[deliverable/linux.git] / drivers / media / v4l2-core / v4l2-clk.c

/*
 * V4L2 clock service
 *
 * Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 *
 * 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/atomic.h>
#include <linux/clk.h>
#include <linux/device.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <media/v4l2-clk.h>
#include <media/v4l2-subdev.h>

static DEFINE_MUTEX(clk_lock);
static LIST_HEAD(clk_list);

static struct v4l2_clk *v4l2_clk_find(const char *dev_id)
{
	struct v4l2_clk *clk;

	list_for_each_entry(clk, &clk_list, list)
		if (!strcmp(dev_id, clk->dev_id))
			return clk;

	return ERR_PTR(-ENODEV);
}

struct v4l2_clk *v4l2_clk_get(struct device *dev, const char *id)
{
	struct v4l2_clk *clk;
	struct clk *ccf_clk = clk_get(dev, id);
	char clk_name[V4L2_CLK_NAME_SIZE];

	if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
		return ERR_PTR(-EPROBE_DEFER);

	if (!IS_ERR_OR_NULL(ccf_clk)) {
		clk = kzalloc(sizeof(*clk), GFP_KERNEL);
		if (!clk) {
			clk_put(ccf_clk);
			return ERR_PTR(-ENOMEM);
		}
		clk->clk = ccf_clk;

		return clk;
	}

	mutex_lock(&clk_lock);
	clk = v4l2_clk_find(dev_name(dev));

	/* if dev_name is not found, try use the OF name to find again  */
	if (PTR_ERR(clk) == -ENODEV && dev->of_node) {
		v4l2_clk_name_of(clk_name, sizeof(clk_name),
				 of_node_full_name(dev->of_node));
		clk = v4l2_clk_find(clk_name);
	}

	if (!IS_ERR(clk))
		atomic_inc(&clk->use_count);
	mutex_unlock(&clk_lock);

	return clk;
}
EXPORT_SYMBOL(v4l2_clk_get);

void v4l2_clk_put(struct v4l2_clk *clk)
{
	struct v4l2_clk *tmp;

	if (IS_ERR(clk))
		return;

	if (clk->clk) {
		clk_put(clk->clk);
		kfree(clk);
		return;
	}

	mutex_lock(&clk_lock);

	list_for_each_entry(tmp, &clk_list, list)
		if (tmp == clk)
			atomic_dec(&clk->use_count);

	mutex_unlock(&clk_lock);
}
EXPORT_SYMBOL(v4l2_clk_put);

static int v4l2_clk_lock_driver(struct v4l2_clk *clk)
{
	struct v4l2_clk *tmp;
	int ret = -ENODEV;

	mutex_lock(&clk_lock);

	list_for_each_entry(tmp, &clk_list, list)
		if (tmp == clk) {
			ret = !try_module_get(clk->ops->owner);
			if (ret)
				ret = -EFAULT;
			break;
		}

	mutex_unlock(&clk_lock);

	return ret;
}

static void v4l2_clk_unlock_driver(struct v4l2_clk *clk)
{
	module_put(clk->ops->owner);
}

int v4l2_clk_enable(struct v4l2_clk *clk)
{
	int ret;

	if (clk->clk)
		return clk_prepare_enable(clk->clk);

	ret = v4l2_clk_lock_driver(clk);
	if (ret < 0)
		return ret;

	mutex_lock(&clk->lock);

	if (++clk->enable == 1 && clk->ops->enable) {
		ret = clk->ops->enable(clk);
		if (ret < 0)
			clk->enable--;
	}

	mutex_unlock(&clk->lock);

	return ret;
}
EXPORT_SYMBOL(v4l2_clk_enable);

