Most likely you will need a PM domain in addition to that, but mostly to avoid
code duplication.

And in the future other types of power state definitions may be hooked up
to that, including ACPI etc.


Signed-off-by: Rafael J. Wysocki <redacted>
---
 drivers/base/power/common.c |   35 +++++++++++++++++++++++++++++++++++
 include/linux/pm.h          |   33 +++++++++++++++++++++++++++++++++
 2 files changed, 68 insertions(+)

Index: linux-pm/include/linux/pm.h
===================================================================

--- linux-pm.orig/include/linux/pm.h
+++ linux-pm/include/linux/pm.h

@@ -550,6 +550,30 @@ struct pm_subsys_data {
 #endif
 };
 
+enum power_state_type {
+	POWER_STATE_GENERIC = 0,
+};
+
+/**
+ * struct power_state_info - information related to device power states.
+ *
+ * @type: Power states definition type.
+ * @power_up: Device power up method.
+ * @power_down: Device power down method.
+ *
+ * @power_up is expected to put the device into a power state in which it can
+ * be operated by software (it doesn't have to be the full power state in
+ * principle as long as the device will respond to all software accesses in
+ * this state) and @power_down is expected to put the device into the lowest
+ * power state the device can be put into given all of the applicable
+ * constraints and limitations (it may not mean completely off).
+ */
+struct power_state_info {
+	enum power_state_type type;
+	int (*power_up)(struct device *dev);
+	int (*power_down)(struct device *dev);
+};
+
 struct dev_pm_info {
 	pm_message_t		power_state;
 	unsigned int		can_wakeup:1;

@@ -600,6 +624,7 @@ struct dev_pm_info {
 	unsigned long		active_jiffies;
 	unsigned long		suspended_jiffies;
 	unsigned long		accounting_timestamp;
+	struct power_state_info	*state;
 #endif
 	struct pm_subsys_data	*subsys_data;  /* Owned by the subsystem. */
 	void (*set_latency_tolerance)(struct device *, s32);

@@ -610,6 +635,14 @@ extern void update_pm_runtime_accounting
 extern int dev_pm_get_subsys_data(struct device *dev);
 extern void dev_pm_put_subsys_data(struct device *dev);
 
+#ifdef CONFIG_PM
+extern int pm_device_power_up(struct device *dev);
+extern int pm_device_power_down(struct device *dev);
+#else
+static inline int pm_device_power_up(struct device *dev) { return 0; }
+static inline int pm_device_power_down(struct device *dev) { return 0; }
+#endif /* CONFIG_PM */
+
 /**
  * struct dev_pm_domain - power management domain representation.
  *

Index: linux-pm/drivers/base/power/common.c
===================================================================

--- linux-pm.orig/drivers/base/power/common.c
+++ linux-pm/drivers/base/power/common.c

@@ -152,3 +152,38 @@ void dev_pm_domain_set(struct device *de
 	device_pm_check_callbacks(dev);
 }
 EXPORT_SYMBOL_GPL(dev_pm_domain_set);
+
+/**
+ * pm_device_power_up - Power up a device using the power states framework.
+ * @dev: Device to power up.
+ *
+ * Put the device into a power state in which it will respond to all software
+ * accesses (that may not mean maximum power) using the callback provided
+ * through the device power state framework, if present.
+ */
+int pm_device_power_up(struct device *dev)
+{
+	if (dev->power.state && dev->power.state->power_up)
+		return dev->power.state->power_up(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm_device_power_up);
+
+/**
+ * pm_device_power_down - Power down a device using the power states framework.
+ * @dev: Device to power down.
+ *
+ * Put the device into the lowest power state it can be put into given the
+ * applicable constraints and limitations (that may not mean maximum power)
+ * using the callback provided through the device power state framework, if
+ * present.
+ */
+int pm_device_power_down(struct device *dev)
+{
+	if (dev->power.state && dev->power.state->power_down)
+		return dev->power.state->power_down(dev);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pm_device_power_down);