On 27 February 2018 at 23:54, Andy Shevchenko <[email protected]> wrote: > On Tue, Feb 27, 2018 at 4:35 AM, Baolin Wang <[email protected]> wrote: >> On 26 February 2018 at 20:02, Andy Shevchenko <[email protected]> >> wrote: >>> On Mon, Feb 26, 2018 at 5:01 AM, Baolin Wang <[email protected]> wrote: >>>> On 25 February 2018 at 20:19, Andy Shevchenko <[email protected]> >>>> wrote: > >>>>>> + for (n = 0; n < chip->ngpio; n++) { >>>>>> + if (!(BIT(n) & val)) >>>>> >>>>> for_each_set_bit(). >>>>> >>>>> At some point you may need just to go across lib/ in the kernel and >>>>> see what we have there. >>>> >>>> I've considered the for_each_set_bit(), it need one 'unsigned long' >>>> type parameter, but we get the value from regmap is 'u32' type. So we >>>> need one extra conversion from 'u32' to 'unsigned long' like: >>>> >>>> unsigned long reg = val; >>>> >>>> for_each_set_bit(n, ®, chip->ngpio) { >>>> ....... >>>> } >>>> >>>> If you like this conversion, then I can change to use >>>> for_each_set_bit(). Thanks. >>> >>> Wouldn't it work like >>> >>> unsigned long val; >>> >>> ...regmap_read(..., &val); >>> >>> ? >> >> It can not work, regmap_read() expects 'unsigned int *'. > > Ah, OK, than the temporary variable is a left approach. > >> But I can >> convert it like this: >> >> for_each_set_bit(n, (unsigned long *)&val, chip->ngpio) { >> ....... >> } > > No, this is a boilerplate for static analyzers and definitely UB.
OK. Thanks for pointing this issue out. -- Baolin.wang Best Regards
