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authorBrian Norris <briannorris@chromium.org>2016-07-15 16:28:43 -0700
committerThierry Reding <thierry.reding@gmail.com>2016-07-25 10:39:36 +0200
commit9e60f50b4a79ae2df791d89d08cf2b78ad7629bd (patch)
treebee8d37f05bf139f38e1e0f52c5fc8458ca3a673
parent38593426ecc7e0e22873dcd7b5d471eb869a0b6e (diff)
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dt-bindings: pwm: Add binding for ChromeOS EC PWM
The ChromeOS Embedded Controller can support controlling its attached PWMs via its host-command interface. The number of supported PWMs varies on a per-board basis, but we can autodetect this by checking the error codes, so we don't need an extra property for this. And because the EC only allows specifying the duty cycle and not the period, we don't specify the period via pwm-cells, and instead have only support for one cell -- to specify the index. Signed-off-by: Brian Norris <briannorris@chromium.org> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
-rw-r--r--Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt23
1 files changed, 23 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt
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+++ b/Documentation/devicetree/bindings/pwm/google,cros-ec-pwm.txt
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+* PWM controlled by ChromeOS EC
+
+Google's ChromeOS EC PWM is a simple PWM attached to the Embedded Controller
+(EC) and controlled via a host-command interface.
+
+An EC PWM node should be only found as a sub-node of the EC node (see
+Documentation/devicetree/bindings/mfd/cros-ec.txt).
+
+Required properties:
+- compatible: Must contain "google,cros-ec-pwm"
+- #pwm-cells: Should be 1. The cell specifies the PWM index.
+
+Example:
+ cros-ec@0 {
+ compatible = "google,cros-ec-spi";
+
+ ...
+
+ cros_ec_pwm: ec-pwm {
+ compatible = "google,cros-ec-pwm";
+ #pwm-cells = <1>;
+ };
+ };