2 * CPU frequency scaling for OMAP using OPP information
4 * Copyright (C) 2005 Nokia Corporation
5 * Written by Tony Lindgren <tony@atomide.com>
7 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
9 * Copyright (C) 2007-2011 Texas Instruments, Inc.
10 * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2 as
14 * published by the Free Software Foundation.
16 #include <linux/types.h>
17 #include <linux/kernel.h>
18 #include <linux/sched.h>
19 #include <linux/cpufreq.h>
20 #include <linux/delay.h>
21 #include <linux/init.h>
22 #include <linux/err.h>
23 #include <linux/clk.h>
25 #include <linux/pm_opp.h>
26 #include <linux/cpu.h>
27 #include <linux/module.h>
28 #include <linux/platform_device.h>
29 #include <linux/regulator/consumer.h>
31 #include <asm/smp_plat.h>
34 /* OPP tolerance in percentage */
35 #define OPP_TOLERANCE 4
37 static struct cpufreq_frequency_table
*freq_table
;
38 static atomic_t freq_table_users
= ATOMIC_INIT(0);
39 static struct clk
*mpu_clk
;
40 static struct device
*mpu_dev
;
41 static struct regulator
*mpu_reg
;
43 static unsigned int omap_getspeed(unsigned int cpu
)
50 rate
= clk_get_rate(mpu_clk
) / 1000;
54 static int omap_target(struct cpufreq_policy
*policy
, unsigned int index
)
57 struct dev_pm_opp
*opp
;
58 unsigned long freq
, volt
= 0, volt_old
= 0, tol
= 0;
59 unsigned int old_freq
, new_freq
;
61 old_freq
= omap_getspeed(policy
->cpu
);
62 new_freq
= freq_table
[index
].frequency
;
64 freq
= new_freq
* 1000;
65 ret
= clk_round_rate(mpu_clk
, freq
);
66 if (IS_ERR_VALUE(ret
)) {
68 "CPUfreq: Cannot find matching frequency for %lu\n",
76 opp
= dev_pm_opp_find_freq_ceil(mpu_dev
, &freq
);
79 dev_err(mpu_dev
, "%s: unable to find MPU OPP for %d\n",
83 volt
= dev_pm_opp_get_voltage(opp
);
85 tol
= volt
* OPP_TOLERANCE
/ 100;
86 volt_old
= regulator_get_voltage(mpu_reg
);
89 dev_dbg(mpu_dev
, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n",
90 old_freq
/ 1000, volt_old
? volt_old
/ 1000 : -1,
91 new_freq
/ 1000, volt
? volt
/ 1000 : -1);
93 /* scaling up? scale voltage before frequency */
94 if (mpu_reg
&& (new_freq
> old_freq
)) {
95 r
= regulator_set_voltage(mpu_reg
, volt
- tol
, volt
+ tol
);
97 dev_warn(mpu_dev
, "%s: unable to scale voltage up.\n",
103 ret
= clk_set_rate(mpu_clk
, new_freq
* 1000);
105 /* scaling down? scale voltage after frequency */
106 if (mpu_reg
&& (new_freq
< old_freq
)) {
107 r
= regulator_set_voltage(mpu_reg
, volt
- tol
, volt
+ tol
);
109 dev_warn(mpu_dev
, "%s: unable to scale voltage down.\n",
111 clk_set_rate(mpu_clk
, old_freq
* 1000);
119 static inline void freq_table_free(void)
121 if (atomic_dec_and_test(&freq_table_users
))
122 dev_pm_opp_free_cpufreq_table(mpu_dev
, &freq_table
);
125 static int omap_cpu_init(struct cpufreq_policy
*policy
)
129 mpu_clk
= clk_get(NULL
, "cpufreq_ck");
131 return PTR_ERR(mpu_clk
);
134 result
= dev_pm_opp_init_cpufreq_table(mpu_dev
, &freq_table
);
137 "%s: cpu%d: failed creating freq table[%d]\n",
138 __func__
, policy
->cpu
, result
);
143 atomic_inc_return(&freq_table_users
);
145 /* FIXME: what's the actual transition time? */
146 result
= cpufreq_generic_init(policy
, freq_table
, 300 * 1000);
156 static int omap_cpu_exit(struct cpufreq_policy
*policy
)
158 cpufreq_frequency_table_put_attr(policy
->cpu
);
164 static struct cpufreq_driver omap_driver
= {
165 .flags
= CPUFREQ_STICKY
,
166 .verify
= cpufreq_generic_frequency_table_verify
,
167 .target_index
= omap_target
,
168 .get
= omap_getspeed
,
169 .init
= omap_cpu_init
,
170 .exit
= omap_cpu_exit
,
172 .attr
= cpufreq_generic_attr
,
175 static int omap_cpufreq_probe(struct platform_device
*pdev
)
177 mpu_dev
= get_cpu_device(0);
179 pr_warning("%s: unable to get the mpu device\n", __func__
);
183 mpu_reg
= regulator_get(mpu_dev
, "vcc");
184 if (IS_ERR(mpu_reg
)) {
185 pr_warning("%s: unable to get MPU regulator\n", __func__
);
189 * Ensure physical regulator is present.
190 * (e.g. could be dummy regulator.)
192 if (regulator_get_voltage(mpu_reg
) < 0) {
193 pr_warn("%s: physical regulator not present for MPU\n",
195 regulator_put(mpu_reg
);
200 return cpufreq_register_driver(&omap_driver
);
203 static int omap_cpufreq_remove(struct platform_device
*pdev
)
205 return cpufreq_unregister_driver(&omap_driver
);
208 static struct platform_driver omap_cpufreq_platdrv
= {
210 .name
= "omap-cpufreq",
211 .owner
= THIS_MODULE
,
213 .probe
= omap_cpufreq_probe
,
214 .remove
= omap_cpufreq_remove
,
216 module_platform_driver(omap_cpufreq_platdrv
);
218 MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
219 MODULE_LICENSE("GPL");