Merge tag 'pm-4.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more power management updates from Rafael Wysocki:
 "These revert a recent PM core change that introduced a regression, fix
  the build when the recently added Kryo cpufreq driver is selected, add
  support for devices attached to multiple power domains to the generic
  power domains (genpd) framework, add support for iowait boosting on
  systens with hardware-managed P-states (HWP) enabled to the
  intel_pstate driver, modify the behavior of the wakeup_count device
  attribute in sysfs, fix a few issues and clean up some ugliness,
  mostly in cpufreq (core and drivers) and in the cpupower utility.

  Specifics:

   - Revert a recent PM core change that attempted to fix an issue
     related to device links, but introduced a regression (Rafael
     Wysocki)

   - Fix build when the recently added cpufreq driver for Kryo
     processors is selected by making it possible to build that driver
     as a module (Arnd Bergmann)

   - Fix the long idle detection mechanism in the out-of-band (ondemand
     and conservative) cpufreq governors (Chen Yu)

   - Add support for devices in multiple power domains to the generic
     power domains (genpd) framework (Ulf Hansson)

   - Add support for iowait boosting on systems with hardware-managed
     P-states (HWP) enabled to the intel_pstate driver and make it use
     that feature on systems with Skylake Xeon processors as it is
     reported to improve performance significantly on those systems
     (Srinivas Pandruvada)

   - Fix and update the acpi_cpufreq, ti-cpufreq and imx6q cpufreq
     drivers (Colin Ian King, Suman Anna, Sébastien Szymanski)

   - Change the behavior of the wakeup_count device attribute in sysfs
     to expose the number of events when the device might have aborted
     system suspend in progress (Ravi Chandra Sadineni)

   - Fix two minor issues in the cpupower utility (Abhishek Goel, Colin
     Ian King)"

* tag 'pm-4.18-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Revert "PM / runtime: Fixup reference counting of device link suppliers at probe"
  cpufreq: imx6q: check speed grades for i.MX6ULL
  cpufreq: governors: Fix long idle detection logic in load calculation
  cpufreq: intel_pstate: enable boost for Skylake Xeon
  PM / wakeup: Export wakeup_count instead of event_count via sysfs
  PM / Domains: Add dev_pm_domain_attach_by_id() to manage multi PM domains
  PM / Domains: Add support for multi PM domains per device to genpd
  PM / Domains: Split genpd_dev_pm_attach()
  PM / Domains: Don't attach devices in genpd with multi PM domains
  PM / Domains: dt: Allow power-domain property to be a list of specifiers
  cpufreq: intel_pstate: New sysfs entry to control HWP boost
  cpufreq: intel_pstate: HWP boost performance on IO wakeup
  cpufreq: intel_pstate: Add HWP boost utility and sched util hooks
  cpufreq: ti-cpufreq: Use devres managed API in probe()
  cpufreq: ti-cpufreq: Fix an incorrect error return value
  cpufreq: ACPI: make function acpi_cpufreq_fast_switch() static
  cpufreq: kryo: allow building as a loadable module
  cpupower : Fix header name to read idle state name
  cpupower: fix spelling mistake: "logilename" -> "logfilename"

1 files changed, 40 insertions, 3 deletions

diff --git a/drivers/base/power/common.c b/drivers/base/power/common.c
index 7ae62b6355b8..df41b4780b3b 100644
--- a/drivers/base/power/common.c
+++ b/drivers/base/power/common.c
@@ -117,13 +117,50 @@ int dev_pm_domain_attach(struct device *dev, bool power_on)
 EXPORT_SYMBOL_GPL(dev_pm_domain_attach);
 
 /**
+ * dev_pm_domain_attach_by_id - Associate a device with one of its PM domains.
+ * @dev: The device used to lookup the PM domain.
+ * @index: The index of the PM domain.
+ *
+ * As @dev may only be attached to a single PM domain, the backend PM domain
+ * provider creates a virtual device to attach instead. If attachment succeeds,
+ * the ->detach() callback in the struct dev_pm_domain are assigned by the
+ * corresponding backend attach function, as to deal with detaching of the
+ * created virtual device.
+ *
+ * This function should typically be invoked by a driver during the probe phase,
+ * in case its device requires power management through multiple PM domains. The
+ * driver may benefit from using the received device, to configure device-links
+ * towards its original device. Depending on the use-case and if needed, the
+ * links may be dynamically changed by the driver, which allows it to control
+ * the power to the PM domains independently from each other.
+ *
+ * Callers must ensure proper synchronization of this function with power
+ * management callbacks.
+ *
+ * Returns the virtual created device when successfully attached to its PM
+ * domain, NULL in case @dev don't need a PM domain, else an ERR_PTR().
+ * Note that, to detach the returned virtual device, the driver shall call
+ * dev_pm_domain_detach() on it, typically during the remove phase.
+ */
+struct device *dev_pm_domain_attach_by_id(struct device *dev,
+					  unsigned int index)
+{
+	if (dev->pm_domain)
+		return ERR_PTR(-EEXIST);
+
+	return genpd_dev_pm_attach_by_id(dev, index);
+}
+EXPORT_SYMBOL_GPL(dev_pm_domain_attach_by_id);
+
+/**
  * dev_pm_domain_detach - Detach a device from its PM domain.
  * @dev: Device to detach.
  * @power_off: Used to indicate whether we should power off the device.
  *
- * This functions will reverse the actions from dev_pm_domain_attach() and thus
- * try to detach the @dev from its PM domain. Typically it should be invoked
- * from subsystem level code during the remove phase.
+ * This functions will reverse the actions from dev_pm_domain_attach() and
+ * dev_pm_domain_attach_by_id(), thus it detaches @dev from its PM domain.
+ * Typically it should be invoked during the remove phase, either from
+ * subsystem level code or from drivers.
  *
  * Callers must ensure proper synchronization of this function with power
  * management callbacks.