[linux-2.6-block.git] / drivers / base / devcon.c

// SPDX-License-Identifier: GPL-2.0
/**
 * Device connections
 *
 * Copyright (C) 2018 Intel Corporation
 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
 */

#include <linux/device.h>
#include <linux/property.h>

static DEFINE_MUTEX(devcon_lock);
static LIST_HEAD(devcon_list);

typedef void *(*devcon_match_fn_t)(struct device_connection *con, int ep,
				   void *data);

static void *
fwnode_graph_devcon_match(struct fwnode_handle *fwnode, const char *con_id,
			  void *data, devcon_match_fn_t match)
{
	struct device_connection con = { .id = con_id };
	struct fwnode_handle *ep;
	void *ret;

	fwnode_graph_for_each_endpoint(fwnode, ep) {
		con.fwnode = fwnode_graph_get_remote_port_parent(ep);
		if (!fwnode_device_is_available(con.fwnode))
			continue;

		ret = match(&con, -1, data);
		fwnode_handle_put(con.fwnode);
		if (ret) {
			fwnode_handle_put(ep);
			return ret;
		}
	}
	return NULL;
}

/**
 * device_connection_find_match - Find physical connection to a device
 * @dev: Device with the connection
 * @con_id: Identifier for the connection
 * @data: Data for the match function
 * @match: Function to check and convert the connection description
 *
 * Find a connection with unique identifier @con_id between @dev and another
 * device. @match will be used to convert the connection description to data the
 * caller is expecting to be returned.
 */
void *device_connection_find_match(struct device *dev, const char *con_id,
				   void *data, devcon_match_fn_t match)
{
	struct fwnode_handle *fwnode = dev_fwnode(dev);
	const char *devname = dev_name(dev);
	struct device_connection *con;
	void *ret = NULL;
	int ep;

	if (!match)
		return NULL;

	if (fwnode) {
		ret = fwnode_graph_devcon_match(fwnode, con_id, data, match);
		if (ret)
			return ret;
	}

	mutex_lock(&devcon_lock);

	list_for_each_entry(con, &devcon_list, list) {
		ep = match_string(con->endpoint, 2, devname);
		if (ep < 0)
			continue;

		if (con_id && strcmp(con->id, con_id))
			continue;

		ret = match(con, !ep, data);
		if (ret)
			break;
	}

	mutex_unlock(&devcon_lock);

	return ret;
}
EXPORT_SYMBOL_GPL(device_connection_find_match);

extern struct bus_type platform_bus_type;
extern struct bus_type pci_bus_type;
extern struct bus_type i2c_bus_type;
extern struct bus_type spi_bus_type;

static struct bus_type *generic_match_buses[] = {
	&platform_bus_type,
#ifdef CONFIG_PCI
	&pci_bus_type,
#endif
#ifdef CONFIG_I2C
	&i2c_bus_type,
#endif
#ifdef CONFIG_SPI_MASTER
	&spi_bus_type,
#endif
	NULL,
};

static int device_fwnode_match(struct device *dev, void *fwnode)
{
	return dev_fwnode(dev) == fwnode;
}

static void *device_connection_fwnode_match(struct device_connection *con)
{
	struct bus_type *bus;
	struct device *dev;

	for (bus = generic_match_buses[0]; bus; bus++) {
		dev = bus_find_device(bus, NULL, (void *)con->fwnode,
				      device_fwnode_match);
		if (dev && !strncmp(dev_name(dev), con->id, strlen(con->id)))
			return dev;

		put_device(dev);
	}
	return NULL;
}

/* This tries to find the device from the most common bus types by name. */
static void *generic_match(struct device_connection *con, int ep, void *data)
{
	struct bus_type *bus;
	struct device *dev;

	if (con->fwnode)
		return device_connection_fwnode_match(con);

	for (bus = generic_match_buses[0]; bus; bus++) {
		dev = bus_find_device_by_name(bus, NULL, con->endpoint[ep]);
		if (dev)
			return dev;
	}

	/*
	 * We only get called if a connection was found, tell the caller to
	 * wait for the other device to show up.
	 */
	return ERR_PTR(-EPROBE_DEFER);
}

