diff mbox series

[1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver bindings

Message ID 20221213224310.543243-2-fabrizio.castro.jz@renesas.com
State New
Headers
Series Driver support for RZ/V2M PWC |

Commit Message

Fabrizio Castro Dec. 13, 2022, 10:43 p.m. UTC 
  Add dt-bindings document for the RZ/V2M PWC GPIO driver.

Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
---
 .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml

Comments

Rob Herring Dec. 14, 2022, 4:10 p.m. UTC | #1 
On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
> Add dt-bindings document for the RZ/V2M PWC GPIO driver.

Bindings are for h/w blocks/devices, not a specific driver.

> 
> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> ---
>  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
>  1 file changed, 62 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> 
> diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> new file mode 100644
> index 000000000000..ecc034d53259
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/gpio/renesas,rzv2m-pwc-gpio.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
> +
> +description: |+
> +  The PWC IP found in the RZ/V2M family of chips comes with General-Purpose
> +  Output pins, alongside the below functions
> +    - external power supply on/off sequence generation
> +    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
> +    - key input signals processing
> +  This node uses syscon to map the register used to control the GPIOs
> +  (the register map is retrieved from the parent dt-node), and the node should
> +  be represented as a sub node of a "syscon", "simple-mfd" node.
> +
> +maintainers:
> +  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
> +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
> +      - const: renesas,rzv2m-pwc-gpio
> +
> +  offset:

Too generic of a name. We want any given property name (globally) to 
have 1 type. With the below comment, this should be replaced with 'reg' 
instead if you have child nodes.

> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: |
> +      Offset in the register map for controlling the GPIOs (in bytes).
> +
> +  regmap:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description: Phandle to the register map node.

Looks like GPIO is a sub-function of some other block. Define the 
binding for that entire block. GPIO can be either either a function of 
that node (just add GPIO provider properties) or you can have GPIO child 
nodes. Depends on what the entire block looks like to decide. Do you 
have multiple instances of the GPIO block would be one reason to have 
child nodes.

> +
> +  gpio-controller: true
> +
> +  '#gpio-cells':
> +    const: 2
> +
> +required:
> +  - compatible
> +  - regmap
> +  - offset
> +  - gpio-controller
> +  - '#gpio-cells'
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    gpio {
> +            compatible = "renesas,r9a09g011-pwc-gpio",
> +                         "renesas,rzv2m-pwc-gpio";
> +            regmap = <&regmapnode>;
> +            offset = <0x80>;
> +            gpio-controller;
> +            #gpio-cells = <2>;
> +    };
> -- 
> 2.34.1
> 
>
Fabrizio Castro Dec. 14, 2022, 6:26 p.m. UTC | #2 
Hi Rob,

Thanks for your feedback!

> From: Rob Herring <robh@kernel.org>
> Sent: 14 December 2022 16:11
> To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
> bindings
> 
> On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
> > Add dt-bindings document for the RZ/V2M PWC GPIO driver.
> 
> Bindings are for h/w blocks/devices, not a specific driver.

Apologies, I will reword the changelog in v2.

