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authorPhilip, Avinash <avinashphilip@ti.com>2012-11-21 07:40:44 (GMT)
committerThierry Reding <thierry.reding@avionic-design.de>2012-11-22 21:47:12 (GMT)
commit83af24027b3df1af5c5a9aa9adcdcfeb3429d3be (patch)
tree3e104ed41554bb7e97378cc7cc3866c842306dff /Documentation/devicetree/bindings/pwm
parent422470a8265fbb1d182c00ab2421f4b416ab2dba (diff)
pwm: Device tree support for PWM polarity
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>
Diffstat (limited to 'Documentation/devicetree/bindings/pwm')
-rw-r--r--Documentation/devicetree/bindings/pwm/pwm.txt17
1 files changed, 14 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt
index 73ec962..06e6724 100644
--- a/Documentation/devicetree/bindings/pwm/pwm.txt
+++ b/Documentation/devicetree/bindings/pwm/pwm.txt
@@ -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
-----------------------

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