On Tue, Sep 25, 2018 at 9:15 AM Nathan Chancellor <natechancellor@xxxxxxxxx> wrote: > > On Tue, Sep 25, 2018 at 12:58:16PM +0200, Linus Walleij wrote: > > On Tue, Sep 25, 2018 at 8:19 AM Nathan Chancellor > > <natechancellor@xxxxxxxxx> wrote: > > > > > Clang warns when one enumerated type is implicitly converted to another, > > > which happens several times in the pinctrl drivers for a few reasons: > > > > > > * The PCONFDUMP macro, which sets the param member in pin_config_item. > > > * The pinconf_generic_params structure, which is used by drivers to > > > configure their bindings, which has a param member like pin_config_item. > > > * The pinconf_to_config_packed, which takes either the generic enum > > > pin_config_param or a specialized one. > > > > > > Drivers are allowed to extend this enumerated type because of the gap > > > betweem PIN_CONFIG_END and PIN_CONFIG_MAX. Make it clear to Clang that > > > this is allowed by changing param's type in all of these instances to > > > int so no conversion needs to happen. > > > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/138 > > > Signed-off-by: Nathan Chancellor <natechancellor@xxxxxxxxx> > > > > I'm not superhappy about this because that enum is great for readability, > > even if the static syntax checker is unhappy. > > > > If we can't have an enum here I would argue that we can just as well > > remove the enum altogether and just use #define for the config > > parameters, would you agree? > > > > Yours, > > Linus Walleij > > Hi Linus, > > I see no reason to get rid of the enums. All this patch should do is > silence Clang's warnings because there is no other way to tell it that > this construct is okay except for changing the parameter/member type to > int (so no conversion needs to happen) or an explicit cast, which will > result in more noise in my opinion since this warning happens at least > 10-15 times in the pinctrl drivers. There's no fundamental change to > how the enums are used. > > See these other commits for similar fixes: > > 3eb95feac113 ("mm/zsmalloc.c: change stat type parameter to int") > 04fecbf51b3c ("mm: memcontrol: use int for event/state parameter in several functions") > > Cheers! > Nathan That or all of the call sites should have explicit casts to the base enum. -- Thanks, ~Nick Desaulniers