ALSA: hda - Update / add kerneldoc comments to exported functions

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 391 insertions, 41 deletions

diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index 5e21b35207ab..e344235da491 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -94,6 +94,13 @@ static void hda_keep_power_on(struct hda_codec *codec);
 static inline void hda_keep_power_on(struct hda_codec *codec) {}
 #endif
 
+/**
+ * snd_hda_get_jack_location - Give a location string of the jack
+ * @cfg: pin default config value
+ *
+ * Parse the pin default config value and returns the string of the
+ * jack location, e.g. "Rear", "Front", etc.
+ */
 const char *snd_hda_get_jack_location(u32 cfg)
 {
         static char *bases[7] = {
@@ -121,6 +128,13 @@ const char *snd_hda_get_jack_location(u32 cfg)
 }
 EXPORT_SYMBOL_HDA(snd_hda_get_jack_location);
 
+/**
+ * snd_hda_get_jack_connectivity - Give a connectivity string of the jack
+ * @cfg: pin default config value
+ *
+ * Parse the pin default config value and returns the string of the
+ * jack connectivity, i.e. external or internal connection.
+ */
 const char *snd_hda_get_jack_connectivity(u32 cfg)
 {
         static char *jack_locations[4] = { "Ext", "Int", "Sep", "Oth" };
@@ -129,6 +143,13 @@ const char *snd_hda_get_jack_connectivity(u32 cfg)
 }
 EXPORT_SYMBOL_HDA(snd_hda_get_jack_connectivity);
 
+/**
+ * snd_hda_get_jack_type - Give a type string of the jack
+ * @cfg: pin default config value
+ *
+ * Parse the pin default config value and returns the string of the
+ * jack type, i.e. the purpose of the jack, such as Line-Out or CD.
+ */
 const char *snd_hda_get_jack_type(u32 cfg)
 {
         static char *jack_types[16] = {
@@ -822,6 +843,16 @@ int snd_hda_add_pincfg(struct hda_codec *codec, struct snd_array *list,
         return 0;
 }
 
+/**
+ * snd_hda_codec_set_pincfg - Override a pin default configuration
+ * @codec: the HDA codec
+ * @nid: NID to set the pin config
+ * @cfg: the pin default config value
+ *
+ * Override a pin default configuration value in the cache.
+ * This value can be read by snd_hda_codec_get_pincfg() in a higher
+ * priority than the real hardware value.
+ */
 int snd_hda_codec_set_pincfg(struct hda_codec *codec,
                              hda_nid_t nid, unsigned int cfg)
 {
@@ -829,7 +860,15 @@ int snd_hda_codec_set_pincfg(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_set_pincfg);
 
-/* get the current pin config value of the given pin NID */
+/**
+ * snd_hda_codec_get_pincfg - Obtain a pin-default configuration
+ * @codec: the HDA codec
+ * @nid: NID to get the pin config
+ *
+ * Get the current pin config value of the given pin NID.
+ * If the pincfg value is cached or overridden via sysfs or driver,
+ * returns the cached value.
+ */
 unsigned int snd_hda_codec_get_pincfg(struct hda_codec *codec, hda_nid_t nid)
 {
         struct hda_pincfg *pin;
@@ -1028,6 +1067,15 @@ int /*__devinit*/ snd_hda_codec_new(struct hda_bus *bus, unsigned int codec_addr
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_new);
 
+/**
+ * snd_hda_codec_configure - (Re-)configure the HD-audio codec
+ * @codec: the HDA codec
+ *
+ * Start parsing of the given codec tree and (re-)initialize the whole
+ * patch instance.
+ *
+ * Returns 0 if successful or a negative error code.
+ */
 int snd_hda_codec_configure(struct hda_codec *codec)
 {
         int err;
@@ -1090,6 +1138,11 @@ void snd_hda_codec_setup_stream(struct hda_codec *codec, hda_nid_t nid,
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_setup_stream);
 
