ALSA: usb-audio: Tidy up mixer_us16x08.c

A few more cleanups and improvements that have been overlooked:

- Use ARRAY_SIZE() macro appropriately
- Code shuffling for minor optimization
- Omit superfluous variable initializations
- Get rid of superfluous NULL checks
- Add const to snd_us16x08_control_params definitions

No functional changes.

Reviewed-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/mixer_us16x08.c

@@ -176,15 +176,9 @@ static int snd_us16x08_recv_urb(struct snd_usb_audio *chip,
  */
 static int snd_us16x08_send_urb(struct snd_usb_audio *chip, char *buf, int size)
 {
-	int err = 0;
-
-	if (chip) {
-		err = snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
+	return snd_usb_ctl_msg(chip->dev, usb_sndctrlpipe(chip->dev, 0),
 			SND_US16X08_URB_REQUEST, SND_US16X08_URB_REQUESTTYPE,
 			0, 0, buf, size);
-	}
-
-	return err;
 }
 
 static int snd_us16x08_route_info(struct snd_kcontrol *kcontrol,
@@ -212,10 +206,7 @@ static int snd_us16x08_route_put(struct snd_kcontrol *kcontrol,
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
 	int index = ucontrol->id.index;
 	char buf[sizeof(route_msg)];
-	int val, val_org, err = 0;
-
-	/* prepare the message buffer from template */
-	memcpy(buf, route_msg, sizeof(route_msg));
+	int val, val_org, err;
 
 	/*  get the new value (no bias for routes) */
 	val = ucontrol->value.enumerated.item[0];
@@ -224,6 +215,9 @@ static int snd_us16x08_route_put(struct snd_kcontrol *kcontrol,
 	if (val < 0 || val > 9)
 		return -EINVAL;
 
+	/* prepare the message buffer from template */
+	memcpy(buf, route_msg, sizeof(route_msg));
+
 	if (val < 2) {
 		/* input comes from a master channel */
 		val_org = val;
@@ -279,12 +273,9 @@ static int snd_us16x08_master_put(struct snd_kcontrol *kcontrol,
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
 	char buf[sizeof(mix_msg_out)];
-	int val, err = 0;
+	int val, err;
 	int index = ucontrol->id.index;
 
-	/* prepare the message buffer from template */
-	memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
-
 	/* new control value incl. bias*/
 	val = ucontrol->value.integer.value[0];
 
@@ -293,6 +284,9 @@ static int snd_us16x08_master_put(struct snd_kcontrol *kcontrol,
 		|| val > SND_US16X08_KCMAX(kcontrol))
 		return -EINVAL;
 
+	/* prepare the message buffer from template */
+	memcpy(buf, mix_msg_out, sizeof(mix_msg_out));
+
 	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
 	buf[6] = elem->head.id;
 
@@ -392,9 +386,6 @@ static int snd_us16x08_channel_put(struct snd_kcontrol *kcontrol,
 	int val, err;
 	int index = ucontrol->id.index;
 
-	/* prepare URB message from template */
-	memcpy(buf, mix_msg_in, sizeof(mix_msg_in));
-
 	val = ucontrol->value.integer.value[0];
 
 	/* sanity check */
@@ -402,6 +393,9 @@ static int snd_us16x08_channel_put(struct snd_kcontrol *kcontrol,
 		|| val > SND_US16X08_KCMAX(kcontrol))
 		return -EINVAL;
 
+	/* prepare URB message from template */
+	memcpy(buf, mix_msg_in, sizeof(mix_msg_in));
+
 	/* add the bias to the new value */
 	buf[8] = val - SND_US16X08_KCBIAS(kcontrol);
 	buf[6] = elem->head.id;
@@ -434,8 +428,7 @@ static int snd_us16x08_comp_get(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
-	struct snd_us16x08_comp_store *store =
-		((struct snd_us16x08_comp_store *) elem->private_data);
+	struct snd_us16x08_comp_store *store = elem->private_data;
 	int index = ucontrol->id.index;
 	int val_idx = COMP_STORE_IDX(elem->head.id);
 
