1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Linux I2C core OF support code
  4 *
  5 * Copyright (C) 2008 Jochen Friedrich <jochen@scram.de>
  6 * based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
  7 *
  8 * Copyright (C) 2013, 2018 Wolfram Sang <wsa@kernel.org>
  9 */
 10
 11#include <dt-bindings/i2c/i2c.h>
 12#include <linux/device.h>
 13#include <linux/err.h>
 14#include <linux/i2c.h>
 15#include <linux/module.h>
 16#include <linux/of.h>
 17#include <linux/of_device.h>
 18#include <linux/sysfs.h>
 19
 20#include "i2c-core.h"
 21
 22int of_i2c_get_board_info(struct device *dev, struct device_node *node,
 23			  struct i2c_board_info *info)
 24{
 25	u32 addr;
 26	int ret;
 27
 28	memset(info, 0, sizeof(*info));
 29
 30	if (of_modalias_node(node, info->type, sizeof(info->type)) < 0) {
 31		dev_err(dev, "of_i2c: modalias failure on %pOF\n", node);
 32		return -EINVAL;
 33	}
 34
 35	ret = of_property_read_u32(node, "reg", &addr);
 36	if (ret) {
 37		dev_err(dev, "of_i2c: invalid reg on %pOF\n", node);
 38		return ret;
 39	}
 40
 41	if (addr & I2C_TEN_BIT_ADDRESS) {
 42		addr &= ~I2C_TEN_BIT_ADDRESS;
 43		info->flags |= I2C_CLIENT_TEN;
 44	}
 45
 46	if (addr & I2C_OWN_SLAVE_ADDRESS) {
 47		addr &= ~I2C_OWN_SLAVE_ADDRESS;
 48		info->flags |= I2C_CLIENT_SLAVE;
 49	}
 50
 51	info->addr = addr;
 52	info->of_node = node;
 53	info->fwnode = of_fwnode_handle(node);
 54
 55	if (of_property_read_bool(node, "host-notify"))
 56		info->flags |= I2C_CLIENT_HOST_NOTIFY;
 57
 58	if (of_get_property(node, "wakeup-source", NULL))
 59		info->flags |= I2C_CLIENT_WAKE;
 60
 61	return 0;
 62}
 63EXPORT_SYMBOL_GPL(of_i2c_get_board_info);
 64
 65static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
 66						 struct device_node *node)
 67{
 68	struct i2c_client *client;
 69	struct i2c_board_info info;
 70	int ret;
 71
 72	dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
 73
 74	ret = of_i2c_get_board_info(&adap->dev, node, &info);
 75	if (ret)
 76		return ERR_PTR(ret);
 77
 78	client = i2c_new_client_device(adap, &info);
 79	if (IS_ERR(client))
 80		dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
 81
 82	return client;
 83}
 84
 85void of_i2c_register_devices(struct i2c_adapter *adap)
 86{
 87	struct device_node *bus, *node;
 88	struct i2c_client *client;
 89
 90	/* Only register child devices if the adapter has a node pointer set */
 91	if (!adap->dev.of_node)
 92		return;
 93
 94	dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
 95
 96	bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
 97	if (!bus)
 98		bus = of_node_get(adap->dev.of_node);
 99
100	for_each_available_child_of_node(bus, node) {
101		if (of_node_test_and_set_flag(node, OF_POPULATED))
102			continue;
103
104		client = of_i2c_register_device(adap, node);
105		if (IS_ERR(client)) {
106			dev_err(&adap->dev,
107				 "Failed to create I2C device for %pOF\n",
108				 node);
109			of_node_clear_flag(node, OF_POPULATED);
110		}
111	}
112
113	of_node_put(bus);
114}
115
116static int of_dev_or_parent_node_match(struct device *dev, const void *data)
117{
118	if (dev->of_node == data)
119		return 1;
120
121	if (dev->parent)
122		return dev->parent->of_node == data;
123
124	return 0;
125}
126
127/* must call put_device() when done with returned i2c_client device */
128struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
129{
130	struct device *dev;
131	struct i2c_client *client;
132
133	dev = bus_find_device_by_of_node(&i2c_bus_type, node);
134	if (!dev)
135		return NULL;
136
137	client = i2c_verify_client(dev);
138	if (!client)
139		put_device(dev);
140
141	return client;
142}
143EXPORT_SYMBOL(of_find_i2c_device_by_node);
144
