![Ulf Hansson](/assets/img/avatar_default.png)
Using the armss clk to update the frequency makes the driver no more directly dependant on the prmcu API. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Mike Turquette <mturquette@linaro.org>
180 lines
4.5 KiB
C
180 lines
4.5 KiB
C
/*
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* Copyright (C) STMicroelectronics 2009
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* Copyright (C) ST-Ericsson SA 2010
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*
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* License Terms: GNU General Public License v2
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* Author: Sundar Iyer <sundar.iyer@stericsson.com>
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* Author: Martin Persson <martin.persson@stericsson.com>
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* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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#include <linux/slab.h>
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#include <linux/platform_device.h>
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#include <linux/clk.h>
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#include <mach/id.h>
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static struct cpufreq_frequency_table *freq_table;
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static struct clk *armss_clk;
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static struct freq_attr *db8500_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, freq_table);
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}
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static int db8500_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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unsigned int idx;
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/* scale the target frequency to one of the extremes supported */
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if (target_freq < policy->cpuinfo.min_freq)
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target_freq = policy->cpuinfo.min_freq;
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if (target_freq > policy->cpuinfo.max_freq)
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target_freq = policy->cpuinfo.max_freq;
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/* Lookup the next frequency */
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if (cpufreq_frequency_table_target
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(policy, freq_table, target_freq, relation, &idx)) {
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return -EINVAL;
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}
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freqs.old = policy->cur;
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freqs.new = freq_table[idx].frequency;
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if (freqs.old == freqs.new)
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return 0;
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/* pre-change notification */
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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/* update armss clk frequency */
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if (clk_set_rate(armss_clk, freq_table[idx].frequency * 1000)) {
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pr_err("db8500-cpufreq: Failed to update armss clk\n");
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return -EINVAL;
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}
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/* post change notification */
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for_each_cpu(freqs.cpu, policy->cpus)
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return 0;
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}
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static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
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{
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int i = 0;
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unsigned long freq = clk_get_rate(armss_clk) / 1000;
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while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
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if (freq <= freq_table[i].frequency)
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return freq_table[i].frequency;
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i++;
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}
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/* We could not find a corresponding frequency. */
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pr_err("db8500-cpufreq: Failed to find cpufreq speed\n");
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return 0;
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}
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static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
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{
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int i = 0;
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int res;
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armss_clk = clk_get(NULL, "armss");
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if (IS_ERR(armss_clk)) {
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pr_err("db8500-cpufreq : Failed to get armss clk\n");
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return PTR_ERR(armss_clk);
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}
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pr_info("db8500-cpufreq : Available frequencies:\n");
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while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
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pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
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i++;
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}
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/* get policy fields based on the table */
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res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
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if (!res)
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cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
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else {
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pr_err("db8500-cpufreq : Failed to read policy table\n");
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clk_put(armss_clk);
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return res;
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}
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policy->min = policy->cpuinfo.min_freq;
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policy->max = policy->cpuinfo.max_freq;
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policy->cur = db8500_cpufreq_getspeed(policy->cpu);
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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/*
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* FIXME : Need to take time measurement across the target()
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* function with no/some/all drivers in the notification
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* list.
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*/
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policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
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/* policy sharing between dual CPUs */
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cpumask_copy(policy->cpus, cpu_present_mask);
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policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
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return 0;
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}
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static struct cpufreq_driver db8500_cpufreq_driver = {
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.flags = CPUFREQ_STICKY,
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.verify = db8500_cpufreq_verify_speed,
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.target = db8500_cpufreq_target,
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.get = db8500_cpufreq_getspeed,
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.init = db8500_cpufreq_init,
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.name = "DB8500",
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.attr = db8500_cpufreq_attr,
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};
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static int db8500_cpufreq_probe(struct platform_device *pdev)
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{
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freq_table = dev_get_platdata(&pdev->dev);
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if (!freq_table) {
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pr_err("db8500-cpufreq: Failed to fetch cpufreq table\n");
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return -ENODEV;
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}
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return cpufreq_register_driver(&db8500_cpufreq_driver);
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}
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static struct platform_driver db8500_cpufreq_plat_driver = {
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.driver = {
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.name = "cpufreq-u8500",
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.owner = THIS_MODULE,
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},
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.probe = db8500_cpufreq_probe,
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};
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static int __init db8500_cpufreq_register(void)
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{
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if (!cpu_is_u8500_family())
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return -ENODEV;
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pr_info("cpufreq for DB8500 started\n");
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return platform_driver_register(&db8500_cpufreq_plat_driver);
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}
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device_initcall(db8500_cpufreq_register);
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MODULE_LICENSE("GPL v2");
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MODULE_DESCRIPTION("cpufreq driver for DB8500");
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