ALSA: hda - Add regmap support

This patch adds an infrastructure to support regmap-based verb
accesses.  Because o the asymmetric nature of HD-audio verbs,
especially the amp verbs, we need to translate the verbs as a sort of
pseudo registers to be mapped uniquely in regmap.

In this patch, a pseudo register is built from the NID, the
AC_VERB_GET_* and 8bit parameters, i.e. almost in the form to be sent
to HD-audio bus but without codec address field.  OTOH, for writing,
the same pseudo register is translated to AC_VERB_SET_* automatically.
The AC_VERB_SET_AMP_* verb is re-encoded from the corresponding
AC_VERB_GET_AMP_* verb and parameter at writing.

Some verbs has a single command for read but multiple for writes.  A
write for such a verb is split automatically to multiple verbs.

The patch provides also a few handy helper functions.  They are
designed to be accessible even without regmap.  When no regmap is set
up (e.g. before the codec device instantiation), the direct hardware
access is used.  Also, it tries to avoid the unnecessary power-up.
The power up/down sequence is performed only on demand.

The codec driver needs to call snd_hdac_regmap_exit() and
snd_hdac_regmap_exit() at probe and remove if it wants the regmap
access.

There is one flag added to hdac_device.  When the flag lazy_cache is
set, regmap helper ignores a write for a suspended device and returns
as if it was actually written.  It reduces the hardware access pretty
much, e.g. when adjusting the mixer volume while in idle.  This
assumes that the driver will sync the cache later at resume properly,
so use it carefully.

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

2 files changed, 149 insertions, 0 deletions

diff --git a/include/sound/hda_regmap.h b/include/sound/hda_regmap.h
new file mode 100644
index 000000000000..95651d26437d
--- /dev/null
+++ b/include/sound/hda_regmap.h
@@ -0,0 +1,145 @@
+/*
+ * HD-audio regmap helpers
+ */
+
+#ifndef __SOUND_HDA_REGMAP_H
+#define __SOUND_HDA_REGMAP_H
+
+#include <linux/regmap.h>
+#include <sound/core.h>
+#include <sound/hdaudio.h>
+
+int snd_hdac_regmap_init(struct hdac_device *codec);
+void snd_hdac_regmap_exit(struct hdac_device *codec);
+
+int snd_hdac_regmap_read_raw(struct hdac_device *codec, unsigned int reg,
+			     unsigned int *val);
+int snd_hdac_regmap_write_raw(struct hdac_device *codec, unsigned int reg,
+			      unsigned int val);
+int snd_hdac_regmap_update_raw(struct hdac_device *codec, unsigned int reg,
+			       unsigned int mask, unsigned int val);
+
+/**
+ * snd_hdac_regmap_encode_verb - encode the verb to a pseudo register
+ * @nid: widget NID
+ * @verb: codec verb
+ *
+ * Returns an encoded pseudo register.
+ */
+#define snd_hdac_regmap_encode_verb(nid, verb)		\
+	(((verb) << 8) | 0x80000 | ((unsigned int)(nid) << 20))
+
+/**
+ * snd_hdac_regmap_encode_amp - encode the AMP verb to a pseudo register
+ * @nid: widget NID
+ * @ch: channel (left = 0, right = 1)
+ * @dir: direction (#HDA_INPUT, #HDA_OUTPUT)
+ * @idx: input index value
+ *
+ * Returns an encoded pseudo register.
+ */
+#define snd_hdac_regmap_encode_amp(nid, ch, dir, idx)			\
+	(snd_hdac_regmap_encode_verb(nid, AC_VERB_GET_AMP_GAIN_MUTE) |	\
+	 ((ch) ? AC_AMP_GET_RIGHT : AC_AMP_GET_LEFT) |			\
+	 ((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
+ * @val: value to write
+ *
+ * For writing an amp value, use snd_hda_regmap_amp_update().
+ */
+static inline int
+snd_hdac_regmap_write(struct hdac_device *codec, hda_nid_t nid,
+		      unsigned int verb, unsigned int val)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_verb(nid, verb);
+
+	return snd_hdac_regmap_write_raw(codec, cmd, val);
+}
+
+/**
+ * snd_hda_regmap_update - Update a verb value with caching
+ * @nid: codec NID
+ * @verb: verb to update
+ * @mask: bit mask to update
+ * @val: value to update
+ *
+ * For updating an amp value, use snd_hda_regmap_amp_update().
+ */
+static inline int
+snd_hdac_regmap_update(struct hdac_device *codec, hda_nid_t nid,
+		       unsigned int verb, unsigned int mask,
+		       unsigned int val)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_verb(nid, verb);
+
+	return snd_hdac_regmap_update_raw(codec, cmd, mask, val);
+}
+
+/**
+ * snd_hda_regmap_read - Read a verb with caching
+ * @nid: codec NID
+ * @verb: verb to read
+ * @val: pointer to store the value
+ *
+ * For reading an amp value, use snd_hda_regmap_get_amp().
+ */
+static inline int
+snd_hdac_regmap_read(struct hdac_device *codec, hda_nid_t nid,
+		     unsigned int verb, unsigned int *val)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_verb(nid, verb);
+
+	return snd_hdac_regmap_read_raw(codec, cmd, val);
+}
+
+/**
+ * snd_hdac_regmap_get_amp - 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)
+ * @val: the pointer to store the value
+ *
+ * Read AMP value.  The volume is between 0 to 0x7f, 0x80 = mute bit.
+ * Returns the value or a negative error.
+ */
+static inline int
+snd_hdac_regmap_get_amp(struct hdac_device *codec, hda_nid_t nid,
+			int ch, int dir, int idx)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_amp(nid, ch, dir, idx);
+	int err, val;
+
+	err = snd_hdac_regmap_read_raw(codec, cmd, &val);
+	return err < 0 ? err : val;
+}
+
+/**
+ * snd_hdac_regmap_update_amp - 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, or a negative error.
+ */
+static inline int
+snd_hdac_regmap_update_amp(struct hdac_device *codec, hda_nid_t nid,
+			   int ch, int dir, int idx, int mask, int val)
+{
+	unsigned int cmd = snd_hdac_regmap_encode_amp(nid, ch, dir, idx);
+
+	return snd_hdac_regmap_update_raw(codec, cmd, mask, val);
+}
+
+#endif /* __SOUND_HDA_REGMAP_H */
diff --git a/include/sound/hdaudio.h b/include/sound/hdaudio.h
index 3abdd3f16528..47e20b741c51 100644
--- a/include/sound/hdaudio.h
+++ b/include/sound/hdaudio.h
@@ -72,6 +72,10 @@ struct hdac_device {
 
 	/* sysfs */
 	struct hdac_widget_tree *widgets;
+
+	/* regmap */
+	struct regmap *regmap;
+	bool lazy_cache:1;	/* don't wake up for writes */
 };
 
 /* device/driver type used for matching */