/*
 * You might Oops if you try to disabled a disabled clock, because then the
 * driver isn't locked and could have been unloaded by now, so, don't do that
 */
void v4l2_clk_disable(struct v4l2_clk *clk)
{
	int enable;

	if (clk->clk)
		return clk_disable_unprepare(clk->clk);

	mutex_lock(&clk->lock);

	enable = --clk->enable;
	if (WARN(enable < 0, "Unbalanced %s() on %s!\n", __func__,
		 clk->dev_id))
		clk->enable++;
	else if (!enable && clk->ops->disable)
		clk->ops->disable(clk);

	mutex_unlock(&clk->lock);

	v4l2_clk_unlock_driver(clk);
}
EXPORT_SYMBOL(v4l2_clk_disable);

unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk)
{
	int ret;

	if (clk->clk)
		return clk_get_rate(clk->clk);

	ret = v4l2_clk_lock_driver(clk);
	if (ret < 0)
		return ret;

	mutex_lock(&clk->lock);
	if (!clk->ops->get_rate)
		ret = -ENOSYS;
	else
		ret = clk->ops->get_rate(clk);
	mutex_unlock(&clk->lock);

	v4l2_clk_unlock_driver(clk);

	return ret;
}
EXPORT_SYMBOL(v4l2_clk_get_rate);

int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate)
{
	int ret;

	if (clk->clk) {
		long r = clk_round_rate(clk->clk, rate);
		if (r < 0)
			return r;
		return clk_set_rate(clk->clk, r);
	}

	ret = v4l2_clk_lock_driver(clk);

	if (ret < 0)
		return ret;

	mutex_lock(&clk->lock);
	if (!clk->ops->set_rate)
		ret = -ENOSYS;
	else
		ret = clk->ops->set_rate(clk, rate);
	mutex_unlock(&clk->lock);

	v4l2_clk_unlock_driver(clk);

	return ret;
}
EXPORT_SYMBOL(v4l2_clk_set_rate);

struct v4l2_clk *v4l2_clk_register(const struct v4l2_clk_ops *ops,
				   const char *dev_id,
				   void *priv)
{
	struct v4l2_clk *clk;
	int ret;

	if (!ops || !dev_id)
		return ERR_PTR(-EINVAL);

	clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL);
	if (!clk)
		return ERR_PTR(-ENOMEM);

	clk->dev_id = kstrdup(dev_id, GFP_KERNEL);
	if (!clk->dev_id) {
		ret = -ENOMEM;
		goto ealloc;
	}
	clk->ops = ops;
	clk->priv = priv;
	atomic_set(&clk->use_count, 0);
	mutex_init(&clk->lock);

	mutex_lock(&clk_lock);
	if (!IS_ERR(v4l2_clk_find(dev_id))) {
		mutex_unlock(&clk_lock);
		ret = -EEXIST;
		goto eexist;
	}
	list_add_tail(&clk->list, &clk_list);
	mutex_unlock(&clk_lock);

	return clk;

eexist:
ealloc:
	kfree(clk->dev_id);
	kfree(clk);
	return ERR_PTR(ret);
}
EXPORT_SYMBOL(v4l2_clk_register);

void v4l2_clk_unregister(struct v4l2_clk *clk)
{
	if (WARN(atomic_read(&clk->use_count),
		 "%s(): Refusing to unregister ref-counted %s clock!\n",
		 __func__, clk->dev_id))
		return;

	mutex_lock(&clk_lock);
	list_del(&clk->list);
	mutex_unlock(&clk_lock);

	kfree(clk->dev_id);
	kfree(clk);
}
EXPORT_SYMBOL(v4l2_clk_unregister);

struct v4l2_clk_fixed {
	unsigned long rate;
	struct v4l2_clk_ops ops;
};

static unsigned long fixed_get_rate(struct v4l2_clk *clk)
{
	struct v4l2_clk_fixed *priv = clk->priv;
	return priv->rate;
}

struct v4l2_clk *__v4l2_clk_register_fixed(const char *dev_id,
				unsigned long rate, struct module *owner)
{
	struct v4l2_clk *clk;
	struct v4l2_clk_fixed *priv = kzalloc(sizeof(*priv), GFP_KERNEL);

	if (!priv)
		return ERR_PTR(-ENOMEM);

	priv->rate = rate;
	priv->ops.get_rate = fixed_get_rate;
	priv->ops.owner = owner;

	clk = v4l2_clk_register(&priv->ops, dev_id, priv);
	if (IS_ERR(clk))
		kfree(priv);

