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authorHans-Christian Egtvedt <egtvedt@samfundet.no>2013-09-16 18:56:41 +0530
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-09-30 20:18:45 +0200
commit848cb944213e88e4929a7efcc1c92bb6b6445353 (patch)
treec41d9a73c97159a6e028c983d6518677e712a8bc /drivers/cpufreq/at32ap-cpufreq.c
parent2e6a5c80e6fa8fd3af6c2ffc5ad6073e798a1690 (diff)
downloadop-kernel-dev-848cb944213e88e4929a7efcc1c92bb6b6445353.zip
op-kernel-dev-848cb944213e88e4929a7efcc1c92bb6b6445353.tar.gz
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>
Diffstat (limited to 'drivers/cpufreq/at32ap-cpufreq.c')
-rw-r--r--drivers/cpufreq/at32ap-cpufreq.c49
1 files changed, 46 insertions, 3 deletions
diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c
index e0c38d9..1d19fa5 100644
--- a/drivers/cpufreq/at32ap-cpufreq.c
+++ b/drivers/cpufreq/at32ap-cpufreq.c
@@ -19,8 +19,10 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
+#include <linux/slab.h>
static struct clk *cpuclk;
+static struct cpufreq_frequency_table *freq_table;
static int at32_verify_speed(struct cpufreq_policy *policy)
{
@@ -85,13 +87,17 @@ static int at32_set_target(struct cpufreq_policy *policy,
static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
+ unsigned int frequency, rate;
+ int retval, steps, i;
+
if (policy->cpu != 0)
return -EINVAL;
cpuclk = clk_get(NULL, "cpu");
if (IS_ERR(cpuclk)) {
pr_debug("cpufreq: could not get CPU clk\n");
- return PTR_ERR(cpuclk);
+ retval = PTR_ERR(cpuclk);
+ goto out_err;
}
policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
@@ -101,9 +107,46 @@ static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
- printk("cpufreq: AT32AP CPU frequency driver\n");
+ /*
+ * AVR32 CPU frequency rate scales in power of two between maximum and
+ * minimum, also add space for the table end marker.
+ *
+ * Further validate that the frequency is usable, and append it to the
+ * frequency table.
+ */
+ steps = fls(policy->cpuinfo.max_freq / policy->cpuinfo.min_freq) + 1;
+ freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
+ GFP_KERNEL);
+ if (!freq_table) {
+ retval = -ENOMEM;
+ goto out_err_put_clk;
+ }
- return 0;
+ frequency = policy->cpuinfo.max_freq;
+ for (i = 0; i < (steps - 1); i++) {
+ rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
+
+ if (rate != frequency)
+ freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+ else
+ freq_table[i].frequency = frequency;
+
+ frequency /= 2;
+ }
+
+ freq_table[steps - 1].frequency = CPUFREQ_TABLE_END;
+
+ retval = cpufreq_table_validate_and_show(policy, freq_table);
+ if (!retval) {
+ printk("cpufreq: AT32AP CPU frequency driver\n");
+ return 0;
+ }
+
+ kfree(freq_table);
+out_err_put_clk:
+ clk_put(cpuclk);
+out_err:
+ return retval;
}
static struct cpufreq_driver at32_driver = {
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