linux-kernel - Re: [PATCH] dt-bindings: max310x: convert to YAML

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Message-Id: <20231012095935.0bf2c58c424559492e7f5c25@hugovil.com>
Date:   Thu, 12 Oct 2023 09:59:35 -0400
From:   Hugo Villeneuve <hugo@...ovil.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jirislaby@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Hugo Villeneuve <hvilleneuve@...onoff.com>,
        linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
        devicetree@...r.kernel.org
Subject: Re: [PATCH] dt-bindings: max310x: convert to YAML

On Thu, 12 Oct 2023 09:53:02 +0200
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org> wrote:

> On 12/10/2023 00:21, Hugo Villeneuve wrote:
> > From: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > 
> > Convert binding from text format to YAML.
> 
> 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. Missing prefix: serial:

Hi,
will add it for V2.


> > 
> > Additions to original text binding:
> >   - add rs485 reference.
> > 
> > Signed-off-by: Hugo Villeneuve <hvilleneuve@...onoff.com>
> > ---
> 
> 
> > diff --git a/Documentation/devicetree/bindings/serial/maxim,max310x.yaml b/Documentation/devicetree/bindings/serial/maxim,max310x.yaml
> > new file mode 100644
> > index 000000000000..05fd00d95260
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/serial/maxim,max310x.yaml
> > @@ -0,0 +1,107 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/serial/maxim,max310x.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Maxim MAX310X Advanced Universal Asynchronous Receiver-Transmitter (UART)
> > +
> > +maintainers:
> > +  - Hugo Villeneuve <hvilleneuve@...onoff.com>
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - maxim,max3107
> > +      - maxim,max3108
> > +      - maxim,max3109
> > +      - maxim,max14830
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  clocks:
> > +    maxItems: 1
> > +
> > +  clock-frequency:
> > +    description:
> > +      When there is no clock provider visible to the platform, this
> > +      is the source crystal frequency for the IC in Hz.
> > +    minimum: 1000000
> > +    maximum: 4000000
> 
> This wasn't in original binding. Explain this in the commit msg.

I will add the corresponding explanation in V2. 

The 'clock-frequency' property is already supported
by the driver but was not documented in the original txt binding.

This is related to the commit d4d6f03c4fb3: serial: max310x: Try to
get crystal clock rate from property (Author: Andy Shevchenko):
    
    In some configurations, mainly ACPI-based, the clock frequency of
    the device is supplied by very well established 'clock-frequency'
    property. Hence, try to get it from the property at last if no other
    providers are available.


> 
> > +
> > +  clock-names:
> > +    enum:
> > +      - xtal # External crystal
> > +      - osc  # External clock source
> 
> clock-names follow immediately clocks.

Will fix for V2.


> 
> > +
> > +  gpio-controller: true
> > +
> > +  "#gpio-cells":
> > +    const: 2
> > +
> > +  gpio-line-names:
> > +    minItems: 1
> > +    maxItems: 16
> > +
> > +allOf:
> 
> allOf: block goes after required: block.

Will fix for V2.


> 
> > +  - $ref: /schemas/spi/spi-peripheral-props.yaml#
> > +  - $ref: /schemas/serial/serial.yaml#
> > +  - $ref: /schemas/serial/rs485.yaml#
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +
> > +oneOf:
> > +  - required:
> > +      - clocks
> > +      - clock-names
> > +  - required:
> > +      - clock-frequency
> 
> That's also something new as well. The original binding required clocks.
> Why are you changing this?

See explanation above about clock-frequency.

If clocks is not provided, than at least 'clock-frequency' must be
provided.


> > +
> > +unevaluatedProperties: false
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +    i2c {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        serial@2c {
> > +            compatible = "maxim,max3107";
> > +            reg = <0x2c>;
> > +            clocks = <&xtal4m>;
> > +            clock-names = "xtal";
> > +            interrupt-parent = <&gpio3>;
> > +            interrupts = <7 IRQ_TYPE_LEVEL_LOW>;
> > +            gpio-controller;
> > +            #gpio-cells = <2>;
> > +        };
> > +
> 
> One example is enuogh. All other are the same.

Not really, clock-names is different for example 2 (osc), and example 3
shows that 'clock-frequency' can be used if no clock is provided?

Hugo.