ALSA: scarlett2: Add scarlett2_mixer_value_to_db()

Refactor scarlett2_usb_get_mix(), moving the scarlett2_mixer_values[]
lookup into scarlett2_mixer_value_to_db().

Signed-off-by: Geoffrey D. Bennett <g@b4.vu>
Link: https://lore.kernel.org/r/7adf869852aba2819fddb850b0ea8df5f7d73931.1703444932.git.g@b4.vu
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/mixer_scarlett2.c b/sound/usb/mixer_scarlett2.c
index 95f6f1454fbfbe130728194ce12f28b9a3a1c9ba..6b026648ac3cf9c53eaea6b62527a25d1388fc1b 100644 (file)
--- a/sound/usb/mixer_scarlett2.c
+++ b/sound/usb/mixer_scarlett2.c
@@ -1763,6 +1763,19 @@ static int scarlett2_has_mixer(struct scarlett2_data *private)
        return !!private->info->mux_assignment[0][0].count;
 }
 
+/* Map from mixer value to (db + 80) * 2
+ * (reverse of scarlett2_mixer_values[])
+ */
+static int scarlett2_mixer_value_to_db(int value)
+{
+       int i;
+
+       for (i = 0; i < SCARLETT2_MIXER_VALUE_COUNT; i++)
+               if (scarlett2_mixer_values[i] >= value)
+                       return i;
+       return SCARLETT2_MIXER_MAX_VALUE;
+}
+
 /* Send a USB message to get the volumes for all inputs of one mix
  * and put the values into private->mix[]
  */
@@ -1772,7 +1785,7 @@ static int scarlett2_usb_get_mix(struct usb_mixer_interface *mixer,
        struct scarlett2_data *private = mixer->private_data;
 
        int num_mixer_in = private->num_mix_in;
-       int err, i, j, k;
+       int err, i, j;
 
        struct {
                __le16 mix_num;
@@ -1790,16 +1803,9 @@ static int scarlett2_usb_get_mix(struct usb_mixer_interface *mixer,
        if (err < 0)
                return err;
 
-       for (i = 0, j = mix_num * num_mixer_in; i < num_mixer_in; i++, j++) {
-               u16 mixer_value = le16_to_cpu(data[i]);
-
-               for (k = 0; k < SCARLETT2_MIXER_VALUE_COUNT; k++)
-                       if (scarlett2_mixer_values[k] >= mixer_value)
-                               break;
-               if (k == SCARLETT2_MIXER_VALUE_COUNT)
-                       k = SCARLETT2_MIXER_MAX_VALUE;
-               private->mix[j] = k;
-       }
+       for (i = 0, j = mix_num * num_mixer_in; i < num_mixer_in; i++, j++)
+               private->mix[j] = scarlett2_mixer_value_to_db(
+                       le16_to_cpu(data[i]));
 
        return 0;
 }