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8a67f0ef VK |
1 | /* |
2 | * Generic big.LITTLE CPUFreq Interface driver | |
3 | * | |
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. | |
6 | * | |
7 | * Copyright (C) 2013 Linaro. | |
8 | * Viresh Kumar <viresh.kumar@linaro.org> | |
9 | * | |
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. | |
13 | * | |
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. | |
18 | */ | |
19 | ||
20 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
21 | ||
22 | #include <linux/cpufreq.h> | |
23 | #include <linux/device.h> | |
24 | #include <linux/export.h> | |
25 | #include <linux/module.h> | |
26 | #include <linux/of.h> | |
27 | #include <linux/opp.h> | |
28 | #include <linux/slab.h> | |
29 | #include <linux/types.h> | |
30 | #include "arm_big_little.h" | |
31 | ||
32 | static int dt_init_opp_table(struct device *cpu_dev) | |
33 | { | |
763f8c3f | 34 | struct device_node *np, *parent; |
8a67f0ef VK |
35 | int count = 0, ret; |
36 | ||
763f8c3f VK |
37 | parent = of_find_node_by_path("/cpus"); |
38 | if (!parent) { | |
39 | pr_err("failed to find OF /cpus\n"); | |
40 | return -ENOENT; | |
41 | } | |
42 | ||
43 | for_each_child_of_node(parent, np) { | |
8a67f0ef VK |
44 | if (count++ != cpu_dev->id) |
45 | continue; | |
763f8c3f VK |
46 | if (!of_get_property(np, "operating-points", NULL)) { |
47 | ret = -ENODATA; | |
48 | } else { | |
49 | cpu_dev->of_node = np; | |
50 | ret = of_init_opp_table(cpu_dev); | |
51 | } | |
52 | of_node_put(np); | |
53 | of_node_put(parent); | |
54 | ||
55 | return ret; | |
8a67f0ef VK |
56 | } |
57 | ||
58 | return -ENODEV; | |
59 | } | |
60 | ||
61 | static int dt_get_transition_latency(struct device *cpu_dev) | |
62 | { | |
763f8c3f | 63 | struct device_node *np, *parent; |
8a67f0ef VK |
64 | u32 transition_latency = CPUFREQ_ETERNAL; |
65 | int count = 0; | |
66 | ||
763f8c3f VK |
67 | parent = of_find_node_by_path("/cpus"); |
68 | if (!parent) { | |
69 | pr_err("failed to find OF /cpus\n"); | |
70 | return -ENOENT; | |
71 | } | |
72 | ||
73 | for_each_child_of_node(parent, np) { | |
8a67f0ef VK |
74 | if (count++ != cpu_dev->id) |
75 | continue; | |
76 | ||
77 | of_property_read_u32(np, "clock-latency", &transition_latency); | |
763f8c3f VK |
78 | of_node_put(np); |
79 | of_node_put(parent); | |
80 | ||
8a67f0ef VK |
81 | return 0; |
82 | } | |
83 | ||
84 | return -ENODEV; | |
85 | } | |
86 | ||
87 | static struct cpufreq_arm_bL_ops dt_bL_ops = { | |
88 | .name = "dt-bl", | |
89 | .get_transition_latency = dt_get_transition_latency, | |
90 | .init_opp_table = dt_init_opp_table, | |
91 | }; | |
92 | ||
93 | static int generic_bL_init(void) | |
94 | { | |
95 | return bL_cpufreq_register(&dt_bL_ops); | |
96 | } | |
97 | module_init(generic_bL_init); | |
98 | ||
99 | static void generic_bL_exit(void) | |
100 | { | |
101 | return bL_cpufreq_unregister(&dt_bL_ops); | |
102 | } | |
103 | module_exit(generic_bL_exit); | |
104 | ||
105 | MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); | |
106 | MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT"); | |
107 | MODULE_LICENSE("GPL"); |