[mirror_ubuntu-jammy-kernel.git] / drivers / devfreq / exynos-bus.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic Exynos Bus frequency driver with DEVFREQ Framework
 *
 * Copyright (c) 2016 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.
 */

#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.h>
#include <linux/pm_opp.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

#define DEFAULT_SATURATION_RATIO	40

struct exynos_bus {
	struct device *dev;

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

	unsigned long curr_freq;

	struct opp_table *opp_table;
	struct clk *clk;
	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;
}

/*
 * devfreq function for both simple-ondemand and passive 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;
	int ret = 0;

	/* Get correct frequency for bus. */
	new_opp = devfreq_recommended_opp(dev, freq, flags);
	if (IS_ERR(new_opp)) {
		dev_err(dev, "failed to get recommended opp instance\n");
		return PTR_ERR(new_opp);
	}

	dev_pm_opp_put(new_opp);

	/* Change voltage and frequency according to new OPP level */
	mutex_lock(&bus->lock);
	ret = dev_pm_opp_set_rate(dev, *freq);
	if (!ret)
		bus->curr_freq = *freq;

	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;

	stat->current_frequency = bus->curr_freq;

	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");

	dev_pm_opp_of_remove_table(dev);
	clk_disable_unprepare(bus->clk);
	if (bus->opp_table) {
		dev_pm_opp_put_regulators(bus->opp_table);
		bus->opp_table = NULL;
	}
}

static void exynos_bus_passive_exit(struct device *dev)
{
	struct exynos_bus *bus = dev_get_drvdata(dev);

	dev_pm_opp_of_remove_table(dev);
	clk_disable_unprepare(bus->clk);
}

static int exynos_bus_parent_parse_of(struct device_node *np,
					struct exynos_bus *bus)
{
	struct device *dev = bus->dev;
	struct opp_table *opp_table;
	const char *vdd = "vdd";
	int i, ret, count, size;

	opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
	if (IS_ERR(opp_table)) {
		ret = PTR_ERR(opp_table);
		dev_err(dev, "failed to set regulators %d\n", ret);
		return ret;
	}

	bus->opp_table = opp_table;

	/*
	 * 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;

	return 0;

err_regulator:
	dev_pm_opp_put_regulators(bus->opp_table);
	bus->opp_table = NULL;

	return ret;
}

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

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

	rate = clk_get_rate(bus->clk);

	opp = devfreq_recommended_opp(dev, &rate, 0);
	if (IS_ERR(opp)) {
		dev_err(dev, "failed to find dev_pm_opp\n");
		ret = PTR_ERR(opp);
		goto err_opp;
	}
	bus->curr_freq = dev_pm_opp_get_freq(opp);
	dev_pm_opp_put(opp);

	return 0;

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

	return ret;
}

static int exynos_bus_profile_init(struct exynos_bus *bus,
				   struct devfreq_dev_profile *profile)
{
	struct device *dev = bus->dev;
	struct devfreq_simple_ondemand_data *ondemand_data;
	int ret;

	/* Initialize the struct profile and governor data for parent device */
	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,
						DEVFREQ_GOV_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");
		goto err_edev;
	}

	return 0;

err_edev:
	if (exynos_bus_disable_edev(bus))
		dev_warn(dev, "failed to disable the devfreq-event devices\n");

	return ret;
}

static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
					   struct devfreq_dev_profile *profile)
{
	struct device *dev = bus->dev;
	struct devfreq_passive_data *passive_data;
	struct devfreq *parent_devfreq;

	/* Initialize the struct profile and governor data for passive device */
	profile->target = exynos_bus_target;
	profile->exit = exynos_bus_passive_exit;

	/* Get the instance of parent devfreq device */
	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
	if (IS_ERR(parent_devfreq))
		return -EPROBE_DEFER;

	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
	if (!passive_data)
		return -ENOMEM;

	passive_data->parent = parent_devfreq;

	/* Add devfreq device for exynos bus with passive governor */
	bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
						passive_data);
	if (IS_ERR(bus->devfreq)) {
		dev_err(dev,
			"failed to add devfreq dev with passive governor\n");
		return PTR_ERR(bus->devfreq);
	}

	return 0;
}

static int exynos_bus_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node, *node;
	struct devfreq_dev_profile *profile;
	struct exynos_bus *bus;
	int ret, max_state;
	unsigned long min_freq, max_freq;
	bool passive = false;

	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);

