Subject: [PATCH] bcm2835: Add Raspberry Pi CPU frequency control to the device tree

From: [email-masked] (Stephen Warren)
Date: Tue, 20 Oct 2015 21:00:18 -0600

On 10/11/2015 01:46 PM, Lubomir Rintel wrote:
> This adds a device tree binding for Broadcom BCM2834 CPU frequency control
> driven via Raspberry Pi VideoCore 4 firmware interface.

Oh I see; that DT binding was sent as a separate patch rather than part
of the series...

DT bindings patches need to be sent to the people/lists in the following
MAINTAINERS entry:

OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS
M:      Rob Herring <[email-masked]>
M:      Pawel Moll <[email-masked]>
M:      Mark Rutland <[email-masked]>
M:      Ian Campbell <[email-masked]>
M:      Kumar Gala <[email-masked]>
L:      devicetree at vger.kernel.org

> diff --git a/Documentation/devicetree/bindings/cpufreq/raspberrypi,bcm2835-cpufreq.txt b/Documentation/devicetree/bindings/cpufreq/raspberrypi,bcm2835-cpufreq.txt
> new file mode 100644
> index 0000000..eb126d3
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/cpufreq/raspberrypi,bcm2835-cpufreq.txt
> @@ -0,0 +1,13 @@
> +Raspberry Pi Broadcom BCM2835 CPU frequency control
> +
> +Required properties:
> +
> +- compatible : should be "raspberrypi,bcm2835-cpufreq"
> +- firmware : the Raspberry Pi firmware node

It'd be best practice to mention the filename of the binding that
defines the firmware. For example:

- firmware : phandle of the Raspberry Pi firmware node, as defined in
  .././arm/bcm/raspberrypi,bcm2835-firmware.txt.

That said, I'm not convinced cpufreq scaling should rely on the firmware
directly, but instead should use the clock API to manipulate the clock.