1 files changed, 364 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
new file mode 100644
index 000000000000..6bbb8b913446
--- /dev/null
+++ b/drivers/cpufreq/cpufreq-dt.c
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
+ *
+ * Copyright (C) 2014 Linaro.
+ * Viresh Kumar <viresh.kumar@linaro.org>
+ *
+ * The OPP code in function set_target() is reused from
+ * drivers/cpufreq/omap-cpufreq.c
+ *
+ * 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)	KBUILD_MODNAME ": " fmt
+
+#include <linux/clk.h>
+#include <linux/cpu.h>
+#include <linux/cpu_cooling.h>
+#include <linux/cpufreq.h>
+#include <linux/cpumask.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pm_opp.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/thermal.h>
+
+struct private_data {
+	struct device *cpu_dev;
+	struct regulator *cpu_reg;
+	struct thermal_cooling_device *cdev;
+	unsigned int voltage_tolerance; /* in percentage */
+};
+
+static int set_target(struct cpufreq_policy *policy, unsigned int index)
+{
+	struct dev_pm_opp *opp;
+	struct cpufreq_frequency_table *freq_table = policy->freq_table;
+	struct clk *cpu_clk = policy->clk;
+	struct private_data *priv = policy->driver_data;
+	struct device *cpu_dev = priv->cpu_dev;
+	struct regulator *cpu_reg = priv->cpu_reg;
+	unsigned long volt = 0, volt_old = 0, tol = 0;
+	unsigned int old_freq, new_freq;
+	long freq_Hz, freq_exact;
+	int ret;
+
+	freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
+	if (freq_Hz <= 0)
+		freq_Hz = freq_table[index].frequency * 1000;
+
+	freq_exact = freq_Hz;
+	new_freq = freq_Hz / 1000;
+	old_freq = clk_get_rate(cpu_clk) / 1000;
+
+	if (!IS_ERR(cpu_reg)) {
+		rcu_read_lock();
+		opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
+		if (IS_ERR(opp)) {
+			rcu_read_unlock();
+			dev_err(cpu_dev, "failed to find OPP for %ld\n",
+				freq_Hz);
+			return PTR_ERR(opp);
+		}
+		volt = dev_pm_opp_get_voltage(opp);
+		rcu_read_unlock();
+		tol = volt * priv->voltage_tolerance / 100;
+		volt_old = regulator_get_voltage(cpu_reg);
+	}
+
+	dev_dbg(cpu_dev, "%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 (!IS_ERR(cpu_reg) && new_freq > old_freq) {
+		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
+		if (ret) {
+			dev_err(cpu_dev, "failed to scale voltage up: %d\n",
+				ret);
+			return ret;
+		}
+	}
+
+	ret = clk_set_rate(cpu_clk, freq_exact);
+	if (ret) {
+		dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+		if (!IS_ERR(cpu_reg))
+			regulator_set_voltage_tol(cpu_reg, volt_old, tol);
+		return ret;
+	}
+
+	/* scaling down?  scale voltage after frequency */
+	if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
+		ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
+		if (ret) {
+			dev_err(cpu_dev, "failed to scale voltage down: %d\n",
+				ret);
+			clk_set_rate(cpu_clk, old_freq * 1000);
+		}
+	}
+
+	return ret;
+}
+
+static int allocate_resources(int cpu, struct device **cdev,
+			      struct regulator **creg, struct clk **cclk)
+{
+	struct device *cpu_dev;
+	struct regulator *cpu_reg;
+	struct clk *cpu_clk;
+	int ret = 0;
+	char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
+
+	cpu_dev = get_cpu_device(cpu);
+	if (!cpu_dev) {
+		pr_err("failed to get cpu%d device\n", cpu);
+		return -ENODEV;
+	}
+
+	/* Try "cpu0" for older DTs */
+	if (!cpu)
+		reg = reg_cpu0;
+	else
+		reg = reg_cpu;
+
+try_again:
+	cpu_reg = regulator_get_optional(cpu_dev, reg);
+	if (IS_ERR(cpu_reg)) {
+		/*
+		 * If cpu's regulator supply node is present, but regulator is
+		 * not yet registered, we should try defering probe.
