diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt | 21 | ||||
| -rw-r--r-- | Documentation/pwm.txt | 10 |
2 files changed, 30 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt b/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt new file mode 100644 index 00000000000..8eae9fe7841 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/bcm-kona-pwm.txt @@ -0,0 +1,21 @@ +Broadcom Kona PWM controller device tree bindings + +This controller has 6 channels. + +Required Properties : +- compatible: should contain "brcm,kona-pwm" +- reg: physical base address and length of the controller's registers +- clocks: phandle + clock specifier pair for the external clock +- #pwm-cells: Should be 3. See pwm.txt in this directory for a + description of the cells format. + +Refer to clocks/clock-bindings.txt for generic clock consumer properties. + +Example: + +pwm: pwm@3e01a000 { + compatible = "brcm,bcm11351-pwm", "brcm,kona-pwm"; + reg = <0x3e01a000 0xc4>; + clocks = <&pwm_clk>; + #pwm-cells = <3>; +}; diff --git a/Documentation/pwm.txt b/Documentation/pwm.txt index 93cb9797498..ca895fd211e 100644 --- a/Documentation/pwm.txt +++ b/Documentation/pwm.txt @@ -19,7 +19,8 @@ should instead register a static mapping that can be used to match PWM consumers to providers, as given in the following example: static struct pwm_lookup board_pwm_lookup[] = { - PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL), + PWM_LOOKUP("tegra-pwm", 0, "pwm-backlight", NULL, + 50000, PWM_POLARITY_NORMAL), }; static void __init board_init(void) @@ -97,6 +98,13 @@ pwm_chip as argument which provides a description of the PWM chip, the number of PWM devices provided by the chip and the chip-specific implementation of the supported PWM operations to the framework. +When implementing polarity support in a PWM driver, make sure to respect the +signal conventions in the PWM framework. By definition, normal polarity +characterizes a signal starts high for the duration of the duty cycle and +goes low for the remainder of the period. Conversely, a signal with inversed +polarity starts low for the duration of the duty cycle and goes high for the +remainder of the period. + Locking ------- |