[RFC PATCH 1/6] ALSA: mixer_audient: Fold in the review changes to patches 12-16

[Will Porter <mrwillporter@gmail.com>]

This patch is not for merging. It carries the changes from the review
of RFC patches 12 to 16 as one diff, so that the patches after it apply
to the RFC with the enum fix. The next version of the series has these
changes in patches 12, 13, 15 and 16.

- Declare snd_audient_int_max(), snd_audient_int_min() and
  snd_audient_int_from_ctl() inline.
- snd_audient_enum_item() returns the item or -EIO, and get propagates
  the error.
- snd_ctl_audient_info() uses a switch.
- A comment on ID14_ENUM() says that readable enums do not use init.
- The two case labels in mixer_quirks.c share one call.
- Rename the create hook to extra_init and say that it is optional.

Assisted-by: Claude:claude-opus-5-5
Signed-off-by: Will Porter <mrwillporter@gmail.com>
---
 sound/usb/mixer_audient.c | 58 +++++++++++++++++++++++----------------
 sound/usb/mixer_quirks.c  |  2 --
 2 files changed, 34 insertions(+), 26 deletions(-)

diff --git a/sound/usb/mixer_audient.c b/sound/usb/mixer_audient.c
index 4180d7d8b325c..df1e25a55a7a9 100644
--- a/sound/usb/mixer_audient.c
+++ b/sound/usb/mixer_audient.c
@@ -219,6 +219,11 @@ SND_AUDIENT_ENUM(snd_audient_id14_optical, snd_audient_id14_optical_texts,
 		.sel = (sel_),				\
 	}
 
+/*
+ * A readable enum. It has no cache entry, so a get always reads the device
+ * and never uses init. Write-only enums set .init and .flags without this
+ * macro.
+ */
 #define ID14_ENUM(unit_, sel_, len_, enum_)		\
 	{						\
 		.type = SNDRV_CTL_ELEM_TYPE_ENUMERATED,	\
@@ -494,8 +499,8 @@ static const struct audient_devinfo {
 	const struct snd_audient_ctrl *controls;
 	const char *const *const matrix_names;
 	const unsigned int matrix_channels;
-	/* controls the tables cannot describe; called after the tables */
-	int (*create)(struct usb_mixer_interface *mixer);
+	/* optional: controls the tables cannot describe, created after them */
+	int (*extra_init)(struct usb_mixer_interface *mixer);
 } audient_devinfo[] = {
 	{
 		.usb_id = USB_ID(USB_AUDIENT_VID, USB_EVO4_PID),
@@ -508,7 +513,7 @@ static const struct audient_devinfo {
 		.controls = snd_audient_id14_mk1_controls,
 		.matrix_names = snd_audient_id14_mk1_matrix,
 		.matrix_channels = 2,
-		.create = snd_audient_id14_mk1_create,
+		.extra_init = snd_audient_id14_mk1_create,
 	},
 	{ 0 } /* sentinel */
 };
@@ -779,13 +784,15 @@ static int snd_ctl_audient_boolean_set(struct snd_kcontrol *kctl,
  * With a step size (res), an integer control counts steps from min:
  * 0 ... (max - min) / res. Without one it shows the device value.
  */
-static long snd_audient_int_max(const struct snd_audient_ctrl_type *ctype)
+static inline long
+snd_audient_int_max(const struct snd_audient_ctrl_type *ctype)
 {
 	return ctype->res ? (ctype->max.integer - ctype->min.integer) / ctype->res
 			  : ctype->max.integer;
 }
 
-static long snd_audient_int_min(const struct snd_audient_ctrl_type *ctype)
+static inline long
+snd_audient_int_min(const struct snd_audient_ctrl_type *ctype)
 {
 	return ctype->res ? 0 : ctype->min.integer;
 }
@@ -802,8 +809,8 @@ static long snd_audient_int_to_ctl(const struct snd_audient_ctrl_type *ctype,
 		   snd_audient_int_max(ctype));
 }
 
