From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel.lezcano@linaro.org (Daniel Lezcano) Date: Mon, 30 Jan 2017 14:35:28 +0100 Subject: [PATCH v5 3/8] ARM: dts: rockchip: add timer entries to rk3188 SoC In-Reply-To: <046978C2-808F-4EC3-9429-063BC1A7CE7B@gmail.com> References: <1485260203-14216-1-git-send-email-al.kochet@gmail.com> <1485260203-14216-4-git-send-email-al.kochet@gmail.com> <20170130110428.GC2206@mai> <20170130120444.GE2206@mai> <046978C2-808F-4EC3-9429-063BC1A7CE7B@gmail.com> Message-ID: <20170130133528.GG2206@mai> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Jan 30, 2017 at 04:13:07PM +0300, Alexander Kochetkov wrote: > > > 30 ???. 2017 ?., ? 15:04, Daniel Lezcano ???????(?): > > > > There is no case when the rockchip timer is used for the clockevent. > The is already timer entry for rk3228 in the DT. And it act as clockevent. I guess it work as backup, > but I cannot test it also. In order to not break DT compatibility I had to provide one timer to be > initialized as clockevent. And implemented implicit rule the driver (first DT timer - clockevent, > second DT timer - clocksource) already exists for other timers. > > > If I'm not wrong, you can check /proc/interrupts and see there is no interrupt > > on the rockchip timer. > > Yes, you right here. I?ve temporary disable smp_twd to test rockchip timer interrupts. > There is no interrupt on the rockchip timer during normal work. > > > - when the CPU enters a deep idle state. But such state does not exist on rk3188 > ARM chip/revision specific? rk3188 specific. Applies also for rk3288 AFAICT. Without entering in the details, the SoC can't handle that. > > - when the system goes to suspend. But the timers are stopped in any case and > > CPU0 is always on. > There is timer for rk3228 in the DT. I guess there are situations where it can be used. > May be the situations are also acceptable for rk3188? May be something like suspend to RAM or > suspend to HDD? I am not expert in that questions. I can do some tests if you give hint/link. Nope, rockchip clockevents won't be used, smp_twd will instead. You can check by commenting the local-timer in the DT, and you should see the /proc/interrupts line for the rockchip incrementing while the 'twd' are zero. > So, as I understood you suggest to leave only one timer what can be used as clocksource > only. I can implement that, but there should be DT rule what allow to setup timer > as clocksource only. I cannot do more without timer framework support. > Looks, like I have to wait your patch to implement that. No, actually I meant the rockchip clockevents won't be used for both rk3188 and rk3288, they are not needed. It is for information, this patch is ok. -- Daniel -- Linaro.org ? Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog