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Merge tag 'nfsd-4.3-2' of git://linux-nfs.org/~bfields/linux
[karo-tx-linux.git] / drivers / cpufreq / davinci-cpufreq.c
1 /*
2  * CPU frequency scaling for DaVinci
3  *
4  * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
5  *
6  * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
7  *
8  *  Copyright (C) 2005 Nokia Corporation
9  *  Written by Tony Lindgren <tony@atomide.com>
10  *
11  *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
12  *
13  * Copyright (C) 2007-2008 Texas Instruments, Inc.
14  * Updated to support OMAP3
15  * Rajendra Nayak <rnayak@ti.com>
16  *
17  * This program is free software; you can redistribute it and/or modify
18  * it under the terms of the GNU General Public License version 2 as
19  * published by the Free Software Foundation.
20  */
21 #include <linux/types.h>
22 #include <linux/cpufreq.h>
23 #include <linux/init.h>
24 #include <linux/err.h>
25 #include <linux/clk.h>
26 #include <linux/platform_device.h>
27 #include <linux/export.h>
28
29 #include <mach/hardware.h>
30 #include <mach/cpufreq.h>
31 #include <mach/common.h>
32
33 struct davinci_cpufreq {
34         struct device *dev;
35         struct clk *armclk;
36         struct clk *asyncclk;
37         unsigned long asyncrate;
38 };
39 static struct davinci_cpufreq cpufreq;
40
41 static int davinci_verify_speed(struct cpufreq_policy *policy)
42 {
43         struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
44         struct cpufreq_frequency_table *freq_table = pdata->freq_table;
45         struct clk *armclk = cpufreq.armclk;
46
47         if (freq_table)
48                 return cpufreq_frequency_table_verify(policy, freq_table);
49
50         if (policy->cpu)
51                 return -EINVAL;
52
53         cpufreq_verify_within_cpu_limits(policy);
54         policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000;
55         policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000;
56         cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
57                                                 policy->cpuinfo.max_freq);
58         return 0;
59 }
60
61 static int davinci_target(struct cpufreq_policy *policy, unsigned int idx)
62 {
63         struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
64         struct clk *armclk = cpufreq.armclk;
65         unsigned int old_freq, new_freq;
66         int ret = 0;
67
68         old_freq = policy->cur;
69         new_freq = pdata->freq_table[idx].frequency;
70
71         /* if moving to higher frequency, up the voltage beforehand */
72         if (pdata->set_voltage && new_freq > old_freq) {
73                 ret = pdata->set_voltage(idx);
74                 if (ret)
75                         return ret;
76         }
77
78         ret = clk_set_rate(armclk, idx);
79         if (ret)
80                 return ret;
81
82         if (cpufreq.asyncclk) {
83                 ret = clk_set_rate(cpufreq.asyncclk, cpufreq.asyncrate);
84                 if (ret)
85                         return ret;
86         }
87
88         /* if moving to lower freq, lower the voltage after lowering freq */
89         if (pdata->set_voltage && new_freq < old_freq)
90                 pdata->set_voltage(idx);
91
92         return 0;
93 }
94
95 static int davinci_cpu_init(struct cpufreq_policy *policy)
96 {
97         int result = 0;
98         struct davinci_cpufreq_config *pdata = cpufreq.dev->platform_data;
99         struct cpufreq_frequency_table *freq_table = pdata->freq_table;
100
101         if (policy->cpu != 0)
102                 return -EINVAL;
103
104         /* Finish platform specific initialization */
105         if (pdata->init) {
106                 result = pdata->init();
107                 if (result)
108                         return result;
109         }
110
111         policy->clk = cpufreq.armclk;
112
113         /*
114          * Time measurement across the target() function yields ~1500-1800us
115          * time taken with no drivers on notification list.
116          * Setting the latency to 2000 us to accommodate addition of drivers
117          * to pre/post change notification list.
118          */
119         return cpufreq_generic_init(policy, freq_table, 2000 * 1000);
120 }
121
122 static struct cpufreq_driver davinci_driver = {
123         .flags          = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
124         .verify         = davinci_verify_speed,
125         .target_index   = davinci_target,
126         .get            = cpufreq_generic_get,
127         .init           = davinci_cpu_init,
128         .name           = "davinci",
129         .attr           = cpufreq_generic_attr,
130 };
131
132 static int __init davinci_cpufreq_probe(struct platform_device *pdev)
133 {
134         struct davinci_cpufreq_config *pdata = pdev->dev.platform_data;
135         struct clk *asyncclk;
136
137         if (!pdata)
138                 return -EINVAL;
139         if (!pdata->freq_table)
140                 return -EINVAL;
141
142         cpufreq.dev = &pdev->dev;
143
144         cpufreq.armclk = clk_get(NULL, "arm");
145         if (IS_ERR(cpufreq.armclk)) {
146                 dev_err(cpufreq.dev, "Unable to get ARM clock\n");
147                 return PTR_ERR(cpufreq.armclk);
148         }
149
150         asyncclk = clk_get(cpufreq.dev, "async");
151         if (!IS_ERR(asyncclk)) {
152                 cpufreq.asyncclk = asyncclk;
153                 cpufreq.asyncrate = clk_get_rate(asyncclk);
154         }
155
156         return cpufreq_register_driver(&davinci_driver);
157 }
158
159 static int __exit davinci_cpufreq_remove(struct platform_device *pdev)
160 {
161         clk_put(cpufreq.armclk);
162
163         if (cpufreq.asyncclk)
164                 clk_put(cpufreq.asyncclk);
165
166         return cpufreq_unregister_driver(&davinci_driver);
167 }
168
169 static struct platform_driver davinci_cpufreq_driver = {
170         .driver = {
171                 .name    = "cpufreq-davinci",
172         },
173         .remove = __exit_p(davinci_cpufreq_remove),
174 };
175
176 int __init davinci_cpufreq_init(void)
177 {
178         return platform_driver_probe(&davinci_cpufreq_driver,
179                                                         davinci_cpufreq_probe);
180 }
181