+/**
+ * snd_hda_codec_cleanup_stream - clean up the codec for closing
+ * @codec: the CODEC to clean up
+ * @nid: the NID to clean up
+ */
 void snd_hda_codec_cleanup_stream(struct hda_codec *codec, hda_nid_t nid)
 {
         if (!nid)
@@ -1165,8 +1218,17 @@ get_alloc_amp_hash(struct hda_codec *codec, u32 key)
         return (struct hda_amp_info *)get_alloc_hash(&codec->amp_cache, key);
 }
 
-/*
- * query AMP capabilities for the given widget and direction
+/**
+ * query_amp_caps - query AMP capabilities
+ * @codec: the HD-auio codec
+ * @nid: the NID to query
+ * @direction: either #HDA_INPUT or #HDA_OUTPUT
+ *
+ * Query AMP capabilities for the given widget and direction.
+ * Returns the obtained capability bits.
+ *
+ * When cap bits have been already read, this doesn't read again but
+ * returns the cached value.
  */
 u32 query_amp_caps(struct hda_codec *codec, hda_nid_t nid, int direction)
 {
@@ -1189,6 +1251,19 @@ u32 query_amp_caps(struct hda_codec *codec, hda_nid_t nid, int direction)
 }
 EXPORT_SYMBOL_HDA(query_amp_caps);
 
+/**
+ * snd_hda_override_amp_caps - Override the AMP capabilities
+ * @codec: the CODEC to clean up
+ * @nid: the NID to clean up
+ * @direction: either #HDA_INPUT or #HDA_OUTPUT
+ * @caps: the capability bits to set
+ *
+ * Override the cached AMP caps bits value by the given one.
+ * This function is useful if the driver needs to adjust the AMP ranges,
+ * e.g. limit to 0dB, etc.
+ *
+ * Returns zero if successful or a negative error code.
+ */
 int snd_hda_override_amp_caps(struct hda_codec *codec, hda_nid_t nid, int dir,
                               unsigned int caps)
 {
@@ -1224,6 +1299,17 @@ static unsigned int read_pin_cap(struct hda_codec *codec, hda_nid_t nid)
         return snd_hda_param_read(codec, nid, AC_PAR_PIN_CAP);
 }
 
+/**
+ * snd_hda_query_pin_caps - Query PIN capabilities
+ * @codec: the HD-auio codec
+ * @nid: the NID to query
+ *
+ * Query PIN capabilities for the given widget.
+ * Returns the obtained capability bits.
+ *
+ * When cap bits have been already read, this doesn't read again but
+ * returns the cached value.
+ */
 u32 snd_hda_query_pin_caps(struct hda_codec *codec, hda_nid_t nid)
 {
         return query_caps_hash(codec, nid, HDA_HASH_PINCAP_KEY(nid),
@@ -1271,8 +1357,15 @@ static void put_vol_mute(struct hda_codec *codec, struct hda_amp_info *info,
         info->vol[ch] = val;
 }
 
-/*
- * read AMP value.  The volume is between 0 to 0x7f, 0x80 = mute bit.
+/**
+ * snd_hda_codec_amp_read - Read AMP value
+ * @codec: HD-audio codec
+ * @nid: NID to read the AMP value
+ * @ch: channel (left=0 or right=1)
+ * @direction: #HDA_INPUT or #HDA_OUTPUT
+ * @index: the index value (only for input direction)
+ *
+ * Read AMP value.  The volume is between 0 to 0x7f, 0x80 = mute bit.
  */
 int snd_hda_codec_amp_read(struct hda_codec *codec, hda_nid_t nid, int ch,
                            int direction, int index)
@@ -1285,8 +1378,18 @@ int snd_hda_codec_amp_read(struct hda_codec *codec, hda_nid_t nid, int ch,
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_amp_read);
 
