbmeas_params *cfg = &block->wbmeas;
> > +       u32 awb_meas_props;
> > +
> > +       /* If the modules is disabled, simply bypass it. */
> > +       if (cfg->header.flags & V4L2_ISP_PARAMS_FL_BLOCK_DISABLE) {
> > +               write(priv, mod->base + AWB_MEAS_PROP_REG, 0);
> > +               return 0;
> > +       }
> > +
> > +       /* Program measurement window. */
> > +       write(priv, mod->base + AWB_MEAS_H_OFFS_REG, cfg->wnd.h_offs);
> > +       write(priv, mod->base + AWB_MEAS_V_OFFS_REG, cfg->wnd.v_offs);
> > +       write(priv, mod->base + AWB_MEAS_H_SIZE_REG, cfg->wnd.h_size);
> > +       write(priv, mod->base + AWB_MEAS_V_SIZE_REG, cfg->wnd.v_size);
> > +
> > +       /* Set number of frames to sample. */
> > +       write(priv, mod->base + AWB_MEAS_FRAMES_REG, cfg->frames);
> > +
> > +       if (cfg->mode == RPPX1_WBMEAS_MODE_YCBCR) {
> > +               write(priv, mod->base + AWB_MEAS_REF_CB_MAX_B_REG,
> > +                     cfg->ref_cb_max_b);
> > +               write(priv, mod->base + AWB_MEAS_REF_CR_MAX_R_REG,
> > +                     cfg->ref_cr_max_r);
> > +               write(priv, mod->base + AWB_MEAS_MAX_Y_REG, cfg->max_y);
> > +               write(priv, mod->base + AWB_MEAS_MIN_Y_MAX_G_REG,
> > +                     cfg->min_y_max_g);
> > +               write(priv, mod->base + AWB_MEAS_MAX_CSUM_REG, cfg->max_csum);
> > +               write(priv, mod->base + AWB_MEAS_MIN_C_REG, cfg->min_c);
> > +
> > +               /*
> > +                * Program the color conversion matrix coefficients and the
> > +                * per-color channel offsets.
> > +                */
> > +               for (unsigned int i = 0; i < 3; i++) {
> > +                       for (unsigned int j = 0; j < 3; j++) {
> > +                               unsigned int index = i * 3 + j;
> > +
> > +                               write(priv,
> > +                                     mod->base + AWB_MEAS_CCOR_COEFF_REG(index),
> > +                                     cfg->ccor_coeff[i][j]);
> > +                       }
> > +               }
> > +
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_R_REG,
> > +                     cfg->ccor_offs[0]);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_G_REG,
> > +                     cfg->ccor_offs[1]);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_B_REG,
> > +                     cfg->ccor_offs[2]);
> > +
> > +               awb_meas_props = cfg->ymax_cmp ? AWB_MEAS_PROP_YMAX : 0;
> > +       } else {
> > +               write(priv, mod->base + AWB_MEAS_REF_CB_MAX_B_REG,
> > +                     cfg->ref_cb_max_b);
> > +               write(priv, mod->base + AWB_MEAS_REF_CR_MAX_R_REG,
> > +                     cfg->ref_cr_max_r);
> > +               write(priv, mod->base + AWB_MEAS_MIN_Y_MAX_G_REG,
> > +                     cfg->min_y_max_g);
> > +
> > +               /* Bypass color conversion matrix and color offsets. */
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(0), 0x1000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(1), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(2), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(3), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(4), 0x1000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(5), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(6), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(7), 0x0000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_COEFF_REG(8), 0x1000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_R_REG, 0x00000000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_G_REG, 0x00000000);
