ALSA: scarlett2: Remove struct scarlett2_usb_volume_status

The struct scarlett2_usb_volume_status matched the config space layout
of a few volume controls that could be read together and were in fixed
locations between Gen 2 and Gen 3 devices.

Gen 4 devices have removed, moved, and new related controls, so this
needs to be cleaned up. By adding SCARLETT2_CONFIG_MASTER_VOLUME (the
only config item that didn't already have its own entry, because it is
read-only), we can remove:
- struct scarlett2_usb_volume_state,
- #define SCARLETT2_USB_VOLUME_STATUS_OFFSET, and
- scarlett2_usb_get_volume_status()
and replace with calls to scarlett2_usb_get_config().
Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/2ee88994857246bf89fab8e62ac279f3bcf96192.1703444932.git.g@b4.vuSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_scarlett2.c

@@ -292,6 +292,7 @@ enum {
 	SCARLETT2_CONFIG_LINE_OUT_VOLUME,
 	SCARLETT2_CONFIG_MUTE_SWITCH,
 	SCARLETT2_CONFIG_SW_HW_SWITCH,
+	SCARLETT2_CONFIG_MASTER_VOLUME,
 	SCARLETT2_CONFIG_LEVEL_SWITCH,
 	SCARLETT2_CONFIG_PAD_SWITCH,
 	SCARLETT2_CONFIG_MSD_SWITCH,
@@ -336,6 +337,9 @@ static const struct scarlett2_config_set scarlett2_config_set_gen2 = {
 		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
 			.offset = 0x66, .size = 8, .activate = 3 },
 
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
 		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
 			.offset = 0x7c, .size = 8, .activate = 7 },
 
@@ -387,6 +391,9 @@ static const struct scarlett2_config_set scarlett2_config_set_gen3b = {
 		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
 			.offset = 0x66, .size = 8, .activate = 3 },
 
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
 		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
 			.offset = 0x7c, .size = 8, .activate = 7 },
 
@@ -435,6 +442,9 @@ static const struct scarlett2_config_set scarlett2_config_set_clarett = {
 		[SCARLETT2_CONFIG_SW_HW_SWITCH] = {
 			.offset = 0x66, .size = 8, .activate = 3 },
 
+		[SCARLETT2_CONFIG_MASTER_VOLUME] = {
+			.offset = 0x76, .size = 16 },
+
 		[SCARLETT2_CONFIG_LEVEL_SWITCH] = {
 			.offset = 0x7c, .size = 8, .activate = 7 },
 
@@ -1330,7 +1340,6 @@ static int scarlett2_get_port_start_num(
 
 #define SCARLETT2_USB_CONFIG_SAVE 6
 
-#define SCARLETT2_USB_VOLUME_STATUS_OFFSET 0x31
 #define SCARLETT2_USB_METER_LEVELS_GET_MAGIC 1
 
 #define SCARLETT2_FLASH_BLOCK_SIZE 4096
@@ -1341,31 +1350,6 @@ static int scarlett2_get_port_start_num(
 #define SCARLETT2_SEGMENT_SETTINGS_NAME "App_Settings"
 #define SCARLETT2_SEGMENT_FIRMWARE_NAME "App_Upgrade"
 
-/* volume status is read together (matches scarlett2_config_items[1]) */
-struct scarlett2_usb_volume_status {
-	/* dim/mute buttons */
-	u8 dim_mute[SCARLETT2_DIM_MUTE_COUNT];
-
-	u8 pad1;
-
-	/* software volume setting */
-	s16 sw_vol[SCARLETT2_ANALOGUE_MAX];
-
-	/* actual volume of output inc. dim (-18dB) */
-	s16 hw_vol[SCARLETT2_ANALOGUE_MAX];
-
-	/* internal mute buttons */
-	u8 mute_switch[SCARLETT2_ANALOGUE_MAX];
-
-	/* sw (0) or hw (1) controlled */
-	u8 sw_hw_switch[SCARLETT2_ANALOGUE_MAX];
-
-	u8 pad3[6];
-
-	/* front panel volume knob */
-	s16 master_vol;
-} __packed;
-
 /* proprietary request/response format */
 struct scarlett2_usb_packet {
 	__le32 cmd;
@@ -1725,15 +1709,6 @@ static int scarlett2_usb_get_sync_status(
 	return 0;
 }
 
-/* Send a USB message to get volume status; result placed in *buf */
-static int scarlett2_usb_get_volume_status(
-	struct usb_mixer_interface *mixer,
-	struct scarlett2_usb_volume_status *buf)
-{
-	return scarlett2_usb_get(mixer, SCARLETT2_USB_VOLUME_STATUS_OFFSET,
-				 buf, sizeof(*buf));
-}
-
 /* Return true if the device has a mixer that we can control */
 static int scarlett2_has_mixer(struct scarlett2_data *private)
 {
@@ -2245,23 +2220,32 @@ static int scarlett2_update_volumes(struct usb_mixer_interface *mixer)
 {
 	struct scarlett2_data *private = mixer->private_data;
 	const struct scarlett2_device_info *info = private->info;
-	struct scarlett2_usb_volume_status volume_status;
+	s16 vol;
 	int err, i;
 	int mute;
 
 	private->vol_updated = 0;
 
