media: rkisp1: Add support for CAC

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>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patch.msgid.link/20260511150957.581049-1-barnabas.pocze@ideasonboard.com
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil+cisco@kernel.org>

1 files changed, 106 insertions, 1 deletions

diff --git a/include/uapi/linux/rkisp1-config.h b/include/uapi/linux/rkisp1-config.h
index 7638b2220600..d97384abc157 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:
+ *
+ * @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])
+ *
+ * For each pixel, the x/y distances from the optical center are calculated and
+ * then transformed into the [0,255] range based on the following formula:
+ *
+ *   (((d << 4) >> ns) * nf) >> 5
+ *
+ * where `d` is the distance, `ns` and `nf` are the normalization parameters:
+ *
+ * @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
+ * is larger than 255. If the pixels have square shape, the two sets of parameters
+ * should be equal.
+ *
+ * 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 ------------*/
 
 /**
@@ -1138,6 +1224,7 @@ struct rkisp1_stat_buffer {
  * @RKISP1_EXT_PARAMS_BLOCK_TYPE_COMPAND_EXPAND: Companding expand curve
  * @RKISP1_EXT_PARAMS_BLOCK_TYPE_COMPAND_COMPRESS: Companding compress curve
  * @RKISP1_EXT_PARAMS_BLOCK_TYPE_WDR: Wide dynamic range
+ * @RKISP1_EXT_PARAMS_BLOCK_TYPE_CAC: Chromatic aberration correction
  */
 enum rkisp1_ext_params_block_type {
 	RKISP1_EXT_PARAMS_BLOCK_TYPE_BLS,
@@ -1161,6 +1248,7 @@ 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 +1595,22 @@ 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 +1636,8 @@ 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))
 
 /**
  * enum rkisp1_ext_param_buffer_version - RkISP1 extensible parameters version