From 9421bade0765d8ffb86b8a99213b611278a3542a Mon Sep 17 00:00:00 2001 From: Boris BREZILLON Date: Tue, 8 Jan 2013 16:36:42 +0100 Subject: pwm: atmel: add Timer Counter Block PWM driver This patch adds a PWM driver based on Atmel Timer Counter Block. The Timer Counter Block is used in Waveform generator mode. A Timer Counter Block provides up to 6 PWM devices grouped by 2: * group 0 = PWM 0 and 1 * group 1 = PWM 2 and 3 * group 2 = PMW 4 and 5 PWM devices in a given group must be configured with the same period value. If a PWM device in a group tries to change the period value and the other device is already configured with a different value an error will be returned. This driver requires device tree support. The Timer Counter Block number used to create a PWM chip is given by the tc-block field in an "atmel,tcb-pwm" compatible node. This patch was tested on kizbox board (at91sam9g20 SoC) with pwm-leds. Signed-off-by: Boris BREZILLON Signed-off-by: Thierry Reding --- .../devicetree/bindings/pwm/atmel-tcb-pwm.txt | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) create mode 100644 Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt b/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt new file mode 100644 index 00000000000..de0eaed8665 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt @@ -0,0 +1,18 @@ +Atmel TCB PWM controller + +Required properties: +- compatible: should be "atmel,tcb-pwm" +- #pwm-cells: Should be 3. The first cell specifies the per-chip index + of the PWM to use, the second cell is the period in nanoseconds and + bit 0 in the third cell is used to encode the polarity of PWM output. + Set bit 0 of the third cell in PWM specifier to 1 for inverse polarity & + set to 0 for normal polarity. +- tc-block: The Timer Counter block to use as a PWM chip. + +Example: + +pwm { + compatible = "atmel,tcb-pwm"; + #pwm-cells = <3>; + tc-block = <1>; +}; -- cgit v1.2.3 From 3ccb1c1702ed4bb07006d20c8173899a69dae242 Mon Sep 17 00:00:00 2001 From: Tony Prisk Date: Thu, 3 Jan 2013 08:44:16 +1300 Subject: pwm: vt8500: Add polarity support Add support to set polarity on PWM devices, allowing for inverted duty cycles. Also update the binding document to #pwm-cells = <3> to allow passing the flags from devicetree. Signed-off-by: Tony Prisk Signed-off-by: Thierry Reding --- Documentation/devicetree/bindings/pwm/vt8500-pwm.txt | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt index bcc63678a9a..d21d82d2985 100644 --- a/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt +++ b/Documentation/devicetree/bindings/pwm/vt8500-pwm.txt @@ -3,14 +3,17 @@ VIA/Wondermedia VT8500/WM8xxx series SoC PWM controller Required properties: - compatible: should be "via,vt8500-pwm" - reg: physical base address and length of the controller's registers -- #pwm-cells: should be 2. The first cell specifies the per-chip index - of the PWM to use and the second cell is the period in nanoseconds. +- #pwm-cells: Should be 3. Number of cells being used to specify PWM property. + First cell specifies the per-chip index of the PWM to use, the second + cell is the period in nanoseconds and bit 0 in the third cell is used to + encode the polarity of PWM output. Set bit 0 of the third in PWM specifier + to 1 for inverse polarity & set to 0 for normal polarity. - clocks: phandle to the PWM source clock Example: pwm1: pwm@d8220000 { - #pwm-cells = <2>; + #pwm-cells = <3>; compatible = "via,vt8500-pwm"; reg = <0xd8220000 0x1000>; clocks = <&clkpwm>; -- cgit v1.2.3