Messages in this thread | | | Date | Thu, 26 Sep 2013 10:52:29 +0200 | From | Daniel Lezcano <> | Subject | Re: [RFC, PATCH] clocksource: provide timekeeping for efm32 SoCs |
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On 09/26/2013 10:20 AM, Uwe Kleine-König wrote: > Hello Daniel, > > On Thu, Sep 26, 2013 at 01:49:52AM +0200, Daniel Lezcano wrote: >> On 09/25/2013 05:32 PM, Uwe Kleine-König wrote: >>>>> +static void __init efm32_timer_init(struct device_node *np) >>>>> +{ >>>>> + static int has_clocksource, has_clockevent; >>>>> + int ret; >>>>> + >>>>> + if (!has_clocksource) { >>>>> + ret = efm32_clocksource_init(np); >>>>> + if (!ret) { >>>>> + has_clocksource = 1; >>>>> + return; >>>>> + } >>>>> + } >>>>> + >>>>> + if (!has_clockevent) { >>>>> + ret = efm32_clockevent_init(np); >>>>> + if (!ret) { >>>>> + has_clockevent = 1; >>>>> + return; >>>>> + } >>>>> + } >>>>> +} >>>> >>>> I don't get the purpose of this initialization, can you explain ? >>> An efm32 SoC has four timer blocks. A single block can only be used for >>> one of clocksource or clockevent device and having more than one >>> clocksource or clockevent device doesn't make sense. So this routine >>> asserts that the first timer is used as clocksource and the second as >>> clockevent device. The others are unused. >> >> Shouldn't be up to the dt to give the timers you want ? > The dt looks as follows: > > timer0: timer@40010000 { > compatible = "efm32,timer"; > reg = <0x40010000 0x400>; > interrupts = <2>; > clocks = <&cmu clk_HFPERCLKTIMER0>; > }; > > timer1: timer@40010400 { > compatible = "efm32,timer"; > reg = <0x40010400 0x400>; > interrupts = <12>; > clocks = <&cmu clk_HFPERCLKTIMER1>; > }; > > timer2: timer@40010800 { > compatible = "efm32,timer"; > reg = <0x40010800 0x400>; > interrupts = <13>; > clocks = <&cmu clk_HFPERCLKTIMER2>; > }; > > timer3: timer@40010c00 { > compatible = "efm32,timer"; > reg = <0x40010c00 0x400>; > interrupts = <14>; > clocks = <&cmu clk_HFPERCLKTIMER3>; > }; > > What is your suggestion now? > Add a property that specifies if the block > should be used as clocksource or clockevent_device? That isn't a > hardware description and so shouldn't go into the device tree.
At this point, I just asked a question and did not make any suggestion.
> Provide two drivers that match on "efm32,timer", one for clocksource and > another for clockevent_device? That wouldn't work, too, as the first > driver to be loaded would grab all four timers and the second would get > none.
Thanks, now I understand the purpose of this routine, it is very similar than:
http://www.spinics.net/lists/arm-kernel/msg273984.html
right ?
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