145/* must call put_device() when done with returned i2c_adapter device */
146struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
147{
148	struct device *dev;
149	struct i2c_adapter *adapter;
150
151	dev = bus_find_device(&i2c_bus_type, NULL, node,
152			      of_dev_or_parent_node_match);
153	if (!dev)
154		return NULL;
155
156	adapter = i2c_verify_adapter(dev);
157	if (!adapter)
158		put_device(dev);
159
160	return adapter;
161}
162EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
163
164/* must call i2c_put_adapter() when done with returned i2c_adapter device */
165struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
166{
167	struct i2c_adapter *adapter;
168
169	adapter = of_find_i2c_adapter_by_node(node);
170	if (!adapter)
171		return NULL;
172
173	if (!try_module_get(adapter->owner)) {
174		put_device(&adapter->dev);
175		adapter = NULL;
176	}
177
178	return adapter;
179}
180EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
181
182static const struct of_device_id*
183i2c_of_match_device_sysfs(const struct of_device_id *matches,
184				  struct i2c_client *client)
185{
186	const char *name;
187
188	for (; matches->compatible[0]; matches++) {
189		/*
190		 * Adding devices through the i2c sysfs interface provides us
191		 * a string to match which may be compatible with the device
192		 * tree compatible strings, however with no actual of_node the
193		 * of_match_device() will not match
194		 */
195		if (sysfs_streq(client->name, matches->compatible))
196			return matches;
197
198		name = strchr(matches->compatible, ',');
199		if (!name)
200			name = matches->compatible;
201		else
202			name++;
203
204		if (sysfs_streq(client->name, name))
205			return matches;
206	}
207
208	return NULL;
209}
210
211const struct of_device_id
212*i2c_of_match_device(const struct of_device_id *matches,
213		     struct i2c_client *client)
214{
215	const struct of_device_id *match;
216
217	if (!(client && matches))
218		return NULL;
219
220	match = of_match_device(matches, &client->dev);
221	if (match)
222		return match;
223
224	return i2c_of_match_device_sysfs(matches, client);
225}
226EXPORT_SYMBOL_GPL(i2c_of_match_device);
227
228#if IS_ENABLED(CONFIG_OF_DYNAMIC)
229static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
230			 void *arg)
231{
232	struct of_reconfig_data *rd = arg;
233	struct i2c_adapter *adap;
234	struct i2c_client *client;
235
236	switch (of_reconfig_get_state_change(action, rd)) {
237	case OF_RECONFIG_CHANGE_ADD:
238		adap = of_find_i2c_adapter_by_node(rd->dn->parent);
239		if (adap == NULL)
240			return NOTIFY_OK;	/* not for us */
241
242		if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
243			put_device(&adap->dev);
244			return NOTIFY_OK;
245		}
246
247		client = of_i2c_register_device(adap, rd->dn);
248		if (IS_ERR(client)) {
249			dev_err(&adap->dev, "failed to create client for '%pOF'\n",
250				 rd->dn);
251			put_device(&adap->dev);
252			of_node_clear_flag(rd->dn, OF_POPULATED);
253			return notifier_from_errno(PTR_ERR(client));
254		}
255		put_device(&adap->dev);
256		break;
257	case OF_RECONFIG_CHANGE_REMOVE:
258		/* already depopulated? */
259		if (!of_node_check_flag(rd->dn, OF_POPULATED))
260			return NOTIFY_OK;
261
262		/* find our device by node */
263		client = of_find_i2c_device_by_node(rd->dn);
264		if (client == NULL)
265			return NOTIFY_OK;	/* no? not meant for us */
266
267		/* unregister takes one ref away */
268		i2c_unregister_device(client);
269
270		/* and put the reference of the find */
271		put_device(&client->dev);
272		break;
273	}
274
275	return NOTIFY_OK;
276}
277
278struct notifier_block i2c_of_notifier = {
279	.notifier_call = of_i2c_notify,
280};
281#endif /* CONFIG_OF_DYNAMIC */