Re: [PATCH v24 08/12] mfd: psci-mfd: Add psci-reboot-mode child cell

Shivendra Pratap <[email protected]>
Newsgroups dev.linux.lists.mfd,org.infradead.lists.linux-arm-kernel,org.kernel.vger.linux-arm-msm,org.kernel.vger.linux-devicetree,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pm
Message-ID <[email protected]>

On 8/12/2026 1:48 PM, Lee Jones wrote:
> On Mon, 03 Aug 2026, Shivendra Pratap wrote:
> 
>> The PSCI "reboot-mode" node does not define a compatible because it is a
>> configuration of boot-states provided by the underlying firmware. With
>> the new firmware-node based cells in mfd-core, this node can now be
>> exposed as a proper child cell.
>>
>> Add the psci-reboot-mode child cell to the psci-mfd driver with a
>> named_fwnode. Add psci-cpuidle-domain cell first to isolate it from
>> reboot-mode failures.
>>
>> Suggested-by: Bartosz Golaszewski <[email protected]>
>> Signed-off-by: Shivendra Pratap <[email protected]>
>> ---
>>   drivers/mfd/psci-mfd.c      | 27 ++++++++++++++++++++++++++-
>>   drivers/power/reset/Kconfig |  2 +-
>>   2 files changed, 27 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mfd/psci-mfd.c b/drivers/mfd/psci-mfd.c
>> index 7affd6bb09dd..7befc4fa86f5 100644
>> --- a/drivers/mfd/psci-mfd.c
>> +++ b/drivers/mfd/psci-mfd.c
>> @@ -14,10 +14,35 @@ static const struct mfd_cell psci_cells[] = {
>>   	},
>>   };
>>   
>> +static const struct mfd_cell psci_reboot_mode_cell[] = {
>> +	{
>> +		.name = "psci-reboot-mode",
>> +		.named_fwnode = "reboot-mode",
>> +	},
>> +};
>> +
>>   static int psci_mfd_probe(struct platform_device *pdev)
>>   {
>> -	return devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, psci_cells,
>> +	int ret;
>> +
>> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO, psci_cells,
>>   				   ARRAY_SIZE(psci_cells), NULL, 0, NULL);
>> +	if (ret)
>> +		goto out;
>> +
>> +	ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
>> +				   psci_reboot_mode_cell,
>> +				   ARRAY_SIZE(psci_reboot_mode_cell),
>> +				   NULL, 0, NULL);
>> +	if (ret) {
>> +		if (ret == -ENOMEM)
>> +			goto out;
>> +		dev_warn(&pdev->dev, "reboot-mode child cell failed to add: %d\n", ret);
> 
> Okay Yoda, but why is this okay?
> 
> Needs a comment.

sure. Will add a comment in code.

psci-mfd adds two child cells, psci-cpuidle-domain and psci-reboot-mode.
psci-cpuidle-domain is boot-critical on supported systems.
psci-reboot-mode is added separately as an optional child. For 
non-critical failures from psci_reboot_mode_cell, we want to continue 
the probe of psci-mfd.

thanks,
Shivendra
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