Re: [PATCH v5 1/5] dt-bindings: gpu: add bindings for the ARM Mali Midgard GPU

[Brian Norris]

Hi Guillaume,

I know this has already been merged, but I figured here was an OK place
to note (inline):

On Wed, May 03, 2017 at 10:56:25AM +0100, Guillaume Tucker wrote:
> The ARM Mali Midgard GPU family is present in a number of SoCs
> from many different vendors such as Samsung Exynos and Rockchip.
> 
> Import the device tree bindings documentation from the r16p0
> release of the Mali Midgard GPU kernel driver:
> 
>   https://developer.arm.com/-/media/Files/downloads/mali-drivers/kernel/mali-midgard-gpu/TX011-SW-99002-r16p0-00rel0.tgz
> 
> Remove the copyright and GPL licence header as deemed not necessary.
> 
> Redesign the "compatible" property strings to list all the Mali
> Midgard GPU types and add vendor specific ones.
> 
> Drop the "clock-names" property as the Mali Midgard GPU uses only one
> clock (the driver now needs to call clk_get with NULL).
> 
> Convert the "interrupt-names" property values to lower-case: "job",
> "mmu" and "gpu".
> 
> Replace the deprecated "operating-points" optional property with
> "operating-points-v2".
> 
> Omit the following optional properties in this initial version as they
> are only used in very specific cases:
> 
>   * snoop_enable_smc
>   * snoop_disable_smc
>   * jm_config
>   * power_model
>   * system-coherency
>   * ipa-model
> 
> Update the example accordingly to reflect all these changes, based on
> rk3288 mali-t760.
> 
> CC: John Reitan <john.reitan@xxxxxxx>
> Tested-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> Signed-off-by: Guillaume Tucker <guillaume.tucker@xxxxxxxxxxxxx>
> ---
>  .../devicetree/bindings/gpu/arm,mali-midgard.txt   | 86 ++++++++++++++++++++++
>  1 file changed, 86 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt
> new file mode 100644
> index 000000000000..d3b6e1a4713a
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpu/arm,mali-midgard.txt

^^ This file name implies we're talking about a base "arm,mali-midgard"
compatible property.

> @@ -0,0 +1,86 @@
> +ARM Mali Midgard GPU
> +====================
> +
> +Required properties:
> +
> +- compatible :
> +  * Must contain one of the following:
> +    + "arm,mali-t604"
> +    + "arm,mali-t624"
> +    + "arm,mali-t628"
> +    + "arm,mali-t720"
> +    + "arm,mali-t760"
> +    + "arm,mali-t820"
> +    + "arm,mali-t830"
> +    + "arm,mali-t860"
> +    + "arm,mali-t880"
> +  * which must be preceded by one of the following vendor specifics:
> +    + "amlogic,meson-gxm-mali"
> +    + "rockchip,rk3288-mali"

But it's not listed here.

> +
> +- reg : Physical base address of the device and length of the register area.
> +
> +- interrupts : Contains the three IRQ lines required by Mali Midgard devices.
> +
> +- interrupt-names : Contains the names of IRQ resources in the order they were
> +  provided in the interrupts property. Must contain: "job", "mmu", "gpu".
> +
> +
> +Optional properties:
> +
> +- clocks : Phandle to clock for the Mali Midgard device.
> +
> +- mali-supply : Phandle to regulator for the Mali device. Refer to
> +  Documentation/devicetree/bindings/regulator/regulator.txt for details.
> +
> +- operating-points-v2 : Refer to Documentation/devicetree/bindings/power/opp.txt
> +  for details.
> +
> +
> +Example for a Mali-T760:
> +
> +gpu@ffa30000 {
> +	compatible = "rockchip,rk3288-mali", "arm,mali-t760", "arm,mali-midgard";

And it *is* used here in this example.

So, should it be used/documented or not?

> +	reg = <0xffa30000 0x10000>;
> +	interrupts = <GIC_SPI 6 IRQ_TYPE_LEVEL_HIGH>,
> +		     <GIC_SPI 7 IRQ_TYPE_LEVEL_HIGH>,
> +		     <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
> +	interrupt-names = "job", "mmu", "gpu";
> +	clocks = <&cru ACLK_GPU>;
> +	mali-supply = <&vdd_gpu>;
> +	operating-points-v2 = <&gpu_opp_table>;
> +	power-domains = <&power RK3288_PD_GPU>;
> +};

[...]

Brian