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

Antoine Bouyer
2026-05-06T13:58:22Z

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.

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
>
>