diff options
| -rw-r--r-- | drivers/sh/clk/core.c | 75 | ||||
| -rw-r--r-- | include/linux/sh_clk.h | 4 |
2 files changed, 79 insertions, 0 deletions
diff --git a/drivers/sh/clk/core.c b/drivers/sh/clk/core.c index 861144360d8..b3840597ad6 100644 --- a/drivers/sh/clk/core.c +++ b/drivers/sh/clk/core.c @@ -541,6 +541,81 @@ 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->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->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) { diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h index 4dca992f309..cea0c38e7a6 100644 --- a/include/linux/sh_clk.h +++ b/include/linux/sh_clk.h @@ -122,6 +122,10 @@ int clk_rate_table_find(struct clk *clk, long clk_rate_div_range_round(struct clk *clk, unsigned int div_min, unsigned int div_max, unsigned long 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); + #define SH_CLK_MSTP32(_parent, _enable_reg, _enable_bit, _flags) \ { \ .parent = _parent, \ |