Re: [PATCH v2 1/4] dt-binding: pinctrl: spacemit: add documents for K1 SoC

[Krzysztof Kozlowski <krzk@xxxxxxxxxx>]

On 25/08/2024 15:10, Yixun Lan wrote:
> Add dt-binding for the pinctrl driver of SpacemiT's K1 SoC.


Please use subject prefixes matching the subsystem. You can get them for
example with `git log --oneline -- DIRECTORY_OR_FILE` on the directory
your patch is touching. For bindings, the preferred subjects are
explained here:
https://www.kernel.org/doc/html/latest/devicetree/bindings/submitting-patches.html#i-for-patch-submitters

It's "dt-bindings:"

> 
> Two vendor specific properties are introduced here, As the pinctrl
> has dedicated slew rate enable control - bit[7], so we have
> spacemit,slew-rate-{enable,disable} for this. For the same reason,
> creating spacemit,strong-pull-up for the strong pull up control.

Huh, no, use generic properties. More on that below



> 
> Signed-off-by: Yixun Lan <dlan@xxxxxxxxxx>
> ---
>  .../bindings/pinctrl/spacemit,k1-pinctrl.yaml      | 134 +++++++++++++++++
>  include/dt-bindings/pinctrl/spacemit,k1-pinctrl.h  | 161 +++++++++++++++++++++
>  2 files changed, 295 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/pinctrl/spacemit,k1-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/spacemit,k1-pinctrl.yaml
> new file mode 100644
> index 0000000000000..8adfc5ebbce37
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pinctrl/spacemit,k1-pinctrl.yaml
> @@ -0,0 +1,134 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pinctrl/spacemit,k1-pinctrl.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: SpacemiT K1 SoC Pin Controller
> +
> +maintainers:
> +  - Yixun Lan <dlan@xxxxxxxxxx>
> +
> +properties:
> +  compatible:
> +    const: spacemit,k1-pinctrl
> +
> +  reg:
> +    items:
> +      - description: pinctrl io memory base
> +
> +patternProperties:
> +  '-cfg$':
> +    type: object
> +    description: |

Do not need '|' unless you need to preserve formatting.

> +      A pinctrl node should contain at least one subnode representing the
> +      pinctrl groups available on the machine.
> +
> +    additionalProperties: false

Keep it before description.

> +
> +    patternProperties:
> +      '-pins$':
> +        type: object
> +        description: |
> +          Each subnode will list the pins it needs, and how they should
> +          be configured, with regard to muxer configuration, bias, input
> +          enable/disable, input schmitt trigger, slew-rate enable/disable,
> +          slew-rate, drive strength, power source.
> +        $ref: /schemas/pinctrl/pincfg-node.yaml
> +
> +        allOf:
> +          - $ref: pincfg-node.yaml#
> +          - $ref: pinmux-node.yaml#

You are duplicating refs.

> +
> +        properties:
> +          pinmux:
> +            description: |
> +              The list of GPIOs and their mux settings that properties in the
> +              node apply to. This should be set using the K1_PADCONF macro to
> +              construct the value.
> +            $ref: /schemas/pinctrl/pinmux-node.yaml#/properties/pinmux

Hm why you need the ref?

> +
> +          bias-disable: true
> +
> +          bias-pull-up: true
> +
> +          bias-pull-down: true
> +
> +          drive-strength-microamp:
> +            description: |
> +              typical current when output high level, but in mA.
> +              1.8V output: 11, 21, 32, 42 (mA)
> +              3.3V output: 7, 10, 13, 16, 19, 23, 26, 29 (mA)
> +            $ref: /schemas/types.yaml#/definitions/uint32
> +
> +          input-schmitt:
> +            description: |
> +              typical threshold for schmitt trigger.
> +              0: buffer mode
> +              1: trigger mode
> +              2, 3: trigger mode
> +            $ref: /schemas/types.yaml#/definitions/uint32
> +            enum: [0, 1, 2, 3]
> +
> +          power-source:
> +            description: external power supplies at 1.8v or 3.3v.
> +            enum: [ 1800, 3300 ]
> +
> +          slew-rate:
> +            description: |
> +              slew rate for output buffer
> +              0, 1: Slow speed

Hm? Surprising, 0 is slow speed?

> +              2: Medium speed
> +              3: Fast speed
> +            $ref: /schemas/types.yaml#/definitions/uint32
> +            enum: [0, 1, 2, 3]
> +
> +          spacemit,slew-rate-enable:
> +            description: enable slew rate.

The presence of slew-rate enables it, doesn't it?

> +            type: boolean
> +
> +          spacemit,slew-rate-disable:
> +            description: disable slew rate.
> +            type: boolean

Just use slew-rate, 0 disable, some value to match real slew-rate.

> +
> +          spacemit,strong-pull-up:
> +            description: enable strong pull up.

Do not duplicate the property name in description. You did not say
anything useful here. What is "strong"? bias-pull-up takes also an argument.

> +            type: boolean
> +
> +        required:
> +          - pinmux
> +
> +        additionalProperties: false

This goes up, before description.

> +
> +required:
> +  - compatible
> +  - reg
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/pinctrl/spacemit,k1-pinctrl.h>
> +
> +    soc {
> +        #address-cells = <2>;
> +        #size-cells = <2>;
> +
> +        pinctrl@d401e000 {
> +            compatible = "spacemit,k1-pinctrl";
> +            reg = <0x0 0xd401e000 0x0 0x400>;
> +            #pinctrl-cells = <2>;
> +            #gpio-range-cells = <3>;

This wasn't ever tested... :(
...

> diff --git a/include/dt-bindings/pinctrl/spacemit,k1-pinctrl.h b/include/dt-bindings/pinctrl/spacemit,k1-pinctrl.h
> new file mode 100644
> index 0000000000000..13ef4aa6c53a3
> --- /dev/null
> +++ b/include/dt-bindings/pinctrl/spacemit,k1-pinctrl.h
> @@ -0,0 +1,161 @@
> +/* SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause */
> +/*
> + * Copyright (c) 2022-2024 SpacemiT (Hangzhou) Technology Co. Ltd
> + * Copyright (c) 2024 Yixun Lan <dlan@xxxxxxxxxx>
> + *
> + */
> +
> +#ifndef _DT_BINDINGS_PINCTRL_K1_H
> +#define _DT_BINDINGS_PINCTRL_K1_H
> +
> +#define PINMUX(pin, mux) \
> +	(((pin) & 0xffff) | (((mux) & 0xff) << 16))
> +
> +/* pin offset */
> +#define PINID(x)	((x) + 1)
> +
> +#define GPIO_INVAL  0
> +#define GPIO_00     PINID(0)

Not really, pin numbers are not bindings. Drop entire header.

...

> +
> +#define SLEW_RATE_SLOW0		0
> +#define SLEW_RATE_SLOW1		1
> +#define SLEW_RATE_MEDIUM	2
> +#define SLEW_RATE_FAST		3

Not a binding, either. No usage in the driver.

> +
> +#define K1_PADCONF(pin, func) (((pin) << 16) | (func))

Not a binding.



Best regards,
Krzysztof