[Intel-gfx] [RFC 0/4] drm/i915/registers: use standard bits.h and bitfield.h macros

[Jani Nikula]

On Thu, 27 Sep 2018, Michal Wajdeczko <michal.wajdeczko at intel.com> wrote:
> On Thu, 27 Sep 2018 11:40:19 +0200, Jani Nikula <jani.nikula at intel.com>  
> wrote:
>
>> This is an RFC to get input on how people feel about moving towards
>> using <linux/bits.h> and <linux/bitfield.h> macros for register field
>> definitions and manipulation:
>>
>> * BIT()
>> * GENMASK()
>
> BIT/GENMASK macros assumes 'unsigned long' type (64b) while our registers
> (and some of our temporary variables) are 'unsigned int' (32b).

I don't see a problem with that as long as we stick to unsigned types.

> It was reported [1] that use of plain BIT(0) may cause compilation issues.

That mixes signed and unsigned types.


BR,
Jani.

>
> Michal
>
> [1]  
> https://lists.freedesktop.org/archives/intel-gfx/2018-September/176704.html
>
>> * FIELD_GET()
>> * FIELD_PREP()
>
>

-- 
Jani Nikula, Intel Open Source Graphics Center