[RFC PATCH 10/11] ALSA: mixer_audient: add control value caching

[Christian Ruppert <arc@gmx.li>]

In preparation of id14 support, add control value caching.

Signed-off-by: Christian Ruppert <arc@gmx.li>
---
 sound/usb/mixer_audient.c | 112 +++++++++++++++++++++++++++-----------
 1 file changed, 81 insertions(+), 31 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 7cb8245a64d0..24b594fb1bc7 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -38,6 +38,7 @@ static const DECLARE_TLV_DB_MINMAX_MUTE(snd_audient_tlv_mixer, -12800, 600);
 #define SND_AUDIENT_CTYPE_FLAGS_SIGNED		(1L <<  0)
 #define SND_AUDIENT_CTYPE_FLAGS_INIT_HW		(1L <<  1)
 #define SND_AUDIENT_CTYPE_FLAGS_FORCE_SET	(1L <<  2)
+#define SND_AUDIENT_CTYPE_FLAGS_CACHE		(1L <<  3)
 
 static const struct snd_audient_ctrl_type {
 	snd_ctl_elem_type_t type;
@@ -49,7 +50,7 @@ static const struct snd_audient_ctrl_type {
 	union {
 		long integer;
 	} max;		/* for booleans holds physical int value for true */
-	u32 init;
+	u32 init;	/* hardware and cache are initialized to this value */
 	const unsigned int *tlv;
 	u8 unit;
 	u8 sel;
@@ -89,7 +90,8 @@ static const struct snd_audient_ctrl_type {
 	},
 	[SND_AUDIENT_TYPE_MIXER] = {
 		.type = SNDRV_CTL_ELEM_TYPE_INTEGER,
-		.flags = SND_AUDIENT_CTYPE_FLAGS_SIGNED,
+		.flags = SND_AUDIENT_CTYPE_FLAGS_SIGNED
+			 | SND_AUDIENT_CTYPE_FLAGS_CACHE,
 		.len = 2,
 		.min.integer = -128 * 256,
 		.max.integer = 6 * 256,
@@ -285,11 +287,18 @@ static inline int snd_audient_set_cur(struct usb_mixer_interface *mixer,
 
 static int snd_audient_raw_get_one(struct usb_mixer_interface *const mixer,
 			const struct snd_audient_ctrl_type *const ctype,
+			const u32 *const cache,
 			const u8 cidx, u32 *const value)
 {
 	int ret;
 	s32 buf = 0;
 
+	if (cache) {
+		*value = cache[cidx];
+
+		return ctype->len;
+	}
+
 	ret = snd_audient_get_cur(mixer, ctype, cidx, &buf);
 	if (ret < 0)
 		return ret;
@@ -309,15 +318,16 @@ static int snd_audient_raw_get_one(struct usb_mixer_interface *const mixer,
 
 static int snd_audient_raw_set_one(struct usb_mixer_interface *const mixer,
 			const struct snd_audient_ctrl_type *const ctype,
-			const u8 cidx, const u32 value)
+			u32 *const cache, const u8 cidx, const u32 value,
+			bool force)
 {
 	int ret;
 	u32 buf;
 
-	if (ctype->flags & SND_AUDIENT_CTYPE_FLAGS_FORCE_SET) {
+	if ((ctype->flags & SND_AUDIENT_CTYPE_FLAGS_FORCE_SET) || force) {
 		buf = !value;		/* just make it different */
 	} else {
-		ret = snd_audient_raw_get_one(mixer, ctype, cidx, &buf);
+		ret = snd_audient_raw_get_one(mixer, ctype, cache, cidx, &buf);
 		if (ret < 0)
 			return ret;
 	}
@@ -328,6 +338,9 @@ static int snd_audient_raw_set_one(struct usb_mixer_interface *const mixer,
 		if (ret < 0)
 			return ret;
 
+		if (cache)
+			cache[cidx] = value;
+
 		return 1;
 	}
 
@@ -338,8 +351,8 @@ static int snd_audient_raw_set_one(struct usb_mixer_interface *const mixer,
 static int snd_ctl_audient_boolean_get(struct snd_kcontrol *kctl,
 				       struct snd_ctl_elem_value *ctl_val)
 {
-	struct usb_mixer_elem_list *const list = snd_kcontrol_chip(kctl);
-	struct usb_mixer_interface *const mixer = list->mixer;
+	struct usb_mixer_elem_info *const elem = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *const mixer = elem->head.mixer;
 
 	const unsigned int nchan = snd_audient_kctl_channels(kctl);
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
@@ -357,7 +370,8 @@ static int snd_ctl_audient_boolean_get(struct snd_kcontrol *kctl,
 		u32 buf;
 		int ret;
 
-		ret = snd_audient_raw_get_one(mixer, ctype, base + i, &buf);
+		ret = snd_audient_raw_get_one(mixer, ctype, elem->private_data,
+					      base + i, &buf);
 		if (ret < 0)
 			return ret;
 
@@ -374,8 +388,8 @@ static int snd_ctl_audient_boolean_get(struct snd_kcontrol *kctl,
 static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
 				       struct snd_ctl_elem_value *ctl_val)
 {
-	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
-	struct usb_mixer_interface *mixer = list->mixer;
+	struct usb_mixer_elem_info *const elem = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *const mixer = elem->head.mixer;
 
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
@@ -394,7 +408,8 @@ static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
 							  : ctype->min.integer;
 		int ret;
 
