ALSA: hda - Add a fake stereo amp register support

HD-audio spec is inconvenient regarding the handling of stereo volume
controls.  It can set and get only single channel at once (although
there is a special option to set the same value to both channels).
This patch provides a fake pseudo-register via the regmap access so
that the stereo channels can be read and written by a single call.
It'd be useful, for example, for implementing DAPM widgets.

A stereo amp pseudo register consists of the encoding like the normal
amp verbs but it has both SET_LEFT (bit 13) and SET_RIGHT (bit 12)
bits set.  The regmap reads and writes a 16bit value for this pseudo
register where the upper 8bit is for the right chanel and the lower
8bit for the left channel.

Note that the driver doesn't recognize conflicts when both stereo and
mono channel registers are mixed.  Mixing them would certainly confuse
the operation.  So, use carefully.

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

1 files changed, 59 insertions, 0 deletions

diff --git a/include/sound/hda_regmap.h b/include/sound/hda_regmap.h
index a6a4f3ddb469..76648ccfbbf8 100644
--- a/include/sound/hda_regmap.h
+++ b/include/sound/hda_regmap.h
@@ -46,6 +46,20 @@ int snd_hdac_regmap_update_raw(struct hdac_device *codec, unsigned int reg,
 	 (idx))
 
 /**
+ * snd_hdac_regmap_encode_amp_stereo - encode a pseudo register for stereo AMPs
+ * @nid: widget NID
+ * @dir: direction (#HDA_INPUT, #HDA_OUTPUT)
+ * @idx: input index value
+ *
+ * Returns an encoded pseudo register.
+ */
+#define snd_hdac_regmap_encode_amp_stereo(nid, dir, idx)		\
+	(snd_hdac_regmap_encode_verb(nid, AC_VERB_GET_AMP_GAIN_MUTE) |	\
+	 AC_AMP_SET_LEFT | AC_AMP_SET_RIGHT | /* both bits set! */	\
+	 ((dir) == HDA_OUTPUT ? AC_AMP_GET_OUTPUT : AC_AMP_GET_INPUT) | \
+	 (idx))
+
+/**
  * snd_hdac_regmap_write - Write a verb with caching
  * @nid: codec NID
  * @reg: verb to write
@@ -143,4 +157,49 @@ snd_hdac_regmap_update_amp(struct hdac_device *codec, hda_nid_t nid,
 	return snd_hdac_regmap_update_raw(codec, cmd, mask, val);
 }
 
+/**
+ * snd_hdac_regmap_get_amp_stereo - Read stereo AMP values
+ * @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)
+ * @val: the pointer to store the value
+ *
+ * Read stereo AMP values.  The lower byte is left, the upper byte is right.
+ * Returns the value or a negative error.
+ */
+static inline int
+snd_hdac_regmap_get_amp_stereo(struct hdac_device *codec, hda_nid_t nid,
+			       int dir, int idx)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_amp_stereo(nid, dir, idx);
+	int err, val;
+
+	err = snd_hdac_regmap_read_raw(codec, cmd, &val);
+	return err < 0 ? err : val;
+}
+
+/**
+ * snd_hdac_regmap_update_amp_stereo - update the stereo AMP value
+ * @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 stereo AMP value with a bit mask.
+ * The lower byte is left, the upper byte is right.
+ * Returns 0 if the value is unchanged, 1 if changed, or a negative error.
+ */
+static inline int
+snd_hdac_regmap_update_amp_stereo(struct hdac_device *codec, hda_nid_t nid,
+				  int dir, int idx, int mask, int val)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_amp_stereo(nid, dir, idx);
+
+	return snd_hdac_regmap_update_raw(codec, cmd, mask, val);
+}
+
 #endif /* __SOUND_HDA_REGMAP_H */