Re: [v6 1/2] dt-bindings: Add bindings for aspeed pwm-tach.

From: Rob Herring
Date: Wed May 19 2021 - 16:20:13 EST


On Tue, May 18, 2021 at 08:55:16AM +0800, Billy Tsai wrote:
> This patch adds device binding for aspeed pwm-tach device which is a
> multi-function device include pwm and tach function and pwm/tach device
> bindings which should be the child-node of pwm-tach device.
>
> Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> ---
> .../bindings/hwmon/aspeed,ast2600-tach.yaml | 66 +++++++++++++++
> .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 84 +++++++++++++++++++
> .../bindings/pwm/aspeed,ast2600-pwm.yaml | 62 ++++++++++++++
> 3 files changed, 212 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/hwmon/aspeed,ast2600-tach.yaml
> create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
> create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
>
> diff --git a/Documentation/devicetree/bindings/hwmon/aspeed,ast2600-tach.yaml b/Documentation/devicetree/bindings/hwmon/aspeed,ast2600-tach.yaml
> new file mode 100644
> index 000000000000..0b23281e9f5c
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/hwmon/aspeed,ast2600-tach.yaml
> @@ -0,0 +1,66 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2021 ASPEED, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/hwmon/aspeed,ast2600-tach.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ASPEED AST2600 Tach controller
> +
> +maintainers:
> + - Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> +
> +description: |
> + The ASPEED Tach controller can support upto 16 fan input.
> + This module is part of the ast2600-pwm-tach multi-function device. For more
> + details see ../mfd/aspeed,ast2600-pwm-tach.yaml.
> +
> +properties:
> + compatible:
> + enum:
> + - aspeed,ast2600-tach
> +
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + pinctrl-0: true
> +
> + pinctrl-names:
> + const: default
> +
> +
> +required:
> + - compatible
> + - "#address-cells"
> + - "#size-cells"
> +
> +additionalProperties:
> + type: object
> + properties:
> + reg:
> + description:
> + The tach channel used for this fan.
> + maxItems: 1

blank line between each DT property sub-schema please.

> + aspeed,min-rpm:
> + description:
> + define the minimal revolutions per minute of the measure fan
> + used to calculate the sample period of tach
> + default: 1000
> + aspeed,pulse-pr:
> + description:
> + Value specifying the number of pulses per revolution of the
> + monitored FAN.
> + default: 2
> + aspeed,tach-div:
> + description:
> + define the tachometer clock divider as an integer. Formula of
> + tach clock = clock source / (2^tach-div)^2
> + minimum: 0
> + maximum: 15
> + # The value that should be used if the property is not present
> + default: 5
> + required:
> + - reg
> diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
> new file mode 100644
> index 000000000000..d742ccfcc003
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
> @@ -0,0 +1,84 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2021 ASPEED, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: PWM Tach controller Device Tree Bindings
> +
> +description: |
> + The PWM Tach controller is represented as a multi-function device which
> + includes:
> + PWM
> + Tach
> +
> +maintainers:
> + - Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> +
> +properties:
> + compatible:
> + items:
> + - enum:
> + - aspeed,ast2600-pwm-tach
> + - const: syscon
> + - const: simple-mfd
> + reg:
> + maxItems: 1
> + clocks:
> + maxItems: 1
> + resets:
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> + - clocks
> + - resets
> +
> +patternProperties:
> + "^pwm(@[0-9a-f]+)?$":
> + $ref: ../pwm/aspeed,ast2600-pwm.yaml
> +
> + "^tach(@[0-9a-f]+)?$":
> + $ref: ../hwmon/aspeed,ast2600-tach.yaml
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> + #include <dt-bindings/clock/ast2600-clock.h>
> + pwm_tach: pwm_tach@1e610000 {
> + compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
> + reg = <0x1e610000 0x100>;
> + clocks = <&syscon ASPEED_CLK_AHB>;
> + resets = <&syscon ASPEED_RESET_PWM>;
> +
> + pwm: pwm {
> + compatible = "aspeed,ast2600-pwm";
> + #address-cells = <1>;
> + #size-cells = <0>;
> + #pwm-cells = <3>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_pwm0_default>;
> + pwm-ch@0 {
> + reg = <0>;
> + aspeed,wdt-reload-enable;
> + aspeed,wdt-reload-duty-point = <32>;

Normally, you configure the PWM on the client side, not the producer
side.

> + };
> + };
> +
> + tach: tach {
> + compatible = "aspeed,ast2600-tach";

Are pwm and tach separate h/w blocks?

> + #address-cells = <1>;
> + #size-cells = <0>;
> + pinctrl-names = "default";
> + pinctrl-0 = <&pinctrl_tach0_default>;
> + fan@0 {
> + reg = <0>;

How does one configure which PWM is connected to each fan?

Existing bindings use 'reg' for PWM channel and another property for
tach channel. Please don't do something different.

> + aspeed,min-rpm = <1000>;
> + aspeed,pulse-pr = <2>;
> + aspeed,tach-div = <5>;
> + };
> + };
> + };
> diff --git a/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> new file mode 100644
> index 000000000000..f1354c8d35b5
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> @@ -0,0 +1,62 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2021 ASPEED, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pwm/aspeed,ast2600-pwm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ASPEED AST2600 PWM controller
> +
> +maintainers:
> + - Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> +
> +description: |
> + The ASPEED PWM controller can support upto 16 PWM outputs.
> + This module is part of the ast2600-pwm-tach multi-function device. For more
> + details see ../mfd/aspeed,ast2600-pwm-tach.yaml.
> +
> +properties:
> + compatible:
> + enum:
> + - aspeed,ast2600-pwm
> +
> + "#pwm-cells":
> + const: 3
> +
> + "#address-cells":
> + const: 1
> +
> + "#size-cells":
> + const: 0
> +
> + pinctrl-0: true
> +
> + pinctrl-names:
> + const: default
> +
> +
> +required:
> + - compatible
> + - "#pwm-cells"
> + - "#address-cells"
> + - "#size-cells"
> +
> +additionalProperties:
> + description: Set extend properties for each pwm channel.
> + type: object
> + properties:
> + reg:
> + description:
> + The pwm channel index.
> + maxItems: 1
> + aspeed,wdt-reload-enable:
> + type: boolean
> + description:
> + Enable the function of wdt reset reload duty point.
> + aspeed,wdt-reload-duty-point:
> + description:
> + Define the duty point after wdt reset, 0 = 100%
> + minimum: 0
> + maximum: 255
> + required:
> + - reg
> --
> 2.25.1
>