[PATCH v6 3/5] clk: shmobile: div6: Extract cpg_div6_register()

[Geert Uytterhoeven <geert+renesas@glider.be>]

Extract cpg_div6_register(), to allow registering div6 clocks from
another clock driver.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
---
v6:
  - Add Acked-by,

v5:
  - Document cpg_div6_register(),
  - Free clock on clock->parents allocation failure,
  - Add include guards to clk-div6.h,
  - Drop RFC state,

v4:
  - New.
---
 drivers/clk/shmobile/clk-div6.c | 132 ++++++++++++++++++++++++++--------------
 drivers/clk/shmobile/clk-div6.h |   7 +++
 2 files changed, 94 insertions(+), 45 deletions(-)
 create mode 100644 drivers/clk/shmobile/clk-div6.h

diff --git a/drivers/clk/shmobile/clk-div6.c b/drivers/clk/shmobile/clk-div6.c
index 57016ff9c585fc6e..9999947694509d58 100644
--- a/drivers/clk/shmobile/clk-div6.c
+++ b/drivers/clk/shmobile/clk-div6.c
@@ -18,6 +18,8 @@
 #include <linux/of_address.h>
 #include <linux/slab.h>
 
+#include "clk-div6.h"
+
 #define CPG_DIV6_CKSTP		BIT(8)
 #define CPG_DIV6_DIV(d)		((d) & 0x3f)
 #define CPG_DIV6_DIV_MASK	0x3f
@@ -172,60 +174,44 @@ static const struct clk_ops cpg_div6_clock_ops = {
 	.set_rate = cpg_div6_clock_set_rate,
 };
 
-static void __init cpg_div6_clock_init(struct device_node *np)
+
+/**
+ * cpg_div6_register - Register a DIV6 clock
+ * @name: Name of the DIV6 clock
+ * @num_parents: Number of parent clocks of the DIV6 clock (1, 4, or 8)
+ * @parent_names: Array containing the names of the parent clocks
+ * @reg: Mapped register used to control the DIV6 clock
+ */
+struct clk * __init cpg_div6_register(const char *name,
+				      unsigned int num_parents,
+				      const char **parent_names,
+				      void __iomem *reg)
 {
-	unsigned int num_parents, valid_parents;
-	const char **parent_names;
+	unsigned int valid_parents;
 	struct clk_init_data init;
 	struct div6_clock *clock;
-	const char *clk_name = np->name;
 	struct clk *clk;
 	unsigned int i;
 
 	clock = kzalloc(sizeof(*clock), GFP_KERNEL);
 	if (!clock)
-		return;
+		return ERR_PTR(-ENOMEM);
 
-	num_parents = of_clk_get_parent_count(np);
-	if (num_parents < 1) {
-		pr_err("%s: no parent found for %s DIV6 clock\n",
-		       __func__, np->name);
-		return;
+	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
+				       GFP_KERNEL);
+	if (!clock->parents) {
+		clk = ERR_PTR(-ENOMEM);
+		goto free_clock;
 	}
 
-	clock->parents = kmalloc_array(num_parents, sizeof(*clock->parents),
-		GFP_KERNEL);
-	parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
-				GFP_KERNEL);
-	if (!parent_names)
-		return;
+	clock->reg = reg;
 
-	/* Remap the clock register and read the divisor. Disabling the
-	 * clock overwrites the divisor, so we need to cache its value for the
-	 * enable operation.
+	/*
+	 * Read the divisor. Disabling the clock overwrites the divisor, so we
+	 * need to cache its value for the enable operation.
 	 */
-	clock->reg = of_iomap(np, 0);
-	if (clock->reg = NULL) {
-		pr_err("%s: failed to map %s DIV6 clock register\n",
-		       __func__, np->name);
-		goto error;
-	}
-
 	clock->div = (clk_readl(clock->reg) & CPG_DIV6_DIV_MASK) + 1;
 