	return clk;
}
EXPORT_SYMBOL(__v4l2_clk_register_fixed);

void v4l2_clk_unregister_fixed(struct v4l2_clk *clk)
{
	kfree(clk->priv);
	v4l2_clk_unregister(clk);
}
EXPORT_SYMBOL(v4l2_clk_unregister_fixed);
Commit	Line	Data
ff5430de GL	1	/*
	2	* V4L2 clock service
	3	*
	4	* Copyright (C) 2012-2013, Guennadi Liakhovetski <g.liakhovetski@gmx.de>
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*/
	10
	11	#include <linux/atomic.h>
4f528afc	12	#include <linux/clk.h>
ff5430de GL	13	#include <linux/device.h>
	14	#include <linux/errno.h>
	15	#include <linux/list.h>
	16	#include <linux/module.h>
	17	#include <linux/mutex.h>
dc51b7d0	18	#include <linux/of.h>
ff5430de GL	19	#include <linux/slab.h>
	20	#include <linux/string.h>
	21
	22	#include <media/v4l2-clk.h>
	23	#include <media/v4l2-subdev.h>
	24
	25	static DEFINE_MUTEX(clk_lock);
	26	static LIST_HEAD(clk_list);
	27
a37462b9	28	static struct v4l2_clk v4l2_clk_find(const char dev_id)
ff5430de GL	29	{
	30	struct v4l2_clk *clk;
	31
a37462b9 GL	32	list_for_each_entry(clk, &clk_list, list)
a37462b9 GL	33	if (!strcmp(dev_id, clk->dev_id))
ff5430de	34	return clk;
ff5430de GL	35
	36	return ERR_PTR(-ENODEV);
	37	}
	38
	39	struct v4l2_clk v4l2_clk_get(struct device dev, const char *id)
	40	{
	41	struct v4l2_clk *clk;
4f528afc	42	struct clk *ccf_clk = clk_get(dev, id);
dc51b7d0	43	char clk_name[V4L2_CLK_NAME_SIZE];
4f528afc GL	44
	45	if (PTR_ERR(ccf_clk) == -EPROBE_DEFER)
	46	return ERR_PTR(-EPROBE_DEFER);
	47
	48	if (!IS_ERR_OR_NULL(ccf_clk)) {
	49	clk = kzalloc(sizeof(*clk), GFP_KERNEL);
	50	if (!clk) {
	51	clk_put(ccf_clk);
	52	return ERR_PTR(-ENOMEM);
	53	}
	54	clk->clk = ccf_clk;
	55
	56	return clk;
	57	}
ff5430de GL	58
ff5430de GL	59	mutex_lock(&clk_lock);
a37462b9	60	clk = v4l2_clk_find(dev_name(dev));
ff5430de	61
dc51b7d0 JW	62	/* if dev_name is not found, try use the OF name to find again */
	63	if (PTR_ERR(clk) == -ENODEV && dev->of_node) {
	64	v4l2_clk_name_of(clk_name, sizeof(clk_name),
	65	of_node_full_name(dev->of_node));
	66	clk = v4l2_clk_find(clk_name);
	67	}
	68
ff5430de GL	69	if (!IS_ERR(clk))
	70	atomic_inc(&clk->use_count);
	71	mutex_unlock(&clk_lock);
	72
	73	return clk;
	74	}
	75	EXPORT_SYMBOL(v4l2_clk_get);
	76
	77	void v4l2_clk_put(struct v4l2_clk *clk)
	78	{
	79	struct v4l2_clk *tmp;
	80
	81	if (IS_ERR(clk))
	82	return;
	83
4f528afc GL	84	if (clk->clk) {
	85	clk_put(clk->clk);
	86	kfree(clk);
	87	return;
	88	}
	89
ff5430de GL	90	mutex_lock(&clk_lock);
	91
	92	list_for_each_entry(tmp, &clk_list, list)
	93	if (tmp == clk)
	94	atomic_dec(&clk->use_count);
	95
	96	mutex_unlock(&clk_lock);
	97	}
	98	EXPORT_SYMBOL(v4l2_clk_put);
	99
	100	static int v4l2_clk_lock_driver(struct v4l2_clk *clk)
