[deliverable/linux.git] / drivers / devfreq / exynos-bus.c

/*
 * Generic Exynos Bus frequency driver with DEVFREQ Framework
 *
 * Copyright (c) 2015 Samsung Electronics Co., Ltd.
 * Author : Chanwoo Choi <cw00.choi@samsung.com>
 *
 * This driver support Exynos Bus frequency feature by using
 * DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.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.
 */

#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/devfreq-event.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

#define DEFAULT_SATURATION_RATIO	40
#define DEFAULT_VOLTAGE_TOLERANCE	2

struct exynos_bus {
	struct device *dev;

	struct devfreq *devfreq;
	struct devfreq_event_dev **edev;
	unsigned int edev_count;
	struct mutex lock;

	struct dev_pm_opp *curr_opp;

	struct regulator *regulator;
	struct clk *clk;
	unsigned int voltage_tolerance;
	unsigned int ratio;
};

/*
 * Control the devfreq-event device to get the current state of bus
 */
#define exynos_bus_ops_edev(ops)				\
static int exynos_bus_##ops(struct exynos_bus *bus)		\
{								\
	int i, ret;						\
								\
	for (i = 0; i < bus->edev_count; i++) {			\
		if (!bus->edev[i])				\
			continue;				\
		ret = devfreq_event_##ops(bus->edev[i]);	\
		if (ret < 0)					\
			return ret;				\
	}							\
								\
	return 0;						\
}
exynos_bus_ops_edev(enable_edev);
exynos_bus_ops_edev(disable_edev);
exynos_bus_ops_edev(set_event);

static int exynos_bus_get_event(struct exynos_bus *bus,
				struct devfreq_event_data *edata)
{
	struct devfreq_event_data event_data;
	unsigned long load_count = 0, total_count = 0;
	int i, ret = 0;

	for (i = 0; i < bus->edev_count; i++) {
		if (!bus->edev[i])
			continue;

		ret = devfreq_event_get_event(bus->edev[i], &event_data);
		if (ret < 0)
			return ret;

		if (i == 0 || event_data.load_count > load_count) {
			load_count = event_data.load_count;
			total_count = event_data.total_count;
		}
	}

	edata->load_count = load_count;
	edata->total_count = total_count;

	return ret;
}

/*
 * Must necessary function for devfreq governor
 */
static int exynos_bus_target(struct device *dev, unsigned long *freq, u32 flags)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);
	struct dev_pm_opp *new_opp;
	unsigned long old_freq, new_freq, old_volt, new_volt, tol;
	int ret = 0;

	/* Get new opp-bus instance according to new bus clock */
	rcu_read_lock();
	new_opp = devfreq_recommended_opp(dev, freq, flags);
	if (IS_ERR(new_opp)) {
		dev_err(dev, "failed to get recommended opp instance\n");
		rcu_read_unlock();
		return PTR_ERR(new_opp);
	}

	new_freq = dev_pm_opp_get_freq(new_opp);
	new_volt = dev_pm_opp_get_voltage(new_opp);
	old_freq = dev_pm_opp_get_freq(bus->curr_opp);
	old_volt = dev_pm_opp_get_voltage(bus->curr_opp);
	rcu_read_unlock();

	if (old_freq == new_freq)
		return 0;
	tol = new_volt * bus->voltage_tolerance / 100;

	/* Change voltage and frequency according to new OPP level */
	mutex_lock(&bus->lock);

	if (old_freq < new_freq) {
		ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
		if (ret < 0) {
			dev_err(bus->dev, "failed to set voltage\n");
			goto out;
		}
	}

	ret = clk_set_rate(bus->clk, new_freq);
	if (ret < 0) {
		dev_err(dev, "failed to change clock of bus\n");
		clk_set_rate(bus->clk, old_freq);
		goto out;
	}

	if (old_freq > new_freq) {
		ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
		if (ret < 0) {
			dev_err(bus->dev, "failed to set voltage\n");
			goto out;
		}
	}
	bus->curr_opp = new_opp;

	dev_dbg(dev, "Set the frequency of bus (%lukHz -> %lukHz)\n",
			old_freq/1000, new_freq/1000);
out:
	mutex_unlock(&bus->lock);

	return ret;
}

static int exynos_bus_get_dev_status(struct device *dev,
				     struct devfreq_dev_status *stat)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);
	struct devfreq_event_data edata;
	int ret;

