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

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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>
This commit is contained in:
Claudiu Beznea
2025-07-03 14:27:06 +03:00
committed by Rafael J. Wysocki
parent 9047685cfd
commit d42c7c6fd6
13 changed files with 23 additions and 17 deletions
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4
drivers/amba/bus.c
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@@ -138,7 +138,7 @@ static int amba_read_periphid(struct amba_device *dev)
void __iomem *tmp;
int i, ret;
ret = dev_pm_domain_attach(&dev->dev, true);
ret = dev_pm_domain_attach(&dev->dev, PD_FLAG_ATTACH_POWER_ON);
if (ret) {
dev_dbg(&dev->dev, "can't get PM domain: %d\n", ret);
goto err_out;
@@ -291,7 +291,7 @@ static int amba_probe(struct device *dev)
if (ret < 0)
break;
ret = dev_pm_domain_attach(dev, true);
ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON);
if (ret)
break;