Initial import

1 files changed, 205 insertions, 0 deletions

diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
new file mode 100644
index 000000000..e3866e0d5
--- /dev/null
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -0,0 +1,205 @@
+/*
+ *  CPU frequency scaling for OMAP using OPP information
+ *
+ *  Copyright (C) 2005 Nokia Corporation
+ *  Written by Tony Lindgren <tony@atomide.com>
+ *
+ *  Based on cpu-sa1110.c, Copyright (C) 2001 Russell King
+ *
+ * Copyright (C) 2007-2011 Texas Instruments, Inc.
+ * - OMAP3/4 support by Rajendra Nayak, Santosh Shilimkar
+ *
+ * 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/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pm_opp.h>
+#include <linux/cpu.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+
+#include <asm/smp_plat.h>
+#include <asm/cpu.h>
+
+/* OPP tolerance in percentage */
+#define	OPP_TOLERANCE	4
+
+static struct cpufreq_frequency_table *freq_table;
+static atomic_t freq_table_users = ATOMIC_INIT(0);
+static struct device *mpu_dev;
+static struct regulator *mpu_reg;
+
+static int omap_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	int r, ret;
+	struct dev_pm_opp *opp;
+	unsigned long freq, volt = 0, volt_old = 0, tol = 0;
+	unsigned int old_freq, new_freq;
+
+	old_freq = policy->cur;
+	new_freq = freq_table[index].frequency;
+
+	freq = new_freq * 1000;
+	ret = clk_round_rate(policy->clk, freq);
+	if (IS_ERR_VALUE(ret)) {
+		dev_warn(mpu_dev,
+			 "CPUfreq: Cannot find matching frequency for %lu\n",
+			 freq);
+		return ret;
+	}
+	freq = ret;
+
+	if (mpu_reg) {
+		rcu_read_lock();
+		opp = dev_pm_opp_find_freq_ceil(mpu_dev, &freq);
+		if (IS_ERR(opp)) {
+			rcu_read_unlock();
+			dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
+				__func__, new_freq);
+			return -EINVAL;
+		}
+		volt = dev_pm_opp_get_voltage(opp);
+		rcu_read_unlock();
+		tol = volt * OPP_TOLERANCE / 100;
+		volt_old = regulator_get_voltage(mpu_reg);
+	}
+
+	dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", 
+		old_freq / 1000, volt_old ? volt_old / 1000 : -1,
+		new_freq / 1000, volt ? volt / 1000 : -1);
+
+	/* scaling up?  scale voltage before frequency */
+	if (mpu_reg && (new_freq > old_freq)) {
+		r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
+		if (r < 0) {
+			dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
+				 __func__);
+			return r;
+		}
+	}
+
+	ret = clk_set_rate(policy->clk, new_freq * 1000);
+
+	/* scaling down?  scale voltage after frequency */
+	if (mpu_reg && (new_freq < old_freq)) {
+		r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
+		if (r < 0) {
+			dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
+				 __func__);
+			clk_set_rate(policy->clk, old_freq * 1000);
+			return r;
+		}
+	}
+
+	return ret;
+}
+
+static inline void freq_table_free(void)
+{
+	if (atomic_dec_and_test(&freq_table_users))
+		dev_pm_opp_free_cpufreq_table(mpu_dev, &freq_table);
+}
+
+static int omap_cpu_init(struct cpufreq_policy *policy)
+{
+	int result;
+
+	policy->clk = clk_get(NULL, "cpufreq_ck");
+	if (IS_ERR(policy->clk))
+		return PTR_ERR(policy->clk);
+
+	if (!freq_table) {
+		result = dev_pm_opp_init_cpufreq_table(mpu_dev, &freq_table);
+		if (result) {
+			dev_err(mpu_dev,
+				"%s: cpu%d: failed creating freq table[%d]\n",
+				__func__, policy->cpu, result);
+			goto fail;
+		}
+	}
+
+	atomic_inc_return(&freq_table_users);
+
+	/* FIXME: what's the actual transition time? */
+	result = cpufreq_generic_init(policy, freq_table, 300 * 1000);
+	if (!result)
+		return 0;
+
+	freq_table_free();
+fail:
+	clk_put(policy->clk);
+	return result;
+}
+
+static int omap_cpu_exit(struct cpufreq_policy *policy)
+{
+	freq_table_free();
+	clk_put(policy->clk);
+	return 0;
+}
+
+static struct cpufreq_driver omap_driver = {
+	.flags		= CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.verify		= cpufreq_generic_frequency_table_verify,
+	.target_index	= omap_target,
+	.get		= cpufreq_generic_get,
+	.init		= omap_cpu_init,
+	.exit		= omap_cpu_exit,
+	.name		= "omap",
+	.attr		= cpufreq_generic_attr,
+};
+
+static int omap_cpufreq_probe(struct platform_device *pdev)
+{
+	mpu_dev = get_cpu_device(0);
+	if (!mpu_dev) {
+		pr_warning("%s: unable to get the mpu device\n", __func__);
+		return -EINVAL;
+	}
+
+	mpu_reg = regulator_get(mpu_dev, "vcc");
+	if (IS_ERR(mpu_reg)) {
+		pr_warning("%s: unable to get MPU regulator\n", __func__);
+		mpu_reg = NULL;
+	} else {
+		/* 
+		 * Ensure physical regulator is present.
+		 * (e.g. could be dummy regulator.)
+		 */
+		if (regulator_get_voltage(mpu_reg) < 0) {
+			pr_warn("%s: physical regulator not present for MPU\n",
+				__func__);
+			regulator_put(mpu_reg);
+			mpu_reg = NULL;
+		}
+	}
+
+	return cpufreq_register_driver(&omap_driver);
+}
+
+static int omap_cpufreq_remove(struct platform_device *pdev)
+{
+	return cpufreq_unregister_driver(&omap_driver);
+}
+
+static struct platform_driver omap_cpufreq_platdrv = {
+	.driver = {
+		.name	= "omap-cpufreq",
+	},
+	.probe		= omap_cpufreq_probe,
+	.remove		= omap_cpufreq_remove,
+};
+module_platform_driver(omap_cpufreq_platdrv);
+
+MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
+MODULE_LICENSE("GPL");