drm/edid: Cleanup kerneldoc

This fixes up a couple of inconsistencies with kerneldoc comments for
the EDID related functions. Functions that return a value now use the
"Return" section consistently. For some exported symbols the kernel-doc
comments were not in the appropriate format and therefore not included
in the generated documentation. Others had no kernel-doc at all.

While at it, fix a couple of whitespace issues and capitalize common
abbreviations (i2c -> I2C, edid -> EDID, ...).
Signed-off-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/drm_edid.c

@@ -984,9 +984,13 @@ static const u8 edid_header[] = {
 	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00
 };
 
- /*
- * Sanity check the header of the base EDID block.  Return 8 if the header
- * is perfect, down to 0 if it's totally wrong.
+/**
+ * drm_edid_header_is_valid - sanity check the header of the base EDID block
+ * @raw_edid: pointer to raw base EDID block
+ *
+ * Sanity check the header of the base EDID block.
+ *
+ * Return: 8 if the header is perfect, down to 0 if it's totally wrong.
  */
 int drm_edid_header_is_valid(const u8 *raw_edid)
 {
@@ -1005,9 +1009,16 @@ module_param_named(edid_fixup, edid_fixup, int, 0400);
 MODULE_PARM_DESC(edid_fixup,
 		 "Minimum number of valid EDID header bytes (0-8, default 6)");
 
-/*
- * Sanity check the EDID block (base or extension).  Return 0 if the block
- * doesn't check out, or 1 if it's valid.
+/**
+ * drm_edid_block_valid - Sanity check the EDID block (base or extension)
+ * @raw_edid: pointer to raw EDID block
+ * @block: type of block to validate (0 for base, extension otherwise)
+ * @print_bad_edid: if true, dump bad EDID blocks to the console
+ *
+ * Validate a base or extension EDID block and optionally dump bad blocks to
+ * the console.
+ *
+ * Return: True if the block is valid, false otherwise.
  */
 bool drm_edid_block_valid(u8 *raw_edid, int block, bool print_bad_edid)
 {
@@ -1077,6 +1088,8 @@ EXPORT_SYMBOL(drm_edid_block_valid);
  * @edid: EDID data
  *
  * Sanity-check an entire EDID record (including extensions)
+ *
+ * Return: True if the EDID data is valid, false otherwise.
  */
 bool drm_edid_is_valid(struct edid *edid)
 {
@@ -1096,18 +1109,15 @@ EXPORT_SYMBOL(drm_edid_is_valid);
 
 #define DDC_SEGMENT_ADDR 0x30
 /**
- * Get EDID information via I2C.
- *
- * @adapter : i2c device adaptor
+ * drm_do_probe_ddc_edid() - get EDID information via I2C
+ * @adapter: I2C device adaptor
  * @buf: EDID data buffer to be filled
  * @block: 128 byte EDID block to start fetching from
  * @len: EDID data buffer length to fetch
  *
- * Returns:
- *
- * 0 on success or -1 on failure.
+ * Try to fetch EDID information by calling I2C driver functions.
  *
- * Try to fetch EDID information by calling i2c driver function.
+ * Return: 0 on success or -1 on failure.
  */
 static int
 drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf,
@@ -1118,7 +1128,8 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf,
 	unsigned char xfers = segment ? 3 : 2;
 	int ret, retries = 5;
 
-	/* The core i2c driver will automatically retry the transfer if the
+	/*
+	 * The core I2C driver will automatically retry the transfer if the
 	 * adapter reports EAGAIN. However, we find that bit-banging transfers
 	 * are susceptible to errors under a heavily loaded machine and
 	 * generate spurious NAKs and timeouts. Retrying the transfer
@@ -1144,10 +1155,10 @@ drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf,
 			}
 		};
 
-	/*
-	 * Avoid sending the segment addr to not upset non-compliant ddc
-	 * monitors.
-	 */
+		/*
+		 * Avoid sending the segment addr to not upset non-compliant
+		 * DDC monitors.
+		 */
 		ret = i2c_transfer(adapter, &msgs[3 - xfers], xfers);
 
 		if (ret == -ENXIO) {
@@ -1246,12 +1257,10 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 }
 
