PM: domains: Add flags to specify power on attach/detach

Calling dev_pm_domain_attach()/dev_pm_domain_detach() in bus driver
probe/remove functions can affect system behavior when the drivers
attached to the bus use devres-managed resources. Since devres actions
may need to access device registers, calling dev_pm_domain_detach() too
early, i.e., before these actions complete, can cause failures on some
systems. One such example is Renesas RZ/G3S SoC-based platforms.

If the device clocks are managed via PM domains, invoking
dev_pm_domain_detach() in the bus driver's remove function removes the
device's clocks from the PM domain, preventing any subsequent
pm_runtime_resume*() calls from enabling those clocks.

The second argument of dev_pm_domain_attach() specifies whether the PM
domain should be powered on during attachment. Likewise, the second
argument of dev_pm_domain_detach() indicates whether the domain should be
powered off during detachment.

Upcoming changes address the issue described above (initially for the
platform bus only) by deferring the call to dev_pm_domain_detach() until
after devres_release_all() in device_unbind_cleanup(). The detach_power_off
field in struct dev_pm_info stores the detach power off info from the
second argument of dev_pm_domain_attach().

Because there are cases where the device's PM domain power-on/off behavior
must be conditional (e.g., in i2c_device_probe()), the patch introduces
PD_FLAG_ATTACH_POWER_ON and PD_FLAG_DETACH_POWER_OFF flags to be passed
to dev_pm_domain_attach().

Finally, dev_pm_domain_attach() and its users are updated to use the newly
introduced PD_FLAG_ATTACH_POWER_ON and PD_FLAG_DETACH_POWER_OFF macros.

This change is preparatory.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Wolfram Sang <wsa+renesas@sang-engineering.com> # I2C
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Link: https://patch.msgid.link/20250703112708.1621607-2-claudiu.beznea.uj@bp.renesas.com
[ rjw: Changelog adjustments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index 781968a128ff..fecb85fa85ac 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -83,7 +83,7 @@ EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
 /**
  * dev_pm_domain_attach - Attach a device to its PM domain.
  * @dev: Device to attach.
- * @power_on: Used to indicate whether we should power on the device.
+ * @flags: indicate whether we should power on/off the device on attach/detach
  *
  * The @dev may only be attached to a single PM domain. By iterating through
  * the available alternatives we try to find a valid PM domain for the device.
@@ -100,14 +100,14 @@ EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
  * Returns 0 on successfully attached PM domain, or when it is found that the
  * device doesn't need a PM domain, else a negative error code.
  */
-int dev_pm_domain_attach(struct device *dev, bool power_on)
+int dev_pm_domain_attach(struct device *dev, u32 flags)
 {
 	int ret;
 
 	if (dev->pm_domain)
 		return 0;
 
-	ret = acpi_dev_pm_attach(dev, power_on);
+	ret = acpi_dev_pm_attach(dev, !!(flags & PD_FLAG_ATTACH_POWER_ON));
 	if (!ret)
 		ret = genpd_dev_pm_attach(dev);