	101	{
	102	struct v4l2_clk *tmp;
	103	int ret = -ENODEV;
	104
	105	mutex_lock(&clk_lock);
	106
	107	list_for_each_entry(tmp, &clk_list, list)
	108	if (tmp == clk) {
	109	ret = !try_module_get(clk->ops->owner);
	110	if (ret)
	111	ret = -EFAULT;
	112	break;
	113	}
	114
	115	mutex_unlock(&clk_lock);
	116
	117	return ret;
	118	}
	119
	120	static void v4l2_clk_unlock_driver(struct v4l2_clk *clk)
	121	{
	122	module_put(clk->ops->owner);
	123	}
	124
	125	int v4l2_clk_enable(struct v4l2_clk *clk)
	126	{
4f528afc GL	127	int ret;
	128
	129	if (clk->clk)
	130	return clk_prepare_enable(clk->clk);
ff5430de	131
4f528afc	132	ret = v4l2_clk_lock_driver(clk);
ff5430de GL	133	if (ret < 0)
	134	return ret;
	135
	136	mutex_lock(&clk->lock);
	137
	138	if (++clk->enable == 1 && clk->ops->enable) {
	139	ret = clk->ops->enable(clk);
	140	if (ret < 0)
	141	clk->enable--;
	142	}
	143
	144	mutex_unlock(&clk->lock);
	145
	146	return ret;
	147	}
	148	EXPORT_SYMBOL(v4l2_clk_enable);
	149
	150	/*
	151	* You might Oops if you try to disabled a disabled clock, because then the
	152	* driver isn't locked and could have been unloaded by now, so, don't do that
	153	*/
	154	void v4l2_clk_disable(struct v4l2_clk *clk)
	155	{
	156	int enable;
	157
4f528afc GL	158	if (clk->clk)
	159	return clk_disable_unprepare(clk->clk);
	160
ff5430de GL	161	mutex_lock(&clk->lock);
	162
	163	enable = --clk->enable;
a37462b9 GL	164	if (WARN(enable < 0, "Unbalanced %s() on %s!\n", __func__,
a37462b9 GL	165	clk->dev_id))
ff5430de GL	166	clk->enable++;
	167	else if (!enable && clk->ops->disable)
	168	clk->ops->disable(clk);
	169
	170	mutex_unlock(&clk->lock);
	171
	172	v4l2_clk_unlock_driver(clk);
	173	}
	174	EXPORT_SYMBOL(v4l2_clk_disable);
	175
	176	unsigned long v4l2_clk_get_rate(struct v4l2_clk *clk)
	177	{
4f528afc GL	178	int ret;
	179
	180	if (clk->clk)
	181	return clk_get_rate(clk->clk);
ff5430de	182
4f528afc	183	ret = v4l2_clk_lock_driver(clk);
ff5430de GL	184	if (ret < 0)
	185	return ret;
	186
	187	mutex_lock(&clk->lock);
	188	if (!clk->ops->get_rate)
	189	ret = -ENOSYS;
	190	else
	191	ret = clk->ops->get_rate(clk);
	192	mutex_unlock(&clk->lock);
	193
	194	v4l2_clk_unlock_driver(clk);
	195
	196	return ret;
	197	}
	198	EXPORT_SYMBOL(v4l2_clk_get_rate);
	199
	200	int v4l2_clk_set_rate(struct v4l2_clk *clk, unsigned long rate)
	201	{
4f528afc GL	202	int ret;
	203
	204	if (clk->clk) {
	205	long r = clk_round_rate(clk->clk, rate);
	206	if (r < 0)
	207	return r;
	208	return clk_set_rate(clk->clk, r);
	209	}
	210
	211	ret = v4l2_clk_lock_driver(clk);
ff5430de GL	212
	213	if (ret < 0)
	214	return ret;
	215
	216	mutex_lock(&clk->lock);
	217	if (!clk->ops->set_rate)
	218	ret = -ENOSYS;
