1 /* 2 * Versatile Express SPC CPUFreq Interface driver 3 * 4 * It provides necessary ops to arm_big_little cpufreq driver. 5 * 6 * Copyright (C) 2013 ARM Ltd. 7 * Sudeep KarkadaNagesha <sudeep.karkadanagesha@arm.com> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License version 2 as 11 * published by the Free Software Foundation. 12 * 13 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 14 * kind, whether express or implied; without even the implied warranty 15 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 */ 18 19 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 20 21 #include <linux/cpu.h> 22 #include <linux/cpufreq.h> 23 #include <linux/module.h> 24 #include <linux/platform_device.h> 25 #include <linux/pm_opp.h> 26 #include <linux/types.h> 27 28 #include "arm_big_little.h" 29 30 static int ve_spc_init_opp_table(const struct cpumask *cpumask) 31 { 32 struct device *cpu_dev = get_cpu_device(cpumask_first(cpumask)); 33 /* 34 * platform specific SPC code must initialise the opp table 35 * so just check if the OPP count is non-zero 36 */ 37 return dev_pm_opp_get_opp_count(cpu_dev) <= 0; 38 } 39 40 static int ve_spc_get_transition_latency(struct device *cpu_dev) 41 { 42 return 1000000; /* 1 ms */ 43 } 44 45 static struct cpufreq_arm_bL_ops ve_spc_cpufreq_ops = { 46 .name = "vexpress-spc", 47 .get_transition_latency = ve_spc_get_transition_latency, 48 .init_opp_table = ve_spc_init_opp_table, 49 }; 50 51 static int ve_spc_cpufreq_probe(struct platform_device *pdev) 52 { 53 return bL_cpufreq_register(&ve_spc_cpufreq_ops); 54 } 55 56 static int ve_spc_cpufreq_remove(struct platform_device *pdev) 57 { 58 bL_cpufreq_unregister(&ve_spc_cpufreq_ops); 59 return 0; 60 } 61 62 static struct platform_driver ve_spc_cpufreq_platdrv = { 63 .driver = { 64 .name = "vexpress-spc-cpufreq", 65 }, 66 .probe = ve_spc_cpufreq_probe, 67 .remove = ve_spc_cpufreq_remove, 68 }; 69 module_platform_driver(ve_spc_cpufreq_platdrv); 70 71 MODULE_LICENSE("GPL"); 72