On Fri, 10 Jun 2016, Thierry Reding wrote: > On Fri, Jun 10, 2016 at 03:06:35PM +0100, Lee Jones wrote: > > On Fri, 10 Jun 2016, Thierry Reding wrote: > > > > > > > > The second documentation adaption entails adding support for PWM > > > > > > capture devices. A new clock is required as well as an IRQ line. > > > > > > We're also adding a new property similar to the one described > > > > > > above, but for capture channels. Typically, there will be less > > > > > > capture channels than PWM-out, since all channels have the latter > > > > > > capability, but only some have capture support. > > > > > > > > > > Humm, sounds like all of this should be implied from compatible strings. > > > > > > > > You mean have a bunch of of_machine_is_compatibles() scattered around? > > > > > > I don't understand why you need this at all. Quite frankly I don't even > > > know why st,pwm-num-devs exists. I probably missed it back at the time. > > > Usually, like Rob suggests, this should be inferred from the compatible > > > string. One commonly used way to avoid scattering explicit checks for > > > the compatible string is to add this information to the of_device_id > > > table. See a bunch of existing drivers for reference. > > > > Yes, I am aware of the strategy, and happy to oblige if this is your > > suggestion. I'll move all platform data into the driver and eradicate > > the DT properties. > > Great! Sorry it's taken so long to get back around to this. So I just had a crack at implementing this solution and ran into issues. Unfortunately, the configuration isn't easy to describe using compatible strings. Unless we are prepared to have strings like: st,sti-pwm-stih407-pwm0 st,sti-pwm-stih407-pwm1 st,sti-pwm-stih416-pwm0 st,sti-pwm-stih416-pwm1 Or perhaps: st,sti-pwm-4out-2cpt st,sti-pwm-1out-1cpt ... since some of the PWMs have an odd number of OUT and CPT channels/devices. In my opinion however, this is ugly. I don't think we do this for any other type of channel/device/port etc, do we? Personally I think there isn't anything wrong with having DT properties describing how many channels/devices there are, but I'm okay with whatever you both decide. No skin of my nose really. :) What say you? -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
