Merge branch 'clk-parent-rewrite' (early part) into clk-next

* 'clk-parent-rewrite' (early part):
  clk: Move of_clk_*() APIs into clk.c from clkdev.c
  clk: Inform the core about consumer devices
  clk: Introduce of_clk_get_hw_from_clkspec()
  clk: core: clarify the check for runtime PM
  clk: Combine __clk_get() and __clk_create_clk()

1 files changed, 203 insertions, 56 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index af3882f04080..14cbf239d9b2 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -57,6 +57,7 @@ struct clk_core {
 	struct clk_core		*new_child;
 	unsigned long		flags;
 	bool			orphan;
+	bool			rpm_enabled;
 	unsigned int		enable_count;
 	unsigned int		prepare_count;
 	unsigned int		protect_count;
@@ -81,6 +82,7 @@ struct clk_core {
 
 struct clk {
 	struct clk_core	*core;
+	struct device *dev;
 	const char *dev_id;
 	const char *con_id;
 	unsigned long min_rate;
@@ -92,9 +94,9 @@ struct clk {
 /***           runtime pm          ***/
 static int clk_pm_runtime_get(struct clk_core *core)
 {
-	int ret = 0;
+	int ret;
 
-	if (!core->dev)
+	if (!core->rpm_enabled)
 		return 0;
 
 	ret = pm_runtime_get_sync(core->dev);
@@ -103,7 +105,7 @@ static int clk_pm_runtime_get(struct clk_core *core)
 
 static void clk_pm_runtime_put(struct clk_core *core)
 {
-	if (!core->dev)
+	if (!core->rpm_enabled)
 		return;
 
 	pm_runtime_put_sync(core->dev);
@@ -223,7 +225,7 @@ static bool clk_core_is_enabled(struct clk_core *core)
 	 * taking enable spinlock, but the below check is needed if one tries
 	 * to call it from other places.
 	 */
-	if (core->dev) {
+	if (core->rpm_enabled) {
 		pm_runtime_get_noresume(core->dev);
 		if (!pm_runtime_active(core->dev)) {
 			ret = false;
@@ -233,7 +235,7 @@ static bool clk_core_is_enabled(struct clk_core *core)
 
 	ret = core->ops->is_enabled(core->hw);
 done:
-	if (core->dev)
+	if (core->rpm_enabled)
 		pm_runtime_put(core->dev);
 
 	return ret;
@@ -3212,43 +3214,106 @@ unlock:
 	return ret;
 }
 
-struct clk *__clk_create_clk(struct clk_hw *hw, const char *dev_id,
+/**
+ * clk_core_link_consumer - Add a clk consumer to the list of consumers in a clk_core
+ * @core: clk to add consumer to
+ * @clk: consumer to link to a clk
+ */
+static void clk_core_link_consumer(struct clk_core *core, struct clk *clk)
+{
+	clk_prepare_lock();
+	hlist_add_head(&clk->clks_node, &core->clks);
+	clk_prepare_unlock();
+}
+
+/**
+ * clk_core_unlink_consumer - Remove a clk consumer from the list of consumers in a clk_core
+ * @clk: consumer to unlink
+ */
+static void clk_core_unlink_consumer(struct clk *clk)
+{
+	lockdep_assert_held(&prepare_lock);
+	hlist_del(&clk->clks_node);
+}
+
+/**
+ * alloc_clk - Allocate a clk consumer, but leave it unlinked to the clk_core
+ * @core: clk to allocate a consumer for
+ * @dev_id: string describing device name
+ * @con_id: connection ID string on device
+ *
+ * Returns: clk consumer left unlinked from the consumer list
+ */
+static struct clk *alloc_clk(struct clk_core *core, const char *dev_id,
 			     const char *con_id)
 {
 	struct clk *clk;
 
-	/* This is to allow this function to be chained to others */
-	if (IS_ERR_OR_NULL(hw))
-		return ERR_CAST(hw);
-
 	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
 	if (!clk)
 		return ERR_PTR(-ENOMEM);
 
-	clk->core = hw->core;
+	clk->core = core;
 	clk->dev_id = dev_id;
 	clk->con_id = kstrdup_const(con_id, GFP_KERNEL);
 	clk->max_rate = ULONG_MAX;
 
-	clk_prepare_lock();
-	hlist_add_head(&clk->clks_node, &hw->core->clks);
-	clk_prepare_unlock();
-
 	return clk;
 }
 
