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 c28dd172f627..fd306c49194b 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 6c27ddac5adf..138a00a2a2d0 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 bb8e1f295835..623bf0e9a1e7 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;