/* * 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. */ #include #include #include #include #include #include #include #include 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("cpufreq: 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("cpufreq: 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("cpufreq: 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("cpufreq: Failed to set VDDARM for %dkHz: %d\n", freqs.new, ret); goto err_clk; } } #endif pr_debug("cpufreq: 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("cpufreq: 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("cpufreq: %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("cpufreq: No frequency information for this CPU\n"); return -ENODEV; } armclk = clk_get(NULL, "armclk"); if (IS_ERR(armclk)) { pr_err("cpufreq: 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("cpufreq: Failed to obtain VDDARM: %d\n", ret); pr_err("cpufreq: Only frequency scaling available\n"); vddarm = NULL; } else { s3c64xx_cpufreq_config_regulator(); } #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("cpufreq: %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("cpufreq: 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);