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.
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.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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