[RFC V4 PATCH 03/19] ALSA: mixer_audient: clarify USB control message definition

[Christian Ruppert <arc@gmx.li>]

Previously, base values for wIndex and wValue were directly given in the
control type. Construct them from a unit ID and selector for clarity.

Signed-off-by: Christian Ruppert <arc@gmx.li>
Signed-off-by: Will Porter <mrwillporter@gmail.com>
---
 sound/usb/mixer_audient.c | 76 +++++++++++++++++++++------------------
 1 file changed, 41 insertions(+), 35 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 2afef52a12d9..63714d00592c 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -45,15 +45,15 @@ static const struct snd_audient_ctrl_type {
 		int integer;
 	} max;
 	const unsigned int *tlv;
-	u16 wValue;
-	u16 wIndex;
+	u8 unit;
+	u8 sel;
 } snd_audient_ctypes[SND_AUDIENT_TYPE_NCTYPES] = {
 	[SND_AUDIENT_TYPE_MONITOR] = {
 		.type = SNDRV_CTL_ELEM_TYPE_INTEGER,
 		.min.integer = 0,
 		.max.integer = 127,
-		.wValue = 0x0000,
-		.wIndex = 0x3800,
+		.unit = 0x38,
+		.sel = 0x00,
 		/* no TLV here because we can't describe the cross-fader */
 	},
 	[SND_AUDIENT_TYPE_PHANTOM] = {
@@ -61,31 +61,31 @@ static const struct snd_audient_ctrl_type {
 		.invert = false,
 		.min.integer = 0,
 		.max.integer = 1,
-		.wValue = 0x0000,
-		.wIndex = 0x3A00,
+		.unit = 0x3A,
+		.sel = 0x00,
 	},
 	[SND_AUDIENT_TYPE_MUTE] = {
 		.type = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
 		.invert = true,
 		.min.integer = 0,
 		.max.integer = 1,
-		.wValue = 0x0200,
-		.wIndex = 0x3A00,
+		.unit = 0x3A,
+		.sel = 0x02,
 	},
 	[SND_AUDIENT_TYPE_MUTE_OUT] = {
 		.type = SNDRV_CTL_ELEM_TYPE_BOOLEAN,
 		.invert = true,
 		.min.integer = 0,
 		.max.integer = 1,
-		.wValue = 0x0100,
-		.wIndex = 0x3B00,
+		.unit = 0x3B,
+		.sel = 0x01,
 	},
 	[SND_AUDIENT_TYPE_MIXER] = {
 		.type = SNDRV_CTL_ELEM_TYPE_INTEGER,
 		.min.integer = -128 * 256,
 		.max.integer = 6 * 256,
-		.wValue = 0x0100,
-		.wIndex = 0x3C00,
+		.unit = 0x3C,
+		.sel = 0x01,
 		.tlv = snd_audient_tlv_mixer,
 	},
 };
@@ -209,7 +209,7 @@ const struct snd_audient_ctrl_type *snd_audient_kctl_type(struct snd_kcontrol
 	return &snd_audient_ctypes[kctl->private_value & 0xFF];
 }
 
-static __always_inline u16 snd_audient_kctl_valoffs(struct snd_kcontrol *kctl)
+static __always_inline u16 snd_audient_kctl_cidxoffs(struct snd_kcontrol *kctl)
 {
 	return (kctl->private_value >> 8) & 0xFF;
 }
@@ -233,11 +233,16 @@ static inline u16 snd_audient_kctl_channels(struct snd_kcontrol *kctl)
 #define AUDIENT_REQTYPE_GET (USB_DIR_IN  | USB_TYPE_CLASS \
 					 | USB_RECIP_INTERFACE)
 
+#define U8_U8(HI, LO) ((((u16)(HI)) << 8) | ((LO) & 0xFF))
+
 static inline int snd_audient_get_cur(struct usb_mixer_interface *mixer,
-				      u16 value, u16 index,
-				      void *buf, size_t len)
+				      const u8 unit, const u8 sel,
+				      const u8 cidx,
+				      void *const buf, const size_t len)
 {
 	struct usb_device *const dev = mixer->chip->dev;
+	const u16 value = U8_U8(sel, cidx);
+	const u16 index = U8_U8(unit, mixer->hostif->desc.bInterfaceNumber);
 
 	return snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
 			       UAC2_CS_CUR, AUDIENT_REQTYPE_GET,
@@ -245,10 +250,13 @@ static inline int snd_audient_get_cur(struct usb_mixer_interface *mixer,
 }
 
