ALSA: usb-audio: Simplify parse_audio_unit()

Minor code refactoring by combining the UAC version and the type in
the switch-case flow, so that we reduce the indentation and
redundancy.  One good bonus is that the duplicated definition of the
same type value (e.g. UAC2_EFFECT_UNIT) can be handled more cleanly.

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

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index a1093fb..34def59 100644 (file)
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -2782,62 +2782,45 @@ static int parse_audio_unit(struct mixer_build *state, int unitid)
                return 0; /* skip invalid unit */
        }
 
-       if (protocol == UAC_VERSION_1 || protocol == UAC_VERSION_2) {
-               switch (p1[2]) {
-               case UAC_INPUT_TERMINAL:
-                       return parse_audio_input_terminal(state, unitid, p1);
-               case UAC_MIXER_UNIT:
-                       return parse_audio_mixer_unit(state, unitid, p1);
-               case UAC2_CLOCK_SOURCE:
-                       return parse_clock_source_unit(state, unitid, p1);
-               case UAC_SELECTOR_UNIT:
-               case UAC2_CLOCK_SELECTOR:
-                       return parse_audio_selector_unit(state, unitid, p1);
-               case UAC_FEATURE_UNIT:
-                       return parse_audio_feature_unit(state, unitid, p1);
-               case UAC1_PROCESSING_UNIT:
-               /*   UAC2_EFFECT_UNIT has the same value */
-                       if (protocol == UAC_VERSION_1)
-                               return parse_audio_processing_unit(state, unitid, p1);
-                       else
-                               return 0; /* FIXME - effect units not implemented yet */
-               case UAC1_EXTENSION_UNIT:
-               /*   UAC2_PROCESSING_UNIT_V2 has the same value */
-                       if (protocol == UAC_VERSION_1)
-                               return parse_audio_extension_unit(state, unitid, p1);
-                       else /* UAC_VERSION_2 */
-                               return parse_audio_processing_unit(state, unitid, p1);
-               case UAC2_EXTENSION_UNIT_V2:
-                       return parse_audio_extension_unit(state, unitid, p1);
-               default:
-                       usb_audio_err(state->chip,
-                               "unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
-                       return -EINVAL;
-               }
-       } else { /* UAC_VERSION_3 */
-               switch (p1[2]) {
-               case UAC_INPUT_TERMINAL:
-                       return parse_audio_input_terminal(state, unitid, p1);
-               case UAC3_MIXER_UNIT:
-                       return parse_audio_mixer_unit(state, unitid, p1);
-               case UAC3_CLOCK_SOURCE:
-                       return parse_clock_source_unit(state, unitid, p1);
-               case UAC3_SELECTOR_UNIT:
-               case UAC3_CLOCK_SELECTOR:
-                       return parse_audio_selector_unit(state, unitid, p1);
-               case UAC3_FEATURE_UNIT:
-                       return parse_audio_feature_unit(state, unitid, p1);
-               case UAC3_EFFECT_UNIT:
-                       return 0; /* FIXME - effect units not implemented yet */
-               case UAC3_PROCESSING_UNIT:
-                       return parse_audio_processing_unit(state, unitid, p1);
-               case UAC3_EXTENSION_UNIT:
-                       return parse_audio_extension_unit(state, unitid, p1);
-               default:
-                       usb_audio_err(state->chip,
-                               "unit %u: unexpected type 0x%02x\n", unitid, p1[2]);
-                       return -EINVAL;
-               }
+#define PTYPE(a, b)    ((a) << 8 | (b))
+       switch (PTYPE(protocol, p1[2])) {
+       case PTYPE(UAC_VERSION_1, UAC_INPUT_TERMINAL):
+       case PTYPE(UAC_VERSION_2, UAC_INPUT_TERMINAL):
+       case PTYPE(UAC_VERSION_3, UAC_INPUT_TERMINAL):
+               return parse_audio_input_terminal(state, unitid, p1);
+       case PTYPE(UAC_VERSION_1, UAC_MIXER_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC_MIXER_UNIT):
+       case PTYPE(UAC_VERSION_3, UAC3_MIXER_UNIT):
+               return parse_audio_mixer_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SOURCE):
+       case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SOURCE):
+               return parse_clock_source_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_1, UAC_SELECTOR_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC_SELECTOR_UNIT):
+       case PTYPE(UAC_VERSION_3, UAC3_SELECTOR_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC2_CLOCK_SELECTOR):
+       case PTYPE(UAC_VERSION_3, UAC3_CLOCK_SELECTOR):
+               return parse_audio_selector_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_1, UAC_FEATURE_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC_FEATURE_UNIT):
+       case PTYPE(UAC_VERSION_3, UAC3_FEATURE_UNIT):
+               return parse_audio_feature_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_1, UAC1_PROCESSING_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC2_PROCESSING_UNIT_V2):
+       case PTYPE(UAC_VERSION_3, UAC3_PROCESSING_UNIT):
+               return parse_audio_processing_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_1, UAC1_EXTENSION_UNIT):
+       case PTYPE(UAC_VERSION_2, UAC2_EXTENSION_UNIT_V2):
+       case PTYPE(UAC_VERSION_3, UAC3_EXTENSION_UNIT):
+               return parse_audio_extension_unit(state, unitid, p1);
+       case PTYPE(UAC_VERSION_2, UAC2_EFFECT_UNIT):
+       case PTYPE(UAC_VERSION_3, UAC3_EFFECT_UNIT):
+               return 0; /* FIXME - effect units not implemented yet */
+       default:
+               usb_audio_err(state->chip,
+                             "unit %u: unexpected type 0x%02x\n",
+                             unitid, p1[2]);
+               return -EINVAL;
        }
 }