avr32: Replace static clock list with dynamic linked list

This replaces the at32_clock_list array with a linked list.
Clocks can now be registered (added) to the list.

Signed-off-by: Alex Raimondi <raimondi@miromico.ch>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>

3 files changed, 58 insertions, 24 deletions

diff --git a/arch/avr32/mach-at32ap/at32ap700x.c b/arch/avr32/mach-at32ap/at32ap700x.c
index c28dd172f62..fd306c49194 100644
--- a/arch/avr32/mach-at32ap/at32ap700x.c
+++ b/arch/avr32/mach-at32ap/at32ap700x.c
@@ -2028,7 +2028,7 @@ static struct clk gclk4 = {
 	.index		= 4,
 };
 
-struct clk *at32_clock_list[] = {
+static __initdata struct clk *init_clocks[] = {
 	&osc32k,
 	&osc0,
 	&osc1,
@@ -2092,7 +2092,6 @@ struct clk *at32_clock_list[] = {
 	&gclk3,
 	&gclk4,
 };
-unsigned int at32_nr_clocks = ARRAY_SIZE(at32_clock_list);
 
 void __init setup_platform(void)
 {
@@ -2123,14 +2122,19 @@ void __init setup_platform(void)
 	genclk_init_parent(&abdac0_sample_clk);
 
 	/*
-	 * Turn on all clocks that have at least one user already, and
-	 * turn off everything else. We only do this for module
-	 * clocks, and even though it isn't particularly pretty to
-	 * check the address of the mode function, it should do the
-	 * trick...
+	 * Build initial dynamic clock list by registering all clocks
+	 * from the array.
+	 * At the same time, turn on all clocks that have at least one
+	 * user already, and turn off everything else. We only do this
+	 * for module clocks, and even though it isn't particularly
+	 * pretty to  check the address of the mode function, it should
+	 * do the trick...
 	 */
-	for (i = 0; i < ARRAY_SIZE(at32_clock_list); i++) {
-		struct clk *clk = at32_clock_list[i];
+	for (i = 0; i < ARRAY_SIZE(init_clocks); i++) {
+		struct clk *clk = init_clocks[i];
+
+		/* first, register clock */
+		at32_clk_register(clk);
 
 		if (clk->users == 0)
 			continue;
diff --git a/arch/avr32/mach-at32ap/clock.c b/arch/avr32/mach-at32ap/clock.c
index 6c27ddac5ad..138a00a2a2d 100644
--- a/arch/avr32/mach-at32ap/clock.c
+++ b/arch/avr32/mach-at32ap/clock.c
@@ -15,24 +15,40 @@
 #include <linux/err.h>
 #include <linux/device.h>
 #include <linux/string.h>
+#include <linux/list.h>
 
 #include <mach/chip.h>
 
 #include "clock.h"
 
+/* at32 clock list */
+static LIST_HEAD(at32_clock_list);
+
 static DEFINE_SPINLOCK(clk_lock);
+static DEFINE_SPINLOCK(clk_list_lock);
+
+void at32_clk_register(struct clk *clk)
+{
+	spin_lock(&clk_list_lock);
+	/* add the new item to the end of the list */
+	list_add_tail(&clk->list, &at32_clock_list);
+	spin_unlock(&clk_list_lock);
+}
 
 struct clk *clk_get(struct device *dev, const char *id)
 {
-	int i;
+	struct clk *clk;
 
-	for (i = 0; i < at32_nr_clocks; i++) {
-		struct clk *clk = at32_clock_list[i];
+	spin_lock(&clk_list_lock);
 
-		if (clk->dev == dev && strcmp(id, clk->name) == 0)
+	list_for_each_entry(clk, &at32_clock_list, list) {
+		if (clk->dev == dev && strcmp(id, clk->name) == 0) {
+			spin_unlock(&clk_list_lock);
 			return clk;
+		}
 	}
 
+	spin_unlock(&clk_list_lock);
 	return ERR_PTR(-ENOENT);
 }
 EXPORT_SYMBOL(clk_get);
@@ -203,8 +219,8 @@ dump_clock(struct clk *parent, struct clkinf *r)
 
 	/* cost of this scan is small, but not linear... */
 	r->nest = nest + NEST_DELTA;
-	for (i = 3; i < at32_nr_clocks; i++) {
-		clk = at32_clock_list[i];
+
+	list_for_each_entry(clk, &at32_clock_list, list) {
 		if (clk->parent == parent)
 			dump_clock(clk, r);
 	}
@@ -215,6 +231,7 @@ static int clk_show(struct seq_file *s, void *unused)
 {
 	struct clkinf	r;
 	int		i;
+	struct clk 	*clk;
 
 	/* show all the power manager registers */
 	seq_printf(s, "MCCTRL  = %8x\n", pm_readl(MCCTRL));
@@ -234,14 +251,25 @@ static int clk_show(struct seq_file *s, void *unused)
 
 	seq_printf(s, "\n");
 
-	/* show clock tree as derived from the three oscillators
-	 * we "know" are at the head of the list
-	 */
 	r.s = s;
 	r.nest = 0;
-	dump_clock(at32_clock_list[0], &r);
-	dump_clock(at32_clock_list[1], &r);
-	dump_clock(at32_clock_list[2], &r);
+	/* protected from changes on the list while dumping */
+	spin_lock(&clk_list_lock);
+
+	/* show clock tree as derived from the three oscillators */
+	clk = clk_get(NULL, "osc32k");
+	dump_clock(clk, &r);
+	clk_put(clk);
+
+	clk = clk_get(NULL, "osc0");
+	dump_clock(clk, &r);
+	clk_put(clk);
+
+	clk = clk_get(NULL, "osc1");
+	dump_clock(clk, &r);
+	clk_put(clk);
+
+	spin_unlock(&clk_list_lock);
 
 	return 0;
 }
diff --git a/arch/avr32/mach-at32ap/clock.h b/arch/avr32/mach-at32ap/clock.h
index bb8e1f29583..623bf0e9a1e 100644
--- a/arch/avr32/mach-at32ap/clock.h
+++ b/arch/avr32/mach-at32ap/clock.h
@@ -12,8 +12,13 @@
  * published by the Free Software Foundation.
  */
 #include <linux/clk.h>
+#include <linux/list.h>
+
+
+void at32_clk_register(struct clk *clk);
 
 struct clk {
+	struct list_head list;		/* linking element */
 	const char	*name;		/* Clock name/function */
 	struct device	*dev;		/* Device the clock is used by */
 	struct clk	*parent;	/* Parent clock, if any */
@@ -25,6 +30,3 @@ struct clk {
 	u16		users;		/* Enabled if non-zero */
 	u16		index;		/* Sibling index */
 };
-
-extern struct clk *at32_clock_list[];
-extern unsigned int at32_nr_clocks;