Subject: linux-next: build warnings after merge of the staging tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 5 Feb 2019 14:22:17 +1100

Hi Greg,

After merging the staging tree, today's linux-next build (x86_64
allmodconfig) produced these warnings:

drivers/iio/chemical/sps30.c: In function 'sps30_read_raw':
drivers/iio/chemical/sps30.c:289:4: warning: this statement may fall through [-Wimplicit-fallthrough=]
    switch (chan->channel2) {
    ^~~~~~
drivers/iio/chemical/sps30.c:299:3: note: here
   default:
   ^~~~~~~
drivers/iio/chemical/sps30.c: In function 'sps30_do_cmd':
drivers/iio/chemical/sps30.c:120:10: warning: this statement may fall through [-Wimplicit-fallthrough=]
   buf[1] = (u8)SPS30_AUTO_CLEANING_PERIOD;
          ^
drivers/iio/chemical/sps30.c:121:2: note: here
  case SPS30_READ_DATA_READY_FLAG:
  ^~~~

Introduced by commits

  232e0f6ddeae ("iio: chemical: add support for Sensirion SPS30 sensor")
  62129a0849d2 ("iio: chemical: sps30: allow changing self cleaning period")

I get this warning because I am building with -Wimplicit-fallthrough
in attempt to catch new additions early.  The gcc warning can be turned
off by adding a /* fall through */ comment at the point the fall through
happens (assuming that the fall through is intentional).

-- 
Cheers,
Stephen Rothwell