| /* |
| * 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 clk *armclk; |
| 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, 66000 }, |
| { 0, 100000 }, |
| { 0, 133000 }, |
| { 1, 200000 }, |
| { 1, 222000 }, |
| { 1, 266000 }, |
| { 2, 333000 }, |
| { 2, 400000 }, |
| { 2, 532000 }, |
| { 2, 533000 }, |
| { 3, 667000 }, |
| { 4, 800000 }, |
| { 0, CPUFREQ_TABLE_END }, |
| }; |
| #endif |
| |
| static int s3c64xx_cpufreq_verify_speed(struct cpufreq_policy *policy) |
| { |
| if (policy->cpu != 0) |
| return -EINVAL; |
| |
| return cpufreq_frequency_table_verify(policy, s3c64xx_freq_table); |
| } |
| |
| static unsigned int s3c64xx_cpufreq_get_speed(unsigned int cpu) |
| { |
| if (cpu != 0) |
| return 0; |
| |
| return clk_get_rate(armclk) / 1000; |
| } |
| |
| static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, |
| unsigned int target_freq, |
| unsigned int relation) |
| { |
| int ret; |
| unsigned int i; |
| struct cpufreq_freqs freqs; |
| struct s3c64xx_dvfs *dvfs; |
| |
| ret = cpufreq_frequency_table_target(policy, s3c64xx_freq_table, |
| target_freq, relation, &i); |
| if (ret != 0) |
| return ret; |
| |
| freqs.cpu = 0; |
| freqs.old = clk_get_rate(armclk) / 1000; |
| freqs.new = s3c64xx_freq_table[i].frequency; |
| freqs.flags = 0; |
| dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[i].index]; |
| |
| if (freqs.old == freqs.new) |
| return 0; |
| |
| pr_debug("Transition %d-%dkHz\n", freqs.old, freqs.new); |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); |
| |
| #ifdef CONFIG_REGULATOR |
| if (vddarm && freqs.new > freqs.old) { |
| ret = regulator_set_voltage(vddarm, |
| dvfs->vddarm_min, |
| dvfs->vddarm_max); |
| if (ret != 0) { |
| pr_err("Failed to set VDDARM for %dkHz: %d\n", |
| freqs.new, ret); |
| goto err; |
| } |
| } |
| #endif |
| |
| ret = clk_set_rate(armclk, freqs.new * 1000); |
| if (ret < 0) { |
| pr_err("Failed to set rate %dkHz: %d\n", |
| freqs.new, ret); |
| goto err; |
| } |
| |
| cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| |
| #ifdef CONFIG_REGULATOR |
| if (vddarm && freqs.new < freqs.old) { |
| ret = regulator_set_voltage(vddarm, |
| dvfs->vddarm_min, |
| dvfs->vddarm_max); |
| if (ret != 0) { |
| pr_err("Failed to set VDDARM for %dkHz: %d\n", |
| freqs.new, ret); |
| goto err_clk; |
| } |
| } |
| #endif |
| |
| pr_debug("Set actual frequency %lukHz\n", |
| clk_get_rate(armclk) / 1000); |
| |
| return 0; |
| |
| err_clk: |
| if (clk_set_rate(armclk, freqs.old * 1000) < 0) |
| pr_err("Failed to restore original clock rate\n"); |
| err: |
| cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_REGULATOR |
| static void __init 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"); |
| } |
| |
| freq = s3c64xx_freq_table; |
| while (count > 0 && freq->frequency != CPUFREQ_TABLE_END) { |
| if (freq->frequency == CPUFREQ_ENTRY_INVALID) |
| continue; |
| |
| dvfs = &s3c64xx_dvfs_table[freq->index]; |
| 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; |
| } |
| |
| freq++; |
| } |
| |
| /* 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; |
| } |
| |
| armclk = clk_get(NULL, "armclk"); |
| if (IS_ERR(armclk)) { |
| pr_err("Unable to obtain ARMCLK: %ld\n", |
| PTR_ERR(armclk)); |
| return PTR_ERR(armclk); |
| } |
| |
| #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(); |
| } |
| |
| vddint = regulator_get(NULL, "vddint"); |
| if (IS_ERR(vddint)) { |
| ret = PTR_ERR(vddint); |
| pr_err("Failed to obtain VDDINT: %d\n", ret); |
| vddint = NULL; |
| } |
| #endif |
| |
| freq = s3c64xx_freq_table; |
| while (freq->frequency != CPUFREQ_TABLE_END) { |
| unsigned long r; |
| |
| /* Check for frequencies we can generate */ |
| r = clk_round_rate(armclk, 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 > s3c64xx_cpufreq_get_speed(0)) |
| freq->frequency = CPUFREQ_ENTRY_INVALID; |
| |
| freq++; |
| } |
| |
| policy->cur = clk_get_rate(armclk) / 1000; |
| |
| /* 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. |
| */ |
| policy->cpuinfo.transition_latency = (500 * 1000) + regulator_latency; |
| |
| ret = cpufreq_frequency_table_cpuinfo(policy, s3c64xx_freq_table); |
| if (ret != 0) { |
| pr_err("Failed to configure frequency table: %d\n", |
| ret); |
| regulator_put(vddarm); |
| clk_put(armclk); |
| } |
| |
| return ret; |
| } |
| |
| static struct cpufreq_driver s3c64xx_cpufreq_driver = { |
| .owner = THIS_MODULE, |
| .flags = 0, |
| .verify = s3c64xx_cpufreq_verify_speed, |
| .target = s3c64xx_cpufreq_set_target, |
| .get = s3c64xx_cpufreq_get_speed, |
| .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); |