+		 */
+		if (PTR_ERR(cpu_reg) == -EPROBE_DEFER) {
+			dev_dbg(cpu_dev, "cpu%d regulator not ready, retry\n",
+				cpu);
+			return -EPROBE_DEFER;
+		}
+
+		/* Try with "cpu-supply" */
+		if (reg == reg_cpu0) {
+			reg = reg_cpu;
+			goto try_again;
+		}
+
+		dev_warn(cpu_dev, "failed to get cpu%d regulator: %ld\n",
+			 cpu, PTR_ERR(cpu_reg));
+	}
+
+	cpu_clk = clk_get(cpu_dev, NULL);
+	if (IS_ERR(cpu_clk)) {
+		/* put regulator */
+		if (!IS_ERR(cpu_reg))
+			regulator_put(cpu_reg);
+
+		ret = PTR_ERR(cpu_clk);
+
+		/*
+		 * If cpu's clk node is present, but clock is not yet
+		 * registered, we should try defering probe.
+		 */
+		if (ret == -EPROBE_DEFER)
+			dev_dbg(cpu_dev, "cpu%d clock not ready, retry\n", cpu);
+		else
+			dev_err(cpu_dev, "failed to get cpu%d clock: %d\n", ret,
+				cpu);
+	} else {
+		*cdev = cpu_dev;
+		*creg = cpu_reg;
+		*cclk = cpu_clk;
+	}
+
+	return ret;
+}
+
+static int cpufreq_init(struct cpufreq_policy *policy)
+{
+	struct cpufreq_frequency_table *freq_table;
+	struct thermal_cooling_device *cdev;
+	struct device_node *np;
+	struct private_data *priv;
+	struct device *cpu_dev;
+	struct regulator *cpu_reg;
+	struct clk *cpu_clk;
+	unsigned int transition_latency;
+	int ret;
+
+	ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
+	if (ret) {
+		pr_err("%s: Failed to allocate resources\n: %d", __func__, ret);
+		return ret;
+	}
+
+	np = of_node_get(cpu_dev->of_node);
+	if (!np) {
+		dev_err(cpu_dev, "failed to find cpu%d node\n", policy->cpu);
+		ret = -ENOENT;
+		goto out_put_reg_clk;
+	}
+
+	/* OPPs might be populated at runtime, don't check for error here */
+	of_init_opp_table(cpu_dev);
+
+	ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+	if (ret) {
+		dev_err(cpu_dev, "failed to init cpufreq table: %d\n", ret);
+		goto out_put_node;
+	}
+
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv) {
+		ret = -ENOMEM;
+		goto out_free_table;
+	}
+
+	of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
+
+	if (of_property_read_u32(np, "clock-latency", &transition_latency))
+		transition_latency = CPUFREQ_ETERNAL;
+
+	if (!IS_ERR(cpu_reg)) {
+		struct dev_pm_opp *opp;
+		unsigned long min_uV, max_uV;
+		int i;
+
+		/*
+		 * OPP is maintained in order of increasing frequency, and
+		 * freq_table initialised from OPP is therefore sorted in the
+		 * same order.
+		 */
+		for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
+			;
+		rcu_read_lock();
+		opp = dev_pm_opp_find_freq_exact(cpu_dev,
+				freq_table[0].frequency * 1000, true);
+		min_uV = dev_pm_opp_get_voltage(opp);
+		opp = dev_pm_opp_find_freq_exact(cpu_dev,
+				freq_table[i-1].frequency * 1000, true);
+		max_uV = dev_pm_opp_get_voltage(opp);
+		rcu_read_unlock();
+		ret = regulator_set_voltage_time(cpu_reg, min_uV, max_uV);
+		if (ret > 0)
+			transition_latency += ret * 1000;
+	}
+
+	/*
+	 * For now, just loading the cooling device;
+	 * thermal DT code takes care of matching them.