-/*
- * update the AMP value, mask = bit mask to set, val = the value
+/**
+ * snd_hda_codec_amp_update - update the AMP value
+ * @codec: HD-audio codec
+ * @nid: NID to read the AMP value
+ * @ch: channel (left=0 or right=1)
+ * @direction: #HDA_INPUT or #HDA_OUTPUT
+ * @idx: the index value (only for input direction)
+ * @mask: bit mask to set
+ * @val: the bits value to set
+ *
+ * Update the AMP value with a bit mask.
+ * Returns 0 if the value is unchanged, 1 if changed.
  */
 int snd_hda_codec_amp_update(struct hda_codec *codec, hda_nid_t nid, int ch,
                              int direction, int idx, int mask, int val)
@@ -1305,8 +1408,17 @@ int snd_hda_codec_amp_update(struct hda_codec *codec, hda_nid_t nid, int ch,
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_amp_update);
 
-/*
- * update the AMP stereo with the same mask and value
+/**
+ * snd_hda_codec_amp_stereo - update the AMP stereo values
+ * @codec: HD-audio codec
+ * @nid: NID to read the AMP value
+ * @direction: #HDA_INPUT or #HDA_OUTPUT
+ * @idx: the index value (only for input direction)
+ * @mask: bit mask to set
+ * @val: the bits value to set
+ *
+ * Update the AMP values like snd_hda_codec_amp_update(), but for a
+ * stereo widget with the same mask and value.
  */
 int snd_hda_codec_amp_stereo(struct hda_codec *codec, hda_nid_t nid,
                              int direction, int idx, int mask, int val)
@@ -1320,7 +1432,12 @@ int snd_hda_codec_amp_stereo(struct hda_codec *codec, hda_nid_t nid,
 EXPORT_SYMBOL_HDA(snd_hda_codec_amp_stereo);
 
 #ifdef SND_HDA_NEEDS_RESUME
-/* resume the all amp commands from the cache */
+/**
+ * snd_hda_codec_resume_amp - Resume all AMP commands from the cache
+ * @codec: HD-audio codec
+ *
+ * Resume the all amp commands from the cache.
+ */
 void snd_hda_codec_resume_amp(struct hda_codec *codec)
 {
         struct hda_amp_info *buffer = codec->amp_cache.buf.list;
@@ -1346,7 +1463,12 @@ void snd_hda_codec_resume_amp(struct hda_codec *codec)
 EXPORT_SYMBOL_HDA(snd_hda_codec_resume_amp);
 #endif /* SND_HDA_NEEDS_RESUME */
 
-/* volume */
+/**
+ * snd_hda_mixer_amp_volume_info - Info callback for a standard AMP mixer
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_volume_info(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_info *uinfo)
 {
@@ -1402,6 +1524,12 @@ update_amp_value(struct hda_codec *codec, hda_nid_t nid,
                                         HDA_AMP_VOLMASK, val);
 }
 
+/**
+ * snd_hda_mixer_amp_volume_get - Get callback for a standard AMP mixer volume
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_volume_get(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
 {
@@ -1421,6 +1549,12 @@ int snd_hda_mixer_amp_volume_get(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_volume_get);
 
+/**
+ * snd_hda_mixer_amp_volume_put - Put callback for a standard AMP mixer volume
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_volume_put(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
 {
@@ -1445,6 +1579,12 @@ int snd_hda_mixer_amp_volume_put(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_volume_put);
 
+/**
+ * snd_hda_mixer_amp_volume_put - TLV callback for a standard AMP mixer volume
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_tlv(struct snd_kcontrol *kcontrol, int op_flag,
                           unsigned int size, unsigned int __user *_tlv)
 {
@@ -1474,8 +1614,16 @@ int snd_hda_mixer_amp_tlv(struct snd_kcontrol *kcontrol, int op_flag,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_tlv);
 
-/*
- * set (static) TLV for virtual master volume; recalculated as max 0dB
+/**
+ * snd_hda_set_vmaster_tlv - Set TLV for a virtual master control
+ * @codec: HD-audio codec
+ * @nid: NID of a reference widget
+ * @dir: #HDA_INPUT or #HDA_OUTPUT
+ * @tlv: TLV data to be stored, at least 4 elements
+ *
+ * Set (static) TLV data for a virtual master volume using the AMP caps
+ * obtained from the reference NID.
+ * The volume range is recalculated as if the max volume is 0dB.
  */
 void snd_hda_set_vmaster_tlv(struct hda_codec *codec, hda_nid_t nid, int dir,
                              unsigned int *tlv)
@@ -1509,6 +1657,13 @@ _snd_hda_find_mixer_ctl(struct hda_codec *codec,
         return snd_ctl_find_id(codec->bus->card, &id);
 }
 