@@ -449,18 +442,11 @@ static int snd_us16x08_comp_put(struct snd_kcontrol *kcontrol,
 {
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
-	struct snd_us16x08_comp_store *store =
-		((struct snd_us16x08_comp_store *) elem->private_data);
+	struct snd_us16x08_comp_store *store = elem->private_data;
 	int index = ucontrol->id.index;
 	char buf[sizeof(comp_msg)];
 	int val_idx, val;
-	int err = 0;
-
-	/* prepare compressor URB message from template  */
-	memcpy(buf, comp_msg, sizeof(comp_msg));
-
-	/* new control value incl. bias*/
-	val_idx = elem->head.id - SND_US16X08_ID_COMP_BASE;
+	int err;
 
 	val = ucontrol->value.integer.value[0];
 
@@ -469,8 +455,14 @@ static int snd_us16x08_comp_put(struct snd_kcontrol *kcontrol,
 		|| val > SND_US16X08_KCMAX(kcontrol))
 		return -EINVAL;
 
+	/* new control value incl. bias*/
+	val_idx = elem->head.id - SND_US16X08_ID_COMP_BASE;
+
 	store->val[val_idx][index] = ucontrol->value.integer.value[0];
 
+	/* prepare compressor URB message from template  */
+	memcpy(buf, comp_msg, sizeof(comp_msg));
+
 	/* place comp values in message buffer watch bias! */
 	buf[8] = store->val[
 		COMP_STORE_IDX(SND_US16X08_ID_COMP_THRESHOLD)][index]
@@ -502,10 +494,9 @@ static int snd_us16x08_comp_put(struct snd_kcontrol *kcontrol,
 static int snd_us16x08_eqswitch_get(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
-	int val = 0;
+	int val;
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
-	struct snd_us16x08_eq_store *store =
-		((struct snd_us16x08_eq_store *) elem->private_data);
+	struct snd_us16x08_eq_store *store = elem->private_data;
 	int index = ucontrol->id.index;
 
 	/* get low switch from cache is enough, cause all bands are together */
@@ -521,10 +512,8 @@ static int snd_us16x08_eqswitch_put(struct snd_kcontrol *kcontrol,
 {
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
-	struct snd_us16x08_eq_store *store =
-		((struct snd_us16x08_eq_store *) elem->private_data);
+	struct snd_us16x08_eq_store *store = elem->private_data;
 	int index = ucontrol->id.index;
-
 	char buf[sizeof(eqs_msq)];
 	int val, err = 0;
 	int b_idx;
@@ -564,10 +553,9 @@ static int snd_us16x08_eqswitch_put(struct snd_kcontrol *kcontrol,
 static int snd_us16x08_eq_get(struct snd_kcontrol *kcontrol,
 	struct snd_ctl_elem_value *ucontrol)
 {
-	int val = 0;
+	int val;
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
-	struct snd_us16x08_eq_store *store =
-		((struct snd_us16x08_eq_store *) elem->private_data);
+	struct snd_us16x08_eq_store *store = elem->private_data;
 	int index = ucontrol->id.index;
 	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
 	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
@@ -584,17 +572,13 @@ static int snd_us16x08_eq_put(struct snd_kcontrol *kcontrol,
 {
 	struct usb_mixer_elem_info *elem = kcontrol->private_data;
 	struct snd_usb_audio *chip = elem->head.mixer->chip;
-	struct snd_us16x08_eq_store *store =
-		((struct snd_us16x08_eq_store *) elem->private_data);
+	struct snd_us16x08_eq_store *store = elem->private_data;
 	int index = ucontrol->id.index;
 	char buf[sizeof(eqs_msq)];
-	int val, err = 0;
+	int val, err;
 	int b_idx = EQ_STORE_BAND_IDX(elem->head.id) - 1;
 	int p_idx = EQ_STORE_PARAM_IDX(elem->head.id);
 
