new file mode 100644
@@ -0,0 +1,51 @@
+* Generic power domains
+
+System on chip designs are often divided into multiple power domains that
+can be used for power gating of selected IP blocks for power saving by
+reduced leakage current.
+
+This device tree binding can be used to bind power domain consumer devices
+with their power domains provided by power domain providers. A power domain
+provider can be represented by any node in the device tree and can provide
+one or more power domains. A consumer node can refer to the provider by
+a phandle and a set of phandle arguments (so called power domain specifier)
+of length specified by #power-domain-cells property in the power domain
+provider node.
+
+==Power domain providers==
+
+Required properties:
+ - #power-domain-cells : Number of cells in a power domain specifier;
+ Typically 0 for nodes representing a single power domain and 1 for nodes
+ providing multiple power domains (e.g. power controllers), but can be
+ any value as specified by device tree binding documentation of particular
+ provider.
+
+Example:
+
+ power: power-controller@12340000 {
+ compatible = "foo,power-controller";
+ reg = <0x12340000 0x1000>;
+ #power-domain-cells = <1>;
+ };
+
+The node above defines a power controller that is a power domain provider
+and expects one cell as its phandle argument.
+
+==Power domain consumers==
+
+Required properties:
+ - power-domain : A phandle and power domain specifier as defined by bindings
+ of power controller specified by phandle.
+
+Example:
+
+ leaky-device@12350000 {
+ compatible = "foo,i-leak-current";
+ reg = <0x12350000 0x1000>;
+ power-domain = <&power 0>;
+ };
+
+The node above defines a typical power domain consumer device, which is located
+inside power domain with index 0 of power controller represented by node with
+label "power".
@@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/io.h>
+#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pm_domain.h>
#include <linux/pm_qos.h>
@@ -2189,3 +2190,285 @@ void pm_genpd_init(struct generic_pm_domain *genpd,
list_add(&genpd->gpd_list_node, &gpd_list);
mutex_unlock(&gpd_list_lock);
}
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+/*
+ * Device Tree based power domain providers.
+ *
+ * The code below implements generic device tree based power domain providers
+ * that bind device tree nodes with generic power domains registered in the
+ * system.
+ *
+ * Any driver that registers generic power domains and need to support binding
+ * of devices to these domains is supposed to register a power domain provider,
+ * which maps a power domain specifier retrieved from device tree to a power
+ * domain.
+ *
+ * Two simple mapping functions have been provided for convenience:
+ * - of_genpd_xlate_simple() for 1:1 device tree node to domain mapping,
+ * - of_genpd_xlate_onecell() for mapping of multiple domains per node
+ * by index.
+ */
+
+/**
+ * struct of_genpd_provider - Power domain provider registration structure
+ * @link: Entry in global list of domain providers
+ * @node: Pointer to device tree node of domain provider
+ * @xlate: Provider-specific xlate callback mapping a set of specifier cells
+ * into a power domain.
+ * @data: context pointer to be passed into @xlate callback
+ */
+struct of_genpd_provider {
+ struct list_head link;
+
+ struct device_node *node;
+ genpd_xlate_t xlate;
+ void *data;
+};
+
+/* List of registered power domain providers. */
+static LIST_HEAD(of_genpd_providers);
+/* Mutex to protect the list above. */
+static DEFINE_MUTEX(of_genpd_mutex);
+
+/**
+ * of_genpd_xlate_simple() - Xlate function for direct node-domain mapping
+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct generic_pm_domain
+ *
+ * This is a generic xlate function that can be used to model power domains
+ * that have their own device tree nodes. The private data of xlate function
+ * needs to be a valid pointer to struct generic_pm_domain.
+ */
+struct generic_pm_domain *of_genpd_xlate_simple(
+ struct of_phandle_args *genpdspec,
+ void *data)
+{
+ if (genpdspec->args_count != 0)
+ return ERR_PTR(-EINVAL);
+ return data;
+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_simple);
+
+/**
+ * of_genpd_xlate_onecell() - Xlate function for providers using single index.
+ * @genpdspec: OF phandle args to map into a power domain
+ * @data: xlate function private data - pointer to struct genpd_onecell_data
+ *
+ * This is a generic xlate function that can be used to model simple power
+ * domain controllers that have one device tree node and provide multiple
+ * power domains. A single cell is used as an index to an array of power
+ * domains specified in genpd_onecell_data struct when registering the
+ * provider.