+/**
+ * snd_hda_find_mixer_ctl - Find a mixer control element with the given name
+ * @codec: HD-audio codec
+ * @name: ctl id name string
+ *
+ * Get the control element with the given id string and IFACE_MIXER.
+ */
 struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,
                                             const char *name)
 {
@@ -1516,7 +1671,24 @@ struct snd_kcontrol *snd_hda_find_mixer_ctl(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_find_mixer_ctl);
 
-/* Add a control element and assign to the codec */
+/**
+ * snd_hda_ctl-add - Add a control element and assign to the codec
+ * @codec: HD-audio codec
+ * @nid: corresponding NID (optional)
+ * @kctl: the control element to assign
+ *
+ * Add the given control element to an array inside the codec instance.
+ * All control elements belonging to a codec are supposed to be added
+ * by this function so that a proper clean-up works at the free or
+ * reconfiguration time.
+ *
+ * If non-zero @nid is passed, the NID is assigned to the control element.
+ * The assignment is shown in the codec proc file.
+ *
+ * snd_hda_ctl_add() checks the control subdev id field whether
+ * #HDA_SUBDEV_NID_FLAG bit is set.  If set (and @nid is zero), the lower
+ * bits value is taken as the NID to assign.
+ */
 int snd_hda_ctl_add(struct hda_codec *codec, hda_nid_t nid,
                     struct snd_kcontrol *kctl)
 {
@@ -1540,7 +1712,10 @@ int snd_hda_ctl_add(struct hda_codec *codec, hda_nid_t nid,
 }
 EXPORT_SYMBOL_HDA(snd_hda_ctl_add);
 
-/* Clear all controls assigned to the given codec */
+/**
+ * snd_hda_ctls_clear - Clear all controls assigned to the given codec
+ * @codec: HD-audio codec
+ */
 void snd_hda_ctls_clear(struct hda_codec *codec)
 {
         int i;
@@ -1572,6 +1747,16 @@ static void hda_unlock_devices(struct snd_card *card)
         spin_unlock(&card->files_lock);
 }
 
+/**
+ * snd_hda_codec_reset - Clear all objects assigned to the codec
+ * @codec: HD-audio codec
+ *
+ * This frees the all PCM and control elements assigned to the codec, and
+ * clears the caches and restores the pin default configurations.
+ *
+ * When a device is being used, it returns -EBSY.  If successfully freed,
+ * returns zero.
+ */
 int snd_hda_codec_reset(struct hda_codec *codec)
 {
         struct snd_card *card = codec->bus->card;
@@ -1635,7 +1820,22 @@ int snd_hda_codec_reset(struct hda_codec *codec)
         return 0;
 }
 
-/* create a virtual master control and add slaves */
+/**
+ * snd_hda_add_vmaster - create a virtual master control and add slaves
+ * @codec: HD-audio codec
+ * @name: vmaster control name
+ * @tlv: TLV data (optional)
+ * @slaves: slave control names (optional)
+ *
+ * Create a virtual master control with the given name.  The TLV data
+ * must be either NULL or a valid data.
+ *
+ * @slaves is a NULL-terminated array of strings, each of which is a
+ * slave control name.  All controls with these names are assigned to
+ * the new virtual master control.
+ *
+ * This function returns zero if successful or a negative error code.
+ */
 int snd_hda_add_vmaster(struct hda_codec *codec, char *name,
                         unsigned int *tlv, const char **slaves)
 {
@@ -1677,7 +1877,12 @@ int snd_hda_add_vmaster(struct hda_codec *codec, char *name,
 }
 EXPORT_SYMBOL_HDA(snd_hda_add_vmaster);
 
