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/*
* Copyright (C) STMicroelectronics 2009
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Author: Sundar Iyer <sundar.iyer@stericsson.com>
* Author: Martin Persson <martin.persson@stericsson.com>
* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
static struct cpufreq_frequency_table *freq_table;
static struct clk *armss_clk;
static struct freq_attr *db8500_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static int db8500_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
unsigned int idx;
/* scale the target frequency to one of the extremes supported */
if (target_freq < policy->cpuinfo.min_freq)
target_freq = policy->cpuinfo.min_freq;
if (target_freq > policy->cpuinfo.max_freq)
target_freq = policy->cpuinfo.max_freq;
/* Lookup the next frequency */
if (cpufreq_frequency_table_target
(policy, freq_table, target_freq, relation, &idx)) {
return -EINVAL;
}
freqs.old = policy->cur;
freqs.new = freq_table[idx].frequency;
if (freqs.old == freqs.new)
return 0;
/* pre-change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
/* update armss clk frequency */
if (clk_set_rate(armss_clk, freq_table[idx].frequency * 1000)) {
pr_err("db8500-cpufreq: Failed to update armss clk\n");
return -EINVAL;
}
/* post change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
{
int i = 0;
unsigned long freq = clk_get_rate(armss_clk) / 1000;
while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
if (freq <= freq_table[i].frequency)
return freq_table[i].frequency;
i++;
}
/* We could not find a corresponding frequency. */
pr_err("db8500-cpufreq: Failed to find cpufreq speed\n");
return 0;
}
static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
{
int i = 0;
int res;
armss_clk = clk_get(NULL, "armss");
if (IS_ERR(armss_clk)) {
pr_err("db8500-cpufreq : Failed to get armss clk\n");
return PTR_ERR(armss_clk);
}
pr_info("db8500-cpufreq : Available frequencies:\n");
while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
i++;
}
/* get policy fields based on the table */
res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (!res)
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
else {
pr_err("db8500-cpufreq : Failed to read policy table\n");
clk_put(armss_clk);
return res;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = db8500_cpufreq_getspeed(policy->cpu);
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
/*
* FIXME : Need to take time measurement across the target()
* function with no/some/all drivers in the notification
* list.
*/
policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
/* policy sharing between dual CPUs */
cpumask_setall(policy->cpus);
return 0;
}
static struct cpufreq_driver db8500_cpufreq_driver = {
.flags = CPUFREQ_STICKY,
.verify = db8500_cpufreq_verify_speed,
.target = db8500_cpufreq_target,
.get = db8500_cpufreq_getspeed,
.init = db8500_cpufreq_init,
.name = "DB8500",
.attr = db8500_cpufreq_attr,
};
static int db8500_cpufreq_probe(struct platform_device *pdev)
{
freq_table = dev_get_platdata(&pdev->dev);
if (!freq_table) {
pr_err("db8500-cpufreq: Failed to fetch cpufreq table\n");
return -ENODEV;
}
return cpufreq_register_driver(&db8500_cpufreq_driver);
}
static struct platform_driver db8500_cpufreq_plat_driver = {
.driver = {
.name = "cpufreq-u8500",
.owner = THIS_MODULE,
},
.probe = db8500_cpufreq_probe,
};
static int __init db8500_cpufreq_register(void)
{
pr_info("cpufreq for DB8500 started\n");
return platform_driver_register(&db8500_cpufreq_plat_driver);
}
device_initcall(db8500_cpufreq_register);
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("cpufreq driver for DB8500");
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