linux-kernel - Re: [PATCH 2/2] pmdomain: thead: create auxiliary device for rebooting

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Message-ID: <CAPDyKFombYNFvTsChewQ6cFY2woS+vSb1YUV0Bp_+DcigrFFXA@mail.gmail.com>
Date: Thu, 4 Sep 2025 12:14:31 +0200
From: Ulf Hansson <ulf.hansson@...aro.org>
To: Icenowy Zheng <uwu@...nowy.me>
Cc: Drew Fustini <fustini@...nel.org>, Guo Ren <guoren@...nel.org>, Fu Wei <wefu@...hat.com>, 
	Michal Wilczynski <m.wilczynski@...sung.com>, Sebastian Reichel <sre@...nel.org>, 
	Han Gao <rabenda.cn@...il.com>, Yao Zi <ziyao@...root.org>, linux-kernel@...r.kernel.org, 
	linux-riscv@...ts.infradead.org, linux-pm@...r.kernel.org
Subject: Re: [PATCH 2/2] pmdomain: thead: create auxiliary device for rebooting

On Mon, 18 Aug 2025 at 09:49, Icenowy Zheng <uwu@...nowy.me> wrote:
>
> The reboot / power off operations require communication with the AON
> firmware too.
>
> As the driver is already present, create an auxiliary device with name
> "reboot" to match that driver, and pass the AON channel by using
> platform_data.
>
> Signed-off-by: Icenowy Zheng <uwu@...nowy.me>
> ---
>  drivers/pmdomain/thead/th1520-pm-domains.c | 35 ++++++++++++++++++++--
>  1 file changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pmdomain/thead/th1520-pm-domains.c b/drivers/pmdomain/thead/th1520-pm-domains.c
> index 9040b698e7f7f..8285f552897b0 100644
> --- a/drivers/pmdomain/thead/th1520-pm-domains.c
> +++ b/drivers/pmdomain/thead/th1520-pm-domains.c
> @@ -129,12 +129,39 @@ static void th1520_pd_init_all_off(struct generic_pm_domain **domains,
>         }
>  }
>
> -static void th1520_pd_pwrseq_unregister_adev(void *adev)
> +static void th1520_pd_unregister_adev(void *adev)
>  {
>         auxiliary_device_delete(adev);
>         auxiliary_device_uninit(adev);
>  }
>
> +static int th1520_pd_reboot_init(struct device *dev, struct th1520_aon_chan *aon_chan)
> +{
> +       struct auxiliary_device *adev;
> +       int ret;
> +
> +       adev = devm_kzalloc(dev, sizeof(*adev), GFP_KERNEL);
> +       if (!adev)
> +               return -ENOMEM;
> +
> +       adev->name = "reboot";
> +       adev->dev.parent = dev;
> +       adev->dev.platform_data = aon_chan;
> +
> +       ret = auxiliary_device_init(adev);
> +       if (ret)
> +               return ret;
> +
> +       ret = auxiliary_device_add(adev);
> +       if (ret) {
> +               auxiliary_device_uninit(adev);
> +               return ret;
> +       }
> +
> +       return devm_add_action_or_reset(dev, th1520_pd_unregister_adev,
> +                                       adev);

We have devm_auxiliary_device_create() now, I suggest we use that instead.

That said, I think it would make sense to convert the pwrseq-gpu
auxiliary device to be registered with devm_auxiliary_device_create()
too, but that's a separate change, of course.

> +}
> +
>  static int th1520_pd_pwrseq_gpu_init(struct device *dev)
>  {
>         struct auxiliary_device *adev;
> @@ -169,7 +196,7 @@ static int th1520_pd_pwrseq_gpu_init(struct device *dev)
>                 return ret;
>         }
>
> -       return devm_add_action_or_reset(dev, th1520_pd_pwrseq_unregister_adev,
> +       return devm_add_action_or_reset(dev, th1520_pd_unregister_adev,
>                                         adev);
>  }
>
> @@ -235,6 +262,10 @@ static int th1520_pd_probe(struct platform_device *pdev)
>         if (ret)
>                 goto err_clean_provider;
>
> +       ret = th1520_pd_reboot_init(dev, aon_chan);
> +       if (ret)
> +               goto err_clean_provider;
> +
>         return 0;
>
>  err_clean_provider:
> --
> 2.50.1
>

Otherwise this looks good to me!

Kind regards
Uffe