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 :( -Paul
