Add PWM normal and complementary modes.
Signed-off-by: Claudiu Beznea <claudiu.beznea@xxxxxxxxxxxxx>
---
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
--
2.7.4
--
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