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path: root/drivers/sh/clk/core.c
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Diffstat (limited to 'drivers/sh/clk/core.c')
-rw-r--r--drivers/sh/clk/core.c96
1 files changed, 94 insertions, 2 deletions
diff --git a/drivers/sh/clk/core.c b/drivers/sh/clk/core.c
index fd0d1b98901c..09615b51d591 100644
--- a/drivers/sh/clk/core.c
+++ b/drivers/sh/clk/core.c
@@ -90,8 +90,8 @@ struct clk_rate_round_data {
static long clk_rate_round_helper(struct clk_rate_round_data *rounder)
{
unsigned long rate_error, rate_error_prev = ~0UL;
- unsigned long rate_best_fit = rounder->rate;
unsigned long highest, lowest, freq;
+ long rate_best_fit = -ENOENT;
int i;
highest = 0;
@@ -146,7 +146,7 @@ long clk_rate_table_round(struct clk *clk,
};
if (clk->nr_freqs < 1)
- return 0;
+ return -ENOSYS;
return clk_rate_round_helper(&table_round);
}
@@ -541,6 +541,98 @@ long clk_round_rate(struct clk *clk, unsigned long rate)
}
EXPORT_SYMBOL_GPL(clk_round_rate);
+long clk_round_parent(struct clk *clk, unsigned long target,
+ unsigned long *best_freq, unsigned long *parent_freq,
+ unsigned int div_min, unsigned int div_max)
+{
+ struct cpufreq_frequency_table *freq, *best = NULL;
+ unsigned long error = ULONG_MAX, freq_high, freq_low, div;
+ struct clk *parent = clk_get_parent(clk);
+
+ if (!parent) {
+ *parent_freq = 0;
+ *best_freq = clk_round_rate(clk, target);
+ return abs(target - *best_freq);
+ }
+
+ for (freq = parent->freq_table; freq->frequency != CPUFREQ_TABLE_END;
+ freq++) {
+ if (freq->frequency == CPUFREQ_ENTRY_INVALID)
+ continue;
+
+ if (unlikely(freq->frequency / target <= div_min - 1)) {
+ unsigned long freq_max;
+
+ freq_max = (freq->frequency + div_min / 2) / div_min;
+ if (error > target - freq_max) {
+ error = target - freq_max;
+ best = freq;
+ if (best_freq)
+ *best_freq = freq_max;
+ }
+
+ pr_debug("too low freq %lu, error %lu\n", freq->frequency,
+ target - freq_max);
+
+ if (!error)
+ break;
+
+ continue;
+ }
+
+ if (unlikely(freq->frequency / target >= div_max)) {
+ unsigned long freq_min;
+
+ freq_min = (freq->frequency + div_max / 2) / div_max;
+ if (error > freq_min - target) {
+ error = freq_min - target;
+ best = freq;
+ if (best_freq)
+ *best_freq = freq_min;
+ }
+
+ pr_debug("too high freq %lu, error %lu\n", freq->frequency,
+ freq_min - target);
+
+ if (!error)
+ break;
+
+ continue;
+ }
+
+ div = freq->frequency / target;
+ freq_high = freq->frequency / div;
+ freq_low = freq->frequency / (div + 1);
+
+ if (freq_high - target < error) {
+ error = freq_high - target;
+ best = freq;
+ if (best_freq)
+ *best_freq = freq_high;
+ }
+
+ if (target - freq_low < error) {
+ error = target - freq_low;
+ best = freq;
+ if (best_freq)
+ *best_freq = freq_low;
+ }
+
+ pr_debug("%u / %lu = %lu, / %lu = %lu, best %lu, parent %u\n",
+ freq->frequency, div, freq_high, div + 1, freq_low,
+ *best_freq, best->frequency);
+
+ if (!error)
+ break;
+ }
+
+ if (parent_freq)
+ *parent_freq = best->frequency;
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(clk_round_parent);
+
#ifdef CONFIG_PM
static int clks_sysdev_suspend(struct sys_device *dev, pm_message_t state)
{