of_clk_get() / devm_clk_get()

Tony Prisk linux at prisktech.co.nz
Thu Feb 14 01:42:13 EST 2013


On Wed, 2013-02-13 at 21:40 -0700, Stephen Warren wrote:
> On 02/13/2013 09:17 PM, Tony Prisk wrote:
> > Currently we have devm_clk_get() which gives a managed-resource clk (by
> > name), or of_clk_get() which gives an unmanaged resource clk (by id).
> > 
> > I just wanted to sound out everyone as to whether there is a need for a
> > managed version of the of_clk_get.
> > 
> > My personal concern about devm_clk_get is that it requires (if I
> > understand correctly) that the DT node have the clock-names property
> > (which is optional). If the optional name is not supplied, it fails.
> > This basically makes it 'not optional' when a driver uses devm_clk_get.
> > (Please correct me if I'm wrong about this).
> 
> I thought supplying NULL for the name/ID simply gave you the first clock
> in the list (clocks property)? I'm sure I've seen plenty of Tegra
> drivers that end up doing that.
> 

I think someone else told me that once before so it is probably correct
- but it doesn't solve the problem of requesting a second clock without
a clock-names property.

That leaves us in the situation of only being able to use managed clocks
when there is only one, or forcing dts files to include the 'optional'
property.

Regards
Tony Prisk




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