> 
> >
> > Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> > ---
> >  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
> >  1 file changed, 62 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> gpio.yaml
> > new file mode 100644
> > index 000000000000..ecc034d53259
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> > @@ -0,0 +1,62 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id:
> https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetre
> e.org%2Fschemas%2Fgpio%2Frenesas%2Crzv2m-pwc-
> gpio.yaml%23&amp;data=05%7C01%7Cfabrizio.castro.jz%40renesas.com%7C603623c
> 766f4421b85bd08daddedcb8c%7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C638
> 066310628408926%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
> IiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=o46ncDZK8YK5HYJ
> ZYDXuq3yfEA34vnaxEsIDBlcroc0%3D&amp;reserved=0
> > +$schema:
> https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetre
> e.org%2Fmeta-
> schemas%2Fcore.yaml%23&amp;data=05%7C01%7Cfabrizio.castro.jz%40renesas.com
> %7C603623c766f4421b85bd08daddedcb8c%7C53d82571da1947e49cb4625a166a4a2a%7C0
> %7C0%7C638066310628408926%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQ
> IjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=VoWvV
> pW782DVH2zdTKIesyzqm6sjiFyacbl833%2BjRis%3D&amp;reserved=0
> > +
> > +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
> > +
> > +description: |+
> > +  The PWC IP found in the RZ/V2M family of chips comes with General-
> Purpose
> > +  Output pins, alongside the below functions
> > +    - external power supply on/off sequence generation
> > +    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
> > +    - key input signals processing
> > +  This node uses syscon to map the register used to control the GPIOs
> > +  (the register map is retrieved from the parent dt-node), and the node
> should
> > +  be represented as a sub node of a "syscon", "simple-mfd" node.
> > +
> > +maintainers:
> > +  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
> > +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
> > +      - const: renesas,rzv2m-pwc-gpio
> > +
> > +  offset:
> 
> Too generic of a name. We want any given property name (globally) to
> have 1 type. With the below comment, this should be replaced with 'reg'
> instead if you have child nodes.

My understanding is that syscon subnodes normally use this name for exactly
the same purpose, for example:
https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/power/reset/syscon-poweroff.yaml#L27
https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml#L30

What am I missing?

> 
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description: |
> > +      Offset in the register map for controlling the GPIOs (in bytes).
> > +
> > +  regmap:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description: Phandle to the register map node.
> 
> Looks like GPIO is a sub-function of some other block. Define the
> binding for that entire block.

That's defined in patch 3 from this series.
I have sent it as patch 3 because that document references:
* /schemas/gpio/renesas,rzv2m-pwc-gpio.yaml
* /schemas/power/reset/renesas,rzv2m-pwc-poweroff.yaml
Which are defined in this patch and in patch 2 in the series.

Do you want me to move patch 3 to patch 1 in v2?

> GPIO can be either either a function of
> that node (just add GPIO provider properties) or you can have GPIO child
> nodes. Depends on what the entire block looks like to decide. Do you
> have multiple instances of the GPIO block would be one reason to have
> child nodes.

From a pure HW point of view, this GPIO block is contained inside the PWC block
(as PWC is basically a MFD device), and it only deals with 2 General-Purpose
Output pins, both controlled by 1 (and the same) register, therefore the GPIO
block is only 1 child.

If possible, I would like to keep the functionality offered by the sub-blocks of
PWC contained in separated drivers and DT nodes (either non-child nodes or child
nodes).

My understanding is that simple-mfd will automatically probe the children of the
simple-mfd node, and also hierarchically it makes sense to me to have the DT nodes
of the PWC sub-blocks as children of the "syscon", "simple-mfd" node. I have found
other instances of this same architecture in the kernel already (plenty from NXP/Freescale),
for example:
https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mm.dtsi#L585
https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mn.dtsi#L586
https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mp.dtsi#L451
https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mq.dtsi#L616
https://github.com/torvalds/linux/blob/master/arch/mips/boot/dts/mti/sead3.dts#L93
etc...

Something like the below could also work, but I don't think it would represent the
HW accurately:
pwc: pwc@a3700000 {
	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
		     "syscon", "simple-mfd";
	reg = <0 0xa3700000 0 0x800>;
};

pwc-gpio {
	compatible = "renesas,r9a09g011-pwc-gpio",
		     "renesas,rzv2m-pwc-gpio";
	regmap = <&pwc>;
	gpio-controller;
	#gpio-cells = <2>;
};

pwc-poweroff {
	compatible = "renesas,r9a09g011-pwc-poweroff",
		     "renesas,rzv2m-pwc-poweroff";
	regmap = <&pwc>;
};


I think the below describes things better:
pwc: pwc@a3700000 {
	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
		     "syscon", "simple-mfd";
	reg = <0 0xa3700000 0 0x800>;

	gpio {
		compatible = "renesas,r9a09g011-pwc-gpio",
			     "renesas,rzv2m-pwc-gpio";
		regmap = <&pwc>;
		offset = <0x80>;
		gpio-controller;
		#gpio-cells = <2>;
	};

	poweroff {
		compatible = "renesas,r9a09g011-pwc-poweroff",
			     "renesas,rzv2m-pwc-poweroff";
		regmap = <&pwc>;
	};
};

Do you think the bindings I have sent out are causing confusion here?
What else can I improve?

