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pwm: Device tree support for PWM polarity

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Add support for encoding PWM properties in bit encoded form with
of_pwm_xlate_with_flags() function support. Platforms require platform
specific PWM properties has to populate in 3rd cell of the pwm-specifier
and PWM driver should also set .of_xlate support with this function.
Currently PWM property polarity encoded in bit position 0 of the third
cell in pwm-specifier.

Signed-off-by: Philip, Avinash <avinashphilip@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
This commit is contained in:
Philip, Avinash
2012-11-21 13:10:44 +05:30
committed by Thierry Reding
parent 422470a826
commit 83af24027b
3 changed files with 45 additions and 3 deletions
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17
Documentation/devicetree/bindings/pwm/pwm.txt
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@@ -37,10 +37,21 @@ device:
pwm-names = "backlight";
};
Note that in the example above, specifying the "pwm-names" is redundant
because the name "backlight" would be used as fallback anyway.
pwm-specifier typically encodes the chip-relative PWM number and the PWM
period in nanoseconds. Note that in the example above, specifying the
"pwm-names" is redundant because the name "backlight" would be used as
fallback anyway.
period in nanoseconds.
Optionally, the pwm-specifier can encode a number of flags in a third cell:
- bit 0: PWM signal polarity (0: normal polarity, 1: inverse polarity)
Example with optional PWM specifier for inverse polarity
bl: backlight {
pwms = <&pwm 0 5000000 1>;
pwm-names = "backlight";
};
2) PWM controller nodes
-----------------------