	219	else
	220	ret = clk->ops->set_rate(clk, rate);
	221	mutex_unlock(&clk->lock);
	222
	223	v4l2_clk_unlock_driver(clk);
	224
	225	return ret;
	226	}
	227	EXPORT_SYMBOL(v4l2_clk_set_rate);
	228
	229	struct v4l2_clk v4l2_clk_register(const struct v4l2_clk_ops ops,
	230	const char *dev_id,
a37462b9	231	void *priv)
ff5430de GL	232	{
	233	struct v4l2_clk *clk;
	234	int ret;
	235
	236	if (!ops \|\| !dev_id)
	237	return ERR_PTR(-EINVAL);
	238
	239	clk = kzalloc(sizeof(struct v4l2_clk), GFP_KERNEL);
	240	if (!clk)
	241	return ERR_PTR(-ENOMEM);
	242
ff5430de	243	clk->dev_id = kstrdup(dev_id, GFP_KERNEL);
a37462b9	244	if (!clk->dev_id) {
ff5430de GL	245	ret = -ENOMEM;
	246	goto ealloc;
	247	}
	248	clk->ops = ops;
	249	clk->priv = priv;
	250	atomic_set(&clk->use_count, 0);
	251	mutex_init(&clk->lock);
	252
	253	mutex_lock(&clk_lock);
a37462b9	254	if (!IS_ERR(v4l2_clk_find(dev_id))) {
ff5430de GL	255	mutex_unlock(&clk_lock);
	256	ret = -EEXIST;
	257	goto eexist;
	258	}
	259	list_add_tail(&clk->list, &clk_list);
	260	mutex_unlock(&clk_lock);
	261
	262	return clk;
	263
	264	eexist:
	265	ealloc:
ff5430de GL	266	kfree(clk->dev_id);
	267	kfree(clk);
	268	return ERR_PTR(ret);
	269	}
	270	EXPORT_SYMBOL(v4l2_clk_register);
	271
	272	void v4l2_clk_unregister(struct v4l2_clk *clk)
	273	{
	274	if (WARN(atomic_read(&clk->use_count),
a37462b9 GL	275	"%s(): Refusing to unregister ref-counted %s clock!\n",
a37462b9 GL	276	__func__, clk->dev_id))
ff5430de GL	277	return;
	278
	279	mutex_lock(&clk_lock);
	280	list_del(&clk->list);
	281	mutex_unlock(&clk_lock);
	282
ff5430de GL	283	kfree(clk->dev_id);
	284	kfree(clk);
	285	}
	286	EXPORT_SYMBOL(v4l2_clk_unregister);
cf326dfe GL	287
	288	struct v4l2_clk_fixed {
	289	unsigned long rate;
	290	struct v4l2_clk_ops ops;
	291	};
	292
	293	static unsigned long fixed_get_rate(struct v4l2_clk *clk)
	294	{
	295	struct v4l2_clk_fixed *priv = clk->priv;
	296	return priv->rate;
	297	}
	298
	299	struct v4l2_clk __v4l2_clk_register_fixed(const char dev_id,
a37462b9	300	unsigned long rate, struct module *owner)
cf326dfe GL	301	{
	302	struct v4l2_clk *clk;
	303	struct v4l2_clk_fixed priv = kzalloc(sizeof(priv), GFP_KERNEL);
	304
	305	if (!priv)
	306	return ERR_PTR(-ENOMEM);
	307
	308	priv->rate = rate;
	309	priv->ops.get_rate = fixed_get_rate;
	310	priv->ops.owner = owner;
	311
a37462b9	312	clk = v4l2_clk_register(&priv->ops, dev_id, priv);
cf326dfe GL	313	if (IS_ERR(clk))
	314	kfree(priv);
	315
	316	return clk;
	317	}
	318	EXPORT_SYMBOL(__v4l2_clk_register_fixed);
	319
	320	void v4l2_clk_unregister_fixed(struct v4l2_clk *clk)
	321	{
	322	kfree(clk->priv);
	323	v4l2_clk_unregister(clk);
	324	}
	325	EXPORT_SYMBOL(v4l2_clk_unregister_fixed);