+	 */
+	if (of_find_property(np, "#cooling-cells", NULL)) {
+		cdev = of_cpufreq_cooling_register(np, cpu_present_mask);
+		if (IS_ERR(cdev))
+			dev_err(cpu_dev,
+				"running cpufreq without cooling device: %ld\n",
+				PTR_ERR(cdev));
+		else
+			priv->cdev = cdev;
+	}
+
+	priv->cpu_dev = cpu_dev;
+	priv->cpu_reg = cpu_reg;
+	policy->driver_data = priv;
+
+	policy->clk = cpu_clk;
+	ret = cpufreq_generic_init(policy, freq_table, transition_latency);
+	if (ret)
+		goto out_cooling_unregister;
+
+	of_node_put(np);
+
+	return 0;
+
+out_cooling_unregister:
+	cpufreq_cooling_unregister(priv->cdev);
+	kfree(priv);
+out_free_table:
+	dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
+out_put_node:
+	of_node_put(np);
+out_put_reg_clk:
+	clk_put(cpu_clk);
+	if (!IS_ERR(cpu_reg))
+		regulator_put(cpu_reg);
+
+	return ret;
+}
+
+static int cpufreq_exit(struct cpufreq_policy *policy)
+{
+	struct private_data *priv = policy->driver_data;
+
+	cpufreq_cooling_unregister(priv->cdev);
+	dev_pm_opp_free_cpufreq_table(priv->cpu_dev, &policy->freq_table);
+	clk_put(policy->clk);
+	if (!IS_ERR(priv->cpu_reg))
+		regulator_put(priv->cpu_reg);
+	kfree(priv);
+
+	return 0;
+}
+
+static struct cpufreq_driver dt_cpufreq_driver = {
+	.flags = CPUFREQ_STICKY | CPUFREQ_NEED_INITIAL_FREQ_CHECK,
+	.verify = cpufreq_generic_frequency_table_verify,
+	.target_index = set_target,
+	.get = cpufreq_generic_get,
+	.init = cpufreq_init,
+	.exit = cpufreq_exit,
+	.name = "cpufreq-dt",
+	.attr = cpufreq_generic_attr,
+};
+
+static int dt_cpufreq_probe(struct platform_device *pdev)
+{
+	struct device *cpu_dev;
+	struct regulator *cpu_reg;
+	struct clk *cpu_clk;
+	int ret;
+
+	/*
+	 * All per-cluster (CPUs sharing clock/voltages) initialization is done
+	 * from ->init(). In probe(), we just need to make sure that clk and
+	 * regulators are available. Else defer probe and retry.
+	 *
+	 * FIXME: Is checking this only for CPU0 sufficient ?
+	 */
+	ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
+	if (ret)
+		return ret;
+
+	clk_put(cpu_clk);
+	if (!IS_ERR(cpu_reg))
+		regulator_put(cpu_reg);
+
+	ret = cpufreq_register_driver(&dt_cpufreq_driver);
+	if (ret)
+		dev_err(cpu_dev, "failed register driver: %d\n", ret);
+
+	return ret;
+}
+
+static int dt_cpufreq_remove(struct platform_device *pdev)
+{
+	cpufreq_unregister_driver(&dt_cpufreq_driver);
+	return 0;
+}
+
+static struct platform_driver dt_cpufreq_platdrv = {
+	.driver = {
+		.name	= "cpufreq-dt",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= dt_cpufreq_probe,
+	.remove		= dt_cpufreq_remove,
+};
+module_platform_driver(dt_cpufreq_platdrv);
+
+MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>");
+MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
+MODULE_DESCRIPTION("Generic cpufreq driver");
+MODULE_LICENSE("GPL");