	rcu_read_lock();
	stat->current_frequency = dev_pm_opp_get_freq(bus->curr_opp);
	rcu_read_unlock();

	ret = exynos_bus_get_event(bus, &edata);
	if (ret < 0) {
		stat->total_time = stat->busy_time = 0;
		goto err;
	}

	stat->busy_time = (edata.load_count * 100) / bus->ratio;
	stat->total_time = edata.total_count;

	dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
							stat->total_time);

err:
	ret = exynos_bus_set_event(bus);
	if (ret < 0) {
		dev_err(dev, "failed to set event to devfreq-event devices\n");
		return ret;
	}

	return ret;
}

static void exynos_bus_exit(struct device *dev)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);
	int ret;

	ret = exynos_bus_disable_edev(bus);
	if (ret < 0)
		dev_warn(dev, "failed to disable the devfreq-event devices\n");

	if (bus->regulator)
		regulator_disable(bus->regulator);

	dev_pm_opp_of_remove_table(dev);
}

static int exynos_bus_parse_of(struct device_node *np,
			      struct exynos_bus *bus)
{
	struct device *dev = bus->dev;
	unsigned long rate;
	int i, ret, count, size;

	/* Get the clock to provide each bus with source clock */
	bus->clk = devm_clk_get(dev, "bus");
	if (IS_ERR(bus->clk)) {
		dev_err(dev, "failed to get bus clock\n");
		return PTR_ERR(bus->clk);
	}

	ret = clk_prepare_enable(bus->clk);
	if (ret < 0) {
		dev_err(dev, "failed to get enable clock\n");
		return ret;
	}

	/* Get the freq/voltage OPP table to scale the bus frequency */
	rcu_read_lock();
	ret = dev_pm_opp_of_add_table(dev);
	if (ret < 0) {
		dev_err(dev, "failed to get OPP table\n");
		rcu_read_unlock();
		goto err_clk;
	}

	rate = clk_get_rate(bus->clk);
	bus->curr_opp = dev_pm_opp_find_freq_ceil(dev, &rate);
	if (IS_ERR(bus->curr_opp)) {
		dev_err(dev, "failed to find dev_pm_opp\n");
		rcu_read_unlock();
		ret = PTR_ERR(bus->curr_opp);
		goto err_opp;
	}
	rcu_read_unlock();

	/* Get the regulator to provide each bus with the power */
	bus->regulator = devm_regulator_get(dev, "vdd");
	if (IS_ERR(bus->regulator)) {
		dev_err(dev, "failed to get VDD regulator\n");
		ret = PTR_ERR(bus->regulator);
		goto err_opp;
	}

	ret = regulator_enable(bus->regulator);
	if (ret < 0) {
		dev_err(dev, "failed to enable VDD regulator\n");
		goto err_opp;
	}

	/*
	 * Get the devfreq-event devices to get the current utilization of
	 * buses. This raw data will be used in devfreq ondemand governor.
	 */
	count = devfreq_event_get_edev_count(dev);
	if (count < 0) {
		dev_err(dev, "failed to get the count of devfreq-event dev\n");
		ret = count;
		goto err_regulator;
	}
	bus->edev_count = count;

	size = sizeof(*bus->edev) * count;
	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
	if (!bus->edev) {
		ret = -ENOMEM;
		goto err_regulator;
	}

	for (i = 0; i < count; i++) {
		bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
		if (IS_ERR(bus->edev[i])) {
			ret = -EPROBE_DEFER;
			goto err_regulator;
		}
	}

	/*
	 * Optionally, Get the saturation ratio according to Exynos SoC
	 * When measuring the utilization of each AXI bus with devfreq-event
	 * devices, the measured real cycle might be much lower than the
	 * total cycle of bus during sampling rate. In result, the devfreq
	 * simple-ondemand governor might not decide to change the current
	 * frequency due to too utilization (= real cycle/total cycle).
	 * So, this property is used to adjust the utilization when calculating
	 * the busy_time in exynos_bus_get_dev_status().
	 */
	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
		bus->ratio = DEFAULT_SATURATION_RATIO;

	if (of_property_read_u32(np, "exynos,voltage-tolerance",
					&bus->voltage_tolerance))
		bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;

	return 0;

err_regulator:
	regulator_disable(bus->regulator);
err_opp:
	dev_pm_opp_of_remove_table(dev);
err_clk:
	clk_disable_unprepare(bus->clk);

	return ret;
}

static int exynos_bus_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct devfreq_dev_profile *profile;
	struct devfreq_simple_ondemand_data *ondemand_data;
	struct exynos_bus *bus;
	int ret;

	if (!np) {
		dev_err(dev, "failed to find devicetree node\n");
		return -EINVAL;
	}