Thanks,
Fab

> 
> > +
> > +  gpio-controller: true
> > +
> > +  '#gpio-cells':
> > +    const: 2
> > +
> > +required:
> > +  - compatible
> > +  - regmap
> > +  - offset
> > +  - gpio-controller
> > +  - '#gpio-cells'
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    gpio {
> > +            compatible = "renesas,r9a09g011-pwc-gpio",
> > +                         "renesas,rzv2m-pwc-gpio";
> > +            regmap = <&regmapnode>;
> > +            offset = <0x80>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +    };
> > --
> > 2.34.1
> >
> >
Krzysztof Kozlowski Dec. 15, 2022, 9:49 a.m. UTC | #3 
On 14/12/2022 19:26, Fabrizio Castro wrote:
> Hi Rob,
> 
> Thanks for your feedback!
> 
>> From: Rob Herring <robh@kernel.org>
>> Sent: 14 December 2022 16:11
>> To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
>> Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
>> bindings
>>
>> On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
>>> Add dt-bindings document for the RZ/V2M PWC GPIO driver.
>>
>> Bindings are for h/w blocks/devices, not a specific driver.
> 
> Apologies, I will reword the changelog in v2.
> 
>>
>>>
>>> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
>>> ---
>>>  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
>>>  1 file changed, 62 insertions(+)
>>>  create mode 100644
>> Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
>> gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
>> gpio.yaml
>>> new file mode 100644
>>> index 000000000000..ecc034d53259
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
>>> @@ -0,0 +1,62 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id:
>> https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetre
>> e.org%2Fschemas%2Fgpio%2Frenesas%2Crzv2m-pwc-
>> gpio.yaml%23&amp;data=05%7C01%7Cfabrizio.castro.jz%40renesas.com%7C603623c
>> 766f4421b85bd08daddedcb8c%7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C638
>> 066310628408926%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMz
>> IiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=o46ncDZK8YK5HYJ
>> ZYDXuq3yfEA34vnaxEsIDBlcroc0%3D&amp;reserved=0
>>> +$schema:
>> https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fdevicetre
>> e.org%2Fmeta-
>> schemas%2Fcore.yaml%23&amp;data=05%7C01%7Cfabrizio.castro.jz%40renesas.com
>> %7C603623c766f4421b85bd08daddedcb8c%7C53d82571da1947e49cb4625a166a4a2a%7C0
>> %7C0%7C638066310628408926%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQ
>> IjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&amp;sdata=VoWvV
>> pW782DVH2zdTKIesyzqm6sjiFyacbl833%2BjRis%3D&amp;reserved=0
>>> +
>>> +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
>>> +
>>> +description: |+
>>> +  The PWC IP found in the RZ/V2M family of chips comes with General-
>> Purpose
>>> +  Output pins, alongside the below functions
>>> +    - external power supply on/off sequence generation
>>> +    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
>>> +    - key input signals processing
>>> +  This node uses syscon to map the register used to control the GPIOs
>>> +  (the register map is retrieved from the parent dt-node), and the node
>> should
>>> +  be represented as a sub node of a "syscon", "simple-mfd" node.
>>> +
>>> +maintainers:
>>> +  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    items:
>>> +      - enum:
>>> +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
>>> +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
>>> +      - const: renesas,rzv2m-pwc-gpio
>>> +
>>> +  offset:
>>
>> Too generic of a name. We want any given property name (globally) to
>> have 1 type. With the below comment, this should be replaced with 'reg'
>> instead if you have child nodes.
> 
> My understanding is that syscon subnodes normally use this name for exactly
> the same purpose, for example:
> https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/power/reset/syscon-poweroff.yaml#L27
> https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/power/reset/syscon-reboot.yaml#L30
> 
> What am I missing?