-		ret = snd_audient_raw_set_one(mixer, ctype, base + i, buf);
+		ret = snd_audient_raw_set_one(mixer, ctype, elem->private_data,
+					      base + i, buf, false);
 		if (ret < 0)
 			return ret;
 
@@ -408,8 +423,8 @@ static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
 static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 				   struct snd_ctl_elem_value *ctl_val)
 {
-	struct usb_mixer_elem_list *const list = snd_kcontrol_chip(kctl);
-	struct usb_mixer_interface *const mixer = list->mixer;
+	struct usb_mixer_elem_info *const elem = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *const mixer = elem->head.mixer;
 
 	const unsigned int nchan = snd_audient_kctl_channels(kctl);
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
@@ -427,7 +442,8 @@ static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 		s32 val;
 		int ret;
 
-		ret = snd_audient_raw_get_one(mixer, ctype, base + i, &val);
+		ret = snd_audient_raw_get_one(mixer, ctype, elem->private_data,
+					      base + i, &val);
 		if (ret < 0)
 			return ret;
 
@@ -449,8 +465,8 @@ static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 				   struct snd_ctl_elem_value *ctl_val)
 {
-	struct usb_mixer_elem_list *list = snd_kcontrol_chip(kctl);
-	struct usb_mixer_interface *mixer = list->mixer;
+	struct usb_mixer_elem_info *const elem = snd_kcontrol_chip(kctl);
+	struct usb_mixer_interface *mixer = elem->head.mixer;
 
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
@@ -475,7 +491,8 @@ static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 		s32 val = ctl_val->value.integer.value[i];
 		int ret;
 
-		ret = snd_audient_raw_set_one(mixer, ctype, base + i, val);
+		ret = snd_audient_raw_set_one(mixer, ctype, elem->private_data,
+					      base + i, val, false);
 		if (ret < 0)
 			return ret;
 
@@ -516,6 +533,8 @@ static int snd_audient_add_ctrl(struct usb_mixer_interface *mixer,
 	struct snd_kcontrol *kctl;
 	struct usb_mixer_elem_info *elem;
 
+	int ret;
+
 	knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
 	knew.name = ctrl->name;
 	knew.info = snd_ctl_audient_info;
@@ -523,7 +542,9 @@ static int snd_audient_add_ctrl(struct usb_mixer_interface *mixer,
 						   ctrl->hwchannels);
 	knew.tlv.p = ctype->tlv;
 	knew.access = SNDRV_CTL_ELEM_ACCESS_READWRITE
-			| SNDRV_CTL_ELEM_ACCESS_VOLATILE
+			| ((ctype->flags & SND_AUDIENT_CTYPE_FLAGS_CACHE)
+			   ? 0
+			   : SNDRV_CTL_ELEM_ACCESS_VOLATILE)
 			| (ctype->tlv ? SNDRV_CTL_ELEM_ACCESS_TLV_READ : 0);
 
 	switch (ctype->type) {
@@ -539,34 +560,63 @@ static int snd_audient_add_ctrl(struct usb_mixer_interface *mixer,
 		return -EINVAL;
 	}
 
+	elem = kzalloc(sizeof(*elem)
+		       + ((ctype->flags & SND_AUDIENT_CTYPE_FLAGS_CACHE)
+			  ? (sizeof(u32) * ctrl->hwchannels)
+			  : 0),
+		       GFP_KERNEL);
+	if (!elem)
+		return -ENOMEM;
+
+	elem->head.mixer = mixer;
+	elem->channels = ctrl->channels;
+
+	if (ctype->flags & SND_AUDIENT_CTYPE_FLAGS_CACHE)
+		elem->private_data = elem + 1;
+
 	if (ctype->flags & SND_AUDIENT_CTYPE_FLAGS_INIT_HW) {
 		int i;
 
 		for (i = 0; i < ctrl->hwchannels; i++) {
-			int ret = snd_audient_raw_set_one(mixer, ctype,
-							  ctrl->val_offs + i,
-							  ctype->init);
+			ret = snd_audient_raw_set_one(mixer, ctype,
+						      elem->private_data,
+						      ctrl->val_offs + i,
+						      ctype->init, true);
 			if (ret < 0)
-				return ret;
+				goto free_elem;
 		}
-	}
-
-	elem = kzalloc_obj(*elem);
-	if (!elem)
-		return -ENOMEM;
+	} else if (elem->private_data) {
+		u32 *const cache = elem->private_data;
+		int i;
 
-	elem->head.mixer = mixer;
-	elem->channels = ctrl->channels;
+		if (ctype->flags & SND_AUDIENT_CTYPE_FLAGS_FORCE_SET)
+			for (i = 0; i < ctrl->hwchannels; i++)
+				cache[i] = ctype->init;
+		else
+			for (i = 0; i < ctrl->hwchannels; i++) {
+				ret = snd_audient_raw_get_one(
+							mixer, ctype, NULL,
+							ctrl->val_offs + i,
+							cache + i);
+				if (ret < 0)
+					goto free_elem;
+			}
+	}
 
 	kctl = snd_ctl_new1(&knew, elem);
 	if (!kctl) {
-		kfree(elem);
-		return -ENOMEM;
+		ret = -ENOMEM;
+		goto free_elem;
 	}
 
 	kctl->private_free = snd_usb_mixer_elem_free;
 
 	return snd_usb_mixer_add_control(&elem->head, kctl);
+
+free_elem:
+	kfree(elem);
+
+	return ret;
 }
 
 
-- 
2.56.0