	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
	if (!profile)
		return -ENOMEM;

	node = of_parse_phandle(dev->of_node, "devfreq", 0);
	if (node) {
		of_node_put(node);
		passive = true;
	} else {
		ret = exynos_bus_parent_parse_of(np, bus);
		if (ret < 0)
			return ret;
	}

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

	if (passive)
		ret = exynos_bus_profile_init_passive(bus, profile);
	else
		ret = exynos_bus_profile_init(bus, profile);

	if (ret < 0)
		goto err;

	max_state = bus->devfreq->profile->max_state;
	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
			dev_name(dev), min_freq, max_freq);

	return 0;

err:
	dev_pm_opp_of_remove_table(dev);
	clk_disable_unprepare(bus->clk);
err_reg:
	if (!passive) {
		dev_pm_opp_put_regulators(bus->opp_table);
		bus->opp_table = NULL;
	}

	return ret;
}

static void exynos_bus_shutdown(struct platform_device *pdev)
{
	struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);

	devfreq_suspend_device(bus->devfreq);
}

#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,
	.shutdown	= exynos_bus_shutdown,
	.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
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
0722249a CC	2	/*
	3	* Generic Exynos Bus frequency driver with DEVFREQ Framework
	4	*
403e0689	5	* Copyright (c) 2016 Samsung Electronics Co., Ltd.
0722249a CC	6	* Author : Chanwoo Choi <cw00.choi@samsung.com>
	7	*
	8	* This driver support Exynos Bus frequency feature by using
	9	* DEVFREQ framework and is based on drivers/devfreq/exynos/exynos4_bus.c.
0722249a CC	10	*/
	11
	12	#include <linux/clk.h>
	13	#include <linux/devfreq.h>
	14	#include <linux/devfreq-event.h>
	15	#include <linux/device.h>
	16	#include <linux/export.h>
	17	#include <linux/module.h>
a4408921	18	#include <linux/of.h>
0722249a CC	19	#include <linux/pm_opp.h>
	20	#include <linux/platform_device.h>
	21	#include <linux/regulator/consumer.h>
0722249a CC	22
0722249a CC	23	#define DEFAULT_SATURATION_RATIO 40
0722249a CC	24
	25	struct exynos_bus {
	26	struct device *dev;
	27
	28	struct devfreq *devfreq;
	29	struct devfreq_event_dev **edev;
	30	unsigned int edev_count;
	31	struct mutex lock;
	32
c8ce82b9	33	unsigned long curr_freq;
0722249a	34
4294a779	35	struct opp_table *opp_table;
0722249a	36	struct clk *clk;
0722249a CC	37	unsigned int ratio;
	38	};
	39
	40	/*
	41	* Control the devfreq-event device to get the current state of bus
	42	*/
	43	#define exynos_bus_ops_edev(ops) \
	44	static int exynos_bus_##ops(struct exynos_bus *bus) \
	45	{ \
	46	int i, ret; \
	47	\
	48	for (i = 0; i < bus->edev_count; i++) { \
	49	if (!bus->edev[i]) \
	50	continue; \
	51	ret = devfreq_event_##ops(bus->edev[i]); \
	52	if (ret < 0) \
	53	return ret; \
	54	} \
	55	\
	56	return 0; \
	57	}
	58	exynos_bus_ops_edev(enable_edev);
	59	exynos_bus_ops_edev(disable_edev);
	60	exynos_bus_ops_edev(set_event);
	61
	62	static int exynos_bus_get_event(struct exynos_bus *bus,
	63	struct devfreq_event_data *edata)
	64	{
	65	struct devfreq_event_data event_data;
	66	unsigned long load_count = 0, total_count = 0;
	67	int i, ret = 0;
	68
	69	for (i = 0; i < bus->edev_count; i++) {
	70	if (!bus->edev[i])
	71	continue;
	72
	73	ret = devfreq_event_get_event(bus->edev[i], &event_data);
	74	if (ret < 0)
	75	return ret;
	76
	77	if (i == 0 \|\| event_data.load_count > load_count) {