These are generic drivers, so they need offset as they do not match any
specific programming model. You are not making a generic device. Address
offsets are not suitable in most cases for DTS. There are of course
exceptions so you can present reasons why this one is exception.
> 
>>
>>> +    $ref: /schemas/types.yaml#/definitions/uint32
>>> +    description: |
>>> +      Offset in the register map for controlling the GPIOs (in bytes).
>>> +
>>> +  regmap:
>>> +    $ref: /schemas/types.yaml#/definitions/phandle
>>> +    description: Phandle to the register map node.
>>
>> Looks like GPIO is a sub-function of some other block. Define the
>> binding for that entire block.
> 
> That's defined in patch 3 from this series.
> I have sent it as patch 3 because that document references:
> * /schemas/gpio/renesas,rzv2m-pwc-gpio.yaml
> * /schemas/power/reset/renesas,rzv2m-pwc-poweroff.yaml
> Which are defined in this patch and in patch 2 in the series.
> 
> Do you want me to move patch 3 to patch 1 in v2?

We do not want regmap, but proper definition of entire hardware.

> 
>> GPIO can be either either a function of
>> that node (just add GPIO provider properties) or you can have GPIO child
>> nodes. Depends on what the entire block looks like to decide. Do you
>> have multiple instances of the GPIO block would be one reason to have
>> child nodes.
> 
> From a pure HW point of view, this GPIO block is contained inside the PWC block
> (as PWC is basically a MFD device), and it only deals with 2 General-Purpose
> Output pins, both controlled by 1 (and the same) register, therefore the GPIO
> block is only 1 child.
> 
> If possible, I would like to keep the functionality offered by the sub-blocks of
> PWC contained in separated drivers and DT nodes (either non-child nodes or child
> nodes).

Driver do not matter for bindings. We talk about regmap field which - as
you explained above - is not needed.


> 
> My understanding is that simple-mfd will automatically probe the children of the
> simple-mfd node, and also hierarchically it makes sense to me to have the DT nodes
> of the PWC sub-blocks as children of the "syscon", "simple-mfd" node. I have found
> other instances of this same architecture in the kernel already (plenty from NXP/Freescale),
> for example:

I don't understand. You do not have here simple-mfd and it still does
not explain Rob's comment and regmap.

> https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mm.dtsi#L585
> https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mn.dtsi#L586
> https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mp.dtsi#L451
> https://github.com/torvalds/linux/blob/master/arch/arm64/boot/dts/freescale/imx8mq.dtsi#L616
> https://github.com/torvalds/linux/blob/master/arch/mips/boot/dts/mti/sead3.dts#L93
> etc...
> 
> Something like the below could also work, but I don't think it would represent the
> HW accurately:
> pwc: pwc@a3700000 {
> 	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
> 		     "syscon", "simple-mfd";
> 	reg = <0 0xa3700000 0 0x800>;
> };
> 
> pwc-gpio {
> 	compatible = "renesas,r9a09g011-pwc-gpio",
> 		     "renesas,rzv2m-pwc-gpio";
> 	regmap = <&pwc>;
> 	gpio-controller;
> 	#gpio-cells = <2>;
> };
> 
> pwc-poweroff {
> 	compatible = "renesas,r9a09g011-pwc-poweroff",
> 		     "renesas,rzv2m-pwc-poweroff";
> 	regmap = <&pwc>;
> };
> 
> 
> I think the below describes things better:
> pwc: pwc@a3700000 {
> 	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
> 		     "syscon", "simple-mfd";
> 	reg = <0 0xa3700000 0 0x800>;
> 
> 	gpio {
> 		compatible = "renesas,r9a09g011-pwc-gpio",
> 			     "renesas,rzv2m-pwc-gpio";
> 		regmap = <&pwc>;

You speak about two different things. So again - drop regmap. You do not
need it.

> 		offset = <0x80>;
> 		gpio-controller;
> 		#gpio-cells = <2>;
> 	};
> 
> 	poweroff {
> 		compatible = "renesas,r9a09g011-pwc-poweroff",
> 			     "renesas,rzv2m-pwc-poweroff";
> 		regmap = <&pwc>;

Drop regmap.

