linux-kernel - Re: [PATCH] mfd: tps65219: Add support for soft shutdown via sys-off API

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Date:   Wed, 1 Mar 2023 10:35:54 -0600
From:   Andrew Davis <afd@...com>
To:     Lee Jones <lee@...nel.org>, Jerome Neanne <jneanne@...libre.com>
CC:     <tony@...mide.com>, <linux-omap@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <khilman@...libre.com>,
        <nm@...com>, <msp@...libre.com>
Subject: Re: [PATCH] mfd: tps65219: Add support for soft shutdown via sys-off
 API

On 3/1/23 10:07 AM, Lee Jones wrote:
> On Fri, 03 Feb 2023, Jerome Neanne wrote:
> 
>> Use new API for power-off mode support:
>> Link: https://lwn.net/Articles/894511/
>> Link: https://lore.kernel.org/all/7hfseqa7l0.fsf@baylibre.com/
>>
>> sys-off API allows support of shutdown handler and restart handler.
>>
>> Shutdown was not supported before that enhancement.
>> This is required for platform that are not using PSCI.
>>

Not sure what platform doesn't have PSCI off, since you tested on
AM62-SK I'm guessing you manually disabled the PSCI off for testing?

Anyway I don't see any huge issues with the code itself, small comment below.

>> Test:
>> - restart:
>>    # reboot
>>    Default is cold reset:
>>    # cat /sys/kernel/reboot/mode
>>    Switch boot mode to warm reset:
>>    # echo warm > /sys/kernel/reboot/mode
>> - power-off:
>>    # halt
>>
>> Tested on AM62-SP-SK board.
>>
>> Signed-off-by: Jerome Neanne <jneanne@...libre.com>
>> Suggested-by: Andrew Davis <afd@...com>
> 
> A review from Andrew would be helpful here.
> 
>> ---
>>   drivers/mfd/tps65219.c | 45 +++++++++++++++++++++++++++++++-----------
>>   1 file changed, 34 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/mfd/tps65219.c b/drivers/mfd/tps65219.c
>> index 0e402fda206b..c134f3f6e202 100644
>> --- a/drivers/mfd/tps65219.c
>> +++ b/drivers/mfd/tps65219.c
>> @@ -25,25 +25,34 @@ static int tps65219_cold_reset(struct tps65219 *tps)
>>   				  TPS65219_MFP_COLD_RESET_I2C_CTRL_MASK);
>>   }
>>   
>> -static int tps65219_restart(struct notifier_block *this,
>> -			    unsigned long reboot_mode, void *cmd)
>> +static int tps65219_soft_shutdown(struct tps65219 *tps)
>>   {
>> -	struct tps65219 *tps;
>> +	return regmap_update_bits(tps->regmap, TPS65219_REG_MFP_CTRL,
>> +				  TPS65219_MFP_I2C_OFF_REQ_MASK,
>> +				  TPS65219_MFP_I2C_OFF_REQ_MASK);
>> +}
>>   
>> -	tps = container_of(this, struct tps65219, nb);
>> +static int tps65219_power_off_handler(struct sys_off_data *data)
>> +{
>> +	tps65219_soft_shutdown(data->cb_data);
>> +	return NOTIFY_DONE;
>> +}
>>   
>> +static int tps65219_restart(struct tps65219 *tps,
>> +			    unsigned long reboot_mode)
>> +{
>>   	if (reboot_mode == REBOOT_WARM)
>>   		tps65219_warm_reset(tps);
>>   	else
>>   		tps65219_cold_reset(tps);
>> -
>>   	return NOTIFY_DONE;
>>   }
>>   
>> -static struct notifier_block pmic_rst_restart_nb = {
>> -	.notifier_call = tps65219_restart,
>> -	.priority = 200,
>> -};
>> +static int tps65219_restart_handler(struct sys_off_data *data)
>> +{
>> +	tps65219_restart(data->cb_data, data->mode);
>> +	return NOTIFY_DONE;
>> +}
>>   
>>   static const struct resource tps65219_pwrbutton_resources[] = {
>>   	DEFINE_RES_IRQ_NAMED(TPS65219_INT_PB_FALLING_EDGE_DETECT, "falling"),
>> @@ -269,13 +278,27 @@ static int tps65219_probe(struct i2c_client *client)
>>   		}
>>   	}
>>   
>> -	tps->nb = pmic_rst_restart_nb;
>> -	ret = register_restart_handler(&tps->nb);
>> +	ret = devm_register_sys_off_handler(tps->dev,
>> +					    SYS_OFF_MODE_RESTART,
>> +					    SYS_OFF_PRIO_HIGH,

Why not default prio? SYS_OFF_PRIO_DEFAULT

Then you can use this new helper devm_register_restart_handler()

>> +					    tps65219_restart_handler,
>> +					    tps);
>> +
>>   	if (ret) {
>>   		dev_err(tps->dev, "cannot register restart handler, %d\n", ret);
>>   		return ret;
>>   	}
>>   
>> +	ret = devm_register_sys_off_handler(tps->dev,
>> +					    SYS_OFF_MODE_POWER_OFF,
>> +					    SYS_OFF_PRIO_DEFAULT,
>> +					    tps65219_power_off_handler,
>> +					    tps);


devm_register_power_off_handler()?

Otherwise I see no major issues,

Reviewed-by: Andrew Davis <afd@...com>

Andrew

>> +	if (ret) {
>> +		dev_err(tps->dev, "failed to register sys-off handler: %d\n",
>> +			ret);
>> +		return ret;
>> +	}
>>   	return 0;
>>   }
>>   
>> -- 
>> 2.34.1
>>
>