Re: [PATCH 1/3] soc: renesas: rz-sysc: Register auxiliary device for PWRRDY power sequencer

[Philipp Zabel <p.zabel@pengutronix.de>]

On Sa, 2026-07-25 at 13:34 +0100, Biju wrote:
> From: Biju Das <biju.das.jz@bp.renesas.com>
> 
> Some RZ SoCs (e.g. RZ/G3L) have a PWRRDY register that is controlled
> through a power sequencer rather than directly by the SYSC driver.
> 
> Add a pwrrdy_pwrseq flag to struct rz_sysc_soc_id_init_data to mark
> SoCs with this property, and set it for RZ/G3L. When set,
> rz_sysc_probe() registers a "pwrseq-pwrrdy" auxiliary device so a
> dedicated driver can handle the PWRRDY sequencing, with automatic
> teardown via devm_add_action_or_reset().
> 
> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> ---
>  drivers/soc/renesas/r9a08g046-sysc.c |  1 +
>  drivers/soc/renesas/rz-sysc.c        | 40 ++++++++++++++++++++++++++++
>  drivers/soc/renesas/rz-sysc.h        |  2 ++
>  3 files changed, 43 insertions(+)
> 
> diff --git a/drivers/soc/renesas/r9a08g046-sysc.c b/drivers/soc/renesas/r9a08g046-sysc.c
> index 90db9d383539..cd129c727461 100644
> --- a/drivers/soc/renesas/r9a08g046-sysc.c
> +++ b/drivers/soc/renesas/r9a08g046-sysc.c
> @@ -76,6 +76,7 @@ static const struct rz_sysc_soc_id_init_data rzg3l_sysc_soc_id_init_data __initc
>  	.devid_offset = 0xa04,
>  	.revision_mask = GENMASK(31, 28),
>  	.specific_id_mask = GENMASK(27, 0),
> +	.pwrrdy_pwrseq = true,
>  };
>  
>  const struct rz_sysc_init_data rzg3l_sysc_init_data __initconst = {
> diff --git a/drivers/soc/renesas/rz-sysc.c b/drivers/soc/renesas/rz-sysc.c
> index 161e8c38eea6..ea49ca51e740 100644
> --- a/drivers/soc/renesas/rz-sysc.c
> +++ b/drivers/soc/renesas/rz-sysc.c
> @@ -5,6 +5,7 @@
>   * Copyright (C) 2024 Renesas Electronics Corp.
>   */
>  
> +#include <linux/auxiliary_bus.h>
>  #include <linux/bitfield.h>
>  #include <linux/cleanup.h>
>  #include <linux/io.h>
> @@ -84,6 +85,41 @@ static int rz_sysc_soc_init(struct rz_sysc *sysc, const struct of_device_id *mat
>  	return 0;
>  }
>  
> +static void rz_sysc_pwrrdy_pwrseq_unregister_adev(void *adev)
> +{
> +	auxiliary_device_delete(adev);
> +	auxiliary_device_uninit(adev);
> +}
> +
> +static int rz_sysc_pwrrdy_pwrseq_init(struct device *dev, const struct rz_sysc_init_data *data)
> +{
> +	const struct rz_sysc_soc_id_init_data *soc_data = data->soc_id_init_data;
> +	struct auxiliary_device *adev;
> +	int ret;
> +
> +	if (!soc_data->pwrrdy_pwrseq)
> +		return 0;
> +
> +	adev = devm_kzalloc(dev, sizeof(*adev), GFP_KERNEL);

The lifetime of this allocation should be tied to adev->dev, not its
parent. Can't you just use devm_auxiliary_device_create() though?

> +	if (!adev)
> +		return -ENOMEM;
> +
> +	adev->name = "pwrseq-pwrrdy";
> +	adev->dev.parent = dev;
> +
> +	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, rz_sysc_pwrrdy_pwrseq_unregister_adev, adev);
> +}

regards
Philipp