linux-kernel - Re: [PATCH 01/16] dt-bindings: mfd: rohm,bd71847-pmic: Correct clock properties requirements

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Message-ID: <b75867fd1c662a83d933ae8f0c4373ba017eb808.camel@fi.rohmeurope.com>
Date:   Tue, 25 Aug 2020 06:23:36 +0000
From:   "Vaittinen, Matti" <Matti.Vaittinen@...rohmeurope.com>
To:     "miquel.raynal@...tlin.com" <miquel.raynal@...tlin.com>,
        "linux-imx@....com" <linux-imx@....com>,
        "han.xu@....com" <han.xu@....com>,
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        "shawnguo@...nel.org" <shawnguo@...nel.org>,
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        "kernel@...gutronix.de" <kernel@...gutronix.de>,
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Subject: Re: [PATCH 01/16] dt-bindings: mfd: rohm,bd71847-pmic: Correct clock
 properties requirements


Hello Krzysztof,

On Mon, 2020-08-24 at 21:06 +0200, Krzysztof Kozlowski wrote:
> The input clock and number of clock provider cells are not required
> for
> the PMIC to operate.  They are needed only for the optional bd718x7
> clock driver.

I have always found the DT bindings hard to do. I quite often end up
having a different view with Rob so I probably could just shut-up and
watch how this evolves :)

But as keeping my mouth is so difficult...

...All of the drivers are optional. The PMIC can power-on without any
drivers. Drivers are mostly used just for disabling the voltage from
graphics accelerator block when it is not needed (optional). Or some
DVS (optional). But yes, maybe the clk driver is "more optional" than
the rest. XD So, I am not against this.

> Add also clock-output-names as driver takes use of it.
> 
> This fixes dtbs_check warnings like:
> 
>     arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dt.yaml: pmic@4b:
> 'clocks' is a required property
>     arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dt.yaml: pmic@4b:
> '#clock-cells' is a required property
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
> ---
>  .../devicetree/bindings/mfd/rohm,bd71847-pmic.yaml       | 9
> +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/mfd/rohm,bd71847-
> pmic.yaml b/Documentation/devicetree/bindings/mfd/rohm,bd71847-
> pmic.yaml
> index 77bcca2d414f..5d531051a153 100644
> --- a/Documentation/devicetree/bindings/mfd/rohm,bd71847-pmic.yaml
> +++ b/Documentation/devicetree/bindings/mfd/rohm,bd71847-pmic.yaml
> @@ -38,6 +38,9 @@ properties:
>    "#clock-cells":
>      const: 0
>  
> +  clock-output-names:
> +    maxItems: 1

I had this in original binding (text) document patch series. For some
reason it was later dropped. Unfortunately I didn't easily find a
reason as to why. Adding it back now is absolutely fine for me though.

> +
>  # The BD71847 abd BD71850 support two different HW states as reset
> target
>  # states. States are called as SNVS and READY. At READY state all
> the PMIC
>  # power outputs go down and OTP is reload. At the SNVS state all
> other logic
> @@ -116,12 +119,14 @@ required:
>    - compatible
>    - reg
>    - interrupts
> -  - clocks
> -  - "#clock-cells"
>    - regulators
>  
>  additionalProperties: false
>  
> +dependencies:
> +  '#clock-cells': [clocks]
> +  clocks: ['#clock-cells']

This is new to me. Please educate me - does this simply mean that if
'#clock-cells' is given, then also the 'clocks' must be given - and the
other way around?

If so, then:
Acked-By: Matti Vaittinen <matti.vaittinen@...rohmeurope.com>



--
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
K
iviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~

Simon says - in Latin please.
"non cogito me" dixit Rene Descarte, deinde evanescavit

(Thanks for the translation Simon)