Re: [PATCH v3 1/2] dt-bindings: pwm: Convert PWM bindings to json-schema

From: Rob Herring <robh@kernel.org>
To: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	"Thierry Reding" <thierry.reding@gmail.com>,
	"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
	linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
	linux-leds@vger.kernel.org, linux-pwm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-tegra@vger.kernel.org,
	bcm-kernel-feedback-list@broadcom.com,
	linux-rpi-kernel@lists.infradead.org,
	linux-amlogic@lists.infradead.org,
	linux-mediatek@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	linux-riscv@lists.infradead.org,
	linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [PATCH v3 1/2] dt-bindings: pwm: Convert PWM bindings to json-schema
Date: Thu, 10 Oct 2019 13:54:32 -0500	[thread overview]
Message-ID: <20191010185432.GA17457@bogus> (raw)
In-Reply-To: <20191002164047.14499-1-krzk@kernel.org>

On Wed, Oct 02, 2019 at 06:40:46PM +0200, Krzysztof Kozlowski wrote:
> Convert generic PWM bindings to DT schema format using json-schema.  The
> consumer bindings are split to separate file.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> 
> ---
> 
> Changes since v2:
> 1. Change also pwm-sprd.txt
> 
> Changes since v1:
> 1. Indent example with four spaces (more readable),
> 2. Change pattern for pwm nodes,
> 3. Remove $ref from #cells.
> ---

> diff --git a/Documentation/devicetree/bindings/pwm/pwm-consumers.yaml b/Documentation/devicetree/bindings/pwm/pwm-consumers.yaml
> new file mode 100644
> index 000000000000..39c844fe6338
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/pwm-consumers.yaml
> @@ -0,0 +1,76 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pwm/pwm-consumers.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Specifying PWM information for devices
> +
> +maintainers:
> +  - Thierry Reding <thierry.reding@gmail.com>
> +
> +description: |
> +  PWM properties should be named "pwms". The exact meaning of each pwms
> +  property must be documented in the device tree binding for each device.
> +  An optional property "pwm-names" may contain a list of strings to label
> +  each of the PWM devices listed in the "pwms" property. If no "pwm-names"
> +  property is given, the name of the user node will be used as fallback.
> +
> +  Drivers for devices that use more than a single PWM device can use the
> +  "pwm-names" property to map the name of the PWM device requested by the
> +  pwm_get() call to an index into the list given by the "pwms" property.
> +
> +properties:
> +  pwms:
> +    $ref: /schemas/types.yaml#/definitions/phandle-array
> +    description: |
> +      Phandle to PWM controller node and pwm-specifier (controller specific).
> +      pwm-specifier typically encodes the chip-relative PWM number and the PWM
> +      period in nanoseconds.
> +      Optionally, the pwm-specifier can encode a number of flags (defined in
> +      <dt-bindings/pwm/pwm.h>) in a third cell:
> +        - PWM_POLARITY_INVERTED: invert the PWM signal polarity
> +
> +  pwm-names:
> +    $ref: /schemas/types.yaml#/definitions/string-array
> +    description:
> +      A list of strings to label each of the PWM devices listed in the "pwms"
> +      property. If no "pwm-names" property is given, the name of the user node
> +      will be used as fallback.
> +
> +required:
> +  - pwms

This schema is never applied because it has no 'select' which is only 
automatic for $nodename or compatible. You could include this from other 
schemas, but why? Any consumer still has to list these properties to 
define their specific constraints.

We already have a schema in dtschema for consumer side. It's just 
missing descriptions which needs relicensing from this.

> +
> +dependencies:
> +  pwm-names: [ pwms ]