Initial import

1 files changed, 227 insertions, 0 deletions

diff --git a/drivers/cpufreq/s3c64xx-cpufreq.c b/drivers/cpufreq/s3c64xx-cpufreq.c
new file mode 100644
index 000000000..176e84cc3
--- /dev/null
+++ b/drivers/cpufreq/s3c64xx-cpufreq.c
@@ -0,0 +1,227 @@
+/*
+ * 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);