diff options
Diffstat (limited to 'drivers/cpufreq/dbx500-cpufreq.c')
| -rw-r--r-- | drivers/cpufreq/dbx500-cpufreq.c | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/drivers/cpufreq/dbx500-cpufreq.c b/drivers/cpufreq/dbx500-cpufreq.c new file mode 100644 index 00000000000..72f0c3efa76 --- /dev/null +++ b/drivers/cpufreq/dbx500-cpufreq.c @@ -0,0 +1,174 @@ +/* + * Copyright (C) STMicroelectronics 2009 + * Copyright (C) ST-Ericsson SA 2010-2012 + * + * 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 *dbx500_cpufreq_attr[] = { + &cpufreq_freq_attr_scaling_available_freqs, + NULL, +}; + +static int dbx500_cpufreq_verify_speed(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, freq_table); +} + +static int dbx500_cpufreq_target(struct cpufreq_policy *policy, + unsigned int target_freq, + unsigned int relation) +{ + struct cpufreq_freqs freqs; + unsigned int idx; + int ret; + + /* 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 */ + ret = clk_set_rate(armss_clk, freqs.new * 1000); + + if (ret) { + pr_err("dbx500-cpufreq: Failed to set armss_clk to %d Hz: error %d\n", + freqs.new * 1000, ret); + return ret; + } + + /* post change notification */ + for_each_cpu(freqs.cpu, policy->cpus) + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + + return 0; +} + +static unsigned int dbx500_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("dbx500-cpufreq: Failed to find cpufreq speed\n"); + return 0; +} + +static int __cpuinit dbx500_cpufreq_init(struct cpufreq_policy *policy) +{ + int res; + + /* 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("dbx500-cpufreq: Failed to read policy table\n"); + return res; + } + + policy->min = policy->cpuinfo.min_freq; + policy->max = policy->cpuinfo.max_freq; + policy->cur = dbx500_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 dbx500_cpufreq_driver = { + .flags = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS, + .verify = dbx500_cpufreq_verify_speed, + .target = dbx500_cpufreq_target, + .get = dbx500_cpufreq_getspeed, + .init = dbx500_cpufreq_init, + .name = "DBX500", + .attr = dbx500_cpufreq_attr, +}; + +static int dbx500_cpufreq_probe(struct platform_device *pdev) +{ + int i = 0; + + freq_table = dev_get_platdata(&pdev->dev); + if (!freq_table) { + pr_err("dbx500-cpufreq: Failed to fetch cpufreq table\n"); + return -ENODEV; + } + + armss_clk = clk_get(&pdev->dev, "armss"); + if (IS_ERR(armss_clk)) { + pr_err("dbx500-cpufreq: Failed to get armss clk\n"); + return PTR_ERR(armss_clk); + } + + pr_info("dbx500-cpufreq: Available frequencies:\n"); + while (freq_table[i].frequency != CPUFREQ_TABLE_END) { + pr_info(" %d Mhz\n", freq_table[i].frequency/1000); + i++; + } + + return cpufreq_register_driver(&dbx500_cpufreq_driver); +} + +static struct platform_driver dbx500_cpufreq_plat_driver = { + .driver = { + .name = "cpufreq-ux500", + .owner = THIS_MODULE, + }, + .probe = dbx500_cpufreq_probe, +}; + +static int __init dbx500_cpufreq_register(void) +{ + return platform_driver_register(&dbx500_cpufreq_plat_driver); +} +device_initcall(dbx500_cpufreq_register); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("cpufreq driver for DBX500"); |