-	err = scarlett2_usb_get_volume_status(mixer, &volume_status);
+	if (!info->line_out_hw_vol)
+		return 0;
+
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_MASTER_VOLUME,
+		1, &vol);
 	if (err < 0)
 		return err;
 
-	private->master_vol = clamp(
-		volume_status.master_vol + SCARLETT2_VOLUME_BIAS,
-		0, SCARLETT2_VOLUME_BIAS);
+	private->master_vol = clamp(vol + SCARLETT2_VOLUME_BIAS,
+				    0, SCARLETT2_VOLUME_BIAS);
 
-	if (info->line_out_hw_vol)
-		for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
-			private->dim_mute[i] = !!volume_status.dim_mute[i];
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_DIM_MUTE,
+		SCARLETT2_DIM_MUTE_COUNT, private->dim_mute);
+	if (err < 0)
+		return err;
+
+	for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
+		private->dim_mute[i] = !!private->dim_mute[i];
 
 	mute = private->dim_mute[SCARLETT2_BUTTON_MUTE];
 
@@ -4518,8 +4502,8 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
 {
 	struct scarlett2_data *private = mixer->private_data;
 	const struct scarlett2_device_info *info = private->info;
-	struct scarlett2_usb_volume_status volume_status;
 	int err, i;
+	s16 sw_vol[SCARLETT2_ANALOGUE_MAX];
 
 	if (scarlett2_has_config_item(private, SCARLETT2_CONFIG_MSD_SWITCH)) {
 		err = scarlett2_usb_get_config(
@@ -4558,38 +4542,46 @@ static int scarlett2_read_configs(struct usb_mixer_interface *mixer)
 	if (err < 0)
 		return err;
 
-	err = scarlett2_usb_get_volume_status(mixer, &volume_status);
+	/* read SW line out volume */
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_LINE_OUT_VOLUME,
+		private->num_line_out, &sw_vol);
 	if (err < 0)
 		return err;
 
-	if (info->line_out_hw_vol)
-		for (i = 0; i < SCARLETT2_DIM_MUTE_COUNT; i++)
-			private->dim_mute[i] = !!volume_status.dim_mute[i];
+	for (i = 0; i < private->num_line_out; i++)
+		private->vol[i] = clamp(
+			sw_vol[i] + SCARLETT2_VOLUME_BIAS,
+			0, SCARLETT2_VOLUME_BIAS);
+
+	/* read SW mute */
+	err = scarlett2_usb_get_config(
+		mixer, SCARLETT2_CONFIG_MUTE_SWITCH,
+		private->num_line_out, &private->mute_switch);
+	if (err < 0)
+		return err;
 
-	private->master_vol = clamp(
-		volume_status.master_vol + SCARLETT2_VOLUME_BIAS,
-		0, SCARLETT2_VOLUME_BIAS);
+	for (i = 0; i < private->num_line_out; i++)
+		private->mute_switch[i] =
+			!!private->mute_switch[i];
 
-	for (i = 0; i < private->num_line_out; i++) {
-		int volume, mute;
-
-		private->vol_sw_hw_switch[i] =
-			info->line_out_hw_vol
-				&& volume_status.sw_hw_switch[i];
-
-		volume = private->vol_sw_hw_switch[i]
-			   ? volume_status.master_vol
-			   : volume_status.sw_vol[i];
-		volume = clamp(volume + SCARLETT2_VOLUME_BIAS,
-			       0, SCARLETT2_VOLUME_BIAS);
-		private->vol[i] = volume;
-
-		mute = private->vol_sw_hw_switch[i]
-			 ? private->dim_mute[SCARLETT2_BUTTON_MUTE]
-			 : volume_status.mute_switch[i];
-		private->mute_switch[i] = mute;
+	/* read SW/HW switches */
+	if (info->line_out_hw_vol) {
+		err = scarlett2_usb_get_config(
+			mixer, SCARLETT2_CONFIG_SW_HW_SWITCH,
+			private->num_line_out, &private->vol_sw_hw_switch);
+		if (err < 0)
+			return err;
+
+		for (i = 0; i < private->num_line_out; i++)
+			private->vol_sw_hw_switch[i] =
+				!!private->vol_sw_hw_switch[i];
 	}
 
+	err = scarlett2_update_volumes(mixer);
+	if (err < 0)
+		return err;
+
 	for (i = 0; i < private->num_mix_out; i++) {
 		err = scarlett2_usb_get_mix(mixer, i);
 		if (err < 0)