-	/* copy URB buffer from EQ template */
-	memcpy(buf, eqs_msq, sizeof(eqs_msq));
-
 	val = ucontrol->value.integer.value[0];
 
 	/* sanity check */
@@ -602,6 +586,9 @@ static int snd_us16x08_eq_put(struct snd_kcontrol *kcontrol,
 		|| val > SND_US16X08_KCMAX(kcontrol))
 		return -EINVAL;
 
+	/* copy URB buffer from EQ template */
+	memcpy(buf, eqs_msq, sizeof(eqs_msq));
+
 	store->val[b_idx][p_idx][index] = val;
 	buf[20] = store->val[b_idx][3][index];
 	buf[17] = store->val[b_idx][2][index];
@@ -713,12 +700,6 @@ static int snd_us16x08_meter_get(struct snd_kcontrol *kcontrol,
 	u8 meter_urb[64];
 	char tmp[sizeof(mix_init_msg2)] = {0};
 
-	if (elem) {
-		store = (struct snd_us16x08_meter_store *) elem->private_data;
-		chip = elem->head.mixer->chip;
-	} else
-		return 0;
-
 	switch (kcontrol->private_value) {
 	case 0:
 		snd_us16x08_send_urb(chip, (char *)mix_init_msg1,
@@ -983,11 +964,11 @@ static struct snd_kcontrol_new snd_us16x08_meter_ctl = {
 /* setup compressor store and assign default value */
 static struct snd_us16x08_comp_store *snd_us16x08_create_comp_store(void)
 {
-	int i = 0;
-	struct snd_us16x08_comp_store *tmp =
-		kmalloc(sizeof(struct snd_us16x08_comp_store), GFP_KERNEL);
+	int i;
+	struct snd_us16x08_comp_store *tmp;
 
-	if (tmp == NULL)
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
 		return NULL;
 
 	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
@@ -1006,10 +987,10 @@ static struct snd_us16x08_comp_store *snd_us16x08_create_comp_store(void)
 static struct snd_us16x08_eq_store *snd_us16x08_create_eq_store(void)
 {
 	int i, b_idx;
-	struct snd_us16x08_eq_store *tmp =
-		kmalloc(sizeof(struct snd_us16x08_eq_store), GFP_KERNEL);
+	struct snd_us16x08_eq_store *tmp;
 
-	if (tmp == NULL)
+	tmp = kmalloc(sizeof(*tmp), GFP_KERNEL);
+	if (!tmp)
 		return NULL;
 
 	for (i = 0; i < SND_US16X08_MAX_CHANNELS; i++) {
@@ -1042,15 +1023,14 @@ static struct snd_us16x08_eq_store *snd_us16x08_create_eq_store(void)
 
 static struct snd_us16x08_meter_store *snd_us16x08_create_meter_store(void)
 {
-	struct snd_us16x08_meter_store *tmp =
-		kzalloc(sizeof(struct snd_us16x08_meter_store), GFP_KERNEL);
+	struct snd_us16x08_meter_store *tmp;
 
+	tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
 	if (!tmp)
 		return NULL;
 	tmp->comp_index = 1;
 	tmp->comp_active_index = 0;
 	return tmp;
-
 }
 