> > +               write(priv, mod->base + AWB_MEAS_CCOR_OFFSET_B_REG, 0x00000000);
> > +
> > +               awb_meas_props = AWB_MEAS_PROP_MEAS_MODE_RGB;
> > +       }
> > +
> > +       write(priv, mod->base + AWB_MEAS_PROP_REG,
> > +             awb_meas_props | AWB_MEAS_PROP_AWB_MODE_ON);
> > +
> > +       return 0;
> > +}
> > +
> > +static int rppx1_wbmeas_fill_stats(struct rpp_module *mod,
> > +                                  union rppx1_stats_block *block)
> > +{
> > +       struct rppx1_wbmeas_stats *stats = &block->wbmeas;
> > +
> > +       /* Return measurements at native hardware precision. */
> > +       stats->cnt = rpp_module_read(mod, AWB_MEAS_WHITE_CNT_REG);
> > +       stats->mean_y_or_g = rpp_module_read(mod, AWB_MEAS_MEAN_Y_G_REG);
> > +       stats->mean_cb_or_b = rpp_module_read(mod, AWB_MEAS_MEAN_CB_B_REG);
> > +       stats->mean_cr_or_r = rpp_module_read(mod, AWB_MEAS_MEAN_CR_R_REG);
> > +
> > +       return 0;
> > +}
> > +
> >   const struct rpp_module_ops rppx1_wbmeas_ops = {
> >          .probe = rppx1_wbmeas_probe,
> > +       .fill_params = rppx1_wbmeas_fill_params,
> > +       .fill_stats = rppx1_wbmeas_fill_stats
> >   };
> > diff --git a/include/uapi/linux/media/dreamchip/rppx1-config.h b/include/uapi/linux/media/dreamchip/rppx1-config.h
> > index 26627be6f483..1d76a85164c8 100644
> > --- a/include/uapi/linux/media/dreamchip/rppx1-config.h
> > +++ b/include/uapi/linux/media/dreamchip/rppx1-config.h
> > @@ -40,13 +40,81 @@ struct rppx1_window {
> >    * wider-than-8-bit results.
> >    */
> >
> > +/**
> > + * enum rppx1_params_block_type - RPP-X1 extensible params block types
> > + *
> > + * NOTE: Only append to the enumeration as the numbers are uAPI.
> > + *
> > + * @RPPX1_PARAMS_BLOCK_TYPE_WBMEAS_POST: AWB Measurement Configuration
> > + */
> > +enum rppx1_params_block_type {
> > +       RPPX1_PARAMS_BLOCK_TYPE_WBMEAS_POST,
> > +};
> > +
> > +/**
> > + * enum rppx1_wbmeas_mode - AWB measurement mode
> > + *
> > + * @RPPX1_WBMEAS_MODE_YCBCR: YCbCr measurement mode
> > + * @RPPX1_WBMEAS_MODE_RGB: RGB measurement mode
> > + */
> > +enum rppx1_wbmeas_mode {
> > +       RPPX1_WBMEAS_MODE_YCBCR,
> > +       RPPX1_WBMEAS_MODE_RGB,
> > +};
> > +
> > +/**
> > + * struct rppx1_wbmeas_params - AWB measurement configuration
> > + *
> > + * The Auto-White Balance measurement module is available on the MAIN_POST pipe.
> > + * It supports two measurement modes, selected by the @mode field. The
> > + * measurement window is programmed through the @wnd field.
> > + *
> > + * To support measurement in YCbCr mode a color conversion matrix with
> > + * programmable offset is available in the @ccor_coeff and @ccor_offs fields.
> > + * The color conversion matrix coefficients are represented as 16 bits signed
> > + * Q4.12 numbers ranging from -8 to +7.99. The per-color channel offsets are
> > + * represented as 25 bits 2's complement integer numbers ranging from -16777216
> > + * to +16777215.
