Add PWM normal and complementary modes.
Signed-off-by: Claudiu Beznea claudiu.beznea@microchip.com --- Documentation/devicetree/bindings/pwm/pwm.txt | 9 +++++++-- Documentation/pwm.txt | 26 +++++++++++++++++++++++--- include/dt-bindings/pwm/pwm.h | 1 + 3 files changed, 31 insertions(+), 5 deletions(-)
diff --git a/Documentation/devicetree/bindings/pwm/pwm.txt b/Documentation/devicetree/bindings/pwm/pwm.txt index 8556263b8502..c2b4b9ba0e3f 100644 --- a/Documentation/devicetree/bindings/pwm/pwm.txt +++ b/Documentation/devicetree/bindings/pwm/pwm.txt @@ -46,11 +46,16 @@ period in nanoseconds. Optionally, the pwm-specifier can encode a number of flags (defined in <dt-bindings/pwm/pwm.h>) in a third cell: - PWM_POLARITY_INVERTED: invert the PWM signal polarity +- PWM_DTMODE_COMPLEMENTARY: PWM complementary working mode (for PWM +channels two outputs); if not specified, the default for PWM channel will +be used
-Example with optional PWM specifier for inverse polarity +Example with optional PWM specifier for inverse polarity and complementary +mode:
bl: backlight { - pwms = <&pwm 0 5000000 PWM_POLARITY_INVERTED>; + pwms = <&pwm 0 5000000 + (PWM_DTMODE_COMPLEMENTARY | PWM_POLARITY_INVERTED)>; pwm-names = "backlight"; };
diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt index 8fbf0aa3ba2d..59592f8cc381 100644 --- a/Documentation/pwm.txt +++ b/Documentation/pwm.txt @@ -61,9 +61,9 @@ In addition to the PWM state, the PWM API also exposes PWM arguments, which are the reference PWM config one should use on this PWM. PWM arguments are usually platform-specific and allows the PWM user to only care about dutycycle relatively to the full period (like, duty = 50% of the -period). struct pwm_args contains 2 fields (period and polarity) and should -be used to set the initial PWM config (usually done in the probe function -of the PWM user). PWM arguments are retrieved with pwm_get_args(). +period). struct pwm_args contains 3 fields (period, polarity and mode) and +should be used to set the initial PWM config (usually done in the probe +function of the PWM user). PWM arguments are retrieved with pwm_get_args().
Using PWMs with the sysfs interface ----------------------------------- @@ -110,6 +110,26 @@ channel that was exported. The following properties will then be available: - 0 - disabled - 1 - enabled
+ mode + Get/set PWM channel working mode. + + Normal mode - for PWM channels with one output; this should be the + default working mode for every PWM channel; output waveforms looks + like this: + __ __ __ __ + PWM __| |__| |__| |__| |__ + <--T--> + + Complementary mode - for PWM channels two outputs; output waveforms + looks line this: + __ __ __ __ + PWMH1 __| |__| |__| |__| |__ + __ __ __ __ __ + PWML1 |__| |__| |__| |__| + <--T--> + + Where T is the signal period. + Implementing a PWM driver -------------------------
diff --git a/include/dt-bindings/pwm/pwm.h b/include/dt-bindings/pwm/pwm.h index ab9a077e3c7d..b4d61269aced 100644 --- a/include/dt-bindings/pwm/pwm.h +++ b/include/dt-bindings/pwm/pwm.h @@ -11,5 +11,6 @@ #define _DT_BINDINGS_PWM_PWM_H
#define PWM_POLARITY_INVERTED (1 << 0) +#define PWM_DTMODE_COMPLEMENTARY (1 << 1)
#endif