[PATCH v19 06/10] power: reset: Add psci-reboot-mode driver
Shivendra Pratap
shivendra.pratap at oss.qualcomm.com
Mon Jan 5 10:05:24 PST 2026
On 1/2/2026 5:27 PM, Bartosz Golaszewski wrote:
> On Sun, Dec 28, 2025 at 6:21 PM Shivendra Pratap
> <shivendra.pratap at oss.qualcomm.com> wrote:
>>
>
> [snip]
>
>> +
>> +static int psci_reboot_mode_probe(struct faux_device *fdev)
>> +{
>> + struct reboot_mode_driver *reboot;
>> + struct device_node *psci_np;
>> + struct device_node *np;
>> + int ret;
>> +
>> + psci_np = of_find_compatible_node(NULL, NULL, "arm,psci-1.0");
>> + if (!psci_np)
>> + return -ENODEV;
>> +
>> + /*
>> + * Find the psci:reboot-mode node.
>> + * If NULL, continue to register predefined modes.
>> + * np refcount to be handled by dev;
>> + * psci_np refcount is decremented by of_find_node_by_name;
>> + */
>
> Can you make this comment into full sentences, I had trouble parsing
> the meaning for a minute.
Ack.
>
>> + np = of_find_node_by_name(psci_np, "reboot-mode");
>> + fdev->dev.of_node = np;
>
> The logic of the device assigning its own node is a bit sketchy,
> ideally this should be done before the device probes.
Will move it to init. thanks.
>
>> +
>> + reboot = devm_kzalloc(&fdev->dev, sizeof(*reboot), GFP_KERNEL);
>> + if (!reboot)
>> + return -ENOMEM;
>> +
>> + psci_reboot_mode_set_predefined_modes(reboot);
>> + reboot->write = psci_reboot_mode_write;
>> + reboot->dev = &fdev->dev;
>> +
>> + ret = devm_reboot_mode_register(&fdev->dev, reboot);
>> + if (ret) {
>> + dev_err(&fdev->dev, "devm_reboot_mode_register failed %d\n", ret);
>> + return ret;
>
> Use dev_err_probe().
Ack.
>
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +static struct faux_device_ops psci_reboot_mode_ops = {
>> + .probe = psci_reboot_mode_probe,
>> +};
>> +
>> +static int __init psci_reboot_mode_init(void)
>> +{
>> + struct faux_device *fdev;
>> +
>> + fdev = faux_device_create("psci-reboot-mode", NULL, &psci_reboot_mode_ops);
>> + if (!fdev)
>> + return -ENODEV;
>
> This will always create this device for everyone who includes this
> module. Move the of_find_compatible_node(NULL, NULL, "arm,psci-1.0")
> call from probe() here instead and don't create the device if it
> fails.
Ack.
Will move both calls to init before creating the faux device.
psci_np = of_find_compatible_node(NULL, NULL, "arm,psci-1.0");
and
np = of_find_node_by_name(psci_np, "reboot-mode");
--
thanks,
Shivendra
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