linux-kernel - Re: [PATCH 2/2] mfd: stpmic1: add pmic poweroff via sys-off handler

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Message-ID: <20230515124631.GF10825@google.com>
Date:   Mon, 15 May 2023 13:46:31 +0100
From:   Lee Jones <lee@...nel.org>
To:     Sean Nyekjaer <sean@...nix.com>
Cc:     p.paillet@...com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] mfd: stpmic1: add pmic poweroff via sys-off handler

On Fri, 28 Apr 2023, Sean Nyekjaer wrote:

> Use devm_register_sys_off_handler() that allows to register multiple
> power-off handlers.
> 
> This can be enabled by adding "st,pmic-poweroff" to device-tree.
> 
> Signed-off-by: Sean Nyekjaer <sean@...nix.com>
> ---
>  drivers/mfd/stpmic1.c | 34 ++++++++++++++++++++++++++++++++++
>  1 file changed, 34 insertions(+)

You need to submit the Device Tree binding with this patch.

> diff --git a/drivers/mfd/stpmic1.c b/drivers/mfd/stpmic1.c
> index 4c9b18d9dec8..c628141eb03c 100644
> --- a/drivers/mfd/stpmic1.c
> +++ b/drivers/mfd/stpmic1.c
> @@ -7,6 +7,7 @@
>  #include <linux/mfd/core.h>
>  #include <linux/mfd/stpmic1.h>
>  #include <linux/module.h>
> +#include <linux/reboot.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
> @@ -117,6 +118,33 @@ static const struct regmap_irq_chip stpmic1_regmap_irq_chip = {
>  	.num_irqs = ARRAY_SIZE(stpmic1_irqs),
>  };
>  
> +static int stpmic1_power_off(struct sys_off_data *data)
> +{
> +	struct stpmic1 *ddata = data->cb_data;
> +
> +	regmap_update_bits(ddata->regmap, MAIN_CR,
> +			   SOFTWARE_SWITCH_OFF, SOFTWARE_SWITCH_OFF);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int stpmic1_power_off_prepare_init(struct stpmic1 *ddata)

This function looks superfluous.

Why not just call devm_register_sys_off_handler() inside the if?

> +{
> +	int ret;
> +
> +	ret = devm_register_sys_off_handler(ddata->dev,
> +					    SYS_OFF_MODE_POWER_OFF,
> +					    SYS_OFF_PRIO_DEFAULT,
> +					    stpmic1_power_off,
> +					    ddata);
> +	if (ret) {
> +		dev_err(ddata->dev, "failed to register sys-off handler: %d\n", ret);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static int stpmic1_probe(struct i2c_client *i2c)
>  {
>  	struct stpmic1 *ddata;
> @@ -159,6 +187,12 @@ static int stpmic1_probe(struct i2c_client *i2c)
>  		return ret;
>  	}
>  
> +	if (of_property_read_bool(i2c->dev.of_node,  "st,pmic-poweroff")) {
> +		ret = stpmic1_power_off_prepare_init(ddata);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	return devm_of_platform_populate(dev);
>  }
>  
> -- 
> 2.40.0
> 

-- 
Lee Jones [李琼斯]