> 	};
> };
> 

Best regards,
Krzysztof
Fabrizio Castro Dec. 20, 2022, 9:15 p.m. UTC | #4 
Hi Rob,

Thanks for the feedback.

> From: Rob Herring <robh@kernel.org>
> Sent: 14 December 2022 16:11
> To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
> bindings
> 
> On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
> > Add dt-bindings document for the RZ/V2M PWC GPIO driver.
> 
> Bindings are for h/w blocks/devices, not a specific driver.

Right, I'll be more careful next time.

> 
> >
> > Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> > ---
> >  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62 +++++++++++++++++++
> >  1 file changed, 62 insertions(+)
> >  create mode 100644
> Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> >
> > diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> gpio.yaml
> > new file mode 100644
> > index 000000000000..ecc034d53259
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> > @@ -0,0 +1,62 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +
> > +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
> > +
> > +description: |+
> > +  The PWC IP found in the RZ/V2M family of chips comes with General-
> Purpose
> > +  Output pins, alongside the below functions
> > +    - external power supply on/off sequence generation
> > +    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
> > +    - key input signals processing
> > +  This node uses syscon to map the register used to control the GPIOs
> > +  (the register map is retrieved from the parent dt-node), and the node
> should
> > +  be represented as a sub node of a "syscon", "simple-mfd" node.
> > +
> > +maintainers:
> > +  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> > +
> > +properties:
> > +  compatible:
> > +    items:
> > +      - enum:
> > +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
> > +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
> > +      - const: renesas,rzv2m-pwc-gpio
> > +
> > +  offset:
> 
> Too generic of a name. We want any given property name (globally) to
> have 1 type. With the below comment, this should be replaced with 'reg'
> instead if you have child nodes.

I'll take it out

> 
> > +    $ref: /schemas/types.yaml#/definitions/uint32
> > +    description: |
> > +      Offset in the register map for controlling the GPIOs (in bytes).
> > +
> > +  regmap:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description: Phandle to the register map node.
> 
> Looks like GPIO is a sub-function of some other block. Define the
> binding for that entire block. GPIO can be either either a function of
> that node (just add GPIO provider properties) or you can have GPIO child
> nodes. Depends on what the entire block looks like to decide. Do you
> have multiple instances of the GPIO block would be one reason to have
> child nodes.

I'll take out this child node.

Thanks,
Fab

> 
> > +
> > +  gpio-controller: true
> > +
> > +  '#gpio-cells':
> > +    const: 2
> > +
> > +required:
> > +  - compatible
> > +  - regmap
> > +  - offset
> > +  - gpio-controller
> > +  - '#gpio-cells'
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > +  - |
> > +    gpio {
> > +            compatible = "renesas,r9a09g011-pwc-gpio",
> > +                         "renesas,rzv2m-pwc-gpio";
> > +            regmap = <&regmapnode>;
> > +            offset = <0x80>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +    };
> > --
> > 2.34.1
> >
> >
Fabrizio Castro Dec. 20, 2022, 9:20 p.m. UTC | #5 
Hi Krzysztof,

Thanks for your feedback.

