LXR linux/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
  19static struct cpufreq_frequency_table *freq_table;
  20static struct clk *armss_clk;
  21
  22static 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
  29static 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
  35static 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
  46static 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
  69static struct platform_driver dbx500_cpufreq_plat_driver = {
  70        .driver = {
  71                .name = "cpufreq-ux500",
  72        },
  73        .probe = dbx500_cpufreq_probe,
  74};
  75
  76static int __init dbx500_cpufreq_register(void)
  77{
  78        return platform_driver_register(&dbx500_cpufreq_plat_driver);
  79}
  80device_initcall(dbx500_cpufreq_register);
  81
  82MODULE_LICENSE("GPL v2");
  83MODULE_DESCRIPTION("cpufreq driver for DBX500");
  84