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/delay.h>
  15 #include <linux/slab.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/clk.h>
  18
  19 static struct cpufreq_frequency_table *freq_table;
  20 static struct clk *armss_clk;
  21
  22 static int dbx500_cpufreq_target(struct cpufreq_policy *policy,
  23                                 unsigned int index)
  24 {
  25         /* update armss clk frequency */
  26         return clk_set_rate(armss_clk, freq_table[index].frequency * 1000);
  27 }
  28
  29 static int dbx500_cpufreq_init(struct cpufreq_policy *policy)
  30 {
  31         policy->clk = armss_clk;
  32         return cpufreq_generic_init(policy, freq_table, 20 * 1000);
  33 }
  34
  35 static struct cpufreq_driver dbx500_cpufreq_driver = {
  36         .flags  = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS |
  37                         CPUFREQ_NEED_INITIAL_FREQ_CHECK,
  38         .verify = cpufreq_generic_frequency_table_verify,
  39         .target_index = dbx500_cpufreq_target,
  40         .get    = cpufreq_generic_get,
  41         .init   = dbx500_cpufreq_init,
  42         .name   = "DBX500",
  43         .attr   = cpufreq_generic_attr,
  44 };
  45
  46 static int dbx500_cpufreq_probe(struct platform_device *pdev)
  47 {
  48         struct cpufreq_frequency_table *pos;
  49
  50         freq_table = dev_get_platdata(&pdev->dev);
  51         if (!freq_table) {
  52                 pr_err("dbx500-cpufreq: Failed to fetch cpufreq table\n");
  53                 return -ENODEV;
  54         }
  55
  56         armss_clk = clk_get(&pdev->dev, "armss");
  57         if (IS_ERR(armss_clk)) {
  58                 pr_err("dbx500-cpufreq: Failed to get armss clk\n");
  59                 return PTR_ERR(armss_clk);
  60         }
  61
  62         pr_info("dbx500-cpufreq: Available frequencies:\n");
  63         cpufreq_for_each_entry(pos, freq_table)
  64                 pr_info("  %d Mhz\n", pos->frequency / 1000);
  65
  66         return cpufreq_register_driver(&dbx500_cpufreq_driver);
  67 }
  68
  69 static struct platform_driver dbx500_cpufreq_plat_driver = {
  70         .driver = {
  71                 .name = "cpufreq-ux500",
  72         },
  73         .probe = dbx500_cpufreq_probe,
  74 };
  75
  76 static int __init dbx500_cpufreq_register(void)
  77 {
  78         return platform_driver_register(&dbx500_cpufreq_plat_driver);
  79 }
  80 device_initcall(dbx500_cpufreq_register);
  81
  82 MODULE_LICENSE("GPL v2");
  83 MODULE_DESCRIPTION("cpufreq driver for DBX500");