ALSA: usb-audio: UAC2: clean up parsing of bmaControls

Introduce two new static inline functions for a more readable parsing
of UAC2 bmaControls.

Signed-off-by: Daniel Mack <daniel@caiaq.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/linux/usb/audio-v2.h b/include/linux/usb/audio-v2.h
index 92f1d99f0f172c377dee4a33a7c6587d7e562bba..8f91be3599c66285169010bab80ab2a909b5d0ea 100644 (file)
--- a/include/linux/usb/audio-v2.h
+++ b/include/linux/usb/audio-v2.h
@@ -18,6 +18,16 @@
 /* v1.0 and v2.0 of this standard have many things in common. For the rest
  * of the definitions, please refer to audio.h */
 
+static inline bool uac2_control_is_readable(u32 bmControls, u8 control)
+{
+       return (bmControls >> (control * 2)) & 0x1;
+}
+
+static inline bool uac2_control_is_writeable(u32 bmControls, u8 control)
+{
+       return (bmControls >> (control * 2)) & 0x2;
+}
+
 /* 4.7.2.1 Clock Source Descriptor */
 
 struct uac_clock_source_descriptor {

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index 03ce971e002760e84b2d36565ee0cbfa56bebd50..43d6417b811ef0547f8b4ebf2f52bc3b45fd8f08 100644 (file)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1188,9 +1188,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
 
                        for (j = 0; j < channels; j++) {
                                unsigned int mask = snd_usb_combine_bytes(bmaControls + csize * (j+1), csize);
-                               if (mask & (1 << (i * 2))) {
+                               if (uac2_control_is_readable(mask, i)) {
                                        ch_bits |= (1 << j);
-                                       if (~mask & (1 << ((i * 2) + 1)))
+                                       if (!uac2_control_is_writeable(mask, i))
                                                ch_read_only |= (1 << j);
                                }
                        }
@@ -1198,9 +1198,9 @@ static int parse_audio_feature_unit(struct mixer_build *state, int unitid, void
                        /* FIXME: the whole unit is read-only if any of the channels is marked read-only */
                        if (ch_bits & 1) /* the first channel must be set (for ease of programming) */
                                build_feature_ctl(state, _ftr, ch_bits, i, &iterm, unitid, !!ch_read_only);
-                       if (master_bits & (1 << i * 2))
+                       if (uac2_control_is_readable(master_bits, i))
                                build_feature_ctl(state, _ftr, 0, i, &iterm, unitid,
-                                                 ~master_bits & (1 << ((i * 2) + 1)));
+                                                 !uac2_control_is_writeable(master_bits, i));
                }
        }