-/* keep in sync with __clk_put */
-void __clk_free_clk(struct clk *clk)
+/**
+ * free_clk - Free a clk consumer
+ * @clk: clk consumer to free
+ *
+ * Note, this assumes the clk has been unlinked from the clk_core consumer
+ * list.
+ */
+static void free_clk(struct clk *clk)
 {
-	clk_prepare_lock();
-	hlist_del(&clk->clks_node);
-	clk_prepare_unlock();
-
 	kfree_const(clk->con_id);
 	kfree(clk);
 }
 
 /**
+ * clk_hw_create_clk: Allocate and link a clk consumer to a clk_core given
+ * a clk_hw
+ * @dev: clk consumer device
+ * @hw: clk_hw associated with the clk being consumed
+ * @dev_id: string describing device name
+ * @con_id: connection ID string on device
+ *
+ * This is the main function used to create a clk pointer for use by clk
+ * consumers. It connects a consumer to the clk_core and clk_hw structures
+ * used by the framework and clk provider respectively.
+ */
+struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
+			      const char *dev_id, const char *con_id)
+{
+	struct clk *clk;
+	struct clk_core *core;
+
+	/* This is to allow this function to be chained to others */
+	if (IS_ERR_OR_NULL(hw))
+		return ERR_CAST(hw);
+
+	core = hw->core;
+	clk = alloc_clk(core, dev_id, con_id);
+	if (IS_ERR(clk))
+		return clk;
+	clk->dev = dev;
+
+	if (!try_module_get(core->owner)) {
+		free_clk(clk);
+		return ERR_PTR(-ENOENT);
+	}
+
+	kref_get(&core->ref);
+	clk_core_link_consumer(core, clk);
+
+	return clk;
+}
+
+/**
  * clk_register - allocate a new clock, register it and return an opaque cookie
  * @dev: device that is registering this clock
  * @hw: link to hardware-specific clock data
@@ -3283,7 +3348,8 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 	core->ops = hw->init->ops;
 
 	if (dev && pm_runtime_enabled(dev))
-		core->dev = dev;
+		core->rpm_enabled = true;
+	core->dev = dev;
 	if (dev && dev->driver)
 		core->owner = dev->driver->owner;
 	core->hw = hw;
@@ -3323,17 +3389,27 @@ struct clk *clk_register(struct device *dev, struct clk_hw *hw)
 
 	INIT_HLIST_HEAD(&core->clks);
 
-	hw->clk = __clk_create_clk(hw, NULL, NULL);
+	/*
+	 * Don't call clk_hw_create_clk() here because that would pin the
+	 * provider module to itself and prevent it from ever being removed.
+	 */
+	hw->clk = alloc_clk(core, NULL, NULL);
 	if (IS_ERR(hw->clk)) {
 		ret = PTR_ERR(hw->clk);
 		goto fail_parents;
 	}
 
+	clk_core_link_consumer(hw->core, hw->clk);
+
 	ret = __clk_core_init(core);
 	if (!ret)
 		return hw->clk;
 
-	__clk_free_clk(hw->clk);
+	clk_prepare_lock();
+	clk_core_unlink_consumer(hw->clk);
+	clk_prepare_unlock();
+
+	free_clk(hw->clk);
 	hw->clk = NULL;
 
 fail_parents:
@@ -3604,20 +3680,7 @@ EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);
 /*
  * clkdev helpers
  */
-int __clk_get(struct clk *clk)
-{
-	struct clk_core *core = !clk ? NULL : clk->core;
-
-	if (core) {
-		if (!try_module_get(core->owner))
-			return 0;
 
-		kref_get(&core->ref);
-	}
-	return 1;
-}
-
-/* keep in sync with __clk_free_clk */
 void __clk_put(struct clk *clk)
 {
 	struct module *owner;
@@ -3651,8 +3714,7 @@ void __clk_put(struct clk *clk)
 
 	module_put(owner);
 
-	kfree_const(clk->con_id);
-	kfree(clk);
+	free_clk(clk);
 }
 
 /***        clk rate change notifiers        ***/
@@ -4009,6 +4071,49 @@ void devm_of_clk_del_provider(struct device *dev)
 }
 EXPORT_SYMBOL(devm_of_clk_del_provider);
 