+ */
+struct generic_pm_domain *of_genpd_xlate_onecell(
+ struct of_phandle_args *genpdspec,
+ void *data)
+{
+ struct genpd_onecell_data *genpd_data = data;
+ unsigned int idx = genpdspec->args[0];
+
+ if (genpdspec->args_count != 1)
+ return ERR_PTR(-EINVAL);
+
+ if (idx >= genpd_data->domain_num) {
+ pr_err("%s: invalid domain index %d\n", __func__, idx);
+ return ERR_PTR(-EINVAL);
+ }
+
+ return genpd_data->domains[idx];
+}
+EXPORT_SYMBOL_GPL(of_genpd_xlate_onecell);
+
+/**
+ * of_genpd_add_provider() - Register a domain provider for a node
+ * @np: Device node pointer associated with domain provider.
+ * @xlate: Callback for decoding domain from phandle arguments.
+ * @data: Context pointer for @genpd_src_get callback.
+ */
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+ void *data)
+{
+ struct of_genpd_provider *cp;
+
+ cp = kzalloc(sizeof(*cp), GFP_KERNEL);
+ if (!cp)
+ return -ENOMEM;
+
+ cp->node = of_node_get(np);
+ cp->data = data;
+ cp->xlate = xlate;
+
+ mutex_lock(&of_genpd_mutex);
+ list_add(&cp->link, &of_genpd_providers);
+ mutex_unlock(&of_genpd_mutex);
+ pr_debug("Added domain provider from %s\n", np->full_name);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(of_genpd_add_provider);
+
+/**
+ * of_genpd_del_provider() - Remove a previously registered domain provider
+ * @np: Device node pointer associated with domain provider
+ */
+void of_genpd_del_provider(struct device_node *np)
+{
+ struct of_genpd_provider *cp;
+
+ mutex_lock(&of_genpd_mutex);
+ list_for_each_entry(cp, &of_genpd_providers, link) {
+ if (cp->node == np) {
+ list_del(&cp->link);
+ of_node_put(cp->node);
+ kfree(cp);
+ break;
+ }
+ }
+ mutex_unlock(&of_genpd_mutex);
+}
+EXPORT_SYMBOL_GPL(of_genpd_del_provider);
+
+/**
+ * of_genpd_get_from_provider() - Look-up power domain
+ * @genpdspec: OF phandle args to use for look-up
+ *
+ * Looks for domain provider under node specified by @genpdspec and if found
+ * uses xlate function of the provider to map phandle args to a power domain.
+ *
+ * Returns a valid pointer to struct generic_pm_domain on success or ERR_PTR()
+ * on failure.
+ */
+static struct generic_pm_domain *of_genpd_get_from_provider(
+ struct of_phandle_args *genpdspec)
+{
+ struct generic_pm_domain *genpd = ERR_PTR(-EPROBE_DEFER);
+ struct of_genpd_provider *provider;
+
+ mutex_lock(&of_genpd_mutex);
+
+ /* Check if we have such a provider in our array */
+ list_for_each_entry(provider, &of_genpd_providers, link) {
+ if (provider->node == genpdspec->np)
+ genpd = provider->xlate(genpdspec, provider->data);
+ if (!IS_ERR(genpd))
+ break;
+ }
+
+ mutex_unlock(&of_genpd_mutex);
+
+ return genpd;
+}
+
+/*
+ * Device<->domain binding using Device Tree look-up.
+ *
+ * The purpose of code below is to manage assignment of devices to their
+ * power domains in an automatic fashion, based on data read from device tree.
+ * The two functions, genpd_bind_domain() and genpd_unbind_domain() are
+ * intended to be called by higher level code that manages devices, i.e.
+ * really_probe() and __device_release_driver() to respectively bind and
+ * unbind device from its power domain.
+ *
+ * Both generic and legacy Samsung-specific DT bindings are supported to
+ * keep backwards compatibility with existing DTBs.
+ */
+
+/**
+ * genpd_bind_domain - Bind device to its power domain using Device Tree.
+ * @dev: Device to bind to its power domain.
+ *
+ * Tries to parse power domain specifier from device's OF node and if succeeds
+ * attaches the device to retrieved power domain.
+ *
+ * Returns 0 on success or negative error code otherwise.
