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authorMagnus Damm <damm@igel.co.jp>2009-05-25 08:10:28 +0000
committerPaul Mundt <lethal@linux-sh.org>2009-05-26 17:08:39 +0900
commitc94a85746f7bdc13035acdf88c130d7b6fa41bde (patch)
tree8aff35100dcb0a62c82452357ea267f92376dc7a /arch/sh/kernel/cpu
parentc9904dd15922f349b5f06839e34b1723d4a75940 (diff)
sh: add shared clock framework frequency table code
Add SuperH-specific clock framework helper functions: - clk_rate_table_build() - build cpufreq table from divisors/multipliers - clk_rate_table_round() - use cpufreq table to find matching frequency Signed-off-by: Magnus Damm <damm@igel.co.jp> Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel/cpu')
-rw-r--r--arch/sh/kernel/cpu/clock.c75
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/clock.c b/arch/sh/kernel/cpu/clock.c
index 012d23476a7..59764d6c5f4 100644
--- a/arch/sh/kernel/cpu/clock.c
+++ b/arch/sh/kernel/cpu/clock.c
@@ -29,6 +29,7 @@
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/debugfs.h>
+#include <linux/cpufreq.h>
#include <asm/clock.h>
#include <asm/machvec.h>
@@ -36,6 +37,80 @@ static LIST_HEAD(clock_list);
static DEFINE_SPINLOCK(clock_lock);
static DEFINE_MUTEX(clock_list_sem);
+void clk_rate_table_build(struct clk *clk,
+ struct cpufreq_frequency_table *freq_table,
+ int nr_freqs,
+ struct clk_div_mult_table *src_table,
+ unsigned long *bitmap)
+{
+ unsigned long mult, div;
+ unsigned long freq;
+ int i;
+
+ for (i = 0; i < nr_freqs; i++) {
+ div = 1;
+ mult = 1;
+
+ if (src_table->divisors && i < src_table->nr_divisors)
+ div = src_table->divisors[i];
+
+ if (src_table->multipliers && i < src_table->nr_multipliers)
+ mult = src_table->multipliers[i];
+
+ if (!div || !mult || (bitmap && !test_bit(i, bitmap)))
+ freq = CPUFREQ_ENTRY_INVALID;
+ else
+ freq = clk->parent->rate * mult / div;
+
+ freq_table[i].index = i;
+ freq_table[i].frequency = freq;
+ }
+
+ /* Termination entry */
+ freq_table[i].index = i;
+ freq_table[i].frequency = CPUFREQ_TABLE_END;
+}
+
+long clk_rate_table_round(struct clk *clk,
+ struct cpufreq_frequency_table *freq_table,
+ unsigned long rate)
+{
+ unsigned long rate_error, rate_error_prev = ~0UL;
+ unsigned long rate_best_fit = rate;
+ unsigned long highest, lowest;
+ int i;
+
+ highest = lowest = 0;
+
+ for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++) {
+ unsigned long freq = freq_table[i].frequency;
+
+ if (freq == CPUFREQ_ENTRY_INVALID)
+ continue;
+
+ if (freq > highest)
+ highest = freq;
+ if (freq < lowest)
+ lowest = freq;
+
+ rate_error = abs(freq - rate);
+ if (rate_error < rate_error_prev) {
+ rate_best_fit = freq;
+ rate_error_prev = rate_error;
+ }
+
+ if (rate_error == 0)
+ break;
+ }
+
+ if (rate >= highest)
+ rate_best_fit = highest;
+ if (rate <= lowest)
+ rate_best_fit = lowest;
+
+ return rate_best_fit;
+}
+
/* Used for clocks that always have same value as the parent clock */
unsigned long followparent_recalc(struct clk *clk)
{