Re[4]: [PATCH 4/4] ARM: clps711x: Added simple clkdev framework

Alexander Shiyan shc_work at mail.ru
Fri Jul 20 14:02:42 EDT 2012


Hello.

Fri, 20 Jul 2012 10:41:59 -0700 от "Turquette, Mike" <mturquette at ti.com>:
> On Fri, Jul 20, 2012 at 10:24 AM, Alexander Shiyan <shc_work at mail.ru> wrote:
> > Hello.
> >
> > Thu, 19 Jul 2012 15:02:00 -0700 от "Turquette, Mike" <mturquette at ti.com>:
> >> On Tue, Jul 17, 2012 at 1:33 PM, Arnd Bergmann <arnd at arndb.de> wrote:
> >> > On Monday 16 July 2012, Alexander Shiyan wrote:
> >> >> Modern CPUs from CLPS711X-line can operate at frequencies other than 73 MHz.
> >> >> This patch adds simple clkdev framework for handling all possible CPU rates.
> >> >> Signed-off-by: Alexander Shiyan <shc_work at mail.ru>
> >> > We just had the exact same discussion about a new clock implementation for
> >> > mcs814x and for the socfpga port. My feeling is that it makes no sense
> >> > to keep adding new private implementations of the API as we're trying
> >> > to get rid of the existing ones and replace them with the common code.
> >> >
> >> > If I understand this correctly, you should be using DEFINE_CLK_FIXED_RATE
> >> > and DEFINE_CLK_DIVIDER etc to define the initial clocks and the lookup
> >> > table, and possibly move all of that to drivers/clk.
> >>
> >> Arnd is correct.  Let's go ahead and move everything over to the
> >> common clk framework.  These patches will have to wait for 3.7
> >> anyways, so there is plenty of time to port it over.
> >
> > OK, I keep this patch and will be create new one, for review, but as I say before,
> > COMMON_CLOCK framework is too overloaded because clps711x-target CPU
> > has no enable/disable and change rate functional for clocks. We only can
> > determine CPU speed from fuses and recalculate some values for system
> > timer and UART.
> 
> It might be worthwhile to implement something like
> drivers/clk/clk-dummy.c which provides no real clk_ops, but
> initializes parents and rates at clk_register-timer.  I haven't looked
> at your patch yet to know if such an idea is applicable or not, but I
> doubt you are the only platform which has "noop" clocks, so it might
> be nice to expose a standard clock type for this.
> 
> What do you think?

If I understand correctly, FIXED_CLK have to deal with it.
Why need one more class?


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