/**
 * device_connection_find - Find two devices connected together
 * @dev: Device with the connection
 * @con_id: Identifier for the connection
 *
 * Find a connection with unique identifier @con_id between @dev and
 * another device. On success returns handle to the device that is connected
 * to @dev, with the reference count for the found device incremented. Returns
 * NULL if no matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a
 * connection was found but the other device has not been enumerated yet.
 */
struct device *device_connection_find(struct device *dev, const char *con_id)
{
	return device_connection_find_match(dev, con_id, NULL, generic_match);
}
EXPORT_SYMBOL_GPL(device_connection_find);

/**
 * device_connection_add - Register a connection description
 * @con: The connection description to be registered
 */
void device_connection_add(struct device_connection *con)
{
	mutex_lock(&devcon_lock);
	list_add_tail(&con->list, &devcon_list);
	mutex_unlock(&devcon_lock);
}
EXPORT_SYMBOL_GPL(device_connection_add);

/**
 * device_connections_remove - Unregister connection description
 * @con: The connection description to be unregistered
 */
void device_connection_remove(struct device_connection *con)
{
	mutex_lock(&devcon_lock);
	list_del(&con->list);
	mutex_unlock(&devcon_lock);
}
EXPORT_SYMBOL_GPL(device_connection_remove);
Commit	Line	Data
f2d9b66d HK	1	// SPDX-License-Identifier: GPL-2.0
	2	/**
	3	* Device connections
	4	*
	5	* Copyright (C) 2018 Intel Corporation
	6	* Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
	7	*/
	8
	9	#include <linux/device.h>
637e9e52	10	#include <linux/property.h>
f2d9b66d HK	11
	12	static DEFINE_MUTEX(devcon_lock);
	13	static LIST_HEAD(devcon_list);
	14
637e9e52 HK	15	typedef void (devcon_match_fn_t)(struct device_connection *con, int ep,
	16	void *data);
	17
	18	static void *
	19	fwnode_graph_devcon_match(struct fwnode_handle fwnode, const char con_id,
	20	void *data, devcon_match_fn_t match)
	21	{
	22	struct device_connection con = { .id = con_id };
	23	struct fwnode_handle *ep;
	24	void *ret;
	25
	26	fwnode_graph_for_each_endpoint(fwnode, ep) {
	27	con.fwnode = fwnode_graph_get_remote_port_parent(ep);
	28	if (!fwnode_device_is_available(con.fwnode))
	29	continue;
	30
	31	ret = match(&con, -1, data);
	32	fwnode_handle_put(con.fwnode);
	33	if (ret) {
	34	fwnode_handle_put(ep);
	35	return ret;
	36	}
	37	}
	38	return NULL;
	39	}
	40
f2d9b66d HK	41	/**
	42	* device_connection_find_match - Find physical connection to a device
	43	* @dev: Device with the connection
	44	* @con_id: Identifier for the connection
	45	* @data: Data for the match function
	46	* @match: Function to check and convert the connection description
	47	*
	48	* Find a connection with unique identifier @con_id between @dev and another
	49	* device. @match will be used to convert the connection description to data the
	50	* caller is expecting to be returned.
	51	*/
	52	void device_connection_find_match(struct device dev, const char *con_id,
637e9e52	53	void *data, devcon_match_fn_t match)
f2d9b66d	54	{
637e9e52	55	struct fwnode_handle *fwnode = dev_fwnode(dev);
f2d9b66d HK	56	const char *devname = dev_name(dev);
	57	struct device_connection *con;
	58	void *ret = NULL;
	59	int ep;
	60
	61	if (!match)
	62	return NULL;
	63
637e9e52 HK	64	if (fwnode) {
	65	ret = fwnode_graph_devcon_match(fwnode, con_id, data, match);
	66	if (ret)
	67	return ret;
	68	}
	69
f2d9b66d HK	70	mutex_lock(&devcon_lock);
	71
	72	list_for_each_entry(con, &devcon_list, list) {