-static long snd_audient_int_from_ctl(const struct snd_audient_ctrl_type *ctype,
-				     long val)
+static inline long
+snd_audient_int_from_ctl(const struct snd_audient_ctrl_type *ctype, long val)
 {
 	return ctype->res ? ctype->min.integer + val * ctype->res : val;
 }
@@ -896,16 +903,16 @@ static int snd_ctl_audient_integer_set(struct snd_kcontrol *kctl,
 	return changed;
 }
 
-static unsigned int snd_audient_enum_item(const struct snd_audient_enum *e,
-					  u32 value)
+/* The item index of a device value, or -EIO if the value is not in the list */
+static int snd_audient_enum_item(const struct snd_audient_enum *e, u32 value)
 {
 	unsigned int item;
 
 	for (item = 0; item < e->items; item++)
 		if (e->values[item] == value)
-			break;
+			return item;
 
-	return item;	/* e->items: not in the list */
+	return -EIO;
 }
 
 static int snd_ctl_audient_enum_get(struct snd_kcontrol *kctl,
@@ -929,8 +936,8 @@ static int snd_ctl_audient_enum_get(struct snd_kcontrol *kctl,
 	guard(mutex)(&mixer->lock);
 
 	for (i = 0; i < hwchan; i++) {
-		unsigned int item;
 		u32 val;
+		int item;
 		int ret;
 
 		ret = snd_audient_raw_get_one(mixer, ctype,
@@ -942,8 +949,8 @@ static int snd_ctl_audient_enum_get(struct snd_kcontrol *kctl,
 			return ret;
 
 		item = snd_audient_enum_item(ctype->enumeration, val);
-		if (item >= ctype->enumeration->items)
-			return -EIO;
+		if (item < 0)
+			return item;
 
 		ctl_val->value.enumerated.item[i] = item;
 	}
@@ -1002,22 +1009,25 @@ static int snd_ctl_audient_info(struct snd_kcontrol *kctl,
 	const struct snd_audient_ctrl_type *const ctype
 						= snd_audient_kctl_type(kctl);
 
-	if (ctype->type == SNDRV_CTL_ELEM_TYPE_ENUMERATED)
-		return snd_ctl_enum_info(uinfo, snd_audient_kctl_channels(kctl),
+	switch (ctype->type) {
+	case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
+		return snd_ctl_enum_info(uinfo,
+					 snd_audient_kctl_channels(kctl),
 					 ctype->enumeration->items,
 					 ctype->enumeration->texts);
-
-	uinfo->type = ctype->type;
-	uinfo->count = snd_audient_kctl_channels(kctl);
-
-	if (ctype->type == SNDRV_CTL_ELEM_TYPE_BOOLEAN) {
+	case SNDRV_CTL_ELEM_TYPE_BOOLEAN:
 		uinfo->value.integer.min = 0;
 		uinfo->value.integer.max = 1;
-	} else {
+		break;
+	default:
 		uinfo->value.integer.min = snd_audient_int_min(ctype);
 		uinfo->value.integer.max = snd_audient_int_max(ctype);
+		break;
 	}
 
+	uinfo->type = ctype->type;
+	uinfo->count = snd_audient_kctl_channels(kctl);
+
 	return 0;
 }
 
@@ -1332,8 +1342,8 @@ int snd_audient_controls_create(struct usb_mixer_interface *mixer)
 		}
 	}
 
-	if (info->create)
-		return info->create(mixer);
+	if (info->extra_init)
+		return info->extra_init(mixer);
 
 	return 0;
 }
diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c
index 41d559d639d22..763bbeb2cd9da 100644
--- a/sound/usb/mixer_quirks.c
+++ b/sound/usb/mixer_quirks.c
@@ -4541,8 +4541,6 @@ int snd_usb_mixer_apply_create_quirk(struct usb_mixer_interface *mixer)
 		break;
 
 	case USB_ID(USB_AUDIENT_VID, USB_EVO4_PID): /* Audient EVO 4 */
-		err = snd_audient_controls_create(mixer);
-		break;
 	case USB_ID(USB_AUDIENT_VID, USB_ID14_MK1_PID): /* Audient iD14 MkI */
 		err = snd_audient_controls_create(mixer);
 		break;
-- 
2.47.3