clk: basic: improve parent_names & return errors

This patch is the basic clk version of 'clk: core: copy parent_names &
return error codes'.

The registration functions are changed to allow the core code to copy
the array of strings and allow platforms to declare those arrays as
__initdata.

This patch also converts all of the basic clk registration functions to
return error codes which better aligns them with the existing clk.h api.
Signed-off-by: Mike Turquette <mturquette@linaro.org>

drivers/clk/clk-divider.c

@@ -153,6 +153,18 @@ const struct clk_ops clk_divider_ops = {
 };
 EXPORT_SYMBOL_GPL(clk_divider_ops);
 
+/**
+ * clk_register_divider - register a divider clock with the clock framework
+ * @dev: device registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @reg: register address to adjust divider
+ * @shift: number of bits to shift the bitfield
+ * @width: width of the bitfield
+ * @clk_divider_flags: divider-specific flags for this clock
+ * @lock: shared register lock for this clock
+ */
 struct clk *clk_register_divider(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 shift, u8 width,
@@ -161,11 +173,11 @@ struct clk *clk_register_divider(struct device *dev, const char *name,
 	struct clk_divider *div;
 	struct clk *clk;
 
+	/* allocate the divider */
 	div = kzalloc(sizeof(struct clk_divider), GFP_KERNEL);
-
 	if (!div) {
 		pr_err("%s: could not allocate divider clk\n", __func__);
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	/* struct clk_divider assignments */
@@ -175,23 +187,15 @@ struct clk *clk_register_divider(struct device *dev, const char *name,
 	div->flags = clk_divider_flags;
 	div->lock = lock;
 
-	if (parent_name) {
-		div->parent[0] = kstrdup(parent_name, GFP_KERNEL);
-		if (!div->parent[0])
-			goto out;
-	}
-
+	/* register the clock */
 	clk = clk_register(dev, name,
 			&clk_divider_ops, &div->hw,
-			div->parent,
+			(parent_name ? &parent_name: NULL),
 			(parent_name ? 1 : 0),
 			flags);
-	if (clk)
-		return clk;
 
-out:
-	kfree(div->parent[0]);
-	kfree(div);
+	if (IS_ERR(clk))
+		kfree(div);
 
-	return NULL;
+	return clk;
 }

drivers/clk/clk-fixed-rate.c

@@ -38,16 +38,23 @@ const struct clk_ops clk_fixed_rate_ops = {
 };
 EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
 
+/**
+ * clk_register_fixed_rate - register fixed-rate clock with the clock framework
+ * @dev: device that is registering this clock
+ * @name: name of this clock
+ * @parent_name: name of clock's parent
+ * @flags: framework-specific flags
+ * @fixed_rate: non-adjustable clock rate
+ */
 struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		unsigned long fixed_rate)
 {
 	struct clk_fixed_rate *fixed;
-	char **parent_names = NULL;
-	u8 len;
+	struct clk *clk;
 
+	/* allocate fixed-rate clock */
 	fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
-
 	if (!fixed) {
 		pr_err("%s: could not allocate fixed clk\n", __func__);
 		return ERR_PTR(-ENOMEM);
@@ -56,26 +63,15 @@ struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
 	/* struct clk_fixed_rate assignments */
 	fixed->fixed_rate = fixed_rate;
 
-	if (parent_name) {
-		parent_names = kmalloc(sizeof(char *), GFP_KERNEL);
-
-		if (! parent_names)
-			goto out;
-
-		len = sizeof(char) * strlen(parent_name);
-
-		parent_names[0] = kmalloc(len, GFP_KERNEL);
-
-		if (!parent_names[0])
-			goto out;
-
-		strncpy(parent_names[0], parent_name, len);
-	}
-
-out:
-	return clk_register(dev, name,
+	/* register the clock */
+	clk = clk_register(dev, name,
 			&clk_fixed_rate_ops, &fixed->hw,
-			parent_names,
+			(parent_name ? &parent_name : NULL),
 			(parent_name ? 1 : 0),
 			flags);
+
+	if (IS_ERR(clk))
+		kfree(fixed);
+
+	return clk;
 }

drivers/clk/clk-gate.c

@@ -105,6 +105,17 @@ const struct clk_ops clk_gate_ops = {
 };
 EXPORT_SYMBOL_GPL(clk_gate_ops);
 
