Re: [PATCH v4 7/9] drm-bridge: it66121: Use fwnode API to acquire device properties

[Sui Jingfeng]

Hi,

On 2024/4/23 04:06, Dmitry Baryshkov wrote:
+
  static int it66121_probe(struct i2c_client *client)
  {
        u32 revision_id, vendor_ids[2] = { 0 }, device_ids[2] = { 0 };
-       struct device_node *ep;
        int ret;
        struct it66121_ctx *ctx;
        struct device *dev = &client->dev;
+       struct fwnode_handle *fwnode = dev_fwnode(dev);
  
  	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                dev_err(dev, "I2C check functionality failed.\n");
@@ -1520,29 +1542,20 @@ static int it66121_probe(struct i2c_client *client)
        if (!ctx)
                return -ENOMEM;
  
-	ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
-       if (!ep)
-               return -EINVAL;
-
        ctx->dev = dev;
        ctx->client = client;
        ctx->info = i2c_get_match_data(client);
  
-	of_property_read_u32(ep, "bus-width", &ctx->bus_width);
-       of_node_put(ep);
-
-       if (ctx->bus_width != 12 && ctx->bus_width != 24)
-               return -EINVAL;
-
-       ep = of_graph_get_remote_node(dev->of_node, 1, -1);
-       if (!ep) {
-               dev_err(ctx->dev, "The endpoint is unconnected\n");
-               return -EINVAL;
-       }
+       ret = it66121_read_bus_width(fwnode, &ctx->bus_width);
+       if (ret)
+               return ret;
  
-	ctx->next_bridge = of_drm_find_bridge(ep);
-       of_node_put(ep);
-       if (!ctx->next_bridge) {
+       ctx->next_bridge = drm_bridge_find_next_bridge_by_fwnode(fwnode, 1);
+       if (IS_ERR(ctx->next_bridge)) {
+               ret = PTR_ERR(ctx->next_bridge);
+               dev_err(dev, "Error in founding the next bridge: %d\n", ret);
+               return ret;
return dev_err_probe(dev, ret, "msg"), if your function doesn't do this.
If it does, just return ret.


My drm_bridge_find_next_bridge_by_fwnode() function won't return -EPROBE_DEFER
this is known for sure. As a//prior(priori) knowledge. Calling the 
dev_err_probe()
just introduce extra overhead. It is useless to use dev_err_probe() here.
 

--
Best regards,
Sui