2 * CPU frequency scaling for DaVinci
4 * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
6 * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows:
8 * Copyright (C) 2005 Nokia Corporation
9 * Written by Tony Lindgren <tony@atomide.com>
11 * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
13 * Copyright (C) 2007-2008 Texas Instruments, Inc.
14 * Updated to support OMAP3
15 * Rajendra Nayak <rnayak@ti.com>
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.
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>
28 #include <mach/hardware.h>
29 #include <mach/cpufreq.h>
30 #include <mach/common.h>
34 struct davinci_cpufreq
{
38 unsigned long asyncrate
;
40 static struct davinci_cpufreq cpufreq
;
42 static int davinci_verify_speed(struct cpufreq_policy
*policy
)
44 struct davinci_cpufreq_config
*pdata
= cpufreq
.dev
->platform_data
;
45 struct cpufreq_frequency_table
*freq_table
= pdata
->freq_table
;
46 struct clk
*armclk
= cpufreq
.armclk
;
49 return cpufreq_frequency_table_verify(policy
, freq_table
);
54 cpufreq_verify_within_limits(policy
, policy
->cpuinfo
.min_freq
,
55 policy
->cpuinfo
.max_freq
);
57 policy
->min
= clk_round_rate(armclk
, policy
->min
* 1000) / 1000;
58 policy
->max
= clk_round_rate(armclk
, policy
->max
* 1000) / 1000;
59 cpufreq_verify_within_limits(policy
, policy
->cpuinfo
.min_freq
,
60 policy
->cpuinfo
.max_freq
);
64 static unsigned int davinci_getspeed(unsigned int cpu
)
69 return clk_get_rate(cpufreq
.armclk
) / 1000;
72 static int davinci_target(struct cpufreq_policy
*policy
,
73 unsigned int target_freq
, unsigned int relation
)
77 struct cpufreq_freqs freqs
;
78 struct davinci_cpufreq_config
*pdata
= cpufreq
.dev
->platform_data
;
79 struct clk
*armclk
= cpufreq
.armclk
;
82 * Ensure desired rate is within allowed range. Some govenors
83 * (ondemand) will just pass target_freq=0 to get the minimum.
85 if (target_freq
< policy
->cpuinfo
.min_freq
)
86 target_freq
= policy
->cpuinfo
.min_freq
;
87 if (target_freq
> policy
->cpuinfo
.max_freq
)
88 target_freq
= policy
->cpuinfo
.max_freq
;
90 freqs
.old
= davinci_getspeed(0);
91 freqs
.new = clk_round_rate(armclk
, target_freq
* 1000) / 1000;
94 if (freqs
.old
== freqs
.new)
97 cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER
,
98 dev_driver_string(cpufreq
.dev
),
99 "transition: %u --> %u\n", freqs
.old
, freqs
.new);
101 ret
= cpufreq_frequency_table_target(policy
, pdata
->freq_table
,
102 freqs
.new, relation
, &idx
);
106 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
108 /* if moving to higher frequency, up the voltage beforehand */
109 if (pdata
->set_voltage
&& freqs
.new > freqs
.old
) {
110 ret
= pdata
->set_voltage(idx
);
115 ret
= clk_set_rate(armclk
, idx
);
119 if (cpufreq
.asyncclk
) {
120 ret
= clk_set_rate(cpufreq
.asyncclk
, cpufreq
.asyncrate
);
125 /* if moving to lower freq, lower the voltage after lowering freq */
126 if (pdata
->set_voltage
&& freqs
.new < freqs
.old
)
127 pdata
->set_voltage(idx
);
130 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
135 static int __init
davinci_cpu_init(struct cpufreq_policy
*policy
)
138 struct davinci_cpufreq_config
*pdata
= cpufreq
.dev
->platform_data
;
139 struct cpufreq_frequency_table
*freq_table
= pdata
->freq_table
;
141 if (policy
->cpu
!= 0)
144 /* Finish platform specific initialization */
146 result
= pdata
->init();
151 policy
->cur
= policy
->min
= policy
->max
= davinci_getspeed(0);
154 result
= cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
156 cpufreq_frequency_table_get_attr(freq_table
,
159 policy
->cpuinfo
.min_freq
= policy
->min
;
160 policy
->cpuinfo
.max_freq
= policy
->max
;
163 policy
->min
= policy
->cpuinfo
.min_freq
;
164 policy
->max
= policy
->cpuinfo
.max_freq
;
165 policy
->cur
= davinci_getspeed(0);
168 * Time measurement across the target() function yields ~1500-1800us
169 * time taken with no drivers on notification list.
170 * Setting the latency to 2000 us to accomodate addition of drivers
171 * to pre/post change notification list.
173 policy
->cpuinfo
.transition_latency
= 2000 * 1000;
177 static int davinci_cpu_exit(struct cpufreq_policy
*policy
)
179 cpufreq_frequency_table_put_attr(policy
->cpu
);
183 static struct freq_attr
*davinci_cpufreq_attr
[] = {
184 &cpufreq_freq_attr_scaling_available_freqs
,
188 static struct cpufreq_driver davinci_driver
= {
189 .flags
= CPUFREQ_STICKY
,
190 .verify
= davinci_verify_speed
,
191 .target
= davinci_target
,
192 .get
= davinci_getspeed
,
193 .init
= davinci_cpu_init
,
194 .exit
= davinci_cpu_exit
,
196 .attr
= davinci_cpufreq_attr
,
199 static int __init
davinci_cpufreq_probe(struct platform_device
*pdev
)
201 struct davinci_cpufreq_config
*pdata
= pdev
->dev
.platform_data
;
202 struct clk
*asyncclk
;
206 if (!pdata
->freq_table
)
209 cpufreq
.dev
= &pdev
->dev
;
211 cpufreq
.armclk
= clk_get(NULL
, "arm");
212 if (IS_ERR(cpufreq
.armclk
)) {
213 dev_err(cpufreq
.dev
, "Unable to get ARM clock\n");
214 return PTR_ERR(cpufreq
.armclk
);
217 asyncclk
= clk_get(cpufreq
.dev
, "async");
218 if (!IS_ERR(asyncclk
)) {
219 cpufreq
.asyncclk
= asyncclk
;
220 cpufreq
.asyncrate
= clk_get_rate(asyncclk
);
223 return cpufreq_register_driver(&davinci_driver
);
226 static int __exit
davinci_cpufreq_remove(struct platform_device
*pdev
)
228 clk_put(cpufreq
.armclk
);
230 if (cpufreq
.asyncclk
)
231 clk_put(cpufreq
.asyncclk
);
233 return cpufreq_unregister_driver(&davinci_driver
);
236 static struct platform_driver davinci_cpufreq_driver
= {
238 .name
= "cpufreq-davinci",
239 .owner
= THIS_MODULE
,
241 .remove
= __exit_p(davinci_cpufreq_remove
),
244 static int __init
davinci_cpufreq_init(void)
246 return platform_driver_probe(&davinci_cpufreq_driver
,
247 davinci_cpufreq_probe
);
249 late_initcall(davinci_cpufreq_init
);