> > + *
> > + * @header: block header (type = RPPX1_PARAMS_BLOCK_TYPE_WBMEAS_POST)
> > + * @mode: measurement mode (from enum rppx1_wbmeas_mode)
> > + * @ymax_cmp: enable Y_MAX compare using @max_y
> > + * @wnd: measurement window
> > + * @frames: number of frames for mean value calculation (0 = 1 frame)
> > + * @ref_cr_max_r: reference Cr or max red value in RGB mode, 24 bits
> > + * @ref_cb_max_b: reference Cb or max blue value in RGB mode, 24 bits
> > + * @min_y_max_g: luminance minimum value or max green value in RGB mode, 24 bits
> > + * @max_y: luminance maximum value, only valid if @mode is set to YCbCr and
> > + *        @ymax_cmp is set to enabled, 24 bits
> > + * @max_csum: chrominance sum maximum value, 24 bits
> > + * @min_c: chrominance minimum value, 24 bits
> > + * @ccor_coeff: coefficients for color conversion matrix, signed 16 bits Q4.6
> > + * @ccor_offs: R-G-B color conversion coefficients, signed 25 bits 2's complement
> > + */
> > +struct rppx1_wbmeas_params {
> > +       struct v4l2_isp_params_block_header header;
> > +       __u8 mode;
> > +       __u8 ymax_cmp;
> > +       struct rppx1_window wnd;
> > +       __u8 frames;
> > +       __u32 ref_cr_max_r;
> > +       __u32 ref_cb_max_b;
> > +       __u32 min_y_max_g;
> > +       __u32 max_y;
> > +       __u32 max_csum;
> > +       __u32 min_c;
> > +       __u16 ccor_coeff[3][3];
> > +       __u32 ccor_offs[3];
> > +};
> > +
> >   /**
> >    * RPPX1_PARAMS_MAX_SIZE - Maximum size of all RPP-X1 parameter blocks
> >    *
> >    * Some types are reported twice as the same block might be instantiated in
> >    * multiple pipes.
> >    */
> > -#define RPPX1_PARAMS_MAX_SIZE 0
> > +#define RPPX1_PARAMS_MAX_SIZE                                          \
> > +       (sizeof(struct rppx1_wbmeas_params))
> >
> >   /* ---------------------------------------------------------------------------
> >    * Statistics Structures
> > @@ -55,12 +123,41 @@ struct rppx1_window {
> >    * wider-than-8-bit results.
> >    */
> >
> > +/**
> > + * enum rppx1_stats_block_type - RPP-X1 extensible stats block types
> > + *
> > + * NOTE: Only append to the enumeration as the numbers are uAPI.
> > + *
> > + * @RPPX1_STATS_BLOCK_TYPE_WBMEAS_POST: post-fusion white-balance measurement
> > + */
> > +enum rppx1_stats_block_type {
> > +       RPPX1_STATS_BLOCK_TYPE_WBMEAS_POST,
> > +};
> > +
> > +/**
> > + * struct rppx1_wbmeas_stats - AWB statistics
> > + *
> > + * @header: block header (type = RPPX1_STATS_BLOCK_TYPE_WBMEAS)
> > + * @cnt: Number of pixels matched
> > + * @mean_y_or_g: mean Y (or G in RGB mode) value, 24-bit
> > + * @mean_cb_or_b: mean Cb (or B in RGB mode) value, 24-bit
> > + * @mean_cr_or_r: mean Cr (or R in RGB mode) value, 24-bit
> > + */
> > +struct rppx1_wbmeas_stats {
> > +       struct v4l2_isp_block_header header;
> > +       __u32 cnt;
> > +       __u32 mean_y_or_g;
> > +       __u32 mean_cb_or_b;
> > +       __u32 mean_cr_or_r;
> > +};
> > +
> >   /**
> >    * RPPX1_STATS_MAX_SIZE - Maximum size of all RPP-X1 statistics
> >    *
> >    * Some types are reported twice as the same block might be instantiated in
> >    * multiple pipes.
> >    */
> > -#define RPPX1_STATS_MAX_SIZE 0
> > +#define RPPX1_STATS_MAX_SIZE                                           \
> > +       (sizeof(struct rppx1_wbmeas_stats))
> >
> >   #endif /* __UAPI_RPP_X1_CONFIG_H */
> > --
> > 2.54.0
> >
> >
>