linux-kernel - Re: [PATCH v8 2/3] pwm: Add Allwinner's D1/T113-S3/R329 SoCs PWM support

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Date: Wed, 31 Jan 2024 14:41:41 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Aleksandr Shubin <privatesub2@...il.com>, linux-kernel@...r.kernel.org
Cc: Brandon Cheo Fusi <fusibrandon13@...il.com>, Uwe
 Kleine-König <u.kleine-koenig@...gutronix.de>, Rob
 Herring <robh+dt@...nel.org>,  Krzysztof Kozlowski
 <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>,
 Chen-Yu Tsai <wens@...e.org>,  Jernej Skrabec <jernej.skrabec@...il.com>,
 Samuel Holland <samuel@...lland.org>, Paul Walmsley
 <paul.walmsley@...ive.com>, Palmer Dabbelt <palmer@...belt.com>, Albert Ou
 <aou@...s.berkeley.edu>, Cristian Ciocaltea
 <cristian.ciocaltea@...labora.com>,  John Watts <contact@...kia.org>, Marc
 Kleine-Budde <mkl@...gutronix.de>, Maksim Kiselev <bigunclemax@...il.com>,
 linux-pwm@...r.kernel.org, devicetree@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev, 
 linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v8 2/3] pwm: Add Allwinner's D1/T113-S3/R329 SoCs PWM
 support

On Mi, 2024-01-31 at 15:59 +0300, Aleksandr Shubin wrote:
> Allwinner's D1, T113-S3 and R329 SoCs have a quite different PWM
> controllers with ones supported by pwm-sun4i driver.
> 
> This patch adds a PWM controller driver for Allwinner's D1,
> T113-S3 and R329 SoCs. The main difference between these SoCs
> is the number of channels defined by the DT property.
> 
> Co-developed-by: Brandon Cheo Fusi <fusibrandon13@...il.com>
> Signed-off-by: Brandon Cheo Fusi <fusibrandon13@...il.com>
> Signed-off-by: Aleksandr Shubin <privatesub2@...il.com>
> ---
>  drivers/pwm/Kconfig      |  10 ++
>  drivers/pwm/Makefile     |   1 +
>  drivers/pwm/pwm-sun20i.c | 380 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 391 insertions(+)
>  create mode 100644 drivers/pwm/pwm-sun20i.c
> 
[...]
> diff --git a/drivers/pwm/pwm-sun20i.c b/drivers/pwm/pwm-sun20i.c
> new file mode 100644
> index 000000000000..19bf3f495155
> --- /dev/null
> +++ b/drivers/pwm/pwm-sun20i.c
> @@ -0,0 +1,380 @@
[...]
> +static int sun20i_pwm_probe(struct platform_device *pdev)
> +{
[...]
> +	sun20i_chip->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL);
> +	if (IS_ERR(sun20i_chip->rst))
> +		return dev_err_probe(&pdev->dev, PTR_ERR(sun20i_chip->rst),
> +				     "failed to get bus reset\n");
> +
> +	ret = of_property_read_u32(pdev->dev.of_node, "allwinner,pwm-channels",
> +				   &sun20i_chip->chip.npwm);
> +	if (ret)
> +		sun20i_chip->chip.npwm = 8;
> +
> +	if (sun20i_chip->chip.npwm > 16)
> +		sun20i_chip->chip.npwm = 16;
> +
> +	/* Deassert reset */
> +	ret = reset_control_deassert(sun20i_chip->rst);
> +	if (ret)
> +		return dev_err_probe(&pdev->dev, ret, "failed to deassert reset\n");

Consider using devm_add_action_or_reset() to automatically assert the
reset control again on error or driver unbind ...

> +
> +	sun20i_chip->chip.dev = &pdev->dev;
> +	sun20i_chip->chip.ops = &sun20i_pwm_ops;
> +
> +	mutex_init(&sun20i_chip->mutex);
> +
> +	ret = pwmchip_add(&sun20i_chip->chip);

.. and devm_pwmchip_add() here. Together, this would allow to drop
sun20i_pwm_remove().


regards
Philipp