clock framework: Don't disable a clock already enabled by boot loader?

[s.hauer@pengutronix.de (Sascha Hauer)]

Hi Dirk,

On Fri, May 24, 2013 at 02:44:58PM +0200, Dirk Behme wrote:
> Hi,
> 
> we register a clock using clk_register_clkdev() etc already enabled
> by a boot loader. We are doing only the clk_register_clkdev(), but
> no clock_enable() etc on this clock.
> 
> With this, enable_count for this clock is zero, while in fact it's
> already on. I.e. the kernel doesn't know that it is on.
> 
> This results in
> 
> late_initcall(clk_disable_unused())
> 
> disabling this clock because the kernel thinks it's unused.
> 
> Is this the intended behavior?

Yes, and it's great since after this point the hardware state is in sync
with the enable counter.

> Is there a way to let the kernel know
> "the clock is enabled already, set enable_count != 0"? Or is the
> only way to do this correctly calling clock_enable() on an already
> enabled clock?

You could set the CLK_IGNORE_UNUSED flag in the clock, but I suggest to
just clk_get/clk_enable the clock in the driver using it.

Sascha

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