media: i2c: adv748x: store number of CSI-2 lanes described in device tree

The adv748x CSI-2 transmitters TXA and TXB can use different number of
lanes to transmit data. In order to be able to configure the device
correctly this information need to be parsed from device tree and stored
in each TX private data structure.

TXA supports 1, 2 and 4 lanes while TXB supports 1 lane.
Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

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

@@ -23,6 +23,7 @@
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-device.h>
 #include <media/v4l2-dv-timings.h>
+#include <media/v4l2-fwnode.h>
 #include <media/v4l2-ioctl.h>
 
 #include "adv748x.h"
@@ -521,12 +522,56 @@ void adv748x_subdev_init(struct v4l2_subdev *sd, struct adv748x_state *state,
 	sd->entity.ops = &adv748x_media_ops;
 }
 
+static int adv748x_parse_csi2_lanes(struct adv748x_state *state,
+				    unsigned int port,
+				    struct device_node *ep)
+{
+	struct v4l2_fwnode_endpoint vep;
+	unsigned int num_lanes;
+	int ret;
+
+	if (port != ADV748X_PORT_TXA && port != ADV748X_PORT_TXB)
+		return 0;
+
+	vep.bus_type = V4L2_MBUS_CSI2_DPHY;
+	ret = v4l2_fwnode_endpoint_parse(of_fwnode_handle(ep), &vep);
+	if (ret)
+		return ret;
+
+	num_lanes = vep.bus.mipi_csi2.num_data_lanes;
+
+	if (vep.base.port == ADV748X_PORT_TXA) {
+		if (num_lanes != 1 && num_lanes != 2 && num_lanes != 4) {
+			adv_err(state, "TXA: Invalid number (%u) of lanes\n",
+				num_lanes);
+			return -EINVAL;
+		}
+
+		state->txa.num_lanes = num_lanes;
+		adv_dbg(state, "TXA: using %u lanes\n", state->txa.num_lanes);
+	}
+
+	if (vep.base.port == ADV748X_PORT_TXB) {
+		if (num_lanes != 1) {
+			adv_err(state, "TXB: Invalid number (%u) of lanes\n",
+				num_lanes);
+			return -EINVAL;
+		}
+
+		state->txb.num_lanes = num_lanes;
+		adv_dbg(state, "TXB: using %u lanes\n", state->txb.num_lanes);
+	}
+
+	return 0;
+}
+
 static int adv748x_parse_dt(struct adv748x_state *state)
 {
 	struct device_node *ep_np = NULL;
 	struct of_endpoint ep;
 	bool out_found = false;
 	bool in_found = false;
+	int ret;
 
 	for_each_endpoint_of_node(state->dev->of_node, ep_np) {
 		of_graph_parse_endpoint(ep_np, &ep);
@@ -557,6 +602,11 @@ static int adv748x_parse_dt(struct adv748x_state *state)
 			in_found = true;
 		else
 			out_found = true;
+
+		/* Store number of CSI-2 lanes used for TXA and TXB. */
+		ret = adv748x_parse_csi2_lanes(state, ep.port, ep_np);
+		if (ret)
+			return ret;
 	}
 
 	return in_found && out_found ? 0 : -ENODEV;

drivers/media/i2c/adv748x/adv748x.h

@@ -79,6 +79,7 @@ struct adv748x_csi2 {
 	struct v4l2_mbus_framefmt format;
 	unsigned int page;
 	unsigned int port;
+	unsigned int num_lanes;
 
 	struct media_pad pads[ADV748X_CSI2_NR_PADS];
 	struct v4l2_ctrl_handler ctrl_hdl;