On Sat, Mar 11, 2017 at 10:38:17PM -0800, Michael Zoran wrote:
Add documentation for the DMA properties required when using the PWM controller of the bcm2835 for analog audio output.
Signed-off-by: Michael Zoran mzoran@crowfest.net
Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt b/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt index cf573e85b11d..08fc06fc083a 100644 --- a/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt +++ b/Documentation/devicetree/bindings/pwm/pwm-bcm2835.txt @@ -1,14 +1,21 @@ BCM2835 PWM controller (Raspberry Pi controller)
Required properties: -- compatible: should be "brcm,bcm2835-pwm" +- compatible: should be "brcm,bcm2835-pwm" or "brcm,bcm2835-analog-audio"
Compatibles are not for selecting usage modes. You should describe the connection to the pwm that makes it an audio output rather than change the compatible.
- reg: physical base address and length of the controller's registers
- clocks: This clock defines the base clock frequency of the PWM hardware system, the period and the duty_cycle of the PWM signal is a multiple of the base period.
+Required properties(PWM Output):
- #pwm-cells: Should be 2. See pwm.txt in this directory for a description of the cells format.
+Required properties(Audio Output): +- dmas: Should contain one entry pointing to the DMA channel used to
- transfer audio data
+- dma-names: Should contain "tx"
Examples:
pwm@2020c000 {
2.11.0