-	/* Parse the DT properties. */
-	of_property_read_string(np, "clock-output-names", &clk_name);
-
-	for (i = 0, valid_parents = 0; i < num_parents; i++) {
-		const char *name = of_clk_get_parent_name(np, i);
-
-		if (name) {
-			parent_names[valid_parents] = name;
-			clock->parents[valid_parents] = i;
-			valid_parents++;
-		}
-	}
-
 	switch (num_parents) {
 	case 1:
 		/* fixed parent clock */
@@ -243,12 +229,22 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 		break;
 	default:
 		pr_err("%s: invalid number of parents for DIV6 clock %s\n",
-		       __func__, np->name);
-		goto error;
+		       __func__, name);
+		clk = ERR_PTR(-EINVAL);
+		goto free_parents;
+	}
+
+	/* Filter out invalid parents */
+	for (i = 0, valid_parents = 0; i < num_parents; i++) {
+		if (parent_names[i]) {
+			parent_names[valid_parents] = parent_names[i];
+			clock->parents[valid_parents] = i;
+			valid_parents++;
+		}
 	}
 
 	/* Register the clock. */
-	init.name = clk_name;
+	init.name = name;
 	init.ops = &cpg_div6_clock_ops;
 	init.flags = CLK_IS_BASIC;
 	init.parent_names = parent_names;
@@ -257,6 +253,53 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 	clock->hw.init = &init;
 
 	clk = clk_register(NULL, &clock->hw);
+	if (IS_ERR(clk))
+		goto free_parents;
+
+	return clk;
+
+free_parents:
+	kfree(clock->parents);
+free_clock:
+	kfree(clock);
+	return clk;
+}
+
+static void __init cpg_div6_clock_init(struct device_node *np)
+{
+	unsigned int num_parents;
+	const char **parent_names;
+	const char *clk_name = np->name;
+	void __iomem *reg;
+	struct clk *clk;
+	unsigned int i;
+
+	num_parents = of_clk_get_parent_count(np);
+	if (num_parents < 1) {
+		pr_err("%s: no parent found for %s DIV6 clock\n",
+		       __func__, np->name);
+		return;
+	}
+
+	parent_names = kmalloc_array(num_parents, sizeof(*parent_names),
+				GFP_KERNEL);
+	if (!parent_names)
+		return;
+
+	reg = of_iomap(np, 0);
+	if (reg = NULL) {
+		pr_err("%s: failed to map %s DIV6 clock register\n",
+		       __func__, np->name);
+		goto error;
+	}
+
+	/* Parse the DT properties. */
+	of_property_read_string(np, "clock-output-names", &clk_name);
+
+	for (i = 0; i < num_parents; i++)
+		parent_names[i] = of_clk_get_parent_name(np, i);
+
+	clk = cpg_div6_register(clk_name, num_parents, parent_names, reg);
 	if (IS_ERR(clk)) {
 		pr_err("%s: failed to register %s DIV6 clock (%ld)\n",
 		       __func__, np->name, PTR_ERR(clk));
@@ -269,9 +312,8 @@ static void __init cpg_div6_clock_init(struct device_node *np)
 	return;
 
 error:
-	if (clock->reg)
-		iounmap(clock->reg);
+	if (reg)
+		iounmap(reg);
 	kfree(parent_names);
-	kfree(clock);
 }
 CLK_OF_DECLARE(cpg_div6_clk, "renesas,cpg-div6-clock", cpg_div6_clock_init);
diff --git a/drivers/clk/shmobile/clk-div6.h b/drivers/clk/shmobile/clk-div6.h
new file mode 100644
index 0000000000000000..9a85a95188daa813
--- /dev/null
+++ b/drivers/clk/shmobile/clk-div6.h
@@ -0,0 +1,7 @@
+#ifndef __SHMOBILE_CLK_DIV6_H__
+#define __SHMOBILE_CLK_DIV6_H__
+
+struct clk *cpg_div6_register(const char *name, unsigned int num_parents,
+			      const char **parent_names, void __iomem *reg);
+
+#endif
-- 
1.9.1