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authorBoris BREZILLON <linux-arm@overkiz.com>2013-01-08 15:36:42 (GMT)
committerThierry Reding <thierry.reding@avionic-design.de>2013-01-08 15:52:10 (GMT)
commit9421bade0765d8ffb86b8a99213b611278a3542a (patch)
tree83bacefbd5536255dae0fba58bff5bdacdf2b6b8 /Documentation/devicetree/bindings/pwm
parentd1c3ed669a2d452cacfb48c2d171a1f364dae2ed (diff)
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 <linux-arm@overkiz.com> Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Diffstat (limited to 'Documentation/devicetree/bindings/pwm')
-rw-r--r--Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt18
1 files changed, 18 insertions, 0 deletions
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 0000000..de0eaed
--- /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>;
+};

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