media: adv748x: Implement .get_frame_desc()

Implement the get_frame_desc subdev pad operation.

Implement the get_frame_desc pad operation to allow retrieving the
stream configuration of the adv748x csi2 subdevice.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>

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

@@ -14,6 +14,50 @@
 
 #include "adv748x.h"
 
+/* Describes a format bit depth and CSI-2 defined Data Type. */
+struct adv748x_csi2_format_info {
+	u8 dt;
+	u8 bpp;
+};
+
+static int adv748x_csi2_get_format_info(struct adv748x_csi2 *tx,
+					u32 mbus_code,
+					struct adv748x_csi2_format_info *fmt)
+{
+	switch (mbus_code) {
+	case MEDIA_BUS_FMT_YUYV8_1X16:
+	case MEDIA_BUS_FMT_YUYV8_2X8:
+		fmt->dt = 0x1e;
+		fmt->bpp = 16;
+		break;
+	case MEDIA_BUS_FMT_YUYV10_2X10:
+	case MEDIA_BUS_FMT_YUYV10_1X20:
+		fmt->dt = 0x1f;
+		fmt->bpp = 20;
+		break;
+	case MEDIA_BUS_FMT_RGB565_1X16:
+	case MEDIA_BUS_FMT_RGB565_2X8_LE:
+	case MEDIA_BUS_FMT_RGB565_2X8_BE:
+		fmt->dt = 0x22;
+		fmt->bpp = 16;
+		break;
+	case MEDIA_BUS_FMT_RGB666_1X18:
+		fmt->dt = 0x23;
+		fmt->bpp = 18;
+		break;
+	case MEDIA_BUS_FMT_RGB888_1X24:
+		fmt->dt = 0x24;
+		fmt->bpp = 24;
+		break;
+	default:
+		dev_err(tx->state->dev,
+			"Unsupported media bus code: %u\n", mbus_code);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 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);
@@ -248,11 +292,60 @@ static int adv748x_csi2_get_mbus_config(struct v4l2_subdev *sd, unsigned int pad
 	return 0;
 }
 
+static int adv748x_csi2_get_frame_desc(struct v4l2_subdev *sd, unsigned int pad,
+				       struct v4l2_mbus_frame_desc *fd)
+{
+	struct adv748x_csi2 *tx = adv748x_sd_to_csi2(sd);
+	struct adv748x_csi2_format_info info = {};
+	struct v4l2_mbus_frame_desc_entry *entry;
+	struct v4l2_subdev_route *route;
+	struct v4l2_subdev_state *state;
+	struct v4l2_mbus_framefmt *fmt;
+	int ret;
+
+	if (pad != ADV748X_CSI2_SOURCE)
+		return -EINVAL;
+
+	state = v4l2_subdev_lock_active_state(sd);
+
+	/* A single route is available. */
+	route = &state->routing.routes[0];
+	fmt = v4l2_state_get_stream_format(state, pad, route->source_stream);
+	if (!fmt) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	ret = adv748x_csi2_get_format_info(tx, fmt->code, &info);
+	if (ret)
+		goto out;
+
+	memset(fd, 0, sizeof(*fd));
+
+	/* A single stream is available. */
+	fd->num_entries = 1;
+	fd->type = V4L2_MBUS_FRAME_DESC_TYPE_CSI2;
+
+	entry = &fd->entry[0];
+	entry->stream = 0;
+	entry->flags = V4L2_MBUS_FRAME_DESC_FL_LEN_MAX;
+	entry->length = fmt->width * fmt->height * info.bpp / 8;
+	entry->pixelcode = fmt->code;
+	entry->bus.csi2.vc = route->source_stream;
+	entry->bus.csi2.dt = info.dt;
+
+out:
+	v4l2_subdev_unlock_state(state);
+
+	return ret;
+}
+
 static const struct v4l2_subdev_pad_ops adv748x_csi2_pad_ops = {
 	.init_cfg = adv748x_csi2_init_cfg,
 	.get_fmt = v4l2_subdev_get_fmt,
 	.set_fmt = adv748x_csi2_set_format,
 	.get_mbus_config = adv748x_csi2_get_mbus_config,
+	.get_frame_desc = adv748x_csi2_get_frame_desc,
 };
 
 /* -----------------------------------------------------------------------------