+ */
+int genpd_bind_domain(struct device *dev)
+{
+ struct of_phandle_args pd_args;
+ struct generic_pm_domain *pd;
+ int ret;
+
+ if (!dev->of_node)
+ return 0;
+
+ ret = of_parse_phandle_with_args(dev->of_node, "power-domain",
+ "#power-domain-cells", 0, &pd_args);
+ if (ret < 0) {
+ if (ret != -ENOENT)
+ return ret;
+
+ /*
+ * Try legacy Samsung-specific bindings
+ * (for backwards compatibility of DT ABI)
+ */
+ pd_args.args_count = 0;
+ pd_args.np = of_parse_phandle(dev->of_node,
+ "samsung,power-domain", 0);
+ if (!pd_args.np)
+ return 0;
+ }
+
+ pd = of_genpd_get_from_provider(&pd_args);
+ if (IS_ERR(pd)) {
+ if (PTR_ERR(pd) != -EPROBE_DEFER)
+ dev_err(dev, "failed to find power domain: %ld\n",
+ PTR_ERR(pd));
+ return PTR_ERR(pd);
+ }
+
+ dev_dbg(dev, "adding to power domain %s\n", pd->name);
+
+ while (1) {
+ ret = pm_genpd_add_device(pd, dev);
+ if (ret != -EAGAIN)
+ break;
+ cond_resched();
+ }
+
+ if (ret < 0) {
+ dev_err(dev, "failed to add to power domain %s: %d",
+ pd->name, ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * genpd_unbind_domain - Unbind device from its power domain.
+ * @dev: Device to unbind from its power domain.
+ *
+ * Unbinds device from power domain previously bound to it.
+ *
+ * Returns 0 on success or negative error code otherwise.
+ */
+int genpd_unbind_domain(struct device *dev)
+{
+ struct generic_pm_domain *pd = dev_to_genpd(dev);
+ int ret;
+
+ if (!dev->of_node || IS_ERR(pd))
+ return 0;
+
+ dev_dbg(dev, "removing from power domain %s\n", pd->name);
+
+ while (1) {
+ ret = pm_genpd_remove_device(pd, dev);
+ if (ret != -EAGAIN)
+ break;
+ cond_resched();
+ }
+
+ if (ret < 0) {
+ dev_err(dev, "failed to remove from power domain %s: %d",
+ pd->name, ret);
+ return ret;
+ }
+
+ /* Check if domain can be powered off after removing this device. */
+ genpd_queue_power_off_work(pd);
+
+ return 0;
+}
+#endif
@@ -310,4 +310,50 @@ static inline void pm_genpd_syscore_poweron(struct device *dev)
pm_genpd_syscore_switch(dev, false);
}
+/* OF power domain providers */
+struct of_device_id;
+
+struct genpd_onecell_data {
+ struct generic_pm_domain **domains;
+ unsigned int domain_num;
+};
+
+typedef struct generic_pm_domain *(*genpd_xlate_t)(struct of_phandle_args *args,
+ void *data);
+
+#ifdef CONFIG_PM_GENERIC_DOMAINS_OF
+int of_genpd_add_provider(struct device_node *np, genpd_xlate_t xlate,
+ void *data);
+void of_genpd_del_provider(struct device_node *np);
+
+struct generic_pm_domain *of_genpd_xlate_simple(
+ struct of_phandle_args *genpdspec,
+ void *data);
+struct generic_pm_domain *of_genpd_xlate_onecell(
+ struct of_phandle_args *genpdspec,
+ void *data);
+
+int genpd_bind_domain(struct device *dev);
+int genpd_unbind_domain(struct device *dev);
+#else /* !CONFIG_PM_GENERIC_DOMAINS_OF */
+static inline int of_genpd_add_provider(struct device_node *np,
+ genpd_xlate_t xlate, void *data)
+{
+ return 0;
+}
+static inline void of_genpd_del_provider(struct device_node *np) {}
+
+#define of_genpd_xlate_simple NULL
+#define of_genpd_xlate_onecell NULL
+
+static inline int genpd_bind_domain(struct device *dev)
+{
+ return 0;
+}
+static inline int genpd_unbind_domain(struct device *dev)
+{
+ return 0;
+}
+#endif /* CONFIG_PM_GENERIC_DOMAINS_OF */
+
#endif /* _LINUX_PM_DOMAIN_H */
@@ -306,6 +306,10 @@ config PM_GENERIC_DOMAINS_RUNTIME
def_bool y
depends on PM_RUNTIME && PM_GENERIC_DOMAINS
+config PM_GENERIC_DOMAINS_OF
+ def_bool y
+ depends on PM_GENERIC_DOMAINS && OF && !ARCH_EXYNOS
+
config CPU_PM
bool
depends on SUSPEND || CPU_IDLE