	78	load_count = event_data.load_count;
	79	total_count = event_data.total_count;
	80	}
	81	}
	82
	83	edata->load_count = load_count;
	84	edata->total_count = total_count;
	85
	86	return ret;
	87	}
	88
	89	/*
4294a779	90	* devfreq function for both simple-ondemand and passive governor
0722249a CC	91	*/
	92	static int exynos_bus_target(struct device dev, unsigned long freq, u32 flags)
	93	{
	94	struct exynos_bus *bus = dev_get_drvdata(dev);
	95	struct dev_pm_opp *new_opp;
0722249a CC	96	int ret = 0;
0722249a CC	97
4294a779	98	/* Get correct frequency for bus. */
0722249a CC	99	new_opp = devfreq_recommended_opp(dev, freq, flags);
	100	if (IS_ERR(new_opp)) {
	101	dev_err(dev, "failed to get recommended opp instance\n");
0722249a CC	102	return PTR_ERR(new_opp);
	103	}
	104
8a31d9d9 VK	105	dev_pm_opp_put(new_opp);
8a31d9d9 VK	106
0722249a CC	107	/* Change voltage and frequency according to new OPP level */
0722249a CC	108	mutex_lock(&bus->lock);
4294a779 KK	109	ret = dev_pm_opp_set_rate(dev, *freq);
	110	if (!ret)
	111	bus->curr_freq = *freq;
0722249a	112
0722249a CC	113	mutex_unlock(&bus->lock);
	114
	115	return ret;
	116	}
	117
	118	static int exynos_bus_get_dev_status(struct device *dev,
	119	struct devfreq_dev_status *stat)
	120	{
	121	struct exynos_bus *bus = dev_get_drvdata(dev);
	122	struct devfreq_event_data edata;
	123	int ret;
	124
c8ce82b9	125	stat->current_frequency = bus->curr_freq;
0722249a CC	126
	127	ret = exynos_bus_get_event(bus, &edata);
	128	if (ret < 0) {
	129	stat->total_time = stat->busy_time = 0;
	130	goto err;
	131	}
	132
	133	stat->busy_time = (edata.load_count * 100) / bus->ratio;
	134	stat->total_time = edata.total_count;
	135
	136	dev_dbg(dev, "Usage of devfreq-event : %lu/%lu\n", stat->busy_time,
	137	stat->total_time);
	138
	139	err:
	140	ret = exynos_bus_set_event(bus);
	141	if (ret < 0) {
	142	dev_err(dev, "failed to set event to devfreq-event devices\n");
	143	return ret;
	144	}
	145
	146	return ret;
	147	}
	148
	149	static void exynos_bus_exit(struct device *dev)
	150	{
	151	struct exynos_bus *bus = dev_get_drvdata(dev);
	152	int ret;
	153
	154	ret = exynos_bus_disable_edev(bus);
	155	if (ret < 0)
	156	dev_warn(dev, "failed to disable the devfreq-event devices\n");
	157
0722249a	158	dev_pm_opp_of_remove_table(dev);
403e0689	159	clk_disable_unprepare(bus->clk);
4294a779 KK	160	if (bus->opp_table) {
	161	dev_pm_opp_put_regulators(bus->opp_table);
	162	bus->opp_table = NULL;
0722249a	163	}
403e0689 CC	164	}
	165
	166	static void exynos_bus_passive_exit(struct device *dev)
	167	{
	168	struct exynos_bus *bus = dev_get_drvdata(dev);
	169
	170	dev_pm_opp_of_remove_table(dev);
	171	clk_disable_unprepare(bus->clk);
	172	}
	173
	174	static int exynos_bus_parent_parse_of(struct device_node *np,
	175	struct exynos_bus *bus)
	176	{
	177	struct device *dev = bus->dev;
4294a779 KK	178	struct opp_table *opp_table;
4294a779 KK	179	const char *vdd = "vdd";
403e0689	180	int i, ret, count, size;
0722249a	181
4294a779 KK	182	opp_table = dev_pm_opp_set_regulators(dev, &vdd, 1);
	183	if (IS_ERR(opp_table)) {
	184	ret = PTR_ERR(opp_table);
	185	dev_err(dev, "failed to set regulators %d\n", ret);
403e0689	186	return ret;
0722249a CC	187	}
0722249a CC	188
4294a779 KK	189	bus->opp_table = opp_table;
4294a779 KK	190
0722249a CC	191	/*
	192	* Get the devfreq-event devices to get the current utilization of
