Le 24 sept. 2018 9:14 AM, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> a écrit : > > On 24/09/2018 08:53, Paul Cercueil wrote: > > > > Le 24 sept. 2018 07:58, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> a écrit : > >> > >> On 24/09/2018 07:49, Paul Cercueil wrote: > >>> > >>> Le 24 sept. 2018 07:35, Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> a > >>> écrit : > >>>> > >>>> On 24/09/2018 07:24, Paul Cercueil wrote: > >>>>> Hi Daniel, > >>>>> > >>>>> Le 24 sept. 2018 05:12, Daniel Lezcano > >>>>> <daniel.lezcano@xxxxxxxxxx> a écrit : > >>>>>> > >>>>>> On 21/08/2018 19:16, Paul Cercueil wrote: > >>>>>>> This driver handles the TCU (Timer Counter Unit) present on > >>>>>>> the Ingenic JZ47xx SoCs, and provides the kernel with a > >>>>>>> system timer, and optionally with a clocksource and a > >>>>>>> sched_clock. > >>>>>>> > >>>>>>> It also provides clocks and interrupt handling to client > >>>>>>> drivers. > >>>>>> > >>>>>> Can you provide a much more complete description of the timer > >>>>>> in order to make my life easier for the review of this patch? > >>>>> > >>>>> See patch [03/24], it adds a doc file that describes the > >>>>> hardware. > >>>> > >>>> Thanks, I went through but it is incomplete to understand what the > >>>> timer do. I will reverse-engineer the code but it would help if you > >>>> can give the gross approach. Why multiple channels ? mutexes and > >>>> completion ? > >>> > >>> Much of the complexity is because of the multi-purpose nature of the > >>> TCU channels. Each one can be used as timer/clocksource, or PWM. > >>> > >>> The driver starts by using channels 0 and 1 as system timer and > >>> clocksource, respectively, the other ones being unused for now. Then, > >>> *if* the PWM driver requests one of the channels in use by the > >>> timer/clocksource driver, say channel 0, the timer/clocksource driver > >>> will dynamically reassign the system timer to a free channel, from > >>> channel 0 to e.g. channel 2. Only in that case the completion/mutex > >>> are actually used. > >> > >> Why do you need to do this? Can't be the channels dedicated and reserved > >> for clocksource and clockevent? > > > > That's what I had in place (ingenic,timer-channel and ingenic,clocksource-channel DT properties), but Rob didn't want any linux-specific properties in the devicetree binding :( > > Isn't possible to specify the channel to use in the DT? like renesas16 ? That's what I did in V6 (and before), but Rob did not want me to add properties for Linux-specific concepts such as clocksource. -Paul
