Hi Bjorn, On 09/08/2018 07:02 AM, Bjorn Andersson wrote: > On Tue 04 Sep 04:01 PDT 2018, Baolin Wang wrote: > >> diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern >> b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern > [..] >> +What: /sys/class/leds/<led>/hw_pattern >> +Date: September 2018 >> +KernelVersion: 4.20 >> +Description: >> + Specify a hardware pattern for the LED, for LED hardware that >> + supports autonomously controlling brightness over time, >> according >> + to some preprogrammed hardware patterns. >> + >> + Since different LED hardware can have different semantics of >> + hardware patterns, each driver is expected to provide its own >> + description for the hardware patterns in their ABI documentation >> + file. >> + > > So, after a full circle we're back at drivers with support for hardware > patterns should have their own ABI for setting that pattern. > > The controls for my hardware is: > * a list of brightness values > * the rate of the pattern > * a flag to indicate that the pattern should be played from start > to end, end to start or start to end to start > * a boolean indicating if the pattern should be played once or repeated > indefinitely. > > Given that the interface now is hw specific, what benefit is there to > attempt to cram these 4 knobs into "hw_pattern"? Or am I allowed to > create additional files for the latter three?
So this is an argument corroborating my concerns raised in [0]. I really think that we should allow for custom pattern interfaces defined by LED class drivers. >> +What: /sys/class/leds/<led>/repeat >> +Date: September 2018 >> +KernelVersion: 4.20 >> +Description: >> + Specify a pattern repeat number. 0 means repeat indefinitely. >> + >> + This file will always return the originally written repeat >> + number. > > I'm still convinced that this will confuse our users and to me it would > be more logical if this denotes the number of times the pattern should > be repeated, with e.g. negative numbers denoting infinite. Sounds reasonable. Let's change this semantics as you propose. > In particular I expect to have to explain why my driver expects that you > write 0 in the file named "repeat" to make it repeat and 1 to make it > not repeat. [0] https://lkml.org/lkml/2018/9/3/1192 -- Best regards, Jacek Anaszewski