	73	ep = match_string(con->endpoint, 2, devname);
	74	if (ep < 0)
	75	continue;
	76
	77	if (con_id && strcmp(con->id, con_id))
	78	continue;
	79
	80	ret = match(con, !ep, data);
	81	if (ret)
	82	break;
	83	}
	84
	85	mutex_unlock(&devcon_lock);
	86
	87	return ret;
	88	}
	89	EXPORT_SYMBOL_GPL(device_connection_find_match);
	90
	91	extern struct bus_type platform_bus_type;
	92	extern struct bus_type pci_bus_type;
	93	extern struct bus_type i2c_bus_type;
	94	extern struct bus_type spi_bus_type;
	95
	96	static struct bus_type *generic_match_buses[] = {
	97	&platform_bus_type,
	98	#ifdef CONFIG_PCI
	99	&pci_bus_type,
	100	#endif
	101	#ifdef CONFIG_I2C
	102	&i2c_bus_type,
	103	#endif
	104	#ifdef CONFIG_SPI_MASTER
	105	&spi_bus_type,
	106	#endif
	107	NULL,
	108	};
	109
80e04837 HK	110	static int device_fwnode_match(struct device dev, void fwnode)
	111	{
	112	return dev_fwnode(dev) == fwnode;
	113	}
	114
	115	static void device_connection_fwnode_match(struct device_connection con)
	116	{
	117	struct bus_type *bus;
	118	struct device *dev;
	119
	120	for (bus = generic_match_buses[0]; bus; bus++) {
	121	dev = bus_find_device(bus, NULL, (void *)con->fwnode,
	122	device_fwnode_match);
	123	if (dev && !strncmp(dev_name(dev), con->id, strlen(con->id)))
	124	return dev;
	125
	126	put_device(dev);
	127	}
	128	return NULL;
	129	}
	130
f2d9b66d HK	131	/* This tries to find the device from the most common bus types by name. */
	132	static void generic_match(struct device_connection con, int ep, void *data)
	133	{
	134	struct bus_type *bus;
	135	struct device *dev;
	136
80e04837 HK	137	if (con->fwnode)
	138	return device_connection_fwnode_match(con);
	139
f2d9b66d HK	140	for (bus = generic_match_buses[0]; bus; bus++) {
	141	dev = bus_find_device_by_name(bus, NULL, con->endpoint[ep]);
	142	if (dev)
	143	return dev;
	144	}
	145
	146	/*
	147	* We only get called if a connection was found, tell the caller to
	148	* wait for the other device to show up.
	149	*/
	150	return ERR_PTR(-EPROBE_DEFER);
	151	}
	152
	153	/**
	154	* device_connection_find - Find two devices connected together
	155	* @dev: Device with the connection
	156	* @con_id: Identifier for the connection
	157	*
	158	* Find a connection with unique identifier @con_id between @dev and
	159	* another device. On success returns handle to the device that is connected
	160	* to @dev, with the reference count for the found device incremented. Returns
	161	* NULL if no matching connection was found, or ERR_PTR(-EPROBE_DEFER) when a
	162	* connection was found but the other device has not been enumerated yet.
	163	*/
	164	struct device device_connection_find(struct device dev, const char *con_id)
	165	{
	166	return device_connection_find_match(dev, con_id, NULL, generic_match);
	167	}
	168	EXPORT_SYMBOL_GPL(device_connection_find);
	169
	170	/**
	171	* device_connection_add - Register a connection description
	172	* @con: The connection description to be registered
	173	*/
	174	void device_connection_add(struct device_connection *con)
	175	{
	176	mutex_lock(&devcon_lock);
	177	list_add_tail(&con->list, &devcon_list);
	178	mutex_unlock(&devcon_lock);
	179	}
	180	EXPORT_SYMBOL_GPL(device_connection_add);
	181
	182	/**
	183	* device_connections_remove - Unregister connection description
	184	* @con: The connection description to be unregistered
	185	*/
	186	void device_connection_remove(struct device_connection *con)
	187	{
	188	mutex_lock(&devcon_lock);
	189	list_del(&con->list);
	190	mutex_unlock(&devcon_lock);
	191	}
	192	EXPORT_SYMBOL_GPL(device_connection_remove);