+/*
+ * Beware the return values when np is valid, but no clock provider is found.
+ * If name == NULL, the function returns -ENOENT.
+ * If name != NULL, the function returns -EINVAL. This is because
+ * of_parse_phandle_with_args() is called even if of_property_match_string()
+ * returns an error.
+ */
+static int of_parse_clkspec(const struct device_node *np, int index,
+			    const char *name, struct of_phandle_args *out_args)
+{
+	int ret = -ENOENT;
+
+	/* Walk up the tree of devices looking for a clock property that matches */
+	while (np) {
+		/*
+		 * For named clocks, first look up the name in the
+		 * "clock-names" property.  If it cannot be found, then index
+		 * will be an error code and of_parse_phandle_with_args() will
+		 * return -EINVAL.
+		 */
+		if (name)
+			index = of_property_match_string(np, "clock-names", name);
+		ret = of_parse_phandle_with_args(np, "clocks", "#clock-cells",
+						 index, out_args);
+		if (!ret)
+			break;
+		if (name && index >= 0)
+			break;
+
+		/*
+		 * No matching clock found on this node.  If the parent node
+		 * has a "clock-ranges" property, then we can try one of its
+		 * clocks.
+		 */
+		np = np->parent;
+		if (np && !of_get_property(np, "clock-ranges", NULL))
+			break;
+		index = 0;
+	}
+
+	return ret;
+}
+
 static struct clk_hw *
 __of_clk_get_hw_from_provider(struct of_clk_provider *provider,
 			      struct of_phandle_args *clkspec)
@@ -4024,36 +4129,26 @@ __of_clk_get_hw_from_provider(struct of_clk_provider *provider,
 	return __clk_get_hw(clk);
 }
 
-struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
-				       const char *dev_id, const char *con_id)
+static struct clk_hw *
+of_clk_get_hw_from_clkspec(struct of_phandle_args *clkspec)
 {
 	struct of_clk_provider *provider;
-	struct clk *clk = ERR_PTR(-EPROBE_DEFER);
-	struct clk_hw *hw;
+	struct clk_hw *hw = ERR_PTR(-EPROBE_DEFER);
 
 	if (!clkspec)
 		return ERR_PTR(-EINVAL);
 
-	/* Check if we have such a provider in our array */
 	mutex_lock(&of_clk_mutex);
 	list_for_each_entry(provider, &of_clk_providers, link) {
 		if (provider->node == clkspec->np) {
 			hw = __of_clk_get_hw_from_provider(provider, clkspec);
-			clk = __clk_create_clk(hw, dev_id, con_id);
-		}
-
-		if (!IS_ERR(clk)) {
-			if (!__clk_get(clk)) {
-				__clk_free_clk(clk);
-				clk = ERR_PTR(-ENOENT);
-			}
-
-			break;
+			if (!IS_ERR(hw))
+				break;
 		}
 	}
 	mutex_unlock(&of_clk_mutex);
 
-	return clk;
+	return hw;
 }
 
 /**
@@ -4066,10 +4161,62 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
  */
 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 {
-	return __of_clk_get_from_provider(clkspec, NULL, __func__);
+	struct clk_hw *hw = of_clk_get_hw_from_clkspec(clkspec);
+
+	return clk_hw_create_clk(NULL, hw, NULL, __func__);
 }
 EXPORT_SYMBOL_GPL(of_clk_get_from_provider);
 
+struct clk_hw *of_clk_get_hw(struct device_node *np, int index,
+			     const char *con_id)
+{
+	int ret;
+	struct clk_hw *hw;
+	struct of_phandle_args clkspec;
+
+	ret = of_parse_clkspec(np, index, con_id, &clkspec);
+	if (ret)
+		return ERR_PTR(ret);
+
+	hw = of_clk_get_hw_from_clkspec(&clkspec);
+	of_node_put(clkspec.np);
+
+	return hw;
+}
+
+static struct clk *__of_clk_get(struct device_node *np,
+				int index, const char *dev_id,
+				const char *con_id)
+{
+	struct clk_hw *hw = of_clk_get_hw(np, index, con_id);
+
+	return clk_hw_create_clk(NULL, hw, dev_id, con_id);
+}
+
+struct clk *of_clk_get(struct device_node *np, int index)
+{
+	return __of_clk_get(np, index, np->full_name, NULL);
+}
+EXPORT_SYMBOL(of_clk_get);
+
+/**
+ * of_clk_get_by_name() - Parse and lookup a clock referenced by a device node
+ * @np: pointer to clock consumer node
+ * @name: name of consumer's clock input, or NULL for the first clock reference
+ *
+ * This function parses the clocks and clock-names properties,
+ * and uses them to look up the struct clk from the registered list of clock
+ * providers.
+ */
+struct clk *of_clk_get_by_name(struct device_node *np, const char *name)
+{
+	if (!np)
+		return ERR_PTR(-ENOENT);
+
+	return __of_clk_get(np, -1, np->full_name, name);
+}
+EXPORT_SYMBOL(of_clk_get_by_name);
+
 /**
  * of_clk_get_parent_count() - Count the number of clocks a device node has
  * @np: device node to count