--- /dev/null
+/*
+ * 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 __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");
+ }
+
+ 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);
Code Review / kvmfornfv.git / blobdiff