	193	* buses. This raw data will be used in devfreq ondemand governor.
	194	*/
	195	count = devfreq_event_get_edev_count(dev);
	196	if (count < 0) {
	197	dev_err(dev, "failed to get the count of devfreq-event dev\n");
	198	ret = count;
	199	goto err_regulator;
	200	}
	201	bus->edev_count = count;
	202
	203	size = sizeof(bus->edev) count;
	204	bus->edev = devm_kzalloc(dev, size, GFP_KERNEL);
	205	if (!bus->edev) {
	206	ret = -ENOMEM;
	207	goto err_regulator;
	208	}
	209
	210	for (i = 0; i < count; i++) {
	211	bus->edev[i] = devfreq_event_get_edev_by_phandle(dev, i);
	212	if (IS_ERR(bus->edev[i])) {
	213	ret = -EPROBE_DEFER;
	214	goto err_regulator;
	215	}
	216	}
	217
	218	/*
	219	* Optionally, Get the saturation ratio according to Exynos SoC
	220	* When measuring the utilization of each AXI bus with devfreq-event
	221	* devices, the measured real cycle might be much lower than the
	222	* total cycle of bus during sampling rate. In result, the devfreq
	223	* simple-ondemand governor might not decide to change the current
	224	* frequency due to too utilization (= real cycle/total cycle).
	225	* So, this property is used to adjust the utilization when calculating
	226	* the busy_time in exynos_bus_get_dev_status().
	227	*/
	228	if (of_property_read_u32(np, "exynos,saturation-ratio", &bus->ratio))
	229	bus->ratio = DEFAULT_SATURATION_RATIO;
	230
0722249a CC	231	return 0;
	232
	233	err_regulator:
4294a779 KK	234	dev_pm_opp_put_regulators(bus->opp_table);
4294a779 KK	235	bus->opp_table = NULL;
403e0689 CC	236
	237	return ret;
	238	}
	239
	240	static int exynos_bus_parse_of(struct device_node *np,
	241	struct exynos_bus *bus)
	242	{
	243	struct device *dev = bus->dev;
c8ce82b9	244	struct dev_pm_opp *opp;
403e0689 CC	245	unsigned long rate;
	246	int ret;
	247
	248	/* Get the clock to provide each bus with source clock */
	249	bus->clk = devm_clk_get(dev, "bus");
	250	if (IS_ERR(bus->clk)) {
	251	dev_err(dev, "failed to get bus clock\n");
	252	return PTR_ERR(bus->clk);
	253	}
	254
	255	ret = clk_prepare_enable(bus->clk);
	256	if (ret < 0) {
	257	dev_err(dev, "failed to get enable clock\n");
	258	return ret;
	259	}
	260
	261	/* Get the freq and voltage from OPP table to scale the bus freq */
403e0689 CC	262	ret = dev_pm_opp_of_add_table(dev);
	263	if (ret < 0) {
	264	dev_err(dev, "failed to get OPP table\n");
403e0689 CC	265	goto err_clk;
	266	}
	267
	268	rate = clk_get_rate(bus->clk);
c8ce82b9	269
c8ce82b9 VK	270	opp = devfreq_recommended_opp(dev, &rate, 0);
c8ce82b9 VK	271	if (IS_ERR(opp)) {
403e0689	272	dev_err(dev, "failed to find dev_pm_opp\n");
c8ce82b9	273	ret = PTR_ERR(opp);
403e0689 CC	274	goto err_opp;
403e0689 CC	275	}
c8ce82b9	276	bus->curr_freq = dev_pm_opp_get_freq(opp);
8a31d9d9	277	dev_pm_opp_put(opp);
403e0689 CC	278
	279	return 0;
	280
0722249a CC	281	err_opp:
	282	dev_pm_opp_of_remove_table(dev);
	283	err_clk:
	284	clk_disable_unprepare(bus->clk);
	285
	286	return ret;
	287	}
	288
a47a97ec AŚ	289	static int exynos_bus_profile_init(struct exynos_bus *bus,
a47a97ec AŚ	290	struct devfreq_dev_profile *profile)
0722249a	291	{
a47a97ec	292	struct device *dev = bus->dev;
0722249a	293	struct devfreq_simple_ondemand_data *ondemand_data;
a47a97ec	294	int ret;
403e0689	295
83cb0e4d	296	/* Initialize the struct profile and governor data for parent device */
0722249a CC	297	profile->polling_ms = 50;