-/* switch */
+/**
+ * snd_hda_mixer_amp_switch_info - Info callback for a standard AMP mixer switch
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_switch_info(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_info *uinfo)
 {
@@ -1691,6 +1896,12 @@ int snd_hda_mixer_amp_switch_info(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_info);
 
+/**
+ * snd_hda_mixer_amp_switch_get - Get callback for a standard AMP mixer switch
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_switch_get(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
 {
@@ -1711,6 +1922,12 @@ int snd_hda_mixer_amp_switch_get(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_get);
 
+/**
+ * snd_hda_mixer_amp_switch_put - Put callback for a standard AMP mixer switch
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_COMPOSE_AMP_VAL*() or related macros.
+ */
 int snd_hda_mixer_amp_switch_put(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_value *ucontrol)
 {
@@ -1742,6 +1959,12 @@ int snd_hda_mixer_amp_switch_put(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_put);
 
+/**
+ * snd_hda_mixer_amp_switch_put_beep - Put callback for a beep AMP switch
+ *
+ * This function calls snd_hda_enable_beep_device(), which behaves differently
+ * depending on beep_mode option.
+ */
 int snd_hda_mixer_amp_switch_put_beep(struct snd_kcontrol *kcontrol,
                                       struct snd_ctl_elem_value *ucontrol)
 {
@@ -1762,6 +1985,12 @@ EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_put_beep);
 #define AMP_VAL_IDX_SHIFT       19
 #define AMP_VAL_IDX_MASK        (0x0f<<19)
 
+/**
+ * snd_hda_mixer_bind_switch_get - Get callback for a bound volume control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_MUTE*() macros.
+ */
 int snd_hda_mixer_bind_switch_get(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
 {
@@ -1779,6 +2008,12 @@ int snd_hda_mixer_bind_switch_get(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_bind_switch_get);
 
+/**
+ * snd_hda_mixer_bind_switch_put - Put callback for a bound volume control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_MUTE*() macros.
+ */
 int snd_hda_mixer_bind_switch_put(struct snd_kcontrol *kcontrol,
                                   struct snd_ctl_elem_value *ucontrol)
 {
@@ -1803,8 +2038,11 @@ int snd_hda_mixer_bind_switch_put(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_bind_switch_put);
 
-/*
- * generic bound volume/swtich controls
+/**
+ * snd_hda_mixer_bind_ctls_info - Info callback for a generic bound control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_VOL() or HDA_BIND_SW() macros.
  */
 int snd_hda_mixer_bind_ctls_info(struct snd_kcontrol *kcontrol,
                                  struct snd_ctl_elem_info *uinfo)
@@ -1823,6 +2061,12 @@ int snd_hda_mixer_bind_ctls_info(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_bind_ctls_info);
 
+/**
+ * snd_hda_mixer_bind_ctls_get - Get callback for a generic bound control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_VOL() or HDA_BIND_SW() macros.
+ */
 int snd_hda_mixer_bind_ctls_get(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
 {
@@ -1840,6 +2084,12 @@ int snd_hda_mixer_bind_ctls_get(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_bind_ctls_get);
 
+/**
+ * snd_hda_mixer_bind_ctls_put - Put callback for a generic bound control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_VOL() or HDA_BIND_SW() macros.
+ */
 int snd_hda_mixer_bind_ctls_put(struct snd_kcontrol *kcontrol,
                                 struct snd_ctl_elem_value *ucontrol)
 {
@@ -1863,6 +2113,12 @@ int snd_hda_mixer_bind_ctls_put(struct snd_kcontrol *kcontrol,
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_bind_ctls_put);
 
+/**
+ * snd_hda_mixer_bind_tlv - TLV callback for a generic bound control
+ *
+ * The control element is supposed to have the private_value field
+ * set up via HDA_BIND_VOL() macro.
+ */
 int snd_hda_mixer_bind_tlv(struct snd_kcontrol *kcontrol, int op_flag,
                            unsigned int size, unsigned int __user *tlv)
 {
@@ -2185,6 +2441,11 @@ static struct snd_kcontrol_new spdif_share_sw = {
         .put = spdif_share_sw_put,
 };
 