	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
	if (!bus)
		return -ENOMEM;
	mutex_init(&bus->lock);
	bus->dev = &pdev->dev;
	platform_set_drvdata(pdev, bus);

	/* Parse the device-tree to get the resource information */
	ret = exynos_bus_parse_of(np, bus);
	if (ret < 0)
		return ret;

	/* Initalize the struct profile and governor data */
	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
	if (!profile)
		return -ENOMEM;
	profile->polling_ms = 50;
	profile->target = exynos_bus_target;
	profile->get_dev_status = exynos_bus_get_dev_status;
	profile->exit = exynos_bus_exit;

	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
	if (!ondemand_data)
		return -ENOMEM;
	ondemand_data->upthreshold = 40;
	ondemand_data->downdifferential = 5;

	/* Add devfreq device to monitor and handle the exynos bus */
	bus->devfreq = devm_devfreq_add_device(dev, profile, "simple_ondemand",
						ondemand_data);
	if (IS_ERR(bus->devfreq)) {
		dev_err(dev, "failed to add devfreq device\n");
		return  PTR_ERR(bus->devfreq);
	}

	/* Register opp_notifier to catch the change of OPP  */
	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
	if (ret < 0) {
		dev_err(dev, "failed to register opp notifier\n");
		return ret;
	}

	/*
	 * Enable devfreq-event to get raw data which is used to determine
	 * current bus load.
	 */
	ret = exynos_bus_enable_edev(bus);
	if (ret < 0) {
		dev_err(dev, "failed to enable devfreq-event devices\n");
		return ret;
	}

	ret = exynos_bus_set_event(bus);
	if (ret < 0) {
		dev_err(dev, "failed to set event to devfreq-event devices\n");
		return ret;
	}

	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int exynos_bus_resume(struct device *dev)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);
	int ret;

	ret = exynos_bus_enable_edev(bus);
	if (ret < 0) {
		dev_err(dev, "failed to enable the devfreq-event devices\n");
		return ret;
	}

	return 0;
}

static int exynos_bus_suspend(struct device *dev)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);
	int ret;

	ret = exynos_bus_disable_edev(bus);
	if (ret < 0) {
		dev_err(dev, "failed to disable the devfreq-event devices\n");
		return ret;
	}

	return 0;
}
#endif

static const struct dev_pm_ops exynos_bus_pm = {
	SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
};

static const struct of_device_id exynos_bus_of_match[] = {
	{ .compatible = "samsung,exynos-bus", },
	{ /* sentinel */ },
};
MODULE_DEVICE_TABLE(of, exynos_bus_of_match);

static struct platform_driver exynos_bus_platdrv = {
	.probe		= exynos_bus_probe,
	.driver = {
		.name	= "exynos-bus",
		.pm	= &exynos_bus_pm,
		.of_match_table = of_match_ptr(exynos_bus_of_match),
	},
};
module_platform_driver(exynos_bus_platdrv);

MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
0722249a CC	1	/*
	2	* Generic Exynos Bus frequency driver with DEVFREQ Framework
	3	*
	4	* Copyright (c) 2015 Samsung Electronics Co., Ltd.
	5	* Author : Chanwoo Choi <cw00.choi@samsung.com>
	6	*
	7	* This driver support Exynos Bus frequency feature by using
	8	* DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
	9	*
	10	* This program is free software; you can redistribute it and/or modify
	11	* it under the terms of the GNU General Public License version 2 as
	12	* published by the Free Software Foundation.
	13	*/
	14
	15	#include <linux/clk.h>
	16	#include <linux/devfreq.h>
	17	#include <linux/devfreq-event.h>
	18	#include <linux/device.h>
	19	#include <linux/export.h>
	20	#include <linux/module.h>
	21	#include <linux/of_device.h>
	22	#include <linux/pm_opp.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/regulator/consumer.h>
	25	#include <linux/slab.h>
	26
	27	#define DEFAULT_SATURATION_RATIO 40
	28	#define DEFAULT_VOLTAGE_TOLERANCE 2
	29
	30	struct exynos_bus {
	31	struct device *dev;
	32
	33	struct devfreq *devfreq;
	34	struct devfreq_event_dev **edev;
	35	unsigned int edev_count;
	36	struct mutex lock;
	37
	38	struct dev_pm_opp *curr_opp;
	39
	40	struct regulator *regulator;
	41	struct clk *clk;
	42	unsigned int voltage_tolerance;
	43	unsigned int ratio;
	44	};
	45
	46	/*
	47	* Control the devfreq-event device to get the current state of bus
	48	*/
	49	#define exynos_bus_ops_edev(ops) \
	50	static int exynos_bus_##ops(struct exynos_bus *bus) \
	51	{ \
	52	int i, ret; \
	53	\
	54	for (i = 0; i < bus->edev_count; i++) { \
	55	if (!bus->edev[i]) \
	56	continue; \
	57	ret = devfreq_event_##ops(bus->edev[i]); \
	58	if (ret < 0) \
	59	return ret; \
	60	} \
	61	\
	62	return 0; \
	63	}
	64	exynos_bus_ops_edev(enable_edev);
65	exynos_bus_ops_edev(disable_edev);
66	exynos_bus_ops_edev(set_event);
67
68	static int exynos_bus_get_event(struct exynos_bus *bus,
69	struct devfreq_event_data *edata)
70	{
71	struct devfreq_event_data event_data;
72	unsigned long load_count = 0, total_count = 0;
73	int i, ret = 0;
74
75	for (i = 0; i < bus->edev_count; i++) {
76	if (!bus->edev[i])
77	continue;
78
79	ret = devfreq_event_get_event(bus->edev[i], &event_data);
80	if (ret < 0)
81	return ret;
82
83	if (i == 0 \|\| event_data.load_count > load_count) {
84	load_count = event_data.load_count;
85	total_count = event_data.total_count;
86	}
87	}
88
89	edata->load_count = load_count;
90	edata->total_count = total_count;
91
92	return ret;
93	}
94
95	/*
96	* Must necessary function for devfreq governor
97	*/
98	static int exynos_bus_target(struct device dev, unsigned long freq, u32 flags)
99	{
100	struct exynos_bus *bus = dev_get_drvdata(dev);
101	struct dev_pm_opp *new_opp;
102	unsigned long old_freq, new_freq, old_volt, new_volt, tol;
103	int ret = 0;
104
105	/* Get new opp-bus instance according to new bus clock */
106	rcu_read_lock();
107	new_opp = devfreq_recommended_opp(dev, freq, flags);
108	if (IS_ERR(new_opp)) {
109	dev_err(dev, "failed to get recommended opp instance\n");
110	rcu_read_unlock();
111	return PTR_ERR(new_opp);
112	}
113
114	new_freq = dev_pm_opp_get_freq(new_opp);
115	new_volt = dev_pm_opp_get_voltage(new_opp);
116	old_freq = dev_pm_opp_get_freq(bus->curr_opp);
117	old_volt = dev_pm_opp_get_voltage(bus->curr_opp);
118	rcu_read_unlock();
119
120	if (old_freq == new_freq)
121	return 0;
122	tol = new_volt * bus->voltage_tolerance / 100;
123
124	/* Change voltage and frequency according to new OPP level */
125	mutex_lock(&bus->lock);
126
127	if (old_freq < new_freq) {
128	ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
129	if (ret < 0) {
130	dev_err(bus->dev, "failed to set voltage\n");
131	goto out;
132	}
133	}
134
135	ret = clk_set_rate(bus->clk, new_freq);
136	if (ret < 0) {
137	dev_err(dev, "failed to change clock of bus\n");
138	clk_set_rate(bus->clk, old_freq);
139	goto out;
140	}
141
142	if (old_freq > new_freq) {
143	ret = regulator_set_voltage_tol(bus->regulator, new_volt, tol);
144	if (ret < 0) {
145	dev_err(bus->dev, "failed to set voltage\n");
