/* * Copyright 2009 Wolfson Microelectronics plc * * S3C64xx CPUfreq Support * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #define pr_fmt(fmt) "cpufreq: " fmt #include <linux/kernel.h> #include <linux/types.h> #include <linux/init.h> #include <linux/cpufreq.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/regulator/consumer.h> #include <linux/module.h> static struct regulator *vddarm; static unsigned long regulator_latency; #ifdef CONFIG_CPU_S3C6410 struct s3c64xx_dvfs { unsigned int vddarm_min; unsigned int vddarm_max; }; static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = { [0] = { 1000000, 1150000 }, [1] = { 1050000, 1150000 }, [2] = { 1100000, 1150000 }, [3] = { 1200000, 1350000 }, [4] = { 1300000, 1350000 }, }; static struct cpufreq_frequency_table s3c64xx_freq_table[] = { { 0, 0, 66000 }, { 0, 0, 100000 }, { 0, 0, 133000 }, { 0, 1, 200000 }, { 0, 1, 222000 }, { 0, 1, 266000 }, { 0, 2, 333000 }, { 0, 2, 400000 }, { 0, 2, 532000 }, { 0, 2, 533000 }, { 0, 3, 667000 }, { 0, 4, 800000 }, { 0, 0, CPUFREQ_TABLE_END }, }; #endif static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) { struct s3c64xx_dvfs *dvfs; unsigned int old_freq, new_freq; int ret; old_freq = clk_get_rate(policy->clk) / 1000; new_freq = s3c64xx_freq_table[index].frequency; dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[index].driver_data]; #ifdef CONFIG_REGULATOR if (vddarm && new_freq > old_freq) { ret = regulator_set_voltage(vddarm, dvfs->vddarm_min, dvfs->vddarm_max); if (ret != 0) { pr_err("Failed to set VDDARM for %dkHz: %d\n", new_freq, ret); return ret; } } #endif ret = clk_set_rate(policy->clk, new_freq * 1000); if (ret < 0) { pr_err("Failed to set rate %dkHz: %d\n", new_freq, ret); return ret; } #ifdef CONFIG_REGULATOR if (vddarm && new_freq < old_freq) { ret = regulator_set_voltage(vddarm, dvfs->vddarm_min, dvfs->vddarm_max); if (ret != 0) { pr_err("Failed to set VDDARM for %dkHz: %d\n", new_freq, ret); if (clk_set_rate(policy->clk, old_freq * 1000) < 0) pr_err("Failed to restore original clock rate\n"); return ret; } } #endif pr_debug("Set actual frequency %lukHz\n", clk_get_rate(policy->clk) / 1000); return 0; } #ifdef CONFIG_REGULATOR static void s3c64xx_cpufreq_config_regulator(void) { int count, v, i, found; struct cpufreq_frequency_table *freq; struct s3c64xx_dvfs *dvfs; count = regulator_count_voltages(vddarm); if (count < 0) { pr_err("Unable to check supported voltages\n"); } if (!count) goto out; cpufreq_for_each_valid_entry(freq, s3c64xx_freq_table) { dvfs = &s3c64xx_dvfs_table[freq->driver_data]; found = 0; for (i = 0; i < count; i++) { v = regulator_list_voltage(vddarm, i); if (v >= dvfs->vddarm_min && v <= dvfs->vddarm_max) found = 1; } if (!found) { pr_debug("%dkHz unsupported by regulator\n", freq->frequency); freq->frequency = CPUFREQ_ENTRY_INVALID; } } out: /* Guess based on having to do an I2C/SPI write; in future we * will be able to query the regulator performance here. */ regulator_latency = 1 * 1000 * 1000; } #endif static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) { int ret; struct cpufreq_frequency_table *freq; if (policy->cpu != 0) return -EINVAL; if (s3c64xx_freq_table == NULL) { pr_err("No frequency information for this CPU\n"); return -ENODEV; } policy->clk = clk_get(NULL, "armclk"); if (IS_ERR(policy->clk)) { pr_err("Unable to obtain ARMCLK: %ld\n", PTR_ERR(policy->clk)); return PTR_ERR(policy->clk); } #ifdef CONFIG_REGULATOR vddarm = regulator_get(NULL, "vddarm"); if (IS_ERR(vddarm)) { ret = PTR_ERR(vddarm); pr_err("Failed to obtain VDDARM: %d\n", ret); pr_err("Only frequency scaling available\n"); vddarm = NULL; } else { s3c64xx_cpufreq_config_regulator(); } #endif cpufreq_for_each_entry(freq, s3c64xx_freq_table) { unsigned long r; /* Check for frequencies we can generate */ r = clk_round_rate(policy->clk, freq->frequency * 1000); r /= 1000; if (r != freq->frequency) { pr_debug("%dkHz unsupported by clock\n", freq->frequency); freq->frequency = CPUFREQ_ENTRY_INVALID; } /* If we have no regulator then assume startup * frequency is the maximum we can support. */ if (!vddarm && freq->frequency > clk_get_rate(policy->clk) / 1000) freq->frequency = CPUFREQ_ENTRY_INVALID; } /* Datasheet says PLL stabalisation time (if we were to use * the PLLs, which we don't currently) is ~300us worst case, * but add some fudge. */ ret = cpufreq_generic_init(policy, s3c64xx_freq_table, (500 * 1000) + regulator_latency); if (ret != 0) { pr_err("Failed to configure frequency table: %d\n", ret); regulator_put(vddarm); clk_put(policy->clk); } return ret; } static struct cpufreq_driver s3c64xx_cpufreq_driver = { .flags = CPUFREQ_NEED_INITIAL_FREQ_CHECK, .verify = cpufreq_generic_frequency_table_verify, .target_index = s3c64xx_cpufreq_set_target, .get = cpufreq_generic_get, .init = s3c64xx_cpufreq_driver_init, .name = "s3c", }; static int __init s3c64xx_cpufreq_init(void) { return cpufreq_register_driver(&s3c64xx_cpufreq_driver); } module_init(s3c64xx_cpufreq_init);