treewide: cleanup continuations and remove logging message whitespace
[linux-2.6.git] / arch / arm / plat-mxc / cpufreq.c
1 /*
2  * Copyright (C) 2010 Freescale Semiconductor, Inc. All Rights Reserved.
3  */
4
5 /*
6  * The code contained herein is licensed under the GNU General Public
7  * License. You may obtain a copy of the GNU General Public License
8  * Version 2 or later at the following locations:
9  *
10  * http://www.opensource.org/licenses/gpl-license.html
11  * http://www.gnu.org/copyleft/gpl.html
12  */
13
14 /*
15  * A driver for the Freescale Semiconductor i.MXC CPUfreq module.
16  * The CPUFREQ driver is for controlling CPU frequency. It allows you to change
17  * the CPU clock speed on the fly.
18  */
19
20 #include <linux/cpufreq.h>
21 #include <linux/clk.h>
22 #include <linux/err.h>
23 #include <linux/slab.h>
24 #include <mach/hardware.h>
25 #include <mach/clock.h>
26
27 #define CLK32_FREQ      32768
28 #define NANOSECOND      (1000 * 1000 * 1000)
29
30 struct cpu_op *(*get_cpu_op)(int *op);
31
32 static int cpu_freq_khz_min;
33 static int cpu_freq_khz_max;
34
35 static struct clk *cpu_clk;
36 static struct cpufreq_frequency_table *imx_freq_table;
37
38 static int cpu_op_nr;
39 static struct cpu_op *cpu_op_tbl;
40
41 static int set_cpu_freq(int freq)
42 {
43         int ret = 0;
44         int org_cpu_rate;
45
46         org_cpu_rate = clk_get_rate(cpu_clk);
47         if (org_cpu_rate == freq)
48                 return ret;
49
50         ret = clk_set_rate(cpu_clk, freq);
51         if (ret != 0) {
52                 printk(KERN_DEBUG "cannot set CPU clock rate\n");
53                 return ret;
54         }
55
56         return ret;
57 }
58
59 static int mxc_verify_speed(struct cpufreq_policy *policy)
60 {
61         if (policy->cpu != 0)
62                 return -EINVAL;
63
64         return cpufreq_frequency_table_verify(policy, imx_freq_table);
65 }
66
67 static unsigned int mxc_get_speed(unsigned int cpu)
68 {
69         if (cpu)
70                 return 0;
71
72         return clk_get_rate(cpu_clk) / 1000;
73 }
74
75 static int mxc_set_target(struct cpufreq_policy *policy,
76                           unsigned int target_freq, unsigned int relation)
77 {
78         struct cpufreq_freqs freqs;
79         int freq_Hz;
80         int ret = 0;
81         unsigned int index;
82
83         cpufreq_frequency_table_target(policy, imx_freq_table,
84                         target_freq, relation, &index);
85         freq_Hz = imx_freq_table[index].frequency * 1000;
86
87         freqs.old = clk_get_rate(cpu_clk) / 1000;
88         freqs.new = freq_Hz / 1000;
89         freqs.cpu = 0;
90         freqs.flags = 0;
91         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
92
93         ret = set_cpu_freq(freq_Hz);
94
95         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
96
97         return ret;
98 }
99
100 static int __init mxc_cpufreq_init(struct cpufreq_policy *policy)
101 {
102         int ret;
103         int i;
104
105         printk(KERN_INFO "i.MXC CPU frequency driver\n");
106
107         if (policy->cpu != 0)
108                 return -EINVAL;
109
110         if (!get_cpu_op)
111                 return -EINVAL;
112
113         cpu_clk = clk_get(NULL, "cpu_clk");
114         if (IS_ERR(cpu_clk)) {
115                 printk(KERN_ERR "%s: failed to get cpu clock\n", __func__);
116                 return PTR_ERR(cpu_clk);
117         }
118
119         cpu_op_tbl = get_cpu_op(&cpu_op_nr);
120
121         cpu_freq_khz_min = cpu_op_tbl[0].cpu_rate / 1000;
122         cpu_freq_khz_max = cpu_op_tbl[0].cpu_rate / 1000;
123
124         imx_freq_table = kmalloc(
125                 sizeof(struct cpufreq_frequency_table) * (cpu_op_nr + 1),
126                         GFP_KERNEL);
127         if (!imx_freq_table) {
128                 ret = -ENOMEM;
129                 goto err1;
130         }
131
132         for (i = 0; i < cpu_op_nr; i++) {
133                 imx_freq_table[i].index = i;
134                 imx_freq_table[i].frequency = cpu_op_tbl[i].cpu_rate / 1000;
135
136                 if ((cpu_op_tbl[i].cpu_rate / 1000) < cpu_freq_khz_min)
137                         cpu_freq_khz_min = cpu_op_tbl[i].cpu_rate / 1000;
138
139                 if ((cpu_op_tbl[i].cpu_rate / 1000) > cpu_freq_khz_max)
140                         cpu_freq_khz_max = cpu_op_tbl[i].cpu_rate / 1000;
141         }
142
143         imx_freq_table[i].index = i;
144         imx_freq_table[i].frequency = CPUFREQ_TABLE_END;
145
146         policy->cur = clk_get_rate(cpu_clk) / 1000;
147         policy->min = policy->cpuinfo.min_freq = cpu_freq_khz_min;
148         policy->max = policy->cpuinfo.max_freq = cpu_freq_khz_max;
149
150         /* Manual states, that PLL stabilizes in two CLK32 periods */
151         policy->cpuinfo.transition_latency = 2 * NANOSECOND / CLK32_FREQ;
152
153         ret = cpufreq_frequency_table_cpuinfo(policy, imx_freq_table);
154
155         if (ret < 0) {
156                 printk(KERN_ERR "%s: failed to register i.MXC CPUfreq with error code %d\n",
157                        __func__, ret);
158                 goto err;
159         }
160
161         cpufreq_frequency_table_get_attr(imx_freq_table, policy->cpu);
162         return 0;
163 err:
164         kfree(imx_freq_table);
165 err1:
166         clk_put(cpu_clk);
167         return ret;
168 }
169
170 static int mxc_cpufreq_exit(struct cpufreq_policy *policy)
171 {
172         cpufreq_frequency_table_put_attr(policy->cpu);
173
174         set_cpu_freq(cpu_freq_khz_max * 1000);
175         clk_put(cpu_clk);
176         kfree(imx_freq_table);
177         return 0;
178 }
179
180 static struct cpufreq_driver mxc_driver = {
181         .flags = CPUFREQ_STICKY,
182         .verify = mxc_verify_speed,
183         .target = mxc_set_target,
184         .get = mxc_get_speed,
185         .init = mxc_cpufreq_init,
186         .exit = mxc_cpufreq_exit,
187         .name = "imx",
188 };
189
190 static int __devinit mxc_cpufreq_driver_init(void)
191 {
192         return cpufreq_register_driver(&mxc_driver);
193 }
194
195 static void mxc_cpufreq_driver_exit(void)
196 {
197         cpufreq_unregister_driver(&mxc_driver);
198 }
199
200 module_init(mxc_cpufreq_driver_init);
201 module_exit(mxc_cpufreq_driver_exit);
202
203 MODULE_AUTHOR("Freescale Semiconductor Inc. Yong Shen <yong.shen@linaro.org>");
204 MODULE_DESCRIPTION("CPUfreq driver for i.MX");
205 MODULE_LICENSE("GPL");