summaryrefslogtreecommitdiff
path: root/drivers/cpufreq/at32ap-cpufreq.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/cpufreq/at32ap-cpufreq.c')
-rw-r--r--drivers/cpufreq/at32ap-cpufreq.c67
1 files changed, 48 insertions, 19 deletions
diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c
index e0c38d938997..7439deddd5cf 100644
--- a/drivers/cpufreq/at32ap-cpufreq.c
+++ b/drivers/cpufreq/at32ap-cpufreq.c
@@ -19,18 +19,10 @@
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/export.h>
+#include <linux/slab.h>
static struct clk *cpuclk;
-
-static int at32_verify_speed(struct cpufreq_policy *policy)
-{
- if (policy->cpu != 0)
- return -EINVAL;
-
- cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
- policy->cpuinfo.max_freq);
- return 0;
-}
+static struct cpufreq_frequency_table *freq_table;
static unsigned int at32_get_speed(unsigned int cpu)
{
@@ -85,31 +77,68 @@ static int at32_set_target(struct cpufreq_policy *policy,
static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)
{
+ unsigned int frequency, rate, min_freq;
+ 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;
- policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
+ min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
+ frequency = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = 0;
- policy->cur = at32_get_speed(0);
- 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(frequency / min_freq) + 1;
+ freq_table = kzalloc(steps * sizeof(struct cpufreq_frequency_table),
+ GFP_KERNEL);
+ if (!freq_table) {
+ retval = -ENOMEM;
+ goto out_err_put_clk;
+ }
+
+ for (i = 0; i < (steps - 1); i++) {
+ rate = clk_round_rate(cpuclk, frequency * 1000) / 1000;
- return 0;
+ 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 = {
.name = "at32ap",
.init = at32_cpufreq_driver_init,
- .verify = at32_verify_speed,
+ .verify = cpufreq_generic_frequency_table_verify,
.target = at32_set_target,
.get = at32_get_speed,
.flags = CPUFREQ_STICKY,