[bug report] ALSA: firewire-motu: add support for MOTU 828mk3 (FireWire/Hybrid) as a model with protocol version 3

[Dan Carpenter <dan.carpenter@oracle.com>]

Hello Takashi Sakamoto,

The patch 5992e30034c4: "ALSA: firewire-motu: add support for MOTU
828mk3 (FireWire/Hybrid) as a model with protocol version 3" from Mar
22, 2017, leads to the following static checker warning:

	sound/firewire/motu/motu-protocol-v3.c:104 v3_get_clock_source()
	warn: mask and shift to zero

sound/firewire/motu/motu-protocol-v3.c
    90  static int v3_get_clock_source(struct snd_motu *motu,
    91                                 enum snd_motu_clock_source *src)
    92  {
    93          __be32 reg;
    94          u32 data;
    95          unsigned int val;
    96          int err;
    97  
    98          err = snd_motu_transaction_read(motu, V3_CLOCK_STATUS_OFFSET, &reg,
    99                                          sizeof(reg));
   100          if (err < 0)
   101                  return err;
   102          data = be32_to_cpu(reg);
   103  
   104          val = (data & V3_CLOCK_SOURCE_MASK) >> V3_CLOCK_SOURCE_SHIFT;
                              0xff >> 8

val is always zero.  These are the only places we use
V3_CLOCK_SOURCE_MASK and V3_CLOCK_SOURCE_SHIFT so I have no idea what
it should be.

   105          if (val == 0x00) {
   106                  *src = SND_MOTU_CLOCK_SOURCE_INTERNAL;
   107          } else if (val == 0x01) {
   108                  *src = SND_MOTU_CLOCK_SOURCE_WORD_ON_BNC;
   109          } else if (val == 0x10) {
   110                  *src = SND_MOTU_CLOCK_SOURCE_SPDIF_ON_COAX;
   111          } else if (val == 0x18 || val == 0x19) {
   112                  err = snd_motu_transaction_read(motu, V3_OPT_IFACE_MODE_OFFSET,
   113                                                  &reg, sizeof(reg));
   114                  if (err < 0)
   115                          return err;

regards,
dan carpenter