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@xxxxxxxxxxxx>
> ---
> 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
>
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