Re: [PATCH 1/7] add binding for stm32 multifunctions timer driver

From: Lee Jones
Date: Tue Nov 22 2016 - 11:50:17 EST


On Tue, 22 Nov 2016, Benjamin Gaignard wrote:

> Add bindings information for stm32 timer MFD
>
> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
> ---
> .../devicetree/bindings/mfd/stm32-timer.txt | 53 ++++++++++++++++++++++
> 1 file changed, 53 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mfd/stm32-timer.txt
>
> diff --git a/Documentation/devicetree/bindings/mfd/stm32-timer.txt b/Documentation/devicetree/bindings/mfd/stm32-timer.txt
> new file mode 100644
> index 0000000..3cefce1
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/stm32-timer.txt
> @@ -0,0 +1,53 @@
> +STM32 multifunctions timer driver

"STM32 Multi-Function Timer/PWM device bindings"

Doesn't this shared device have a better name?

> +stm32 timer MFD allow to handle at the same time pwm and IIO timer devices

No need for this sentence.

> +Required parameters:
> +- compatible: must be one of the follow value:
> + "st,stm32-mfd-timer1"
> + "st,stm32-mfd-timer2"
> + "st,stm32-mfd-timer3"
> + "st,stm32-mfd-timer4"
> + "st,stm32-mfd-timer5"
> + "st,stm32-mfd-timer6"
> + "st,stm32-mfd-timer7"
> + "st,stm32-mfd-timer8"
> + "st,stm32-mfd-timer9"
> + "st,stm32-mfd-timer10"
> + "st,stm32-mfd-timer11"
> + "st,stm32-mfd-timer12"
> + "st,stm32-mfd-timer13"
> + "st,stm32-mfd-timer14"

We don't normally number devices.

What's stopping you from simply doing:

pwm1: pwm1@40010000 {
compatible = "st,stm32-pwm";
};
pwm2: pwm1@40020000 {
compatible = "st,stm32-pwm";
};
pwm3: pwm1@40030000 {
compatible = "st,stm32-pwm";
};

> +- reg : Physical base address and length of the controller's
> + registers.
> +- clock-names: Set to "mfd_timer_clk".

How many clocks are there?

If only 1, you don't need this property.

"mfd_timer_clk" is not the correct name.

What is it called in the datasheet?

> +- clocks: Phandle of the clock used by the timer module.

"Phandle to the clock ..."

> + For Clk properties, please refer to [1].
> +- interrupts : Reference to the timer interrupt

Reference to?

See how other binding documents describe this property.

> +Optional parameters:
> +- resets : Reference to a reset controller asserting the timer

As above.

> +Optional subnodes:

Either use ":" or " :" or "<tab>:", but keep it consistent.

> +- pwm: See Documentation/devicetree/bindings/pwm/pwm-stm32.txt
> +- iiotimer: See Documentation/devicetree/bindings/iio/timer/stm32-iio-timer.txt
> +
> +[1] Documentation/devicetree/bindings/clock/clock-bindings.txt

Use the relative paths "../clock/", "../pwm/", "../iio/".

> +Example:
> + mfd_timer1: mfdtimer1@40010000 {

This is not an "MFD timer". MFD is a Linuxisum.

> + compatible = "st,stm32-mfd-timer1";

Better description required.

> + reg = <0x40010000 0x400>;
> + clocks = <&rcc 0 160>;
> + clock-names = "mfd_timer_clk";
> + interrupts = <27>;
> +
> + pwm1: pwm1@40010000 {
> + compatible = "st,stm32-pwm1";
> + };
> +
> + iiotimer1: iiotimer1@40010000 {
> + compatible = "st,stm32-iio-timer1";
> + };
> + };

--
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org â Open source software for ARM SoCs
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