+/**
+ * snd_hda_create_spdif_share_sw - create Default PCM switch
+ * @codec: the HDA codec
+ * @mout: multi-out instance
+ */
 int snd_hda_create_spdif_share_sw(struct hda_codec *codec,
                                   struct hda_multi_out *mout)
 {
@@ -2352,7 +2613,12 @@ int snd_hda_codec_write_cache(struct hda_codec *codec, hda_nid_t nid,
 }
 EXPORT_SYMBOL_HDA(snd_hda_codec_write_cache);
 
-/* resume the all commands from the cache */
+/**
+ * snd_hda_codec_resume_cache - Resume the all commands from the cache
+ * @codec: HD-audio codec
+ *
+ * Execute all verbs recorded in the command caches to resume.
+ */
 void snd_hda_codec_resume_cache(struct hda_codec *codec)
 {
         struct hda_cache_head *buffer = codec->cmd_cache.buf.list;
@@ -2778,8 +3044,12 @@ static int snd_hda_query_supported_pcm(struct hda_codec *codec, hda_nid_t nid,
 }
 
 /**
- * snd_hda_is_supported_format - check whether the given node supports
- * the format val
+ * snd_hda_is_supported_format - Check the validity of the format
+ * @codec: HD-audio codec
+ * @nid: NID to check
+ * @format: the HD-audio format value to check
+ *
+ * Check whether the given node supports the format value.
  *
  * Returns 1 if supported, 0 if not.
  */
@@ -2899,6 +3169,7 @@ static int set_pcm_default_values(struct hda_codec *codec,
         return 0;
 }
 
+/* global */
 const char *snd_hda_pcm_type_name[HDA_PCM_NTYPES] = {
         "Audio", "SPDIF", "HDMI", "Modem"
 };
@@ -3216,6 +3487,7 @@ static void hda_keep_power_on(struct hda_codec *codec)
         codec->power_jiffies = jiffies;
 }
 
+/* update the power on/off account with the current jiffies */
 void snd_hda_update_power_acct(struct hda_codec *codec)
 {
         unsigned long delta = jiffies - codec->power_jiffies;
@@ -3226,6 +3498,13 @@ void snd_hda_update_power_acct(struct hda_codec *codec)
         codec->power_jiffies += delta;
 }
 
+/**
+ * snd_hda_power_up - Power-up the codec
+ * @codec: HD-audio codec
+ *
+ * Increment the power-up counter and power up the hardware really when
+ * not turned on yet.
+ */ 
 void snd_hda_power_up(struct hda_codec *codec)
 {
         struct hda_bus *bus = codec->bus;
@@ -3248,9 +3527,13 @@ EXPORT_SYMBOL_HDA(snd_hda_power_up);
 #define power_save(codec)       \
         ((codec)->bus->power_save ? *(codec)->bus->power_save : 0)
 
-#define power_save(codec)       \
-        ((codec)->bus->power_save ? *(codec)->bus->power_save : 0)
-
+/**
+ * snd_hda_power_down - Power-down the codec
+ * @codec: HD-audio codec
+ *
+ * Decrement the power-up counter and schedules the power-off work if
+ * the counter rearches to zero.
+ */ 
 void snd_hda_power_down(struct hda_codec *codec)
 {
         --codec->power_count;
@@ -3264,6 +3547,19 @@ void snd_hda_power_down(struct hda_codec *codec)
 }
 EXPORT_SYMBOL_HDA(snd_hda_power_down);
 
