diff options
author | Boris BREZILLON <linux-arm@overkiz.com> | 2013-01-08 10:36:42 -0500 |
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committer | Thierry Reding <thierry.reding@avionic-design.de> | 2013-01-08 10:52:10 -0500 |
commit | 9421bade0765d8ffb86b8a99213b611278a3542a (patch) | |
tree | 83bacefbd5536255dae0fba58bff5bdacdf2b6b8 /Documentation | |
parent | d1c3ed669a2d452cacfb48c2d171a1f364dae2ed (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')
-rw-r--r-- | Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt | 18 |
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 000000000000..de0eaed86651 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/atmel-tcb-pwm.txt | |||
@@ -0,0 +1,18 @@ | |||
1 | Atmel TCB PWM controller | ||
2 | |||
3 | Required properties: | ||
4 | - compatible: should be "atmel,tcb-pwm" | ||
5 | - #pwm-cells: Should be 3. The first cell specifies the per-chip index | ||
6 | of the PWM to use, the second cell is the period in nanoseconds and | ||
7 | bit 0 in the third cell is used to encode the polarity of PWM output. | ||
8 | Set bit 0 of the third cell in PWM specifier to 1 for inverse polarity & | ||
9 | set to 0 for normal polarity. | ||
10 | - tc-block: The Timer Counter block to use as a PWM chip. | ||
11 | |||
12 | Example: | ||
13 | |||
14 | pwm { | ||
15 | compatible = "atmel,tcb-pwm"; | ||
16 | #pwm-cells = <3>; | ||
17 | tc-block = <1>; | ||
18 | }; | ||