media: cec-notifier: also search for HDMI devices on I2C

Currently the cec_notifier_parse_hdmi_phandle function can only be used
if the HDMI device associated with the CEC device is a platform device.
Extend the function to cover I2C devices as well, as there do exist
some I2C HDMI devices which don't handle CEC internally and need an
external CEC adapter.

[hverkuil: add missing linux/i2c.h header]
[hverkuil: only attempt to find the i2c device if CONFIG_I2C is set]
Signed-off-by: Johan Fjeldtvedt <johfjeld@cisco.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/media/cec/core/cec-notifier.c

@@ -9,6 +9,7 @@
 #include <linux/export.h>
 #include <linux/string.h>
 #include <linux/slab.h>
+#include <linux/i2c.h>
 #include <linux/list.h>
 #include <linux/kref.h>
 #include <linux/of_platform.h>
@@ -221,10 +222,22 @@ struct device *cec_notifier_parse_hdmi_phandle(struct device *dev)
 		dev_err(dev, "Failed to find HDMI node in device tree\n");
 		return ERR_PTR(-ENODEV);
 	}
+
 	hdmi_pdev = of_find_device_by_node(np);
-	of_node_put(np);
-	if (hdmi_pdev) {
+	if (hdmi_pdev)
 		hdmi_dev = &hdmi_pdev->dev;
+#if IS_ENABLED(CONFIG_I2C)
+	if (!hdmi_dev) {
+		struct i2c_client *hdmi_client = of_find_i2c_device_by_node(np);
+
+		if (hdmi_client)
+			hdmi_dev = &hdmi_client->dev;
+	}
+#endif
+	of_node_put(np);
+	if (!hdmi_dev)
+		return ERR_PTR(-EPROBE_DEFER);
+
 	/*
 	 * Note that the device struct is only used as a key into the
 	 * cec_notifiers list, it is never actually accessed.
@@ -233,7 +246,5 @@ struct device *cec_notifier_parse_hdmi_phandle(struct device *dev)
 	 */
 	put_device(hdmi_dev);
 	return hdmi_dev;
-	}
-	return ERR_PTR(-EPROBE_DEFER);
 }
 EXPORT_SYMBOL_GPL(cec_notifier_parse_hdmi_phandle);