	298	profile->target = exynos_bus_target;
	299	profile->get_dev_status = exynos_bus_get_dev_status;
	300	profile->exit = exynos_bus_exit;
	301
	302	ondemand_data = devm_kzalloc(dev, sizeof(*ondemand_data), GFP_KERNEL);
a4408921 AŚ	303	if (!ondemand_data)
	304	return -ENOMEM;
	305
0722249a CC	306	ondemand_data->upthreshold = 40;
	307	ondemand_data->downdifferential = 5;
	308
	309	/* Add devfreq device to monitor and handle the exynos bus */
aa7c352f CC	310	bus->devfreq = devm_devfreq_add_device(dev, profile,
aa7c352f CC	311	DEVFREQ_GOV_SIMPLE_ONDEMAND,
0722249a CC	312	ondemand_data);
	313	if (IS_ERR(bus->devfreq)) {
	314	dev_err(dev, "failed to add devfreq device\n");
a4408921	315	return PTR_ERR(bus->devfreq);
0722249a CC	316	}
	317
	318	/* Register opp_notifier to catch the change of OPP */
	319	ret = devm_devfreq_register_opp_notifier(dev, bus->devfreq);
	320	if (ret < 0) {
	321	dev_err(dev, "failed to register opp notifier\n");
a4408921	322	return ret;
0722249a CC	323	}
	324
	325	/*
	326	* Enable devfreq-event to get raw data which is used to determine
	327	* current bus load.
	328	*/
	329	ret = exynos_bus_enable_edev(bus);
	330	if (ret < 0) {
	331	dev_err(dev, "failed to enable devfreq-event devices\n");
a4408921	332	return ret;
0722249a CC	333	}
	334
	335	ret = exynos_bus_set_event(bus);
	336	if (ret < 0) {
	337	dev_err(dev, "failed to set event to devfreq-event devices\n");
6c315d8f	338	goto err_edev;
0722249a CC	339	}
0722249a CC	340
a4408921	341	return 0;
6c315d8f YL	342
	343	err_edev:
	344	if (exynos_bus_disable_edev(bus))
	345	dev_warn(dev, "failed to disable the devfreq-event devices\n");
	346
	347	return ret;
a47a97ec AŚ	348	}
a47a97ec AŚ	349
a05bb963 AŚ	350	static int exynos_bus_profile_init_passive(struct exynos_bus *bus,
	351	struct devfreq_dev_profile *profile)
	352	{
	353	struct device *dev = bus->dev;
	354	struct devfreq_passive_data *passive_data;
	355	struct devfreq *parent_devfreq;
a05bb963 AŚ	356
	357	/* Initialize the struct profile and governor data for passive device */
	358	profile->target = exynos_bus_target;
	359	profile->exit = exynos_bus_passive_exit;
	360
	361	/* Get the instance of parent devfreq device */
	362	parent_devfreq = devfreq_get_devfreq_by_phandle(dev, 0);
a4408921 AŚ	363	if (IS_ERR(parent_devfreq))
a4408921 AŚ	364	return -EPROBE_DEFER;
a05bb963 AŚ	365
a05bb963 AŚ	366	passive_data = devm_kzalloc(dev, sizeof(*passive_data), GFP_KERNEL);
a4408921 AŚ	367	if (!passive_data)
	368	return -ENOMEM;
	369
a05bb963 AŚ	370	passive_data->parent = parent_devfreq;
	371
	372	/* Add devfreq device for exynos bus with passive governor */
	373	bus->devfreq = devm_devfreq_add_device(dev, profile, DEVFREQ_GOV_PASSIVE,
	374	passive_data);
	375	if (IS_ERR(bus->devfreq)) {
	376	dev_err(dev,
	377	"failed to add devfreq dev with passive governor\n");
a4408921	378	return PTR_ERR(bus->devfreq);
a05bb963 AŚ	379	}
a05bb963 AŚ	380
a4408921	381	return 0;
a05bb963 AŚ	382	}
a05bb963 AŚ	383
a47a97ec AŚ	384	static int exynos_bus_probe(struct platform_device *pdev)
	385	{
	386	struct device *dev = &pdev->dev;
	387	struct device_node np = dev->of_node, node;
	388	struct devfreq_dev_profile *profile;
a47a97ec AŚ	389	struct exynos_bus *bus;
	390	int ret, max_state;
	391	unsigned long min_freq, max_freq;
	392	bool passive = false;
	393
	394	if (!np) {
	395	dev_err(dev, "failed to find devicetree node\n");
