3 files changed, 268 insertions, 1 deletions

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 29475101a7b3..aef63c8e3d2d 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1241,7 +1241,7 @@ endmenu
 
 menu "CPU Power Management"
 
-if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_PXA)
+if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_PXA || ARCH_S3C64XX)
 
 source "drivers/cpufreq/Kconfig"
 
@@ -1272,6 +1272,10 @@ config CPU_FREQ_PXA
         default y
         select CPU_FREQ_DEFAULT_GOV_USERSPACE
 
+config CPU_FREQ_S3C64XX
+        bool "CPUfreq support for Samsung S3C64XX CPUs"
+        depends on CPU_FREQ && CPU_S3C6410
+
 endif
 
 source "drivers/cpuidle/Kconfig"
diff --git a/arch/arm/plat-s3c64xx/Makefile b/arch/arm/plat-s3c64xx/Makefile
index 2ed5df34f9ea..3c8882cd6268 100644
--- a/arch/arm/plat-s3c64xx/Makefile
+++ b/arch/arm/plat-s3c64xx/Makefile
@@ -23,6 +23,7 @@ obj-y				+= gpiolib.o
 
 obj-$(CONFIG_CPU_S3C6400_INIT)  += s3c6400-init.o
 obj-$(CONFIG_CPU_S3C6400_CLOCK) += s3c6400-clock.o
+obj-$(CONFIG_CPU_FREQ_S3C64XX)  += cpufreq.o
 
 # PM support
 
diff --git a/arch/arm/plat-s3c64xx/cpufreq.c b/arch/arm/plat-s3c64xx/cpufreq.c
new file mode 100644
index 000000000000..e6e0843215df
--- /dev/null
+++ b/arch/arm/plat-s3c64xx/cpufreq.c
@@ -0,0 +1,262 @@
+/* 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);