146	goto out;
147	}
148	}
149	bus->curr_opp = new_opp;
150
151	dev_dbg(dev, "Set the frequency of bus (%lukHz -> %lukHz)\n",
152	old_freq/1000, new_freq/1000);
153	out:
154	mutex_unlock(&bus->lock);
155
156	return ret;
157	}
158
159	static int exynos_bus_get_dev_status(struct device *dev,
160	struct devfreq_dev_status *stat)
161	{
162	struct exynos_bus *bus = dev_get_drvdata(dev);
163	struct devfreq_event_data edata;
164	int ret;
165
166	rcu_read_lock();
167	stat->current_frequency = dev_pm_opp_get_freq(bus->curr_opp);
168	rcu_read_unlock();
169
170	ret = exynos_bus_get_event(bus, &edata);
171	if (ret < 0) {
172	stat->total_time = stat->busy_time = 0;
173	goto err;
174	}
175
176	stat->busy_time = (edata.load_count * 100) / bus->ratio;
177	stat->total_time = edata.total_count;
178
179	dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
180	stat->total_time);
181
182	err:
183	ret = exynos_bus_set_event(bus);
184	if (ret < 0) {
185	dev_err(dev, "failed to set event to devfreq-event devices\n");
186	return ret;
187	}
188
189	return ret;
190	}
191
192	static void exynos_bus_exit(struct device *dev)
193	{
194	struct exynos_bus *bus = dev_get_drvdata(dev);
195	int ret;
196
197	ret = exynos_bus_disable_edev(bus);
198	if (ret < 0)
199	dev_warn(dev, "failed to disable the devfreq-event devices\n");
200
201	if (bus->regulator)
202	regulator_disable(bus->regulator);
203
204	dev_pm_opp_of_remove_table(dev);
205	}
206
207	static int exynos_bus_parse_of(struct device_node *np,
208	struct exynos_bus *bus)
209	{
210	struct device *dev = bus->dev;
211	unsigned long rate;
212	int i, ret, count, size;
213
214	/* Get the clock to provide each bus with source clock */
215	bus->clk = devm_clk_get(dev, "bus");
216	if (IS_ERR(bus->clk)) {
217	dev_err(dev, "failed to get bus clock\n");
218	return PTR_ERR(bus->clk);
219	}
220
221	ret = clk_prepare_enable(bus->clk);
222	if (ret < 0) {
223	dev_err(dev, "failed to get enable clock\n");
224	return ret;
225	}
226
227	/* Get the freq/voltage OPP table to scale the bus frequency */
228	rcu_read_lock();
229	ret = dev_pm_opp_of_add_table(dev);
230	if (ret < 0) {
231	dev_err(dev, "failed to get OPP table\n");
232	rcu_read_unlock();
233	goto err_clk;
234	}
235
236	rate = clk_get_rate(bus->clk);
237	bus->curr_opp = dev_pm_opp_find_freq_ceil(dev, &rate);
238	if (IS_ERR(bus->curr_opp)) {
239	dev_err(dev, "failed to find dev_pm_opp\n");
240	rcu_read_unlock();
241	ret = PTR_ERR(bus->curr_opp);
242	goto err_opp;
243	}
244	rcu_read_unlock();
245
246	/* Get the regulator to provide each bus with the power */
247	bus->regulator = devm_regulator_get(dev, "vdd");
248	if (IS_ERR(bus->regulator)) {
249	dev_err(dev, "failed to get VDD regulator\n");
250	ret = PTR_ERR(bus->regulator);
251	goto err_opp;
252	}
253
254	ret = regulator_enable(bus->regulator);
255	if (ret < 0) {
256	dev_err(dev, "failed to enable VDD regulator\n");
257	goto err_opp;
258	}
259
260	/*
261	* Get the devfreq-event devices to get the current utilization of
262	* buses. This raw data will be used in devfreq ondemand governor.
263	*/
264	count = devfreq_event_get_edev_count(dev);
265	if (count < 0) {
266	dev_err(dev, "failed to get the count of devfreq-event dev\n");
267	ret = count;
268	goto err_regulator;
269	}
270	bus->edev_count = count;
271
272	size = sizeof(bus->edev) count;
273	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
274	if (!bus->edev) {
275	ret = -ENOMEM;
276	goto err_regulator;
277	}
278
279	for (i = 0; i < count; i++) {
280	bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
281	if (IS_ERR(bus->edev[i])) {
282	ret = -EPROBE_DEFER;
283	goto err_regulator;
284	}
285	}
286
287	/*
288	* Optionally, Get the saturation ratio according to Exynos SoC
289	* When measuring the utilization of each AXI bus with devfreq-event
290	* devices, the measured real cycle might be much lower than the
291	* total cycle of bus during sampling rate. In result, the devfreq
292	* simple-ondemand governor might not decide to change the current
293	* frequency due to too utilization (= real cycle/total cycle).
294	* So, this property is used to adjust the utilization when calculating
