ALSA: control: Define SNDRV_CTL_TLV_OP_* constants

Instead of hard-coded magic numbers, define constants for op_flag to
tlv callbacks.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/control.h

@@ -31,10 +31,15 @@ typedef int (snd_kcontrol_info_t) (struct snd_kcontrol * kcontrol, struct snd_ct
 typedef int (snd_kcontrol_get_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
 typedef int (snd_kcontrol_put_t) (struct snd_kcontrol * kcontrol, struct snd_ctl_elem_value * ucontrol);
 typedef int (snd_kcontrol_tlv_rw_t)(struct snd_kcontrol *kcontrol,
-				    int op_flag, /* 0=read,1=write,-1=command */
+				    int op_flag, /* SNDRV_CTL_TLV_OP_XXX */
 				    unsigned int size,
 				    unsigned int __user *tlv);
 
+enum {
+	SNDRV_CTL_TLV_OP_READ = 0,
+	SNDRV_CTL_TLV_OP_WRITE = 1,
+	SNDRV_CTL_TLV_OP_CMD = -1,
+};
 
 struct snd_kcontrol_new {
 	snd_ctl_elem_iface_t iface;	/* interface identifier */

sound/core/control.c

@@ -1406,11 +1406,11 @@ static long snd_ctl_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 	case SNDRV_CTL_IOCTL_SUBSCRIBE_EVENTS:
 		return snd_ctl_subscribe_events(ctl, ip);
 	case SNDRV_CTL_IOCTL_TLV_READ:
-		return snd_ctl_tlv_ioctl(ctl, argp, 0);
+		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_READ);
 	case SNDRV_CTL_IOCTL_TLV_WRITE:
-		return snd_ctl_tlv_ioctl(ctl, argp, 1);
+		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_WRITE);
 	case SNDRV_CTL_IOCTL_TLV_COMMAND:
-		return snd_ctl_tlv_ioctl(ctl, argp, -1);
+		return snd_ctl_tlv_ioctl(ctl, argp, SNDRV_CTL_TLV_OP_CMD);
 	case SNDRV_CTL_IOCTL_POWER:
 		return -ENOPROTOOPT;
 	case SNDRV_CTL_IOCTL_POWER_STATE: