On Fri, Apr 24, 2020 at 07:34:10PM +0300, Andy Shevchenko wrote: > On Fri, Apr 24, 2020 at 11:09:26AM -0400, William Breathitt Gray wrote: > > On Fri, Apr 24, 2020 at 05:00:58PM +0200, Lukas Wunner wrote: > > > On Fri, Apr 24, 2020 at 08:22:38PM +0530, Syed Nayyar Waris wrote: > > > > On Fri, Apr 24, 2020 at 7:40 PM Lukas Wunner wrote: > > > > > On Fri, Apr 24, 2020 at 05:55:21PM +0530, Syed Nayyar Waris wrote: > > ... > > > > > So, this function preserves the behaviour of earlier > > > > bitmap_set_value8() function and also adds extra functionality to > > > > that. > > > > > > Please leave drivers as is which use exclusively 8-bit accesses, > > > e.g. gpio-max3191x.c and gpio-74x164.c. I'm fearing a performance > > > regression if your new generic variant is used. They work perfectly > > > fine the way they are and I don't see any benefit this series may have > > > for them. > > > > > > If there are other drivers which benefit from the flexibility of your > > > generic variant then I'm not opposed to changing those. > > > We can leave of course bitmap_set_value8 alone, but for 8-bit values the > > difference in latency I suspect is primarily due to the conditional test > > for the word boundaries. This latency is surely overshadowed by the I/O > > latency of the GPIO drivers, so I don't think there's much harm in > > changing those to use the generic function when the bottleneck will not > > be due to the bitmap_set_value/bitmap_get_value operations. > > Okay, how many new (non-8-bit) users this will target? > > -- > With Best Regards, > Andy Shevchenko Within this patchset the only non-8-bit users are gpio-thunderx and gpio-xilinix. The gpio-xilinx has configurable port widths so in some instances it can behave like the 8-bit users, but not always. If you want to keep the existing for_each_set_clump8 and related functions, ignore [PATCH 3/6] and [PATCH 4/6]. That should allow this patchset to be just an introduction of the new generic functions without affecting the existing 8-bit users. William Breathitt Gray