[alsa-devel] Checkpatch warnings on switch case fallthru

[Lars-Peter Clausen]

On 04/09/2016 11:06 AM, Takashi Iwai wrote:
> On Fri, 08 Apr 2016 00:23:03 +0200,
> Harvey, Ryan wrote:
>>
>> Hello,
>>
>> I receive a set of checkpatch warnings against my switch fallthru
>> structure in readable_registers().  I¹m able to eliminate these warnings
>> with a preceding comment, but that does messy the code.  Is there a method
>> better than switch for accomplishing this?
>>
>> static bool cs43130_readable_register(struct device *dev, unsigned int reg)
>> {
>>         switch (reg) {
>>         case CS43130_DEVID_AB ... CS43130_SYS_CLK_CTL_1:
>>         case CS43130_PWDN_CTL:
>>         case CS43130_PLL_SET_1 ... CS43130_PLL_SET_6:
>>         case CS43130_PLL_SET_7:
>>         case CS43130_PLL_SET_8:
>>         case CS43130_PLL_SET_9:
>>         case CS43130_PLL_SET_10:
>>         case CS43130_CLKOUT_CTL:
>>         case CS43130_ASP_NUM_1 ... CS43130_ASP_FRAME_CONF:
>>         case CS43130_HP_OUT_CTL_1:
>>         case CS43130_PCM_FILT_OPT ... CS43130_PCM_PATH_CTL_2:
>>         case CS43130_CLASS_H_CTL:
>>         case CS43130_HP_DETECT ... CS43130_HP_STATUS:
>>         case CS43130_HP_LOAD_1:
>>         case CS43130_HP_LOAD_STAT:
>>         case CS43130_INT_MASK_1 ... CS43130_INT_MASK_5:
>>                 return true;
>>         default:
>>                 return false;
>>         }
>> }
>>
>>
>> 140: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_PLL_SET_7:
>> 141: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_PLL_SET_8:
>> 142: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_PLL_SET_9:
>> 143: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_PLL_SET_10:
>> 144: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_CLKOUT_CTL:
>> 152: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_HP_OUT_CTL_1:
>> 154: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_CLASS_H_CTL:
>> 156: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_HP_LOAD_1:
>> 160: [WARNING] Possible switch case/default not preceeded by break or
>> fallthrough comment
>> +	case CS43130_HP_LOAD_STAT:
> 
> You may ignore the warnings.  The purpose of checkpatch is to improve
> the code readability, and what it suggests is exactly opposite.

It's a bug in checkpatch. It seems to get confused by the "...". The
best approach to solving those warnings is to create a fix for checkpatch.