On Mon, Oct 09, 2023 at 04:18:08PM +0300, Dmitry Rokosov wrote: > On Fri, Oct 06, 2023 at 09:03:47PM +0300, Andy Shevchenko wrote: > > On Fri, Oct 6, 2023 at 7:05 PM Dmitry Rokosov > > <ddrokosov@xxxxxxxxxxxxxxxxx> wrote: > > > > > > From: George Stark <gnstark@xxxxxxxxxxxxxxxxx> > > > > > > use DIV_ROUND_UP instead of coarse div > > > > Please, respect English grammar and punctuation. > > Refer to macros and functions as func() (note the parentheses). > > > > ... > > > > > #define AW200XX_REG_DIM2FADE(x) ((x) + 1) > > > +#define AW200XX_REG_FADE2DIM(fade) \ > > > + DIV_ROUND_UP((fade) * AW200XX_DIM_MAX, AW200XX_FADE_MAX) > > > > Have you checked if the overflow is _now_ possible (compiling on > > 32-bit platforms as well)? > > I suppose we shouldn't carry on about overflow here because the value of > fade cannot exceed 255, and DIM_MAX is set at 63 > > You can find maximum values of fade and dim in the aw200xx driver > header: > > #define AW200XX_DIM_MAX (BIT(6) - 1) > #define AW200XX_FADE_MAX (BIT(8) - 1) I agree that checking if the fade is not greater than FADE_MAX will not be excessive. The LED subsystem is capable of sending brightness levels higher than 255 -- Thank you, Dmitry
