Messages in this thread | | | Subject | Re: [PATCH v3 2/3] clocksource: Add NPS400 timers driver | From | Daniel Lezcano <> | Date | Tue, 9 Feb 2016 23:55:13 +0100 |
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On 02/09/2016 10:47 PM, Noam Camus wrote: >> From: Daniel Lezcano <daniel.lezcano@linaro.org> Sent: Tuesday, >> February 9, 2016 3:38 PM > >> Actually I was referring to clk_prepare_enable, >> clocksource_register_hz. Agree clk_get_rate is always valid. > Thanks for making this clear. Any way as you can see I do call > pr_err() in case of error just like most drivers around. By "hang" do > you mean calling panic()?
No. I meant the errors are caught but no action is taken, the execution continues normally as nothing wrong happened. This is why I asked if you expect the host to hang at boot time with the last error as a hint.
I was expecting to see a call to clk_disable_unprepare if clocksource_register_hz fails, and returning 'ret' if clk_prepare_enable fails.
> What if there is another clocksource in DT (even with worse rating)? > I still prefer using it then having non workable machine.
You are right. This is why failing gracefully in the init function is important.
>>>> You can simplify the driver even more by using >>>> clocksource_mmio_init. >>> Since my base address depends on cluster number, which CPU is >>> part of, this interface is not much of a use. On top of that it >>> assumes that I am little endian by using readl family >>> accessories. > >> Why can't you use ? > >> clocksource_mmio_init(nps_msu_reg_low_addr, "EZnps-tick", >> nps_timer_rate, 32, nps_clksrc_read); > > I believe that the simplification is meant for drivers that can > actually use the clocksource_mmio..() accessories. Could you explain > what is the advantage here, for my case, to use clocksource_mmio > driver?
Using the mmio generic code will save:
+static struct clocksource nps_counter = { + .name = "EZnps-tick", + .rating = 301, + .read = nps_clksrc_read, + .mask = CLOCKSOURCE_MASK(32), + .flags = CLOCK_SOURCE_IS_CONTINUOUS, +};
Up to you.
-- Daniel
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