media: i2c: Provide ov7251_check_hwcfg()

Move the endpoint checking from .probe() to a dedicated function,
and additionally check that the firmware provided link frequencies
are a match for those supported by the driver. Finally, return
-EPROBE_DEFER if the endpoint is not available, as it could be built
by the ipu3-cio2 driver if that probes later.

Signed-off-by: Daniel Scally <djrscally@gmail.com>

diff --git a/drivers/media/i2c/ov7251.c b/drivers/media/i2c/ov7251.c
index aaaeca1..e4faf28 100644 (file)
--- a/drivers/media/i2c/ov7251.c
+++ b/drivers/media/i2c/ov7251.c
@@ -1255,11 +1255,74 @@ static const struct v4l2_subdev_ops ov7251_subdev_ops = {
        .pad = &ov7251_subdev_pad_ops,
 };
 
+static int ov7251_check_hwcfg(struct ov7251 *ov7251)
+{
+       struct fwnode_handle *fwnode = dev_fwnode(ov7251->dev);
+       struct v4l2_fwnode_endpoint bus_cfg = {
+               .bus_type = V4L2_MBUS_CSI2_DPHY,
+       };
+       struct fwnode_handle *endpoint;
+       bool freq_found;
+       int i, j;
+       int ret;
+
+       endpoint = fwnode_graph_get_next_endpoint(fwnode, NULL);
+       if (!endpoint)
+               return -EPROBE_DEFER; /* could be provided by cio2-bridge */
+
+       ret = v4l2_fwnode_endpoint_alloc_parse(endpoint, &bus_cfg);
+       fwnode_handle_put(endpoint);
+       if (ret)
+               return dev_err_probe(ov7251->dev, ret,
+                                    "parsing endpoint node failed\n");
+
+       if (bus_cfg.bus_type != V4L2_MBUS_CSI2_DPHY) {
+               ret = -EINVAL;
+               dev_err(ov7251->dev, "invalid bus type (%u), must be (%u)\n",
+                       bus_cfg.bus_type, V4L2_MBUS_CSI2_DPHY);
+               goto out_free_bus_cfg;
+       }
+
+       if (bus_cfg.bus.mipi_csi2.num_data_lanes != 1) {
+               dev_err(ov7251->dev, "only a 1-lane CSI2 config is supported");
+               ret = -EINVAL;
+               goto out_free_bus_cfg;
+       }
+
+       if (!bus_cfg.nr_of_link_frequencies) {
+               dev_err(ov7251->dev, "no link frequencies defined\n");
+               ret = -EINVAL;
+               goto out_free_bus_cfg;
+       }
+
+       freq_found = false;
+       for (i = 0; i < bus_cfg.nr_of_link_frequencies; i++) {
+               if (freq_found)
+                       break;
+
+               for (j = 0; j < ARRAY_SIZE(link_freq); j++)
+                       if (bus_cfg.link_frequencies[i] == link_freq[j]) {
+                               freq_found = true;
+                               break;
+                       }
+       }
+
+       if (i == bus_cfg.nr_of_link_frequencies) {
+               dev_err(ov7251->dev, "no supported link freq found\n");
+               ret = -EINVAL;
+               goto out_free_bus_cfg;
+       }
+
+out_free_bus_cfg:
+       v4l2_fwnode_endpoint_free(&bus_cfg);
+
+       return ret;
+}
+
 static int ov7251_probe(struct i2c_client *client)
 {
        struct v4l2_fwnode_device_properties props;
        struct device *dev = &client->dev;
-       struct fwnode_handle *endpoint;
        struct ov7251 *ov7251;
        u8 chip_id_high, chip_id_low, chip_rev;
        int ret;
@@ -1271,24 +1334,9 @@ static int ov7251_probe(struct i2c_client *client)
        ov7251->i2c_client = client;
        ov7251->dev = dev;
 
-       endpoint = fwnode_graph_get_next_endpoint(dev_fwnode(dev), NULL);
-       if (!endpoint) {
-               dev_err(dev, "endpoint node not found\n");
-               return -EINVAL;
-       }
-
-       ret = v4l2_fwnode_endpoint_parse(endpoint, &ov7251->ep);
-       fwnode_handle_put(endpoint);
-       if (ret < 0) {
-               dev_err(dev, "parsing endpoint node failed\n");
+       ret = ov7251_check_hwcfg(ov7251);
+       if (ret)
                return ret;
-       }
-
-       if (ov7251->ep.bus_type != V4L2_MBUS_CSI2_DPHY) {
-               dev_err(dev, "invalid bus type (%u), must be CSI2 (%u)\n",
-                       ov7251->ep.bus_type, V4L2_MBUS_CSI2_DPHY);
-               return -EINVAL;
-       }
 
        /* get system clock (xclk) */
        ov7251->xclk = devm_clk_get(dev, "xclk");