> From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
> Sent: 15 December 2022 09:49
> To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>; Rob Herring
> <robh@kernel.org>
> Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
> bindings
> 
> On 14/12/2022 19:26, Fabrizio Castro wrote:
> > Hi Rob,
> >
> > Thanks for your feedback!
> >
> >> From: Rob Herring <robh@kernel.org>
> >> Sent: 14 December 2022 16:11
> >> To: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> >> Subject: Re: [PATCH 1/5] dt-bindings: gpio: Add RZ/V2M PWC GPIO driver
> >> bindings
> >>
> >> On Tue, Dec 13, 2022 at 10:43:06PM +0000, Fabrizio Castro wrote:
> >>> Add dt-bindings document for the RZ/V2M PWC GPIO driver.
> >>
> >> Bindings are for h/w blocks/devices, not a specific driver.
> >
> > Apologies, I will reword the changelog in v2.
> >
> >>
> >>>
> >>> Signed-off-by: Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> >>> ---
> >>>  .../bindings/gpio/renesas,rzv2m-pwc-gpio.yaml | 62
> +++++++++++++++++++
> >>>  1 file changed, 62 insertions(+)
> >>>  create mode 100644
> >> Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
> >>>
> >>> diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> >> gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> >> gpio.yaml
> >>> new file mode 100644
> >>> index 000000000000..ecc034d53259
> >>> --- /dev/null
> >>> +++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-
> gpio.yaml
> >>> @@ -0,0 +1,62 @@
> >>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>> +%YAML 1.2
> >>> +---
> >>> +
> >>> +title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
> >>> +
> >>> +description: |+
> >>> +  The PWC IP found in the RZ/V2M family of chips comes with General-
> >> Purpose
> >>> +  Output pins, alongside the below functions
> >>> +    - external power supply on/off sequence generation
> >>> +    - on/off signal generation for the LPDDR4 core power supply
> (LPVDD)
> >>> +    - key input signals processing
> >>> +  This node uses syscon to map the register used to control the GPIOs
> >>> +  (the register map is retrieved from the parent dt-node), and the
> node
> >> should
> >>> +  be represented as a sub node of a "syscon", "simple-mfd" node.
> >>> +
> >>> +maintainers:
> >>> +  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
> >>> +
> >>> +properties:
> >>> +  compatible:
> >>> +    items:
> >>> +      - enum:
> >>> +          - renesas,r9a09g011-pwc-gpio # RZ/V2M
> >>> +          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
> >>> +      - const: renesas,rzv2m-pwc-gpio
> >>> +
> >>> +  offset:
> >>
> >> Too generic of a name. We want any given property name (globally) to
> >> have 1 type. With the below comment, this should be replaced with 'reg'
> >> instead if you have child nodes.
> >
> > My understanding is that syscon subnodes normally use this name for
> exactly
> > the same purpose, for example:
> >
> >
> > What am I missing?
> 
> These are generic drivers, so they need offset as they do not match any
> specific programming model. You are not making a generic device. Address
> offsets are not suitable in most cases for DTS. There are of course
> exceptions so you can present reasons why this one is exception.

Thanks for the explanation

> >
> >>
> >>> +    $ref: /schemas/types.yaml#/definitions/uint32
> >>> +    description: |
> >>> +      Offset in the register map for controlling the GPIOs (in
> bytes).
> >>> +
> >>> +  regmap:
> >>> +    $ref: /schemas/types.yaml#/definitions/phandle
> >>> +    description: Phandle to the register map node.
> >>
> >> Looks like GPIO is a sub-function of some other block. Define the
> >> binding for that entire block.
> >
> > That's defined in patch 3 from this series.
> > I have sent it as patch 3 because that document references:
> > * /schemas/gpio/renesas,rzv2m-pwc-gpio.yaml
> > * /schemas/power/reset/renesas,rzv2m-pwc-poweroff.yaml
> > Which are defined in this patch and in patch 2 in the series.
> >
> > Do you want me to move patch 3 to patch 1 in v2?
> 
> We do not want regmap, but proper definition of entire hardware.

Will do. I'll drop regmap.

> 
> >
> >> GPIO can be either either a function of
> >> that node (just add GPIO provider properties) or you can have GPIO
> child
> >> nodes. Depends on what the entire block looks like to decide. Do you
> >> have multiple instances of the GPIO block would be one reason to have
> >> child nodes.
> >
> > From a pure HW point of view, this GPIO block is contained inside the
> PWC block
> > (as PWC is basically a MFD device), and it only deals with 2 General-
> Purpose
> > Output pins, both controlled by 1 (and the same) register, therefore the
> GPIO
> > block is only 1 child.
> >
> > If possible, I would like to keep the functionality offered by the sub-
> blocks of
> > PWC contained in separated drivers and DT nodes (either non-child nodes
> or child
> > nodes).
> 
> Driver do not matter for bindings. We talk about regmap field which - as
> you explained above - is not needed.

