On Mon, Jun 29, 2020 at 01:32:12PM +0100, Lee Jones wrote: > Since its conception in 2012 brightness has been artificially capped > at 127 since the variable carrying the value is u8. We could go to > the trouble of changing the whole API (crossing 3 different subsystems), > but clearly this hasn't bothered anyone in the best part of a decade. > > Simply, cap BRIGHTNESS_MAX to 127 instead (for now at least).
Hmm. This patch is clearly broken and would contrary to the claim be introducing an artificial cap at half brightness. u8 can hold the max brightness value 255 just fine. > Fixes the following W=1 warning(s): > > drivers/mfd/lm3533-ctrlbank.c: In function ‘lm3533_ctrlbank_set_brightness’: > drivers/mfd/lm3533-ctrlbank.c:98:10: warning: comparison is always false due > to limited range of data type [-Wtype-limits] > 98 | if (val > LM3533_##_NAME##_MAX) | ^ > drivers/mfd/lm3533-ctrlbank.c:125:1: note: in expansion of macro > ‘lm3533_ctrlbank_set’ > 125 | lm3533_ctrlbank_set(brightness, BRIGHTNESS); > | ^~~~~~~~~~~~~~~~~~~ This warning is benign. The same macro is used to defined two function where in one case the max value coincides with U8_MAX so that the sanity check becomes redundant. > Cc: Johan Hovold <[email protected]> > Signed-off-by: Lee Jones <[email protected]> > --- > drivers/mfd/lm3533-ctrlbank.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/mfd/lm3533-ctrlbank.c b/drivers/mfd/lm3533-ctrlbank.c > index 34fba06ec7057..348ce67453092 100644 > --- a/drivers/mfd/lm3533-ctrlbank.c > +++ b/drivers/mfd/lm3533-ctrlbank.c > @@ -17,7 +17,7 @@ > #define LM3533_MAX_CURRENT_MAX 29800 > #define LM3533_MAX_CURRENT_STEP 800 > > -#define LM3533_BRIGHTNESS_MAX 255 > +#define LM3533_BRIGHTNESS_MAX 127 /* Capped by API - could > be up to 255 */ > #define LM3533_PWM_MAX 0x3f > > #define LM3533_REG_PWM_BASE 0x14 Johan
