On Sun, Nov 26, 2023 at 11:45 PM Billy Tsai <billy_tsai@xxxxxxxxxxxxxx> wrote: > > > > > > Document the compatible for aspeed,ast2600-pwm-tach device, which can > > > > > support up to 16 PWM outputs and 16 fan tach input. > > > > > > > > > > Signed-off-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx> > > > > > --- > > > > > .../bindings/hwmon/aspeed,g6-pwm-tach.yaml | 69 +++++++++++++++++++ > > > > > 1 file changed, 69 insertions(+) > > > > > create mode 100644 Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml > > > > > > > > > > diff --git a/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml b/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml > > > > > new file mode 100644 > > > > > index 000000000000..c615fb10705c > > > > > --- /dev/null > > > > > +++ b/Documentation/devicetree/bindings/hwmon/aspeed,g6-pwm-tach.yaml > > > > > @@ -0,0 +1,69 @@ > > > > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > > > > +# Copyright (C) 2023 Aspeed, Inc. > > > > > +%YAML 1.2 > > > > > +--- > > > > > +$id: http://devicetree.org/schemas/hwmon/aspeed,g6-pwm-tach.yaml# > > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > > > > + > > > > > +title: ASPEED G6 PWM and Fan Tach controller > > > > > + > > > > > +maintainers: > > > > > + - Billy Tsai <billy_tsai@xxxxxxxxxxxxxx> > > > > > + > > > > > +description: | > > > > > + The ASPEED PWM controller can support up to 16 PWM outputs. > > > > > + The ASPEED Fan Tacho controller can support up to 16 fan tach input. > > > > > + They are independent hardware blocks, which are different from the > > > > > + previous version of the ASPEED chip. > > > > > + > > > > > +properties: > > > > > + compatible: > > > > > + enum: > > > > > + - aspeed,ast2600-pwm-tach > > > > > + > > > > > + reg: > > > > > + maxItems: 1 > > > > > + > > > > > + clocks: > > > > > + maxItems: 1 > > > > > + > > > > > + resets: > > > > > + maxItems: 1 > > > > > + > > > > > + "#pwm-cells": > > > > > + const: 3 > > > > > + > > > > > +patternProperties: > > > > > + "^fan-[0-9]+$": > > > > > + $ref: fan-common.yaml# > > > > > + unevaluatedProperties: false > > > > > + required: > > > > > + - tach-ch > > > > > + > > > > > +required: > > > > > + - reg > > > > > + - clocks > > > > > + - resets > > > > > + - "#pwm-cells" > > > > > + - compatible > > > > > + > > > > > +additionalProperties: false > > > > > + > > > > > +examples: > > > > > + - | > > > > > + #include <dt-bindings/clock/aspeed-clock.h> > > > > > + pwm_tach: pwm-tach-controller@1e610000 { > > > > > + compatible = "aspeed,ast2600-pwm-tach"; > > > > > + reg = <0x1e610000 0x100>; > > > > > + clocks = <&syscon ASPEED_CLK_AHB>; > > > > > + resets = <&syscon ASPEED_RESET_PWM>; > > > > > + #pwm-cells = <3>; > > > > > + > > > > > + fan-0 { > > > > > > > I assume there's a PWM connection here? How do you know which PWM? You > > > > said the tach channel is independent, so it is not that. > > > > > > > It should not be 0 from 'fan-0' because that's just a meaningless index. > > > > > > > You either need 'pwms' here or you can use 'reg' and the reg value is > > > > the PWM channel. > > > > > > Hi Rob, this binding is used to export the PWM provider and the Fan monitor (i.e., Tach). > > > If the user wants to add the PWM connection for the fan, it can be done as follows: > > > > > > fan0: pwm-fan0 { > > > compatible = "pwm-fan"; > > > pwms = <&pwm_tach 0 40000 0>; > > > cooling-min-state = <0>; > > > cooling-max-state = <3>; > > > #cooling-cells = <2>; > > > cooling-levels = <0 15 128 255>; > > > }; > > > > > > This will reuse the existing PWM fan driver (e.g., pwm-fan.c). > > > I'm confused now. So what are the child nodes you have? You are > > defining the fan in 2 places? The "pwm-fan" driver supports a tach via > > an interrupt, so how would this work in your case? > > Hi Rob, > > The tach interrupt for the pwm-fan is option. In our case, the dts just reuse the pwm control function > of the pwm-fan, and the part of the tach monitor will be created by our fan child nodes. > So the dts will like followings: > > // Use to declare the tach monitor for fan. > &pwm_tach { > fan-0 { > tach-ch = /bits/ 8 <0x0>; > }; > fan-1 { > tach-ch = /bits/ 8 <0x1>; > }; > ... > } > > // Reuse the pwm-fan.c to control the behavior of the PWM for fan. > fan0: pwm-fan0 { > compatible = "pwm-fan"; > pwms = <&pwm_tach 0 40000 0>; /* Target freq:25 kHz */ > cooling-min-state = <0>; > cooling-max-state = <3>; > #cooling-cells = <2>; > cooling-levels = <0 15 128 255>; > }; No, you can't have a fan described by 2 different nodes. Can't you just merge everything from the pwm-fan0 node into the fan-0 node? Rob