Okay, I'll rework, and I'll send v2.

Thanks,
Fab

> 
> 
> >
> > My understanding is that simple-mfd will automatically probe the
> children of the
> > simple-mfd node, and also hierarchically it makes sense to me to have
> the DT nodes
> > of the PWC sub-blocks as children of the "syscon", "simple-mfd" node. I
> have found
> > other instances of this same architecture in the kernel already (plenty
> from NXP/Freescale),
> > for example:
> 
> I don't understand. You do not have here simple-mfd and it still does
> not explain Rob's comment and regmap.
> 
> >
> > etc...
> >
> > Something like the below could also work, but I don't think it would
> represent the
> > HW accurately:
> > pwc: pwc@a3700000 {
> > 	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
> > 		     "syscon", "simple-mfd";
> > 	reg = <0 0xa3700000 0 0x800>;
> > };
> >
> > pwc-gpio {
> > 	compatible = "renesas,r9a09g011-pwc-gpio",
> > 		     "renesas,rzv2m-pwc-gpio";
> > 	regmap = <&pwc>;
> > 	gpio-controller;
> > 	#gpio-cells = <2>;
> > };
> >
> > pwc-poweroff {
> > 	compatible = "renesas,r9a09g011-pwc-poweroff",
> > 		     "renesas,rzv2m-pwc-poweroff";
> > 	regmap = <&pwc>;
> > };
> >
> >
> > I think the below describes things better:
> > pwc: pwc@a3700000 {
> > 	compatible = "renesas,r9a09g011-pwc", "renesas,rzv2m-pwc",
> > 		     "syscon", "simple-mfd";
> > 	reg = <0 0xa3700000 0 0x800>;
> >
> > 	gpio {
> > 		compatible = "renesas,r9a09g011-pwc-gpio",
> > 			     "renesas,rzv2m-pwc-gpio";
> > 		regmap = <&pwc>;
> 
> You speak about two different things. So again - drop regmap. You do not
> need it.
> 
> > 		offset = <0x80>;
> > 		gpio-controller;
> > 		#gpio-cells = <2>;
> > 	};
> >
> > 	poweroff {
> > 		compatible = "renesas,r9a09g011-pwc-poweroff",
> > 			     "renesas,rzv2m-pwc-poweroff";
> > 		regmap = <&pwc>;
> 
> Drop regmap.
> 
> > 	};
> > };
> >
> 
> Best regards,
> Krzysztof
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
new file mode 100644
index 000000000000..ecc034d53259
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/renesas,rzv2m-pwc-gpio.yaml
@@ -0,0 +1,62 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/renesas,rzv2m-pwc-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Renesas RZ/V2M External Power Sequence Controller (PWC) GPIO
+
+description: |+
+  The PWC IP found in the RZ/V2M family of chips comes with General-Purpose
+  Output pins, alongside the below functions
+    - external power supply on/off sequence generation
+    - on/off signal generation for the LPDDR4 core power supply (LPVDD)
+    - key input signals processing
+  This node uses syscon to map the register used to control the GPIOs
+  (the register map is retrieved from the parent dt-node), and the node should
+  be represented as a sub node of a "syscon", "simple-mfd" node.
+
+maintainers:
+  - Fabrizio Castro <fabrizio.castro.jz@renesas.com>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - renesas,r9a09g011-pwc-gpio # RZ/V2M
+          - renesas,r9a09g055-pwc-gpio # RZ/V2MA
+      - const: renesas,rzv2m-pwc-gpio
+
+  offset:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: |
+      Offset in the register map for controlling the GPIOs (in bytes).
+
+  regmap:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: Phandle to the register map node.
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+required:
+  - compatible
+  - regmap
+  - offset
+  - gpio-controller
+  - '#gpio-cells'
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio {
+            compatible = "renesas,r9a09g011-pwc-gpio",
+                         "renesas,rzv2m-pwc-gpio";
+            regmap = <&regmapnode>;
+            offset = <0x80>;
+            gpio-controller;
+            #gpio-cells = <2>;
+    };