Re: [PATCH] cpufreq: add frequency table to at32ap driver

On 13 August 2013 00:40, Hans-Christian Egtvedt egtvedt@samfundet.no wrote:

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

drivers/cpufreq/at32ap-cpufreq.c | 47 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c index 6544887..dbf3f3d 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 +87,19 @@ static int at32_set_target(struct cpufreq_policy *policy,

static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy) {

•   unsigned int frequency;
  

•   int retval;
  

•   int steps;
  

•   int 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 +109,46 @@ static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy) policy->min = policy->cpuinfo.min_freq; policy->max = policy->cpuinfo.max_freq;

•   /*
  

•    * 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;
  

•   }
  

•   frequency = policy->cpuinfo.max_freq;
  

•   for (i = 0; i < (steps - 1); i++) {
  

•           unsigned int rate = clk_round_rate(cpuclk, frequency * 1000);
  

•           rate /= 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_frequency_table_cpuinfo(policy, freq_table);
  

•   if (retval)
  

•           goto out_err_kfree;
  

•   printk("cpufreq: AT32AP CPU frequency driver\n");
  
    return 0;
  

+out_err_kfree:

•   kfree(freq_table);
  

+out_err_put_clk:

•   clk_put(cpuclk);
  

+out_err:

•   return retval;
  

}

static struct cpufreq_driver at32_driver = {

Thanks for your patch, I have folded below patch with your patch while applying..

diff --git a/drivers/cpufreq/at32ap-cpufreq.c b/drivers/cpufreq/at32ap-cpufreq.c index eaac7cb..c586d3e 100644 --- a/drivers/cpufreq/at32ap-cpufreq.c +++ b/drivers/cpufreq/at32ap-cpufreq.c @@ -87,10 +87,8 @@ static int at32_set_target(struct cpufreq_policy *policy,

static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy) { - unsigned int frequency; - int retval; - int steps; - int i; + unsigned int frequency, rate; + int retval, steps, i;

if (policy->cpu != 0) return -EINVAL; @@ -126,20 +124,23 @@ static int __init at32_cpufreq_driver_init(struct cpufreq_policy *policy)

frequency = policy->cpuinfo.max_freq; for (i = 0; i < (steps - 1); i++) { - unsigned int rate = clk_round_rate(cpuclk, frequency * 1000); - rate /= 1000; + 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_frequency_table_cpuinfo(policy, freq_table); if (retval) goto out_err_kfree;

+ cpufreq_frequency_table_get_attr(freq_table, policy->cpu); printk("cpufreq: AT32AP CPU frequency driver\n");

return 0;