2 * Copyright (C) 2012 Freescale Semiconductor, Inc.
4 * The OPP code in function cpu0_set_target() is reused from
5 * drivers/cpufreq/omap-cpufreq.c
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
14 #include <linux/clk.h>
15 #include <linux/cpu.h>
16 #include <linux/cpufreq.h>
17 #include <linux/err.h>
18 #include <linux/module.h>
20 #include <linux/opp.h>
21 #include <linux/regulator/consumer.h>
22 #include <linux/slab.h>
24 static unsigned int transition_latency
;
25 static unsigned int voltage_tolerance
; /* in percentage */
27 static struct device
*cpu_dev
;
28 static struct clk
*cpu_clk
;
29 static struct regulator
*cpu_reg
;
30 static struct cpufreq_frequency_table
*freq_table
;
32 static int cpu0_verify_speed(struct cpufreq_policy
*policy
)
34 return cpufreq_frequency_table_verify(policy
, freq_table
);
37 static unsigned int cpu0_get_speed(unsigned int cpu
)
39 return clk_get_rate(cpu_clk
) / 1000;
42 static int cpu0_set_target(struct cpufreq_policy
*policy
,
43 unsigned int target_freq
, unsigned int relation
)
45 struct cpufreq_freqs freqs
;
47 unsigned long freq_Hz
, volt
= 0, volt_old
= 0, tol
= 0;
48 unsigned int index
, cpu
;
51 ret
= cpufreq_frequency_table_target(policy
, freq_table
, target_freq
,
54 pr_err("failed to match target freqency %d: %d\n",
59 freq_Hz
= clk_round_rate(cpu_clk
, freq_table
[index
].frequency
* 1000);
61 freq_Hz
= freq_table
[index
].frequency
* 1000;
62 freqs
.new = freq_Hz
/ 1000;
63 freqs
.old
= clk_get_rate(cpu_clk
) / 1000;
65 if (freqs
.old
== freqs
.new)
68 for_each_online_cpu(cpu
) {
70 cpufreq_notify_transition(&freqs
, CPUFREQ_PRECHANGE
);
74 opp
= opp_find_freq_ceil(cpu_dev
, &freq_Hz
);
76 pr_err("failed to find OPP for %ld\n", freq_Hz
);
79 volt
= opp_get_voltage(opp
);
80 tol
= volt
* voltage_tolerance
/ 100;
81 volt_old
= regulator_get_voltage(cpu_reg
);
84 pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
85 freqs
.old
/ 1000, volt_old
? volt_old
/ 1000 : -1,
86 freqs
.new / 1000, volt
? volt
/ 1000 : -1);
88 /* scaling up? scale voltage before frequency */
89 if (cpu_reg
&& freqs
.new > freqs
.old
) {
90 ret
= regulator_set_voltage_tol(cpu_reg
, volt
, tol
);
92 pr_err("failed to scale voltage up: %d\n", ret
);
93 freqs
.new = freqs
.old
;
98 ret
= clk_set_rate(cpu_clk
, freqs
.new * 1000);
100 pr_err("failed to set clock rate: %d\n", ret
);
102 regulator_set_voltage_tol(cpu_reg
, volt_old
, tol
);
106 /* scaling down? scale voltage after frequency */
107 if (cpu_reg
&& freqs
.new < freqs
.old
) {
108 ret
= regulator_set_voltage_tol(cpu_reg
, volt
, tol
);
110 pr_err("failed to scale voltage down: %d\n", ret
);
111 clk_set_rate(cpu_clk
, freqs
.old
* 1000);
112 freqs
.new = freqs
.old
;
117 for_each_online_cpu(cpu
) {
119 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
125 static int cpu0_cpufreq_init(struct cpufreq_policy
*policy
)
129 if (policy
->cpu
!= 0)
132 ret
= cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
134 pr_err("invalid frequency table: %d\n", ret
);
138 policy
->cpuinfo
.transition_latency
= transition_latency
;
139 policy
->cur
= clk_get_rate(cpu_clk
) / 1000;
142 * The driver only supports the SMP configuartion where all processors
143 * share the clock and voltage and clock. Use cpufreq affected_cpus
144 * interface to have all CPUs scaled together.
146 policy
->shared_type
= CPUFREQ_SHARED_TYPE_ANY
;
147 cpumask_setall(policy
->cpus
);
149 cpufreq_frequency_table_get_attr(freq_table
, policy
->cpu
);
154 static int cpu0_cpufreq_exit(struct cpufreq_policy
*policy
)
156 cpufreq_frequency_table_put_attr(policy
->cpu
);
161 static struct freq_attr
*cpu0_cpufreq_attr
[] = {
162 &cpufreq_freq_attr_scaling_available_freqs
,
166 static struct cpufreq_driver cpu0_cpufreq_driver
= {
167 .flags
= CPUFREQ_STICKY
,
168 .verify
= cpu0_verify_speed
,
169 .target
= cpu0_set_target
,
170 .get
= cpu0_get_speed
,
171 .init
= cpu0_cpufreq_init
,
172 .exit
= cpu0_cpufreq_exit
,
173 .name
= "generic_cpu0",
174 .attr
= cpu0_cpufreq_attr
,
177 static int cpu0_cpufreq_driver_init(void)
179 struct device_node
*np
;
182 np
= of_find_node_by_path("/cpus/cpu@0");
184 pr_err("failed to find cpu0 node\n");
188 cpu_dev
= get_cpu_device(0);
190 pr_err("failed to get cpu0 device\n");
195 cpu_dev
->of_node
= np
;
197 cpu_clk
= clk_get(cpu_dev
, NULL
);
198 if (IS_ERR(cpu_clk
)) {
199 ret
= PTR_ERR(cpu_clk
);
200 pr_err("failed to get cpu0 clock: %d\n", ret
);
204 cpu_reg
= regulator_get(cpu_dev
, "cpu0");
205 if (IS_ERR(cpu_reg
)) {
206 pr_warn("failed to get cpu0 regulator\n");
210 ret
= of_init_opp_table(cpu_dev
);
212 pr_err("failed to init OPP table: %d\n", ret
);
216 ret
= opp_init_cpufreq_table(cpu_dev
, &freq_table
);
218 pr_err("failed to init cpufreq table: %d\n", ret
);
222 of_property_read_u32(np
, "voltage-tolerance", &voltage_tolerance
);
224 if (of_property_read_u32(np
, "clock-latency", &transition_latency
))
225 transition_latency
= CPUFREQ_ETERNAL
;
229 unsigned long min_uV
, max_uV
;
233 * OPP is maintained in order of increasing frequency, and
234 * freq_table initialised from OPP is therefore sorted in the
237 for (i
= 0; freq_table
[i
].frequency
!= CPUFREQ_TABLE_END
; i
++)
239 opp
= opp_find_freq_exact(cpu_dev
,
240 freq_table
[0].frequency
* 1000, true);
241 min_uV
= opp_get_voltage(opp
);
242 opp
= opp_find_freq_exact(cpu_dev
,
243 freq_table
[i
-1].frequency
* 1000, true);
244 max_uV
= opp_get_voltage(opp
);
245 ret
= regulator_set_voltage_time(cpu_reg
, min_uV
, max_uV
);
247 transition_latency
+= ret
* 1000;
250 ret
= cpufreq_register_driver(&cpu0_cpufreq_driver
);
252 pr_err("failed register driver: %d\n", ret
);
260 opp_free_cpufreq_table(cpu_dev
, &freq_table
);
265 late_initcall(cpu0_cpufreq_driver_init
);
267 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
268 MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
269 MODULE_LICENSE("GPL");