rockchip: video: document externally visible functions for rk_hdmi

Documents the externally visible functions shared between the HDMI
drivers for the RK3288 and RK3399.

Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

drivers/video/rockchip/rk_hdmi.h

@@ -23,10 +23,54 @@ struct rk_hdmi_priv {
 	void *grf;
 };
 
+/**
+ * rk_hdmi_read_edid() - read the attached HDMI/DVI monitor's EDID
+ *
+ * N.B.: The buffer should be large enough to hold 2 EDID blocks, as
+ *       this function calls dw_hdmi_read_edid, which ignores buf_size
+ *       argument and assumes that there's always enough space for 2
+ *       EDID blocks.
+ *
+ * @dev:	device
+ * @buf:	output buffer for the EDID
+ * @buf_size:	number of bytes in the buffer
+ * @return number of bytes read if OK, -ve if something went wrong
+ */
 int rk_hdmi_read_edid(struct udevice *dev, u8 *buf, int buf_size);
+
+/**
+ * rk_hdmi_probe_regulators() - probe (autoset + enable) regulators
+ *
+ * Probes a list of regulators by performing autoset and enable
+ * operations on them.  The list of regulators is an array of string
+ * pointers and any individual regulator-probe may fail without
+ * counting as an error.
+ *
+ * @dev:	device
+ * @names:	array of string-pointers to regulator names to probe
+ * @cnt:	number of elements in the 'names' array
+ */
 void rk_hdmi_probe_regulators(struct udevice *dev,
 			      const char * const *names, int cnt);
+/**
+ * rk_hdmi_ofdata_to_platdata() - common ofdata_to_platdata implementation
+ *
+ * @dev:	device
+ * @return 0 if OK, -ve if something went wrong
+ */
 int rk_hdmi_ofdata_to_platdata(struct udevice *dev);
+
+/**
+ * rk_hdmi_probe() - common probe implementation
+ *
+ * Performs the following, common initialisation steps:
+ * 1. checks for HPD (i.e. a HDMI monitor being attached)
+ * 2. initialises the Designware HDMI core
+ * 3. initialises the Designware HDMI PHY
+ *
+ * @dev:	device
+ * @return 0 if OK, -ve if something went wrong
+ */
 int rk_hdmi_probe(struct udevice *dev);
 
 #endif