| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 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_device.h> |
| 27 | #include <linux/pm_opp.h> |
| 28 | #include <linux/platform_device.h> |
| 29 | #include <linux/slab.h> |
| 30 | #include <linux/types.h> |
| 31 | #include "arm_big_little.h" |
| 32 | |
| 33 | /* get cpu node with valid operating-points */ |
| 34 | static struct device_node *get_cpu_node_with_valid_op(int cpu) |
| 35 | { |
| 36 | struct device_node *np = of_cpu_device_node_get(cpu); |
| 37 | |
| 38 | if (!of_get_property(np, "operating-points", NULL)) { |
| 39 | of_node_put(np); |
| 40 | np = NULL; |
| 41 | } |
| 42 | |
| 43 | return np; |
| 44 | } |
| 45 | |
| 46 | static int dt_init_opp_table(struct device *cpu_dev) |
| 47 | { |
| 48 | struct device_node *np; |
| 49 | int ret; |
| 50 | |
| 51 | np = of_node_get(cpu_dev->of_node); |
| 52 | if (!np) { |
| 53 | pr_err("failed to find cpu%d node\n", cpu_dev->id); |
| 54 | return -ENOENT; |
| 55 | } |
| 56 | |
| 57 | ret = dev_pm_opp_of_add_table(cpu_dev); |
| 58 | of_node_put(np); |
| 59 | |
| 60 | return ret; |
| 61 | } |
| 62 | |
| 63 | static int dt_get_transition_latency(struct device *cpu_dev) |
| 64 | { |
| 65 | struct device_node *np; |
| 66 | u32 transition_latency = CPUFREQ_ETERNAL; |
| 67 | |
| 68 | np = of_node_get(cpu_dev->of_node); |
| 69 | if (!np) { |
| 70 | pr_info("Failed to find cpu node. Use CPUFREQ_ETERNAL transition latency\n"); |
| 71 | return CPUFREQ_ETERNAL; |
| 72 | } |
| 73 | |
| 74 | of_property_read_u32(np, "clock-latency", &transition_latency); |
| 75 | of_node_put(np); |
| 76 | |
| 77 | pr_debug("%s: clock-latency: %d\n", __func__, transition_latency); |
| 78 | return transition_latency; |
| 79 | } |
| 80 | |
| 81 | static struct cpufreq_arm_bL_ops dt_bL_ops = { |
| 82 | .name = "dt-bl", |
| 83 | .get_transition_latency = dt_get_transition_latency, |
| 84 | .init_opp_table = dt_init_opp_table, |
| 85 | .free_opp_table = dev_pm_opp_of_remove_table, |
| 86 | }; |
| 87 | |
| 88 | static int generic_bL_probe(struct platform_device *pdev) |
| 89 | { |
| 90 | struct device_node *np; |
| 91 | |
| 92 | np = get_cpu_node_with_valid_op(0); |
| 93 | if (!np) |
| 94 | return -ENODEV; |
| 95 | |
| 96 | of_node_put(np); |
| 97 | return bL_cpufreq_register(&dt_bL_ops); |
| 98 | } |
| 99 | |
| 100 | static int generic_bL_remove(struct platform_device *pdev) |
| 101 | { |
| 102 | bL_cpufreq_unregister(&dt_bL_ops); |
| 103 | return 0; |
| 104 | } |
| 105 | |
| 106 | static struct platform_driver generic_bL_platdrv = { |
| 107 | .driver = { |
| 108 | .name = "arm-bL-cpufreq-dt", |
| 109 | }, |
| 110 | .probe = generic_bL_probe, |
| 111 | .remove = generic_bL_remove, |
| 112 | }; |
| 113 | module_platform_driver(generic_bL_platdrv); |
| 114 | |
| 115 | MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); |
| 116 | MODULE_DESCRIPTION("Generic ARM big LITTLE cpufreq driver via DT"); |
| 117 | MODULE_LICENSE("GPL v2"); |