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

From: Stephen Rothwell <[email-masked]>
Date: Thu, 6 Jun 2019 10:32:20 +1000

Hi all,

After merging the hwmon-staging tree, today's linux-next build (x86_64
allmodconfig) produced this warning:

drivers/hwmon/nct7904.c: In function 'nct7904_in_is_visible':
drivers/hwmon/nct7904.c:313:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (channel > 0 && (data->vsen_mask & BIT(index)))
      ^
drivers/hwmon/nct7904.c:315:2: note: here
  case hwmon_in_min:
  ^~~~
drivers/hwmon/nct7904.c: In function 'nct7904_fan_is_visible':
drivers/hwmon/nct7904.c:230:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (data->fanin_mask & (1 << channel))
      ^
drivers/hwmon/nct7904.c:232:2: note: here
  case hwmon_fan_min:
  ^~~~
drivers/hwmon/nct7904.c: In function 'nct7904_temp_is_visible':
drivers/hwmon/nct7904.c:443:6: warning: this statement may fall through [-Wimplicit-fallthrough=]
   if (channel < 5) {
      ^
drivers/hwmon/nct7904.c:450:2: note: here
  case hwmon_temp_max:
  ^~~~

Introduced by commit

  af55ab0b0792 ("hwmon: (nct7904) Add extra sysfs support for fan, voltage and temperature.")

I get these warnings 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