drivers/cpufreq/dbx500-cpufreq.c

   1 /*
   2  * Copyright (C) STMicroelectronics 2009
   3  * Copyright (C) ST-Ericsson SA 2010-2012
   4  *
   5  * License Terms: GNU General Public License v2
   6  * Author: Sundar Iyer <sundar.iyer@stericsson.com>
   7  * Author: Martin Persson <martin.persson@stericsson.com>
   8  * Author: Jonas Aaberg <jonas.aberg@stericsson.com>
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/cpu_cooling.h>
  15 #include <linux/delay.h>
  16 #include <linux/slab.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/clk.h>
  19
  20 static struct cpufreq_frequency_table *freq_table;
  21 static struct clk *armss_clk;
  22 static struct thermal_cooling_device *cdev;
  23
  24 static int dbx500_cpufreq_target(struct cpufreq_policy *policy,
  25                                 unsigned int index)
  26 {
  27         /* update armss clk frequency */
  28         return clk_set_rate(armss_clk, freq_table[index].frequency * 1000);
  29 }
  30
  31 static int dbx500_cpufreq_init(struct cpufreq_policy *policy)
  32 {
  33         policy->clk = armss_clk;
  34         return cpufreq_generic_init(policy, freq_table, 20 * 1000);
  35 }
  36
  37 static int dbx500_cpufreq_exit(struct cpufreq_policy *policy)
  38 {
  39         if (!IS_ERR(cdev))
  40                 cpufreq_cooling_unregister(cdev);
  41         return 0;
  42 }
  43
  44 static void dbx500_cpufreq_ready(struct cpufreq_policy *policy)
  45 {
  46         cdev = cpufreq_cooling_register(policy);
  47         if (IS_ERR(cdev))
  48                 pr_err("Failed to register cooling device %ld\n", PTR_ERR(cdev));
  49         else
  50                 pr_info("Cooling device registered: %s\n", cdev->type);
  51 }
  52
  53 static struct cpufreq_driver dbx500_cpufreq_driver = {
  54         .flags  = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS |
  55                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
  56         .verify = cpufreq_generic_frequency_table_verify,
  57         .target_index = dbx500_cpufreq_target,
  58         .get    = cpufreq_generic_get,
  59         .init   = dbx500_cpufreq_init,
  60         .exit  = dbx500_cpufreq_exit,
  61         .ready  = dbx500_cpufreq_ready,
  62         .name   = "DBX500",
  63         .attr   = cpufreq_generic_attr,
  64 };
  65
  66 static int dbx500_cpufreq_probe(struct platform_device *pdev)
  67 {
  68         struct cpufreq_frequency_table *pos;
  69
  70         freq_table = dev_get_platdata(&pdev->dev);
  71         if (!freq_table) {
  72                 pr_err("dbx500-cpufreq: Failed to fetch cpufreq table\n");
  73                 return -ENODEV;
  74         }
  75
  76         armss_clk = clk_get(&pdev->dev, "armss");
  77         if (IS_ERR(armss_clk)) {
  78                 pr_err("dbx500-cpufreq: Failed to get armss clk\n");
  79                 return PTR_ERR(armss_clk);
  80         }
  81
  82         pr_info("dbx500-cpufreq: Available frequencies:\n");
  83         cpufreq_for_each_entry(pos, freq_table)
  84                 pr_info("  %d Mhz\n", pos->frequency / 1000);
  85
  86         return cpufreq_register_driver(&dbx500_cpufreq_driver);
  87 }
  88
  89 static struct platform_driver dbx500_cpufreq_plat_driver = {
  90         .driver = {
  91                 .name = "cpufreq-ux500",
  92         },
  93         .probe = dbx500_cpufreq_probe,
  94 };
  95
  96 static int __init dbx500_cpufreq_register(void)
  97 {
  98         return platform_driver_register(&dbx500_cpufreq_plat_driver);
  99 }
 100 device_initcall(dbx500_cpufreq_register);
 101
 102 MODULE_LICENSE("GPL v2");
 103 MODULE_DESCRIPTION("cpufreq driver for DBX500");