[PATCH 3/3] Documentation: Add documentation for APM X-Gene clock binding.

[Mark Rutland]

On Fri, Jun 21, 2013 at 04:30:05PM +0100, Loc Ho wrote:
> Documentation: Add documentation for APM X-Gene clock binding with PLL and 
> device clocks.
> 
> Signed-off-by: Loc Ho <lho at apm.com>
> Signed-off-by: Kumar Sankaran <ksankaran at apm.com>
> Signed-off-by: Vinayak Kale <vkale at apm.com>
> Signed-off-by: Feng Kan <fkan at apm.com>
> ---
>  Documentation/devicetree/bindings/clock/xgene.txt |   90 +++++++++++++++++++++
>  1 files changed, 90 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/clock/xgene.txt
> 
> diff --git a/Documentation/devicetree/bindings/clock/xgene.txt b/Documentation/devicetree/bindings/clock/xgene.txt
> new file mode 100644
> index 0000000..fcdee79
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/xgene.txt
> @@ -0,0 +1,90 @@
> +Device Tree Clock bindings for APM X-Gene
> +
> +This binding uses the common clock binding[1].
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt
> +
> +Required properties:
> +- compatible : shall be one of the following:
> +	"apm,xgene-pll-clock" - for a X-Gene PLL clock
> +	"apm,xgene-device-clock" - for a X-Gene device clock
> +
> +Required properties for PLL clocks:
> +- reg : shall be the physical PLL register address for the pll clock.
> +- clocks : shall be the input parent clock phandle for the clock. This should
> +	be the reference clock.
> +- #clock-cells : shall be set to 1.
> +- clock-output-names : shall be the name of the PLL referenced by derive
> +  clock.
> +- type : shall be 1 for SoC PLL and 0 for PCP PLL.

That makes the binding very difficult for a human to read, could this not be
part of the compatible string? e.g. "apm,xgene-pcp-pll-clock".

> +Optional properties for PLL clocks:
> +- clock-names : shall be the name of the PLL. If missing, use the device name.
> +
> +Required properties for device clocks:
> +- reg : shall be the physical CSR reset address base and physical CSR divider
> +        address base. If one does not exist, specify 0 for address and 0 for 
> +        size.
> +- clocks : shall be the input parent clock phandle for the clock.
> +- #clock-cells : shall be set to 1.
> +- clock-output-names : shall be the name of the device referenced.
> +Optional properties for device clocks:
> +- clock-names : shall be the name of the device clock. If missing, use the
> +                device name.
> +- flags : Any clock flags. ie. use 0x8 to leave clock un-touch if not
> +          referenced. Default is 0.

What flags are these? We should *not* be exporting Linux-internal flags as
devicetree bindings.

> +- csr-offset : Offset to the CSR reset register from the reset address base.
> +               Default is 0.
> +- csr-mask : CSR reset mask bit. Default is 0xF.
> +- enable-offset : Offset to the enable register from the reset address base.
> +                  Default is 0x8.
> +- enable-mask : CSR enable mask bit. Default is 0xF.
> +- divider-offset : Offset to the divider CSR register from the divider base.
> +                   Default is 0x0.
> +- divider-width : Width of the divider register. Default is 0.
> +- divider-shift : Bit shift of the divider register. Default is 0.
> +
> +For example:
> +
> +	pcppll: pcppll at 17000100 {
> +		compatible = "apm,xgene-pll-clock";
> +		#clock-cells = <1>;
> +		clocks = <&refclk 0>;
> +		clock-names = "pcppll";
> +		reg = <0x0 0x17000100 0x0 0x1000>;
> +		clock-output-names = "pcppll";
> +		type = <0>;
> +	};
> +
> +	socpll: socpll at 17000120 {
> +		compatible = "apm,xgene-pll-clock";
> +		#clock-cells = <1>;
> +		clocks = <&refclk 0>;
> +		clock-names = "socpll";
> +		reg = <0x0 0x17000120 0x0 0x1000>;
> +		clock-output-names = "socpll";
> +		type = <1>;
> +	};
> +
> +	qmlclk: qmlclk {
> +		compatible = "apm,xgene-device-clock";
> +		#clock-cells = <1>;
> +		clocks = <&socplldiv2 0>;
> +		clock-names = "qmlclk";
> +		reg = <0x0 0x1703C000 0x0 0x1000
> +			0x0 0x00000000 0x0 0x0000>;
> +		clock-output-names = "qmlclk";
> +	};
> +
> +	ethclk: ethclk {
> +		compatible = "apm,xgene-device-clock";
> +		#clock-cells = <1>;
> +		clocks = <&socplldiv2 0>;
> +		clock-names = "ethclk";
> +		reg = <0x0 0x00000000 0x0 0x0000
> +			0x0 0x17000000 0x0 0x1000>;
> +			divider-offset = <0x238>;

Extraneous tab here.

Thanks,
Mark.