diff options
| author | Philip, Avinash <avinashphilip@ti.com> | 2012-11-21 08:40:44 +0100 |
|---|---|---|
| committer | Thierry Reding <thierry.reding@avionic-design.de> | 2012-11-22 22:47:12 +0100 |
| commit | 83af24027b3df1af5c5a9aa9adcdcfeb3429d3be (patch) | |
| tree | 3e104ed41554bb7e97378cc7cc3866c842306dff /Documentation | |
| parent | pwm: vt8500: Ensure PWM clock is enabled during pwm_config (diff) | |
| download | linux-83af24027b3df1af5c5a9aa9adcdcfeb3429d3be.tar.xz linux-83af24027b3df1af5c5a9aa9adcdcfeb3429d3be.zip | |
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')
| -rw-r--r-- | Documentation/devicetree/bindings/pwm/pwm.txt | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt index 73ec962bfe8c..06e67247859a 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 ----------------------- |