 /* release elem->private_free as well; called only once for each *_store */
@@ -1067,7 +1047,7 @@ static void elem_private_free(struct snd_kcontrol *kctl)
 static int add_new_ctl(struct usb_mixer_interface *mixer,
 	const struct snd_kcontrol_new *ncontrol,
 	int index, int val_type, int channels,
-	const char *name, const void *opt,
+	const char *name, void *opt,
 	bool do_private_free,
 	struct usb_mixer_elem_info **elem_ret)
 {
@@ -1088,7 +1068,7 @@ static int add_new_ctl(struct usb_mixer_interface *mixer,
 	elem->head.id = index;
 	elem->val_type = val_type;
 	elem->channels = channels;
-	elem->private_data = (void *) opt;
+	elem->private_data = opt;
 
 	kctl = snd_ctl_new1(ncontrol, elem);
 	if (!kctl) {
@@ -1113,10 +1093,8 @@ static int add_new_ctl(struct usb_mixer_interface *mixer,
 	return 0;
 }
 
-static struct snd_us16x08_control_params control_params;
-
 /* table of EQ controls */
-static struct snd_us16x08_control_params eq_controls[] = {
+static const struct snd_us16x08_control_params eq_controls[] = {
 	{ /* EQ switch */
 		.kcontrol_new = &snd_us16x08_eq_switch_ctl,
 		.control_id = SND_US16X08_ID_EQENABLE,
@@ -1197,7 +1175,7 @@ static struct snd_us16x08_control_params eq_controls[] = {
 };
 
 /* table of compressor controls */
-static struct snd_us16x08_control_params comp_controls[] = {
+static const struct snd_us16x08_control_params comp_controls[] = {
 	{ /* Comp enable */
 		.kcontrol_new = &snd_us16x08_compswitch_ctl,
 		.control_id = SND_US16X08_ID_COMP_SWITCH,
@@ -1243,7 +1221,7 @@ static struct snd_us16x08_control_params comp_controls[] = {
 };
 
 /* table of channel controls */
-static struct snd_us16x08_control_params channel_controls[] = {
+static const struct snd_us16x08_control_params channel_controls[] = {
 	{ /* Phase */
 		.kcontrol_new = &snd_us16x08_ch_boolean_ctl,
 		.control_id = SND_US16X08_ID_PHASE,
@@ -1279,7 +1257,7 @@ static struct snd_us16x08_control_params channel_controls[] = {
 };
 
 /* table of master controls */
-static struct snd_us16x08_control_params master_controls[] = {
+static const struct snd_us16x08_control_params master_controls[] = {
 	{ /* Master */
 		.kcontrol_new = &snd_us16x08_master_ctl,
 		.control_id = SND_US16X08_ID_FADER,
@@ -1347,10 +1325,7 @@ int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
 			return -ENOMEM;
 
 		/* add master controls */
-		for (i = 0;
-			i < sizeof(master_controls)
-			/ sizeof(control_params);
-			i++) {
+		for (i = 0; i < ARRAY_SIZE(master_controls); i++) {
 
 			err = add_new_ctl(mixer,
 				master_controls[i].kcontrol_new,
@@ -1368,10 +1343,7 @@ int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
 		}
 
 		/* add channel controls */
-		for (i = 0;
-			i < sizeof(channel_controls)
-			/ sizeof(control_params);
-			i++) {
+		for (i = 0; i < ARRAY_SIZE(channel_controls); i++) {
 
 			err = add_new_ctl(mixer,
 				channel_controls[i].kcontrol_new,
@@ -1396,8 +1368,7 @@ int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
 			return -ENOMEM;
 
 		/* add EQ controls */
-		for (i = 0; i < sizeof(eq_controls) /
-			sizeof(control_params); i++) {
+		for (i = 0; i < ARRAY_SIZE(eq_controls); i++) {
 
 			err = add_new_ctl(mixer,
 				eq_controls[i].kcontrol_new,
@@ -1413,10 +1384,7 @@ int snd_us16x08_controls_create(struct usb_mixer_interface *mixer)
 		}
 
 		/* add compressor controls */
-		for (i = 0;
-			i < sizeof(comp_controls)
-			/ sizeof(control_params);
-			i++) {
+		for (i = 0; i < ARRAY_SIZE(comp_controls); i++) {
 
 			err = add_new_ctl(mixer,
 				comp_controls[i].kcontrol_new,