[PATCH v2 4/4] drm-bridge: it66121: Use fwnode API to acquire device properties

[Sui Jingfeng <sui.jingfeng@linux.dev>]

Make this driver less DT-dependent by calling the freshly created helpers,
should be no functional changes for DT based systems. But open the door for
otherwise use cases. Even though there is no user emerged yet, this still
do no harms. In fact, we reduce some boilerplate across drm bridge drivers.

Signed-off-by: Sui Jingfeng <sui.jingfeng@linux.dev>
---
 drivers/gpu/drm/bridge/ite-it66121.c | 63 ++++++++++++++++------------
 1 file changed, 36 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
index 1c3433b5e366..a2cf2be86065 100644
--- a/drivers/gpu/drm/bridge/ite-it66121.c
+++ b/drivers/gpu/drm/bridge/ite-it66121.c
@@ -15,7 +15,6 @@
 #include <linux/bitfield.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
-#include <linux/of_graph.h>
 #include <linux/gpio/consumer.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/regulator/consumer.h>
@@ -1480,7 +1479,7 @@ static int it66121_audio_codec_init(struct it66121_ctx *ctx, struct device *dev)
 
 	dev_dbg(dev, "%s\n", __func__);
 
-	if (!of_property_read_bool(dev->of_node, "#sound-dai-cells")) {
+	if (!fwnode_property_present(dev_fwnode(dev), "#sound-dai-cells")) {
 		dev_info(dev, "No \"#sound-dai-cells\", no audio\n");
 		return 0;
 	}
@@ -1503,13 +1502,37 @@ static const char * const it66121_supplies[] = {
 	"vcn33", "vcn18", "vrf12"
 };
 
+static int it66121_read_bus_width(struct fwnode_handle *fwnode, u32 port,
+				  u32 *bus_width)
+{
+	struct fwnode_handle *endpoint;
+	u32 val;
+	int ret;
+
+	endpoint = fwnode_graph_get_endpoint_by_id(fwnode, port, 0, 0);
+	if (!endpoint)
+		return -EINVAL;
+
+	ret = fwnode_property_read_u32(endpoint, "bus-width", &val);
+	fwnode_handle_put(endpoint);
+	if (ret)
+		return ret;
+
+	if (val != 12 && val != 24)
+		return -EINVAL;
+
+	*bus_width = val;
+
+	return 0;
+}
+
 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");
@@ -1520,37 +1543,23 @@ 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;
-	}
-
-	if (!of_device_is_available(ep)) {
-		of_node_put(ep);
-		dev_err(ctx->dev, "The remote device is disabled\n");
-		return -ENODEV;
-	}
+	/* Endpoint of port@0 contains the bus-width property */
+	ret = it66121_read_bus_width(fwnode, 0, &ctx->bus_width);
+	if (ret)
+		return ret;
 
-	ctx->next_bridge = of_drm_find_bridge(ep);
-	of_node_put(ep);
+	ctx->next_bridge = drm_bridge_find_next_bridge_by_fwnode(fwnode, 1);
 	if (!ctx->next_bridge) {
 		dev_dbg(ctx->dev, "Next bridge not found, deferring probe\n");
 		return -EPROBE_DEFER;
+	} else 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;
 	}
 
 	i2c_set_clientdata(client, ctx);
@@ -1584,9 +1593,9 @@ static int it66121_probe(struct i2c_client *client)
 	}
 
 	ctx->bridge.funcs = &it66121_bridge_funcs;
-	ctx->bridge.of_node = dev->of_node;
 	ctx->bridge.type = DRM_MODE_CONNECTOR_HDMIA;
 	ctx->bridge.ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
+	drm_bridge_set_node(&ctx->bridge, fwnode);
 
 	ret = devm_request_threaded_irq(dev, client->irq, NULL,	it66121_irq_threaded_handler,
 					IRQF_ONESHOT, dev_name(dev), ctx);
-- 
2.34.1