295	* the busy_time in exynos_bus_get_dev_status().
296	*/
297	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
298	bus->ratio = DEFAULT_SATURATION_RATIO;
299
300	if (of_property_read_u32(np, "exynos,voltage-tolerance",
301	&bus->voltage_tolerance))
302	bus->voltage_tolerance = DEFAULT_VOLTAGE_TOLERANCE;
303
304	return 0;
305
306	err_regulator:
307	regulator_disable(bus->regulator);
308	err_opp:
309	dev_pm_opp_of_remove_table(dev);
310	err_clk:
311	clk_disable_unprepare(bus->clk);
312
313	return ret;
314	}
315
316	static int exynos_bus_probe(struct platform_device *pdev)
317	{
318	struct device *dev = &pdev->dev;
319	struct device_node *np = dev->of_node;
320	struct devfreq_dev_profile *profile;
321	struct devfreq_simple_ondemand_data *ondemand_data;
322	struct exynos_bus *bus;
323	int ret;
324
325	if (!np) {
326	dev_err(dev, "failed to find devicetree node\n");
327	return -EINVAL;
328	}
329
330	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
331	if (!bus)
332	return -ENOMEM;
333	mutex_init(&bus->lock);
334	bus->dev = &pdev->dev;
335	platform_set_drvdata(pdev, bus);
336
337	/* Parse the device-tree to get the resource information */
338	ret = exynos_bus_parse_of(np, bus);
339	if (ret < 0)
340	return ret;
341
342	/* Initalize the struct profile and governor data */
343	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
344	if (!profile)
345	return -ENOMEM;
346	profile->polling_ms = 50;
347	profile->target = exynos_bus_target;
348	profile->get_dev_status = exynos_bus_get_dev_status;
349	profile->exit = exynos_bus_exit;
350
351	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
352	if (!ondemand_data)
353	return -ENOMEM;
354	ondemand_data->upthreshold = 40;
355	ondemand_data->downdifferential = 5;
356
357	/* Add devfreq device to monitor and handle the exynos bus */
358	bus->devfreq = devm_devfreq_add_device(dev, profile, "simple_ondemand",
359	ondemand_data);
360	if (IS_ERR(bus->devfreq)) {
361	dev_err(dev, "failed to add devfreq device\n");
362	return PTR_ERR(bus->devfreq);
363	}
364
365	/* Register opp_notifier to catch the change of OPP */
366	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
367	if (ret < 0) {
368	dev_err(dev, "failed to register opp notifier\n");
369	return ret;
370	}
371
372	/*
373	* Enable devfreq-event to get raw data which is used to determine
374	* current bus load.
375	*/
376	ret = exynos_bus_enable_edev(bus);
377	if (ret < 0) {
378	dev_err(dev, "failed to enable devfreq-event devices\n");
379	return ret;
380	}
381
382	ret = exynos_bus_set_event(bus);
383	if (ret < 0) {
384	dev_err(dev, "failed to set event to devfreq-event devices\n");
385	return ret;
386	}
387
388	return 0;
389	}
390
391	#ifdef CONFIG_PM_SLEEP
392	static int exynos_bus_resume(struct device *dev)
393	{
394	struct exynos_bus *bus = dev_get_drvdata(dev);
395	int ret;
396
397	ret = exynos_bus_enable_edev(bus);
398	if (ret < 0) {
399	dev_err(dev, "failed to enable the devfreq-event devices\n");
400	return ret;
401	}
402
403	return 0;
404	}
405
406	static int exynos_bus_suspend(struct device *dev)
407	{
408	struct exynos_bus *bus = dev_get_drvdata(dev);
409	int ret;
410
411	ret = exynos_bus_disable_edev(bus);
412	if (ret < 0) {
413	dev_err(dev, "failed to disable the devfreq-event devices\n");
414	return ret;
415	}
416
417	return 0;
418	}
419	#endif
420
421	static const struct dev_pm_ops exynos_bus_pm = {
422	SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
423	};
424
425	static const struct of_device_id exynos_bus_of_match[] = {
426	{ .compatible = "samsung,exynos-bus", },
427	{ /* sentinel */ },
428	};
429	MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
430
431	static struct platform_driver exynos_bus_platdrv = {
432	.probe = exynos_bus_probe,
433	.driver = {
434	.name = "exynos-bus",
435	.pm = &exynos_bus_pm,
436	.of_match_table = of_match_ptr(exynos_bus_of_match),
437	},
438	};
439	module_platform_driver(exynos_bus_platdrv);
440
441	MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
442	MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
443	MODULE_LICENSE("GPL v2");