linux-kernel - Re: [PATCH v2 0/4] Introduce Allwinner H616 PWM controller

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Message-ID: <6113404.MhkbZ0Pkbq@jernej-laptop>
Date: Sun, 21 Dec 2025 20:12:18 +0100
From: Jernej Škrabec <jernej.skrabec@...il.com>
To: Uwe Kleine-König <u.kleine-koenig@...libre.com>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
 Samuel Holland <samuel@...lland.org>, Philipp Zabel <p.zabel@...gutronix.de>,
 Richard Genoud <richard.genoud@...tlin.com>
Cc: Thomas Petazzoni <thomas.petazzoni@...tlin.com>,
 linux-pwm@...r.kernel.org, devicetree@...r.kernel.org,
 linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
 linux-kernel@...r.kernel.org, Richard Genoud <richard.genoud@...tlin.com>
Subject: Re: [PATCH v2 0/4] Introduce Allwinner H616 PWM controller

Dne sreda, 17. december 2025 ob 09:25:00 Srednjeevropski standardni čas je Richard Genoud napisal(a):
> Allwinner H616 PWM controller is quite different from the A10 one.
> 
> It can drive 6 PWM channels, and like for the A10, each channel has a
> bypass that permits to output a clock, bypassing the PWM logic, when
> enabled.
> 
> But, the channels are paired 2 by 2, sharing a first set of
> MUX/prescaler/gate.
> Then, for each channel, there's another prescaler (that will be bypassed
> if the bypass is enabled for this channel).
> 
> It looks like that:
>             _____      ______      ________
> OSC24M --->|     |    |      |    |        |
> APB1 ----->| Mux |--->| Gate |--->| /div_m |-----> PWM_clock_src_xy
>            |_____|    |______|    |________|
>                           ________
>                          |        |
>                       +->| /div_k |---> PWM_clock_x
>                       |  |________|
>                       |    ______
>                       |   |      |
>                       +-->| Gate |----> PWM_bypass_clock_x
>                       |   |______|
> PWM_clock_src_xy -----+   ________
>                       |  |        |
>                       +->| /div_k |---> PWM_clock_y
>                       |  |________|
>                       |    ______
>                       |   |      |
>                       +-->| Gate |----> PWM_bypass_clock_y
>                           |______|
> 
> Where xy can be 0/1, 2/3, 4/5
> 
> PWM_clock_x/y serve for the PWM purpose.
> PWM_bypass_clock_x/y serve for the clock-provider purpose.
> The common clock framework has been used to manage those clocks.
> 
> This PWM driver serves as a clock-provider for PWM_bypass_clocks.
> This is needed for example by the embedded AC300 PHY which clock comes
> from PMW5 pin (PB12).

No. Drop all clocks related code and make this pure PWM driver, like pwm-sun4i
is. For AC300, AC200 or whatever other device may need clock produced by PWM,
pwm-clock can be used like this:

ac300_pwm_clk: ac300-clk {
	compatible = "pwm-clock";
	#clock-cells = <0>;
	clock-frequency = <24000000>;
	pinctrl-names = "default";
	pinctrl-0 = <&pwm1_pin>;
	pwms = <&pwm 1 42 0>;
};

ac300 {
	...
	clocks = <&ac300_pwm_clk>;
	...
};

Best regards,
Jernej

> 
> This series is based onto v6.19-rc1
> 
> Changes since v1:
> - rebase onto v6.19-rc1
> - add missing headers
> - remove MODULE_ALIAS (suggested by Krzysztof)
> - use sun4i-pwm binding instead of creating a new one (suggested by Krzysztof)
> - retrieve the parent clocks from the devicetree
> - switch num_parents to unsigned int
> 
> Richard Genoud (4):
>   dt-bindings: pwm: allwinner: add h616 pwm compatible
>   pwm: sun50i: Add H616 PWM support
>   arm64: dts: allwinner: h616: add PWM controller
>   MAINTAINERS: Add entry on Allwinner H616 PWM driver
> 
>  .../bindings/pwm/allwinner,sun4i-a10-pwm.yaml |  19 +-
>  MAINTAINERS                                   |   5 +
>  .../arm64/boot/dts/allwinner/sun50i-h616.dtsi |  47 +
>  drivers/pwm/Kconfig                           |  12 +
>  drivers/pwm/Makefile                          |   1 +
>  drivers/pwm/pwm-sun50i-h616.c                 | 892 ++++++++++++++++++
>  6 files changed, 975 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/pwm/pwm-sun50i-h616.c
> 
> 
> base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
>