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>
27 #include <linux/export.h>
29 #include <mach/hardware.h>
30 #include <mach/cpufreq.h>
31 #include <mach/common.h>
33 struct davinci_cpufreq
{
37 unsigned long asyncrate
;
39 static struct davinci_cpufreq cpufreq
;
41 static int davinci_verify_speed(struct cpufreq_policy
*policy
)
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
;
48 return cpufreq_frequency_table_verify(policy
, freq_table
);
53 cpufreq_verify_within_limits(policy
, policy
->cpuinfo
.min_freq
,
54 policy
->cpuinfo
.max_freq
);
56 policy
->min
= clk_round_rate(armclk
, policy
->min
* 1000) / 1000;
57 policy
->max
= clk_round_rate(armclk
, policy
->max
* 1000) / 1000;
58 cpufreq_verify_within_limits(policy
, policy
->cpuinfo
.min_freq
,
59 policy
->cpuinfo
.max_freq
);
63 static unsigned int davinci_getspeed(unsigned int cpu
)
68 return clk_get_rate(cpufreq
.armclk
) / 1000;
71 static int davinci_target(struct cpufreq_policy
*policy
,
72 unsigned int target_freq
, unsigned int relation
)
76 struct cpufreq_freqs freqs
;
77 struct davinci_cpufreq_config
*pdata
= cpufreq
.dev
->platform_data
;
78 struct clk
*armclk
= cpufreq
.armclk
;
80 freqs
.old
= davinci_getspeed(0);
81 freqs
.new = clk_round_rate(armclk
, target_freq
* 1000) / 1000;
83 if (freqs
.old
== freqs
.new)
86 dev_dbg(cpufreq
.dev
, "transition: %u --> %u\n", freqs
.old
, freqs
.new);
88 ret
= cpufreq_frequency_table_target(policy
, pdata
->freq_table
,
89 freqs
.new, relation
, &idx
);
93 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_PRECHANGE
);
95 /* if moving to higher frequency, up the voltage beforehand */
96 if (pdata
->set_voltage
&& freqs
.new > freqs
.old
) {
97 ret
= pdata
->set_voltage(idx
);
102 ret
= clk_set_rate(armclk
, idx
);
106 if (cpufreq
.asyncclk
) {
107 ret
= clk_set_rate(cpufreq
.asyncclk
, cpufreq
.asyncrate
);
112 /* if moving to lower freq, lower the voltage after lowering freq */
113 if (pdata
->set_voltage
&& freqs
.new < freqs
.old
)
114 pdata
->set_voltage(idx
);
117 cpufreq_notify_transition(policy
, &freqs
, CPUFREQ_POSTCHANGE
);
122 static int davinci_cpu_init(struct cpufreq_policy
*policy
)
125 struct davinci_cpufreq_config
*pdata
= cpufreq
.dev
->platform_data
;
126 struct cpufreq_frequency_table
*freq_table
= pdata
->freq_table
;
128 if (policy
->cpu
!= 0)
131 /* Finish platform specific initialization */
133 result
= pdata
->init();
138 policy
->cur
= davinci_getspeed(0);
140 result
= cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
142 pr_err("%s: cpufreq_frequency_table_cpuinfo() failed",
147 cpufreq_frequency_table_get_attr(freq_table
, policy
->cpu
);
150 * Time measurement across the target() function yields ~1500-1800us
151 * time taken with no drivers on notification list.
152 * Setting the latency to 2000 us to accommodate addition of drivers
153 * to pre/post change notification list.
155 policy
->cpuinfo
.transition_latency
= 2000 * 1000;
159 static int davinci_cpu_exit(struct cpufreq_policy
*policy
)
161 cpufreq_frequency_table_put_attr(policy
->cpu
);
165 static struct freq_attr
*davinci_cpufreq_attr
[] = {
166 &cpufreq_freq_attr_scaling_available_freqs
,
170 static struct cpufreq_driver davinci_driver
= {
171 .flags
= CPUFREQ_STICKY
,
172 .verify
= davinci_verify_speed
,
173 .target
= davinci_target
,
174 .get
= davinci_getspeed
,
175 .init
= davinci_cpu_init
,
176 .exit
= davinci_cpu_exit
,
178 .attr
= davinci_cpufreq_attr
,
181 static int __init
davinci_cpufreq_probe(struct platform_device
*pdev
)
183 struct davinci_cpufreq_config
*pdata
= pdev
->dev
.platform_data
;
184 struct clk
*asyncclk
;
188 if (!pdata
->freq_table
)
191 cpufreq
.dev
= &pdev
->dev
;
193 cpufreq
.armclk
= clk_get(NULL
, "arm");
194 if (IS_ERR(cpufreq
.armclk
)) {
195 dev_err(cpufreq
.dev
, "Unable to get ARM clock\n");
196 return PTR_ERR(cpufreq
.armclk
);
199 asyncclk
= clk_get(cpufreq
.dev
, "async");
200 if (!IS_ERR(asyncclk
)) {
201 cpufreq
.asyncclk
= asyncclk
;
202 cpufreq
.asyncrate
= clk_get_rate(asyncclk
);
205 return cpufreq_register_driver(&davinci_driver
);
208 static int __exit
davinci_cpufreq_remove(struct platform_device
*pdev
)
210 clk_put(cpufreq
.armclk
);
212 if (cpufreq
.asyncclk
)
213 clk_put(cpufreq
.asyncclk
);
215 return cpufreq_unregister_driver(&davinci_driver
);
218 static struct platform_driver davinci_cpufreq_driver
= {
220 .name
= "cpufreq-davinci",
221 .owner
= THIS_MODULE
,
223 .remove
= __exit_p(davinci_cpufreq_remove
),
226 int __init
davinci_cpufreq_init(void)
228 return platform_driver_probe(&davinci_cpufreq_driver
,
229 davinci_cpufreq_probe
);