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mfd: db8500: Avoid uninitialized variable reference

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The prcmu_config_clkout() function ensures that the 'clkout' argument
can only be '0' or '1' using an appropriate BUG_ON(), so the compiler
should know that the div_mask, mask, and bits variables are always
initialized later on. However, it doesn't understand this in gcc-5.2
and produces a false positive warning instead:

drivers/mfd/db8500-prcmu.c: In function 'prcmu_config_clkout':
drivers/mfd/db8500-prcmu.c:762:10: error: 'div_mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  if (val & div_mask) {
          ^
drivers/mfd/db8500-prcmu.c:769:13: error: 'mask' may be used uninitialized in this function [-Werror=maybe-uninitialized]
    if ((val & mask & ~div_mask) != bits) {
             ^
drivers/mfd/db8500-prcmu.c:757:7: error: 'bits' may be used uninitialized in this function [-Werror=maybe-uninitialized]

Replacing the switch() statement with an equivalent if() lets
gcc figure this out reliably and avoids the warnings.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
This commit is contained in:
Arnd Bergmann 2016-01-25 17:02:24 +01:00 committed by Lee Jones
parent b45b719ee0
commit a7e4631772
1 changed files with 2 additions and 5 deletions
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7
drivers/mfd/db8500-prcmu.c
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@ -739,20 +739,17 @@ int prcmu_config_clkout(u8 clkout, u8 source, u8 div)
if (!div && !requests[clkout])
return -EINVAL;
switch (clkout) {
case 0:
if (clkout == 0) {
div_mask = PRCM_CLKOCR_CLKODIV0_MASK;
mask = (PRCM_CLKOCR_CLKODIV0_MASK | PRCM_CLKOCR_CLKOSEL0_MASK);
bits = ((source << PRCM_CLKOCR_CLKOSEL0_SHIFT) |
(div << PRCM_CLKOCR_CLKODIV0_SHIFT));
break;
case 1:
} else {
div_mask = PRCM_CLKOCR_CLKODIV1_MASK;
mask = (PRCM_CLKOCR_CLKODIV1_MASK | PRCM_CLKOCR_CLKOSEL1_MASK |
PRCM_CLKOCR_CLK1TYPE);
bits = ((source << PRCM_CLKOCR_CLKOSEL1_SHIFT) |
(div << PRCM_CLKOCR_CLKODIV1_SHIFT));
break;
}
bits &= mask;