tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 unsigned int dbx500_cpufreq_getspeed(unsigned int cpu)
30{
31 int i = 0;
32 unsigned long freq = clk_get_rate(armss_clk) / 1000;
33
34 /* The value is rounded to closest frequency in the defined table. */
35 while (freq_table[i + 1].frequency != CPUFREQ_TABLE_END) {
36 if (freq < freq_table[i].frequency +
37 (freq_table[i + 1].frequency - freq_table[i].frequency) / 2)
38 return freq_table[i].frequency;
39 i++;
40 }
41
42 return freq_table[i].frequency;
43}
44
45static int dbx500_cpufreq_init(struct cpufreq_policy *policy)
46{
47 return cpufreq_generic_init(policy, freq_table, 20 * 1000);
48}
49
50static struct cpufreq_driver dbx500_cpufreq_driver = {
51 .flags = CPUFREQ_STICKY | CPUFREQ_CONST_LOOPS,
52 .verify = cpufreq_generic_frequency_table_verify,
53 .target_index = dbx500_cpufreq_target,
54 .get = dbx500_cpufreq_getspeed,
55 .init = dbx500_cpufreq_init,
56 .name = "DBX500",
57 .attr = cpufreq_generic_attr,
58};
59
60static int dbx500_cpufreq_probe(struct platform_device *pdev)
61{
62 int i = 0;
63
64 freq_table = dev_get_platdata(&pdev->dev);
65 if (!freq_table) {
66 pr_err("dbx500-cpufreq: Failed to fetch cpufreq table\n");
67 return -ENODEV;
68 }
69
70 armss_clk = clk_get(&pdev->dev, "armss");
71 if (IS_ERR(armss_clk)) {
72 pr_err("dbx500-cpufreq: Failed to get armss clk\n");
73 return PTR_ERR(armss_clk);
74 }
75
76 pr_info("dbx500-cpufreq: Available frequencies:\n");
77 while (freq_table[i].frequency != CPUFREQ_TABLE_END) {
78 pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
79 i++;
80 }
81
82 return cpufreq_register_driver(&dbx500_cpufreq_driver);
83}
84
85static struct platform_driver dbx500_cpufreq_plat_driver = {
86 .driver = {
87 .name = "cpufreq-ux500",
88 .owner = THIS_MODULE,
89 },
90 .probe = dbx500_cpufreq_probe,
91};
92
93static int __init dbx500_cpufreq_register(void)
94{
95 return platform_driver_register(&dbx500_cpufreq_plat_driver);
96}
97device_initcall(dbx500_cpufreq_register);
98
99MODULE_LICENSE("GPL v2");
100MODULE_DESCRIPTION("cpufreq driver for DBX500");