2 * Generic big.LITTLE CPUFreq Interface driver
4 * It provides necessary ops to arm_big_little cpufreq driver and gets
5 * Frequency information from Device Tree. Freq table in DT must be in KHz.
7 * Copyright (C) 2013 Linaro.
8 * Viresh Kumar <viresh.kumar@linaro.org>
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
14 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
15 * kind, whether express or implied; without even the implied warranty
16 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22 #include <linux/cpufreq.h>
23 #include <linux/device.h>
24 #include <linux/export.h>
25 #include <linux/module.h>
27 #include <linux/opp.h>
28 #include <linux/slab.h>
29 #include <linux/types.h>
30 #include "arm_big_little.h"
32 static int dt_init_opp_table(struct device
*cpu_dev
)
34 struct device_node
*np
, *parent
;
37 parent
= of_find_node_by_path("/cpus");
39 pr_err("failed to find OF /cpus\n");
43 for_each_child_of_node(parent
, np
) {
44 if (count
++ != cpu_dev
->id
)
46 if (!of_get_property(np
, "operating-points", NULL
)) {
49 cpu_dev
->of_node
= np
;
50 ret
= of_init_opp_table(cpu_dev
);
61 static int dt_get_transition_latency(struct device
*cpu_dev
)
63 struct device_node
*np
, *parent
;
64 u32 transition_latency
= CPUFREQ_ETERNAL
;
67 parent
= of_find_node_by_path("/cpus");
69 pr_err("failed to find OF /cpus\n");
73 for_each_child_of_node(parent
, np
) {
74 if (count
++ != cpu_dev
->id
)
77 of_property_read_u32(np
, "clock-latency", &transition_latency
);
87 static struct cpufreq_arm_bL_ops dt_bL_ops
= {
89 .get_transition_latency
= dt_get_transition_latency
,
90 .init_opp_table
= dt_init_opp_table
,
93 static int generic_bL_init(void)
95 return bL_cpufreq_register(&dt_bL_ops
);
97 module_init(generic_bL_init
);
99 static void generic_bL_exit(void)
101 return bL_cpufreq_unregister(&dt_bL_ops
);
103 module_exit(generic_bL_exit
);
105 MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
106 MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT");
107 MODULE_LICENSE("GPL");