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
);
75 opp
= opp_find_freq_ceil(cpu_dev
, &freq_Hz
);
78 pr_err("failed to find OPP for %ld\n", freq_Hz
);
81 volt
= opp_get_voltage(opp
);
83 tol
= volt
* voltage_tolerance
/ 100;
84 volt_old
= regulator_get_voltage(cpu_reg
);
87 pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
88 freqs
.old
/ 1000, volt_old
? volt_old
/ 1000 : -1,
89 freqs
.new / 1000, volt
? volt
/ 1000 : -1);
91 /* scaling up? scale voltage before frequency */
92 if (cpu_reg
&& freqs
.new > freqs
.old
) {
93 ret
= regulator_set_voltage_tol(cpu_reg
, volt
, tol
);
95 pr_err("failed to scale voltage up: %d\n", ret
);
96 freqs
.new = freqs
.old
;
101 ret
= clk_set_rate(cpu_clk
, freqs
.new * 1000);
103 pr_err("failed to set clock rate: %d\n", ret
);
105 regulator_set_voltage_tol(cpu_reg
, volt_old
, tol
);
109 /* scaling down? scale voltage after frequency */
110 if (cpu_reg
&& freqs
.new < freqs
.old
) {
111 ret
= regulator_set_voltage_tol(cpu_reg
, volt
, tol
);
113 pr_err("failed to scale voltage down: %d\n", ret
);
114 clk_set_rate(cpu_clk
, freqs
.old
* 1000);
115 freqs
.new = freqs
.old
;
120 for_each_online_cpu(cpu
) {
122 cpufreq_notify_transition(&freqs
, CPUFREQ_POSTCHANGE
);
128 static int cpu0_cpufreq_init(struct cpufreq_policy
*policy
)
132 if (policy
->cpu
!= 0)
135 ret
= cpufreq_frequency_table_cpuinfo(policy
, freq_table
);
137 pr_err("invalid frequency table: %d\n", ret
);
141 policy
->cpuinfo
.transition_latency
= transition_latency
;
142 policy
->cur
= clk_get_rate(cpu_clk
) / 1000;
145 * The driver only supports the SMP configuartion where all processors
146 * share the clock and voltage and clock. Use cpufreq affected_cpus
147 * interface to have all CPUs scaled together.
149 policy
->shared_type
= CPUFREQ_SHARED_TYPE_ANY
;
150 cpumask_setall(policy
->cpus
);
152 cpufreq_frequency_table_get_attr(freq_table
, policy
->cpu
);
157 static int cpu0_cpufreq_exit(struct cpufreq_policy
*policy
)
159 cpufreq_frequency_table_put_attr(policy
->cpu
);
164 static struct freq_attr
*cpu0_cpufreq_attr
[] = {
165 &cpufreq_freq_attr_scaling_available_freqs
,
169 static struct cpufreq_driver cpu0_cpufreq_driver
= {
170 .flags
= CPUFREQ_STICKY
,
171 .verify
= cpu0_verify_speed
,
172 .target
= cpu0_set_target
,
173 .get
= cpu0_get_speed
,
174 .init
= cpu0_cpufreq_init
,
175 .exit
= cpu0_cpufreq_exit
,
176 .name
= "generic_cpu0",
177 .attr
= cpu0_cpufreq_attr
,
180 static int cpu0_cpufreq_driver_init(void)
182 struct device_node
*np
;
185 np
= of_find_node_by_path("/cpus/cpu@0");
187 pr_err("failed to find cpu0 node\n");
191 cpu_dev
= get_cpu_device(0);
193 pr_err("failed to get cpu0 device\n");
198 cpu_dev
->of_node
= np
;
200 cpu_clk
= clk_get(cpu_dev
, NULL
);
201 if (IS_ERR(cpu_clk
)) {
202 ret
= PTR_ERR(cpu_clk
);
203 pr_err("failed to get cpu0 clock: %d\n", ret
);
207 cpu_reg
= regulator_get(cpu_dev
, "cpu0");
208 if (IS_ERR(cpu_reg
)) {
209 pr_warn("failed to get cpu0 regulator\n");
213 ret
= of_init_opp_table(cpu_dev
);
215 pr_err("failed to init OPP table: %d\n", ret
);
219 ret
= opp_init_cpufreq_table(cpu_dev
, &freq_table
);
221 pr_err("failed to init cpufreq table: %d\n", ret
);
225 of_property_read_u32(np
, "voltage-tolerance", &voltage_tolerance
);
227 if (of_property_read_u32(np
, "clock-latency", &transition_latency
))
228 transition_latency
= CPUFREQ_ETERNAL
;
232 unsigned long min_uV
, max_uV
;
236 * OPP is maintained in order of increasing frequency, and
237 * freq_table initialised from OPP is therefore sorted in the
240 for (i
= 0; freq_table
[i
].frequency
!= CPUFREQ_TABLE_END
; i
++)
243 opp
= opp_find_freq_exact(cpu_dev
,
244 freq_table
[0].frequency
* 1000, true);
245 min_uV
= opp_get_voltage(opp
);
246 opp
= opp_find_freq_exact(cpu_dev
,
247 freq_table
[i
-1].frequency
* 1000, true);
248 max_uV
= opp_get_voltage(opp
);
250 ret
= regulator_set_voltage_time(cpu_reg
, min_uV
, max_uV
);
252 transition_latency
+= ret
* 1000;
255 ret
= cpufreq_register_driver(&cpu0_cpufreq_driver
);
257 pr_err("failed register driver: %d\n", ret
);
265 opp_free_cpufreq_table(cpu_dev
, &freq_table
);
270 late_initcall(cpu0_cpufreq_driver_init
);
272 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
273 MODULE_DESCRIPTION("Generic CPU0 cpufreq driver");
274 MODULE_LICENSE("GPL");