cpufreq: at32ap: add frequency table
This patch adds a dynamically calculated frequency table to the at32ap driver. In short the architecture can scale in power of two between a maximum and minimum frequency. Min, max, and the steps in between are added to the table. Signed-off-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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@ -19,8 +19,10 @@
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#include <linux/clk.h>
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#include <linux/err.h>
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#include <linux/export.h>
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#include <linux/slab.h>
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static struct clk *cpuclk;
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static struct cpufreq_frequency_table *freq_table;
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static int at32_verify_speed(struct cpufreq_policy *policy)
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{
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@ -85,13 +87,17 @@ static int at32_set_target(struct cpufreq_policy *policy,
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static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
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{
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unsigned int frequency, rate;
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int retval, steps, i;
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if (policy->cpu != 0)
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return -EINVAL;
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cpuclk = clk_get(NULL, "cpu");
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if (IS_ERR(cpuclk)) {
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pr_debug("cpufreq: could not get CPU clk\n");
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return PTR_ERR(cpuclk);
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retval = PTR_ERR(cpuclk);
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goto out_err;
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}
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policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
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@ -101,9 +107,46 @@ static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
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policy->min = policy->cpuinfo.min_freq;
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policy->max = policy->cpuinfo.max_freq;
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printk("cpufreq: AT32AP CPU frequency driver\n");
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/*
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* AVR32 CPU frequency rate scales in power of two between maximum and
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* minimum, also add space for the table end marker.
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*
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* Further validate that the frequency is usable, and append it to the
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* frequency table.
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*/
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steps = fls(policy->cpuinfo.max_freq / policy->cpuinfo.min_freq) + 1;
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freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
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GFP_KERNEL);
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if (!freq_table) {
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retval = -ENOMEM;
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goto out_err_put_clk;
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}
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return 0;
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frequency = policy->cpuinfo.max_freq;
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for (i = 0; i < (steps - 1); i++) {
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rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
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if (rate != frequency)
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freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
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else
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freq_table[i].frequency = frequency;
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frequency /= 2;
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}
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freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
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retval = cpufreq_table_validate_and_show(policy, freq_table);
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if (!retval) {
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printk("cpufreq: AT32AP CPU frequency driver\n");
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return 0;
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}
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kfree(freq_table);
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out_err_put_clk:
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clk_put(cpuclk);
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out_err:
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return retval;
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}
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static struct cpufreq_driver at32_driver = {
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