ALSA: Add new TLV types for dBwith min/max

Add new types for TLV dB scale specified with min/max values instead
of min/step since the resolution can't match always with the one
a device provides.  For example, usb audio devices give 1/256 dB
resolution while ALSA TLV is based on 1/100 dB resolution.
The new min/max types have less problems because the possible
rounding error happens only at min/max.

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

diff --git a/include/sound/tlv.h b/include/sound/tlv.h
index d136ea2..9fd5b19 100644 (file)
--- a/include/sound/tlv.h
+++ b/include/sound/tlv.h
@@ -35,6 +35,8 @@
 #define SNDRV_CTL_TLVT_DB_SCALE        1       /* dB scale */
 #define SNDRV_CTL_TLVT_DB_LINEAR 2     /* linear volume */
 #define SNDRV_CTL_TLVT_DB_RANGE 3      /* dB range container */
+#define SNDRV_CTL_TLVT_DB_MINMAX 4     /* dB scale with min/max */
+#define SNDRV_CTL_TLVT_DB_MINMAX_MUTE 5        /* dB scale with min/max with mute */
 
 #define TLV_DB_SCALE_ITEM(min, step, mute)                     \
        SNDRV_CTL_TLVT_DB_SCALE, 2 * sizeof(unsigned int),      \
@@ -42,6 +44,18 @@
 #define DECLARE_TLV_DB_SCALE(name, min, step, mute) \
        unsigned int name[] = { TLV_DB_SCALE_ITEM(min, step, mute) }
 
+/* dB scale specified with min/max values instead of step */
+#define TLV_DB_MINMAX_ITEM(min_dB, max_dB)                     \
+       SNDRV_CTL_TLVT_DB_MINMAX, 2 * sizeof(unsigned int),     \
+       (min_dB), (max_dB)
+#define TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB)                        \
+       SNDRV_CTL_TLVT_DB_MINMAX_MUTE, 2 * sizeof(unsigned int),        \
+       (min_dB), (max_dB)
+#define DECLARE_TLV_DB_MINMAX(name, min_dB, max_dB) \
+       unsigned int name[] = { TLV_DB_MINMAX_ITEM(min_dB, max_dB) }
+#define DECLARE_TLV_DB_MINMAX_MUTE(name, min_dB, max_dB) \
+       unsigned int name[] = { TLV_DB_MINMAX_MUTE_ITEM(min_dB, max_dB) }
+
 /* linear volume between min_dB and max_dB (.01dB unit) */
 #define TLV_DB_LINEAR_ITEM(min_dB, max_dB)                 \
        SNDRV_CTL_TLVT_DB_LINEAR, 2 * sizeof(unsigned int), \

diff --git a/sound/core/vmaster.c b/sound/core/vmaster.c
index 257624b..3b9b550 100644 (file)
--- a/sound/core/vmaster.c
+++ b/sound/core/vmaster.c
@@ -353,7 +353,8 @@ static void master_free(struct snd_kcontrol *kcontrol)
  *
  * The optional argument @tlv can be used to specify the TLV information
  * for dB scale of the master control.  It should be a single element
- * with #SNDRV_CTL_TLVT_DB_SCALE type, and should be the max 0dB.
+ * with #SNDRV_CTL_TLVT_DB_SCALE, #SNDRV_CTL_TLV_DB_MINMAX or
+ * #SNDRV_CTL_TLVT_DB_MINMAX_MUTE type, and should be the max 0dB.
  */
 struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
                                                 const unsigned int *tlv)
@@ -384,7 +385,10 @@ struct snd_kcontrol *snd_ctl_make_virtual_master(char *name,
        kctl->private_free = master_free;
 
        /* additional (constant) TLV read */
-       if (tlv && tlv[0] == SNDRV_CTL_TLVT_DB_SCALE) {
+       if (tlv &&
+           (tlv[0] == SNDRV_CTL_TLVT_DB_SCALE ||
+            tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX ||
+            tlv[0] == SNDRV_CTL_TLVT_DB_MINMAX_MUTE)) {
                kctl->vd[0].access |= SNDRV_CTL_ELEM_ACCESS_TLV_READ;
                memcpy(master->tlv, tlv, sizeof(master->tlv));
                kctl->tlv.p = master->tlv;