+/**
+ * snd_hda_check_amp_list_power - Check the amp list and update the power
+ * @codec: HD-audio codec
+ * @check: the object containing an AMP list and the status
+ * @nid: NID to check / update
+ *
+ * Check whether the given NID is in the amp list.  If it's in the list,
+ * check the current AMP status, and update the the power-status according
+ * to the mute status.
+ *
+ * This function is supposed to be set or called from the check_power_status
+ * patch ops.
+ */ 
 int snd_hda_check_amp_list_power(struct hda_codec *codec,
                                  struct hda_loopback_check *check,
                                  hda_nid_t nid)
@@ -3305,6 +3601,10 @@ EXPORT_SYMBOL_HDA(snd_hda_check_amp_list_power);
 /*
  * Channel mode helper
  */
+
+/**
+ * snd_hda_ch_mode_info - Info callback helper for the channel mode enum
+ */
 int snd_hda_ch_mode_info(struct hda_codec *codec,
                          struct snd_ctl_elem_info *uinfo,
                          const struct hda_channel_mode *chmode,
@@ -3321,6 +3621,9 @@ int snd_hda_ch_mode_info(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_ch_mode_info);
 
+/**
+ * snd_hda_ch_mode_get - Get callback helper for the channel mode enum
+ */
 int snd_hda_ch_mode_get(struct hda_codec *codec,
                         struct snd_ctl_elem_value *ucontrol,
                         const struct hda_channel_mode *chmode,
@@ -3339,6 +3642,9 @@ int snd_hda_ch_mode_get(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_ch_mode_get);
 
+/**
+ * snd_hda_ch_mode_put - Put callback helper for the channel mode enum
+ */
 int snd_hda_ch_mode_put(struct hda_codec *codec,
                         struct snd_ctl_elem_value *ucontrol,
                         const struct hda_channel_mode *chmode,
@@ -3363,6 +3669,10 @@ EXPORT_SYMBOL_HDA(snd_hda_ch_mode_put);
 /*
  * input MUX helper
  */
+
+/**
+ * snd_hda_input_mux_info_info - Info callback helper for the input-mux enum
+ */
 int snd_hda_input_mux_info(const struct hda_input_mux *imux,
                            struct snd_ctl_elem_info *uinfo)
 {
@@ -3381,6 +3691,9 @@ int snd_hda_input_mux_info(const struct hda_input_mux *imux,
 }
 EXPORT_SYMBOL_HDA(snd_hda_input_mux_info);
 
+/**
+ * snd_hda_input_mux_info_put - Put callback helper for the input-mux enum
+ */
 int snd_hda_input_mux_put(struct hda_codec *codec,
                           const struct hda_input_mux *imux,
                           struct snd_ctl_elem_value *ucontrol,
@@ -3440,7 +3753,10 @@ static void cleanup_dig_out_stream(struct hda_codec *codec, hda_nid_t nid)
         }
 }
 
-/* call each reboot notifier */
+/**
+ * snd_hda_bus_reboot_notify - call the reboot notifier of each codec
+ * @bus: HD-audio bus
+ */
 void snd_hda_bus_reboot_notify(struct hda_bus *bus)
 {
         struct hda_codec *codec;
@@ -3458,8 +3774,8 @@ void snd_hda_bus_reboot_notify(struct hda_bus *bus)
 }
 EXPORT_SYMBOL_HDA(snd_hda_bus_reboot_notify);
 
-/*
- * open the digital out in the exclusive mode
+/**
+ * snd_hda_multi_out_dig_open - open the digital out in the exclusive mode
  */
 int snd_hda_multi_out_dig_open(struct hda_codec *codec,
                                struct hda_multi_out *mout)
@@ -3474,6 +3790,9 @@ int snd_hda_multi_out_dig_open(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_dig_open);
 
+/**
+ * snd_hda_multi_out_dig_prepare - prepare the digital out stream
+ */
 int snd_hda_multi_out_dig_prepare(struct hda_codec *codec,
                                   struct hda_multi_out *mout,
                                   unsigned int stream_tag,
@@ -3487,6 +3806,9 @@ int snd_hda_multi_out_dig_prepare(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_dig_prepare);
 
+/**
+ * snd_hda_multi_out_dig_cleanup - clean-up the digital out stream
+ */
 int snd_hda_multi_out_dig_cleanup(struct hda_codec *codec,
                                   struct hda_multi_out *mout)
 {
@@ -3497,8 +3819,8 @@ int snd_hda_multi_out_dig_cleanup(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_dig_cleanup);
 
-/*
- * release the digital out
+/**
+ * snd_hda_multi_out_dig_close - release the digital out stream
  */
 int snd_hda_multi_out_dig_close(struct hda_codec *codec,
                                 struct hda_multi_out *mout)
@@ -3510,8 +3832,12 @@ int snd_hda_multi_out_dig_close(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_dig_close);
 
-/*
- * set up more restrictions for analog out
+/**
+ * snd_hda_multi_out_analog_open - open analog outputs
+ *
+ * Open analog outputs and set up the hw-constraints.
+ * If the digital outputs can be opened as slave, open the digital
+ * outputs, too.
  */
 int snd_hda_multi_out_analog_open(struct hda_codec *codec,
                                   struct hda_multi_out *mout,
@@ -3556,9 +3882,11 @@ int snd_hda_multi_out_analog_open(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_analog_open);
 
-/*
- * set up the i/o for analog out
- * when the digital out is available, copy the front out to digital out, too.
+/**
+ * snd_hda_multi_out_analog_prepare - Preapre the analog outputs.
+ *
+ * Set up the i/o for analog out.
+ * When the digital out is available, copy the front out to digital out, too.
  */
 int snd_hda_multi_out_analog_prepare(struct hda_codec *codec,
                                      struct hda_multi_out *mout,
@@ -3615,8 +3943,8 @@ int snd_hda_multi_out_analog_prepare(struct hda_codec *codec,
 }
 EXPORT_SYMBOL_HDA(snd_hda_multi_out_analog_prepare);
 
-/*
- * clean up the setting for analog out
+/**
+ * snd_hda_multi_out_analog_cleanup - clean up the setting for analog out
  */
 int snd_hda_multi_out_analog_cleanup(struct hda_codec *codec,
                                      struct hda_multi_out *mout)
@@ -4002,8 +4330,14 @@ EXPORT_SYMBOL_HDA(snd_hda_resume);
  * generic arrays
  */
 
-/* get a new element from the given array
- * if it exceeds the pre-allocated array size, re-allocate the array
+/**
+ * snd_array_new - get a new element from the given array
+ * @array: the array object
+ * 
+ * Get a new element from the given array.  If it exceeds the
+ * pre-allocated array size, re-allocate the array.
+ *
+ * Returns NULL if allocation failed.
  */
 void *snd_array_new(struct snd_array *array)
 {
@@ -4027,7 +4361,10 @@ void *snd_array_new(struct snd_array *array)
 }
 EXPORT_SYMBOL_HDA(snd_array_new);
 
-/* free the given array elements */
+/**
+ * snd_array_free - free the given array elements
+ * @array: the array object
+ */
 void snd_array_free(struct snd_array *array)
 {
         kfree(array->list);
@@ -4037,7 +4374,12 @@ void snd_array_free(struct snd_array *array)
 }
 EXPORT_SYMBOL_HDA(snd_array_free);
 
-/*
+/**
+ * snd_print_pcm_rates - Print the supported PCM rates to the string buffer
+ * @pcm: PCM caps bits
+ * @buf: the string buffer to write
+ * @buflen: the max buffer length
+ *
  * used by hda_proc.c and hda_eld.c
  */
 void snd_print_pcm_rates(int pcm, char *buf, int buflen)
@@ -4056,6 +4398,14 @@ void snd_print_pcm_rates(int pcm, char *buf, int buflen)
 }
 EXPORT_SYMBOL_HDA(snd_print_pcm_rates);
 
+/**
+ * snd_print_pcm_bits - Print the supported PCM fmt bits to the string buffer
+ * @pcm: PCM caps bits
+ * @buf: the string buffer to write
+ * @buflen: the max buffer length
+ *
+ * used by hda_proc.c and hda_eld.c
+ */
 void snd_print_pcm_bits(int pcm, char *buf, int buflen)
 {
         static unsigned int bits[] = { 8, 16, 20, 24, 32 };