[RFC PATCH 11/11] ALSA: mixer_audient: Create matrix programmatically

[Christian Ruppert <arc@gmx.li>]

Most Audient devices seem to have a similar mixer matrix with many
identical channels. The only difference between devices seems to be
the matrix' dimension. Create it programmatically in a loop rather
than from the controls table.

Signed-off-by: Christian Ruppert <arc@gmx.li>
---
 sound/usb/mixer_audient.c | 75 +++++++++++++++++----------------------
 1 file changed, 32 insertions(+), 43 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 24b594fb1bc7..30f2f20b1dbb 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -103,7 +103,7 @@ static const struct snd_audient_ctrl_type {
 
 
 struct snd_audient_ctrl {
-	char *name;
+	const char *const name;
 	enum snd_audient_type type;
 	unsigned int channels;
 	unsigned int hwchannels;
@@ -132,48 +132,6 @@ static const struct snd_audient_ctrl snd_audient_evo4_controls[] = {
 		.hwchannels = 1,
 		.val_offs = 0,
 	},
-	{
-		.name = "Mic 1 Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 0,
-	},
-	{
-		.name = "Mic 2 Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 2,
-	},
-	{
-		.name = "Master Left Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 4,
-	},
-	{
-		.name = "Master Right Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 6,
-	},
-	{
-		.name = "Loopback Left Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 8,
-	},
-	{
-		.name = "Loopback Right Capture Volume",
-		.type = SND_AUDIENT_TYPE_MIXER,
-		.channels = 2,
-		.hwchannels = 2,
-		.val_offs = 10,
-	},
 	{
 		.name = "Mic 1 Phantom Capture Switch",
 		.type = SND_AUDIENT_TYPE_PHANTOM,
@@ -191,13 +149,27 @@ static const struct snd_audient_ctrl snd_audient_evo4_controls[] = {
 	{ 0 }, /* sentinel */
 };
 
+static const char *const snd_audient_evo4_matrix[] = {
+	"Mic 1 Capture Volume",
+	"Mic 2 Capture Volume",
+	"Master Left Capture Volume",
+	"Master Right Capture Volume",
+	"Loopback Left Capture Volume",
+	"Loopback Right Capture Volume",
+	NULL
+};
+
 static const struct audient_devinfo {
 	u32 usb_id;
 	const struct snd_audient_ctrl *controls;
+	const char *const *const matrix_names;
+	const unsigned int matrix_channels;
 } audient_devinfo[] = {
 	{
 		.usb_id = USB_ID(USB_AUDIENT_VID, USB_EVO4_PID),
 		.controls = snd_audient_evo4_controls,
+		.matrix_names = snd_audient_evo4_matrix,
+		.matrix_channels = 2,
 	},
 	{ 0 } /* sentinel */
 };
@@ -626,6 +598,8 @@ int snd_audient_controls_create(struct usb_mixer_interface *mixer)
 	const struct audient_devinfo *info;
 	const struct snd_audient_ctrl *ctrl;
 
+	int i;
+
 	for (info = audient_devinfo; info->controls; info++)
 		if (info->usb_id == mixer->chip->usb_id)
 			break;
@@ -640,5 +614,20 @@ int snd_audient_controls_create(struct usb_mixer_interface *mixer)
 			return ret;
 	}
 
+	for (i = 0; info->matrix_names[i]; i++) {
+		const struct snd_audient_ctrl c = {
+			.name = info->matrix_names[i],
+			.type = SND_AUDIENT_TYPE_MIXER,
+			.channels = info->matrix_channels,
+			.hwchannels = info->matrix_channels,
+			.val_offs = i * info->matrix_channels,
+		};
+
+		const int ret = snd_audient_add_ctrl(mixer, &c);
+
+		if (ret < 0)
+			return ret;
+	}
+
 	return 0;
 }
-- 
2.56.0