 /**
- * Probe DDC presence.
- * @adapter: i2c adapter to probe
+ * drm_probe_ddc() - probe DDC presence
+ * @adapter: I2C adapter to probe
  *
- * Returns:
- *
- * 1 on success
+ * Return: True on success, false on failure.
  */
 bool
 drm_probe_ddc(struct i2c_adapter *adapter)
@@ -1265,12 +1274,12 @@ EXPORT_SYMBOL(drm_probe_ddc);
 /**
  * drm_get_edid - get EDID data, if available
  * @connector: connector we're probing
- * @adapter: i2c adapter to use for DDC
+ * @adapter: I2C adapter to use for DDC
  *
- * Poke the given i2c channel to grab EDID data if possible.  If found,
+ * Poke the given I2C channel to grab EDID data if possible.  If found,
  * attach it to the connector.
  *
- * Return edid data or NULL if we couldn't find any.
+ * Return: Pointer to valid EDID or NULL if we couldn't find any.
  */
 struct edid *drm_get_edid(struct drm_connector *connector,
 			  struct i2c_adapter *adapter)
@@ -1288,7 +1297,7 @@ EXPORT_SYMBOL(drm_get_edid);
  * drm_edid_duplicate - duplicate an EDID and the extensions
  * @edid: EDID to duplicate
  *
- * Return duplicate edid or NULL on allocation failure.
+ * Return: Pointer to duplicated EDID or NULL on allocation failure.
  */
 struct edid *drm_edid_duplicate(const struct edid *edid)
 {
@@ -1411,7 +1420,8 @@ mode_is_rb(const struct drm_display_mode *mode)
  * @rb: Mode reduced-blanking-ness
  *
  * Walk the DMT mode list looking for a match for the given parameters.
- * Return a newly allocated copy of the mode, or NULL if not found.
+ *
+ * Return: A newly allocated copy of the mode, or NULL if not found.
  */
 struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
 					   int hsize, int vsize, int fresh,
@@ -2139,7 +2149,7 @@ do_established_modes(struct detailed_timing *timing, void *c)
 
 /**
  * add_established_modes - get est. modes from EDID and add them
- * @connector: connector of for the EDID block
+ * @connector: connector to add mode(s) to
  * @edid: EDID block to scan
  *
  * Each EDID block contains a bitmap of the supported "established modes" list
@@ -2201,7 +2211,7 @@ do_standard_modes(struct detailed_timing *timing, void *c)
 
 /**
  * add_standard_modes - get std. modes from EDID and add them
- * @connector: connector of for the EDID block
+ * @connector: connector to add mode(s) to
  * @edid: EDID block to scan
  *
  * Standard modes can be calculated using the appropriate standard (DMT,
@@ -2422,7 +2432,7 @@ cea_mode_alternate_clock(const struct drm_display_mode *cea_mode)
  * drm_match_cea_mode - look for a CEA mode matching given mode
  * @to_match: display mode
  *
- * Returns the CEA Video ID (VIC) of the mode or 0 if it isn't a CEA-861
+ * Return: The CEA Video ID (VIC) of the mode or 0 if it isn't a CEA-861
  * mode.
  */
 u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
@@ -3036,11 +3046,9 @@ monitor_name(struct detailed_timing *t, void *data)
  * @connector: connector corresponding to the HDMI/DP sink
  * @edid: EDID to parse
  *
- * Fill the ELD (EDID-Like Data) buffer for passing to the audio driver.
- * Some ELD fields are left to the graphics driver caller:
- * - Conn_Type
- * - HDCP
- * - Port_ID
+ * Fill the ELD (EDID-Like Data) buffer for passing to the audio driver. The
+ * Conn_Type, HDCP and Port_ID ELD fields are left for the graphics driver to
+ * fill in.
  */
 void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
 {
@@ -3124,9 +3132,10 @@ EXPORT_SYMBOL(drm_edid_to_eld);
  * @sads: pointer that will be set to the extracted SADs
  *
  * Looks for CEA EDID block and extracts SADs (Short Audio Descriptors) from it.
- * Note: returned pointer needs to be kfreed
  *
- * Return number of found SADs or negative number on error.
+ * Note: The returned pointer needs to be freed using kfree().
+ *
+ * Return: The number of found SADs or negative number on error.
  */
 int drm_edid_to_sad(struct edid *edid, struct cea_sad **sads)
 {
@@ -3183,9 +3192,11 @@ EXPORT_SYMBOL(drm_edid_to_sad);
  * @sadb: pointer to the speaker block
  *
  * Looks for CEA EDID block and extracts the Speaker Allocation Data Block from it.
- * Note: returned pointer needs to be kfreed
  *
- * Return number of found Speaker Allocation Blocks or negative number on error.
+ * Note: The returned pointer needs to be freed using kfree().
+ *
+ * Return: The number of found Speaker Allocation Blocks or negative number on
+ * error.
  */
 int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)
 {
@@ -3232,9 +3243,12 @@ int drm_edid_to_speaker_allocation(struct edid *edid, u8 **sadb)
 EXPORT_SYMBOL(drm_edid_to_speaker_allocation);
 