+/**
+ * clk_register_gate - register a gate clock with the clock framework
+ * @dev: device that is registering this clock
+ * @name: name of this clock
+ * @parent_name: name of this clock's parent
+ * @flags: framework-specific flags for this clock
+ * @reg: register address to control gating of this clock
+ * @bit_idx: which bit in the register controls gating of this clock
+ * @clk_gate_flags: gate-specific flags for this clock
+ * @lock: shared register lock for this clock
+ */
 struct clk *clk_register_gate(struct device *dev, const char *name,
 		const char *parent_name, unsigned long flags,
 		void __iomem *reg, u8 bit_idx,
@@ -113,11 +124,11 @@ struct clk *clk_register_gate(struct device *dev, const char *name,
 	struct clk_gate *gate;
 	struct clk *clk;
 
+	/* allocate the gate */
 	gate = kzalloc(sizeof(struct clk_gate), GFP_KERNEL);
-
 	if (!gate) {
 		pr_err("%s: could not allocate gated clk\n", __func__);
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	/* struct clk_gate assignments */
@@ -126,22 +137,15 @@ struct clk *clk_register_gate(struct device *dev, const char *name,
 	gate->flags = clk_gate_flags;
 	gate->lock = lock;
 
-	if (parent_name) {
-		gate->parent[0] = kstrdup(parent_name, GFP_KERNEL);
-		if (!gate->parent[0])
-			goto out;
-	}
-
+	/* register the clock */
 	clk = clk_register(dev, name,
 			&clk_gate_ops, &gate->hw,
-			gate->parent,
+			(parent_name ? &parent_name : NULL),
 			(parent_name ? 1 : 0),
 			flags);
-	if (clk)
-		return clk;
-out:
-	kfree(gate->parent[0]);
-	kfree(gate);
 
-	return NULL;
+	if (IS_ERR(clk))
+		kfree(gate);
+
+	return clk;
 }

drivers/clk/clk-mux.c

@@ -94,9 +94,10 @@ struct clk *clk_register_mux(struct device *dev, const char *name,
 		u8 clk_mux_flags, spinlock_t *lock)
 {
 	struct clk_mux *mux;
+	struct clk *clk;
 
+	/* allocate the mux */
 	mux = kzalloc(sizeof(struct clk_mux), GFP_KERNEL);
-
 	if (!mux) {
 		pr_err("%s: could not allocate mux clk\n", __func__);
 		return ERR_PTR(-ENOMEM);
@@ -109,6 +110,11 @@ struct clk *clk_register_mux(struct device *dev, const char *name,
 	mux->flags = clk_mux_flags;
 	mux->lock = lock;
 
-	return clk_register(dev, name, &clk_mux_ops, &mux->hw,
+	clk = clk_register(dev, name, &clk_mux_ops, &mux->hw,
 			parent_names, num_parents, flags);
+
+	if (IS_ERR(clk))
+		kfree(mux);
+
+	return clk;
 }

include/linux/clk-provider.h

@@ -176,7 +176,6 @@ struct clk_gate {
 	u8		bit_idx;
 	u8		flags;
 	spinlock_t	*lock;
-	const char	*parent[1];
 };
 
 #define CLK_GATE_SET_TO_DISABLE		BIT(0)
@@ -214,7 +213,6 @@ struct clk_divider {
 	u8		width;
 	u8		flags;
 	spinlock_t	*lock;
-	const char	*parent[1];
 };
 
 #define CLK_DIVIDER_ONE_BASED		BIT(0)