media: adv748x-csi2: Implement enum_mbus_codes

Define a list of supported mbus codes for the TXA and TXB CSI-2
transmitters and implement the enum_mbus_code operation.

The TXB transmitter only support YUV422 while the TXA one supports
multiple formats as reported by the chip's manual in section 9.7.
but the HDMI and AFE subdevices only provide RGB888 and YUV422, so only
list those ones here.
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Link: https://lore.kernel.org/r/20240617161135.130719-6-jacopo.mondi@ideasonboard.comSigned-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/media/i2c/adv748x/adv748x-csi2.c

@@ -14,6 +14,15 @@
 
 #include "adv748x.h"
 
+static const unsigned int adv748x_csi2_txa_fmts[] = {
+	MEDIA_BUS_FMT_UYVY8_1X16,
+	MEDIA_BUS_FMT_RGB888_1X24,
+};
+
+static const unsigned int adv748x_csi2_txb_fmts[] = {
+	MEDIA_BUS_FMT_UYVY8_1X16,
+};
+
 int adv748x_csi2_set_virtual_channel(struct adv748x_csi2 *tx, unsigned int vc)
 {
 	return tx_write(tx, ADV748X_CSI_VC_REF, vc << ADV748X_CSI_VC_REF_SHIFT);
@@ -139,6 +148,41 @@ static const struct v4l2_subdev_video_ops adv748x_csi2_video_ops = {
  * But we must support setting the pad formats for format propagation.
  */
 
+static int adv748x_csi2_enum_mbus_code(struct v4l2_subdev *sd,
+				       struct v4l2_subdev_state *sd_state,
+				       struct v4l2_subdev_mbus_code_enum *code)
+{
+	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
+	const unsigned int *codes = is_txa(tx) ?
+				    adv748x_csi2_txa_fmts :
+				    adv748x_csi2_txb_fmts;
+	size_t num_fmts = is_txa(tx) ? ARRAY_SIZE(adv748x_csi2_txa_fmts)
+				     : ARRAY_SIZE(adv748x_csi2_txb_fmts);
+
+	/*
+	 * The format available on the source pad is the one applied on the sink
+	 * pad.
+	 */
+	if (code->pad == ADV748X_CSI2_SOURCE) {
+		struct v4l2_mbus_framefmt *fmt;
+
+		if (code->index)
+			return -EINVAL;
+
+		fmt = v4l2_subdev_state_get_format(sd_state, ADV748X_CSI2_SINK);
+		code->code = fmt->code;
+
+		return 0;
+	}
+
+	if (code->index >= num_fmts)
+		return -EINVAL;
+
+	code->code = codes[code->index];
+
+	return 0;
+}
+
 static struct v4l2_mbus_framefmt *
 adv748x_csi2_get_pad_format(struct v4l2_subdev *sd,
 			    struct v4l2_subdev_state *sd_state,
@@ -228,6 +272,7 @@ static int adv748x_csi2_get_mbus_config(struct v4l2_subdev *sd, unsigned int pad
 }
 
 static const struct v4l2_subdev_pad_ops adv748x_csi2_pad_ops = {
+	.enum_mbus_code = adv748x_csi2_enum_mbus_code,
 	.get_fmt = adv748x_csi2_get_format,
 	.set_fmt = adv748x_csi2_set_format,
 	.get_mbus_config = adv748x_csi2_get_mbus_config,