	396	return -EINVAL;
	397	}
	398
	399	bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
	400	if (!bus)
	401	return -ENOMEM;
	402	mutex_init(&bus->lock);
	403	bus->dev = &pdev->dev;
	404	platform_set_drvdata(pdev, bus);
	405
	406	profile = devm_kzalloc(dev, sizeof(*profile), GFP_KERNEL);
	407	if (!profile)
	408	return -ENOMEM;
	409
	410	node = of_parse_phandle(dev->of_node, "devfreq", 0);
	411	if (node) {
	412	of_node_put(node);
	413	passive = true;
	414	} else {
	415	ret = exynos_bus_parent_parse_of(np, bus);
	416	if (ret < 0)
	417	return ret;
	418	}
	419
	420	/* Parse the device-tree to get the resource information */
	421	ret = exynos_bus_parse_of(np, bus);
	422	if (ret < 0)
	423	goto err_reg;
	424
	425	if (passive)
a4408921 AŚ	426	ret = exynos_bus_profile_init_passive(bus, profile);
	427	else
	428	ret = exynos_bus_profile_init(bus, profile);
a47a97ec	429
a05bb963	430	if (ret < 0)
403e0689	431	goto err;
403e0689	432
403e0689 CC	433	max_state = bus->devfreq->profile->max_state;
	434	min_freq = (bus->devfreq->profile->freq_table[0] / 1000);
	435	max_freq = (bus->devfreq->profile->freq_table[max_state - 1] / 1000);
	436	pr_info("exynos-bus: new bus device registered: %s (%6ld KHz ~ %6ld KHz)\n",
	437	dev_name(dev), min_freq, max_freq);
	438
0722249a	439	return 0;
403e0689 CC	440
	441	err:
	442	dev_pm_opp_of_remove_table(dev);
	443	clk_disable_unprepare(bus->clk);
2c2b20e0	444	err_reg:
4294a779 KK	445	if (!passive) {
	446	dev_pm_opp_put_regulators(bus->opp_table);
	447	bus->opp_table = NULL;
	448	}
403e0689 CC	449
403e0689 CC	450	return ret;
0722249a CC	451	}
0722249a CC	452
fbb9c3c9 MS	453	static void exynos_bus_shutdown(struct platform_device *pdev)
	454	{
	455	struct exynos_bus *bus = dev_get_drvdata(&pdev->dev);
	456
	457	devfreq_suspend_device(bus->devfreq);
	458	}
	459
0722249a CC	460	#ifdef CONFIG_PM_SLEEP
	461	static int exynos_bus_resume(struct device *dev)
	462	{
	463	struct exynos_bus *bus = dev_get_drvdata(dev);
	464	int ret;
	465
	466	ret = exynos_bus_enable_edev(bus);
	467	if (ret < 0) {
	468	dev_err(dev, "failed to enable the devfreq-event devices\n");
	469	return ret;
	470	}
	471
	472	return 0;
	473	}
	474
	475	static int exynos_bus_suspend(struct device *dev)
	476	{
	477	struct exynos_bus *bus = dev_get_drvdata(dev);
	478	int ret;
	479
	480	ret = exynos_bus_disable_edev(bus);
	481	if (ret < 0) {
	482	dev_err(dev, "failed to disable the devfreq-event devices\n");
	483	return ret;
	484	}
	485
	486	return 0;
	487	}
	488	#endif
	489
	490	static const struct dev_pm_ops exynos_bus_pm = {
	491	SET_SYSTEM_SLEEP_PM_OPS(exynos_bus_suspend, exynos_bus_resume)
	492	};
	493
	494	static const struct of_device_id exynos_bus_of_match[] = {
	495	{ .compatible = "samsung,exynos-bus", },
	496	{ /* sentinel */ },
	497	};
	498	MODULE_DEVICE_TABLE(of, exynos_bus_of_match);
	499
	500	static struct platform_driver exynos_bus_platdrv = {
	501	.probe = exynos_bus_probe,
fbb9c3c9	502	.shutdown = exynos_bus_shutdown,
0722249a CC	503	.driver = {
	504	.name = "exynos-bus",
	505	.pm = &exynos_bus_pm,
	506	.of_match_table = of_match_ptr(exynos_bus_of_match),
	507	},
	508	};
	509	module_platform_driver(exynos_bus_platdrv);
	510
	511	MODULE_DESCRIPTION("Generic Exynos Bus frequency driver");
	512	MODULE_AUTHOR("Chanwoo Choi <cw00.choi@samsung.com>");
	513	MODULE_LICENSE("GPL v2");