From d42c7c6fd66a6e2a78ae1da666c5df6c2fde8389 Mon Sep 17 00:00:00 2001 From: Claudiu Beznea Date: Thu, 3 Jul 2025 14:27:06 +0300 Subject: 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 Reviewed-by: Mathieu Poirier Acked-by: Wolfram Sang # I2C Reviewed-by: Ulf Hansson Link: https://patch.msgid.link/20250703112708.1621607-2-claudiu.beznea.uj@bp.renesas.com [ rjw: Changelog adjustments ] Signed-off-by: Rafael J. Wysocki --- drivers/gpu/drm/display/drm_dp_aux_bus.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/gpu/drm') diff --git a/drivers/gpu/drm/display/drm_dp_aux_bus.c b/drivers/gpu/drm/display/drm_dp_aux_bus.c index ec7eac6b595f..718c9122bc3a 100644 --- a/drivers/gpu/drm/display/drm_dp_aux_bus.c +++ b/drivers/gpu/drm/display/drm_dp_aux_bus.c @@ -57,7 +57,7 @@ static int dp_aux_ep_probe(struct device *dev) container_of(aux_ep, struct dp_aux_ep_device_with_data, aux_ep); int ret; - ret = dev_pm_domain_attach(dev, true); + ret = dev_pm_domain_attach(dev, PD_FLAG_ATTACH_POWER_ON); if (ret) return dev_err_probe(dev, ret, "Failed to attach to PM Domain\n"); -- cgit v1.2.3