 /**
- * drm_av_sync_delay - HDMI/DP sink audio-video sync delay in millisecond
+ * drm_av_sync_delay - compute the HDMI/DP sink audio-video sync delay
  * @connector: connector associated with the HDMI/DP sink
  * @mode: the display mode
+ *
+ * Return: The HDMI/DP sink's audio-video sync delay in milliseconds or 0 if
+ * the sink doesn't support audio or video.
  */
 int drm_av_sync_delay(struct drm_connector *connector,
 		      struct drm_display_mode *mode)
@@ -3276,6 +3290,9 @@ EXPORT_SYMBOL(drm_av_sync_delay);
  *
  * It's possible for one encoder to be associated with multiple HDMI/DP sinks.
  * The policy is now hard coded to simply use the first HDMI/DP sink's ELD.
+ *
+ * Return: The connector associated with the first HDMI/DP sink that has ELD
+ * attached to it.
  */
 struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
 				     struct drm_display_mode *mode)
@@ -3292,11 +3309,12 @@ struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
 EXPORT_SYMBOL(drm_select_eld);
 
 /**
- * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
+ * drm_detect_hdmi_monitor - detect whether monitor is HDMI
  * @edid: monitor EDID information
  *
  * Parse the CEA extension according to CEA-861-B.
- * Return true if HDMI, false if not or unknown.
+ *
+ * Return: True if the monitor is HDMI, false if not or unknown.
  */
 bool drm_detect_hdmi_monitor(struct edid *edid)
 {
@@ -3334,6 +3352,7 @@ EXPORT_SYMBOL(drm_detect_hdmi_monitor);
  * audio format, assume at least 'basic audio' support, even if 'basic
  * audio' is not defined in EDID.
  *
+ * Return: True if the monitor supports audio, false otherwise.
  */
 bool drm_detect_monitor_audio(struct edid *edid)
 {
@@ -3377,6 +3396,8 @@ EXPORT_SYMBOL(drm_detect_monitor_audio);
  * Check whether the monitor reports the RGB quantization range selection
  * as supported. The AVI infoframe can then be used to inform the monitor
  * which quantization range (full or limited) is used.
+ *
+ * Return: True if the RGB quantization range is selectable, false otherwise.
  */
 bool drm_rgb_quant_range_selectable(struct edid *edid)
 {
@@ -3481,11 +3502,11 @@ static void drm_add_display_info(struct edid *edid,
 /**
  * drm_add_edid_modes - add modes from EDID data, if available
  * @connector: connector we're probing
- * @edid: edid data
+ * @edid: EDID data
  *
  * Add the specified modes to the connector's mode list.
  *
- * Return number of modes added or 0 if we couldn't find any.
+ * Return: The number of modes added or 0 if we couldn't find any.
  */
 int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
 {
@@ -3547,7 +3568,7 @@ EXPORT_SYMBOL(drm_add_edid_modes);
  * Add the specified modes to the connector's mode list. Only when the
  * hdisplay/vdisplay is not beyond the given limit, it will be added.
  *
- * Return number of modes added or 0 if we couldn't find any.
+ * Return: The number of modes added or 0 if we couldn't find any.
  */
 int drm_add_modes_noedid(struct drm_connector *connector,
 			int hdisplay, int vdisplay)
@@ -3586,13 +3607,22 @@ int drm_add_modes_noedid(struct drm_connector *connector,
 }
 EXPORT_SYMBOL(drm_add_modes_noedid);
 
+/**
+ * drm_set_preferred_mode - Sets the preferred mode of a connector
+ * @connector: connector whose mode list should be processed
+ * @hpref: horizontal resolution of preferred mode
+ * @vpref: vertical resolution of preferred mode
+ *
+ * Marks a mode as preferred if it matches the resolution specified by @hpref
+ * and @vpref.
+ */
 void drm_set_preferred_mode(struct drm_connector *connector,
 			   int hpref, int vpref)
 {
 	struct drm_display_mode *mode;
 
 	list_for_each_entry(mode, &connector->probed_modes, head) {
-		if (mode->hdisplay  == hpref &&
+		if (mode->hdisplay == hpref &&
 		    mode->vdisplay == vpref)
 			mode->type |= DRM_MODE_TYPE_PREFERRED;
 	}
@@ -3605,7 +3635,7 @@ EXPORT_SYMBOL(drm_set_preferred_mode);
  * @frame: HDMI AVI infoframe
  * @mode: DRM display mode
  *
- * Returns 0 on success or a negative error code on failure.
+ * Return: 0 on success or a negative error code on failure.
  */
 int
 drm_hdmi_avi_infoframe_from_display_mode(struct hdmi_avi_infoframe *frame,
@@ -3676,7 +3706,7 @@ s3d_structure_from_display_mode(const struct drm_display_mode *mode)
  * 4k or stereoscopic 3D mode. So when giving any other mode as input this
  * function will return -EINVAL, error that can be safely ignored.
  *
- * Returns 0 on success or a negative error code on failure.
+ * Return: 0 on success or a negative error code on failure.
  */
 int
 drm_hdmi_vendor_infoframe_from_display_mode(struct hdmi_vendor_infoframe *frame,