drivers: base: Port power management code from Linux

Port an extremely abridged version of power management/power domain
code from Linux as a dependency of i.MX7D PCIe work. Currenlty only
bare minimum of functionality is implemented.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 82 insertions, 0 deletions

diff --git a/include/pm_domain.h b/include/pm_domain.h
new file mode 100644
index 0000000000..6d59587ece
--- /dev/null
+++ b/include/pm_domain.h
@@ -0,0 +1,82 @@
+#ifndef _PM_DOMAIN_H
+#define _PM_DOMAIN_H
+
+enum gpd_status {
+	GPD_STATE_ACTIVE = 0,	/* PM domain is active */
+	GPD_STATE_POWER_OFF,	/* PM domain is off */
+};
+
+struct generic_pm_domain {
+	const char *name;
+	struct list_head gpd_list_node;	/* Node in the global PM domains list */
+
+	enum gpd_status status;	/* Current state of the domain */
+
+	int (*power_off)(struct generic_pm_domain *domain);
+	int (*power_on)(struct generic_pm_domain *domain);
+};
+
+typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
+						   void *data);
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS
+
+int genpd_dev_pm_attach(struct device_d *dev);
+
+/**
+ * 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.
+ *
+ * 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.
+ * As attachment succeeds, the ->detach() callback in the struct dev_pm_domain
+ * should be assigned by the corresponding attach function.
+ *
+ * This function should typically be invoked from subsystem level code during
+ * the probe phase. Especially for those that holds devices which requires
+ * power management through PM domains.
+ *
+ * Callers must ensure proper synchronization of this function with power
+ * management callbacks.
+ *
+ * Returns 0 on successfully attached PM domain or negative error code.
+ */
+static inline int dev_pm_domain_attach(struct device_d *dev, bool power_on)
+{
+	return genpd_dev_pm_attach(dev);
+}
+
+int pm_genpd_init(struct generic_pm_domain *genpd, void *gov, bool is_off);
+
+int of_genpd_add_provider_simple(struct device_node *np,
+				 struct generic_pm_domain *genpd);
+
+#else
+
+static inline int pm_genpd_init(struct generic_pm_domain *genpd,
+				void *gov, bool is_off)
+{
+	return -ENOSYS;
+}
+
+static inline int genpd_dev_pm_attach(struct device_d *dev)
+{
+	return 0;
+}
+
+static inline int dev_pm_domain_attach(struct device_d *dev, bool power_on)
+{
+	return 0;
+}
+
+static inline int
+of_genpd_add_provider_simple(struct device_node *np,
+			     struct generic_pm_domain *genpd)
+{
+	return -ENOTSUPP;
+}
+
+#endif
+
+#endif
\ No newline at end of file