--- /dev/null
+/* linux/arch/arm/plat-s3c64xx/cpufreq.c
+ *
+ * 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 <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>
+
+static struct clk *armclk;
+static struct regulator *vddarm;
+
+#ifdef CONFIG_CPU_S3C6410
+struct s3c64xx_dvfs {
+ unsigned int vddarm_min;
+ unsigned int vddarm_max;
+};
+
+static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = {
+ [0] = { 1000000, 1000000 },
+ [1] = { 1000000, 1050000 },
+ [2] = { 1050000, 1100000 },
+ [3] = { 1050000, 1150000 },
+ [4] = { 1250000, 1350000 },
+};
+
+static struct cpufreq_frequency_table s3c64xx_freq_table[] = {
+ { 0, 66000 },
+ { 0, 133000 },
+ { 1, 222000 },
+ { 1, 266000 },
+ { 2, 333000 },
+ { 2, 400000 },
+ { 3, 532000 },
+ { 3, 533000 },
+ { 4, 667000 },
+ { 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;
+ }
+
+#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
+
+ cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+
+ 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_constrain_voltages(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");
+ return;
+ }
+
+ freq = s3c64xx_freq_table;
+ while (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++;
+ }
+}
+#endif
+
+static int __init 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_constrain_voltages();
+ }
+#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)
+ 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;
+
+ /* Pick a conservative guess in ns: we'll need ~1 I2C/SPI
+ * write plus clock reprogramming. */
+ policy->cpuinfo.transition_latency = 2 * 1000 * 1000;
+
+ 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);
projects / deliverable / linux.git / commitdiff
