Messages in this thread | | | Date | Thu, 26 Sep 2013 16:13:29 +0300 | From | Maxime Ripard <> | Subject | Re: [PATCH 2/5] clocksource: Add Allwinner SoCs HS timers driver |
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On Wed, Sep 25, 2013 at 08:23:14PM -0300, Emilio López wrote: > El 25/09/13 11:03, Maxime Ripard escribió: > >Most of the Allwinner SoCs (at this time, all but the A10) also have a > >High Speed timers that are not using the 24MHz oscillator as a source > >but rather the AHB clock running much faster. > > > >The IP is slightly different between the A10s/A13 and the one used in > >the A20/A31, since the latter have 4 timers available, while the former > >have only 2 of them. > > > >Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> > >--- > > [...] > > >+static void __init sun5i_timer_init(struct device_node *node) > >+{ > >+ unsigned long rate; > >+ struct clk *clk; > >+ int ret, irq; > >+ u32 val; > >+ > >+ timer_base = of_iomap(node, 0); > >+ if (!timer_base) > >+ panic("Can't map registers"); > >+ > >+ irq = irq_of_parse_and_map(node, 0); > >+ if (irq <= 0) > >+ panic("Can't parse IRQ"); > >+ > >+ clk = of_clk_get(node, 0); > >+ if (IS_ERR(clk)) > >+ panic("Can't get timer clock"); > > I'm not familiar with clocksources, but does this have to be as > fatal as it is considering the kernel also supports the slower sun4i > timer?
Hmmm, I don't know, one might choose to enable only this timer, in that case that would make sense to panic, since it would be the only timer in that case.
> Also, would any special considerations be needed when adjusting the > ahb clock? A future cpufreq driver will most likely need to.
While this will be needed at some point, I don't really see how to handle that properly. The clock framework doesn't seem to have any callback when it comes to reconfiguring a clock that a device might use.
This will also creates trouble for IPs such as the I2C that have to setup internal dividers, and use clk_get_rate to do so.
Maxime
-- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com [unhandled content-type:application/pgp-signature] | |