 static inline int snd_audient_set_cur(struct usb_mixer_interface *mixer,
-				      u16 value, u16 index,
-				      void *buf, size_t len)
+				      const u8 unit, const u8 sel,
+				      const u8 cidx,
+				      void *const buf, const size_t len)
 {
 	struct usb_device *const dev = mixer->chip->dev;
+	const u16 value = U8_U8(sel, cidx);
+	const u16 index = U8_U8(unit, mixer->hostif->desc.bInterfaceNumber);
 
 	return snd_usb_ctl_msg(dev, usb_sndctrlpipe(dev, 0),
 			       UAC2_CS_CUR, AUDIENT_REQTYPE_SET,
@@ -266,8 +274,7 @@ static int snd_ctl_audient_boolean_get(struct snd_kcontrol *kctl,
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
 						= snd_audient_kctl_type(kctl);
-	const u16 value = ctype->wValue + snd_audient_kctl_valoffs(kctl);
-	const u16 index = ctype->wIndex;
+	const u8 base = snd_audient_kctl_cidxoffs(kctl);
 
 	int i;
 
@@ -279,8 +286,8 @@ static int snd_ctl_audient_boolean_get(struct snd_kcontrol *kctl,
 		u32 buf;
 		int ret;
 
-		ret = snd_audient_get_cur(mixer, value + i, index,
-					  &buf, sizeof(buf));
+		ret = snd_audient_get_cur(mixer, ctype->unit, ctype->sel,
+					  base + i, &buf, sizeof(buf));
 		if (ret < 0)
 			return ret;
 
@@ -307,8 +314,7 @@ static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
 						= snd_audient_kctl_type(kctl);
-	const u16 value = ctype->wValue + snd_audient_kctl_valoffs(kctl);
-	const u16 index = ctype->wIndex;
+	const u8 base = snd_audient_kctl_cidxoffs(kctl);
 
 	int changed = 0;
 	int i;
@@ -325,15 +331,16 @@ static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
 		if (ctype->invert)
 			buf ^= cpu_to_le32(0x1);
 
-		ret = snd_audient_get_cur(mixer, value + i, index,
-				      &rbuf, sizeof(rbuf));
+		ret = snd_audient_get_cur(mixer, ctype->unit, ctype->sel,
+					  base + i, &rbuf, sizeof(rbuf));
 		if (ret < 0)
 			return ret;
 
 		if (rbuf != buf) {
 			changed = 1;
 
-			ret = snd_audient_set_cur(mixer, value + i, index,
+			ret = snd_audient_set_cur(mixer, ctype->unit,
+						  ctype->sel, base + i,
 						  &buf, sizeof(buf));
 			if (ret < 0)
 				return ret;
@@ -353,8 +360,7 @@ static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
 						= snd_audient_kctl_type(kctl);
-	const u16 value = ctype->wValue + snd_audient_kctl_valoffs(kctl);
-	const u16 index = ctype->wIndex;
+	const u8 base = snd_audient_kctl_cidxoffs(kctl);
 
 	int i;
 
@@ -367,8 +373,8 @@ static int snd_ctl_audient_integer_get(struct snd_kcontrol *kctl,
 		s16 val;
 		int ret;
 
-		ret = snd_audient_get_cur(mixer, value + i, index,
-					  &buf, sizeof(buf));
+		ret = snd_audient_get_cur(mixer, ctype->unit, ctype->sel,
+					  base + i, &buf, sizeof(buf));
 		if (ret < 0)
 			return ret;
 
@@ -391,8 +397,7 @@ static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 	const unsigned int hwchan = snd_audient_kctl_hwchannels(kctl);
 	const struct snd_audient_ctrl_type *const ctype
 						= snd_audient_kctl_type(kctl);
-	const u16 value = ctype->wValue + snd_audient_kctl_valoffs(kctl);
-	const u16 index = ctype->wIndex;
+	const u8 base = snd_audient_kctl_cidxoffs(kctl);
 
 	int changed = 0;
 	int i;
@@ -406,15 +411,16 @@ static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 		s16 buf = cpu_to_le16(ctl_val->value.integer.value[i]);
 		int ret;
 
-		ret = snd_audient_get_cur(mixer, value + i, index,
-					  &rbuf, sizeof(rbuf));
+		ret = snd_audient_get_cur(mixer, ctype->unit, ctype->sel,
+					  base + i, &rbuf, sizeof(rbuf));
 		if (ret < 0)
 			return ret;
 
 		if (rbuf != buf) {
 			changed = 1;
 
-			ret = snd_audient_set_cur(mixer, value + i, index,
+			ret = snd_audient_set_cur(mixer, ctype->unit,
+						  ctype->sel, base + i,
 						  &buf, sizeof(buf));
 			if (ret < 0)
 				return ret;
-- 
2.56.1