On Tuesday 20 of August 2013 14:34:30 Stephen Warren wrote:

On 08/20/2013 11:31 AM, Tomasz Figa wrote:

quoted

PWM driver consumes at least one and up to three clocks, which need to
be specified in device tree when used. This patch updates bindings
documentation to add information about clocks.

diff --git a/Documentation/devicetree/bindings/pwm/pwm-samsung.txt

b/Documentation/devicetree/bindings/pwm/pwm-samsung.txt

+- clock-names: should contain all following required clock names:
+    - "timers" - PWM base clock used to generate PWM signals,
+  and any subset of following optional clock names:
+    - "pwm-tclk0" - first external PWM clock source,
+    - "pwm-tclk1" - second external PWM clock source.
+  Note that not all IP variants allow using all external clock
sources. +  Refer to SoC documentation to learn which clock source
configurations +  are available.

It might be nice to explicitly enumerate which variants (or rather, I
suppose which exact compatible values) support which optional clocks.
However, I suppose it's fine to just say "go read the HW manual"
instead.

I don't have enough information about some of the variants, so I decided 
to put it this way, instead of making an incomplete list or speculating 
about things.

So, this patch,
Acked-by: Stephen Warren <redacted>

Thanks.

(although this patch isn't backwards-compatible since before now, DT
nodes didn't need to provide any entries in clocks)

The thing is that the clocks were supposed to be there from the beginning, 
but in a hurry I forgot to specify them in original bindings documentation 
and things were running over compatibility clkdev aliases anyway, so 
nobody (including me) noticed.

Best regards,
Tomasz