1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (c) 2017 Red Hat, Inc
6 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/libps2.h>
11 #include <linux/i2c.h>
12 #include <linux/serio.h>
13 #include <linux/slab.h>
14 #include <linux/workqueue.h>
17 struct psmouse_smbus_dev {
18 struct i2c_board_info board;
19 struct psmouse *psmouse;
20 struct i2c_client *client;
21 struct list_head node;
26 static LIST_HEAD(psmouse_smbus_list);
27 static DEFINE_MUTEX(psmouse_smbus_mutex);
29 static struct workqueue_struct *psmouse_smbus_wq;
31 static void psmouse_smbus_check_adapter(struct i2c_adapter *adapter)
33 struct psmouse_smbus_dev *smbdev;
35 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
38 mutex_lock(&psmouse_smbus_mutex);
40 list_for_each_entry(smbdev, &psmouse_smbus_list, node) {
48 * Here would be a good place to check if device is actually
49 * present, but it seems that SMBus will not respond unless we
50 * fully reset PS/2 connection. So cross our fingers, and try
51 * to switch over, hopefully our system will not have too many
52 * "host notify" I2C adapters.
54 psmouse_dbg(smbdev->psmouse,
55 "SMBus candidate adapter appeared, triggering rescan\n");
56 serio_rescan(smbdev->psmouse->ps2dev.serio);
59 mutex_unlock(&psmouse_smbus_mutex);
62 static void psmouse_smbus_detach_i2c_client(struct i2c_client *client)
64 struct psmouse_smbus_dev *smbdev, *tmp;
66 mutex_lock(&psmouse_smbus_mutex);
68 list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
69 if (smbdev->client != client)
72 kfree(client->dev.platform_data);
73 client->dev.platform_data = NULL;
76 psmouse_dbg(smbdev->psmouse,
77 "Marking SMBus companion %s as gone\n",
78 dev_name(&smbdev->client->dev));
80 device_link_remove(&smbdev->client->dev,
81 &smbdev->psmouse->ps2dev.serio->dev);
82 serio_rescan(smbdev->psmouse->ps2dev.serio);
84 list_del(&smbdev->node);
89 mutex_unlock(&psmouse_smbus_mutex);
92 static int psmouse_smbus_notifier_call(struct notifier_block *nb,
93 unsigned long action, void *data)
95 struct device *dev = data;
98 case BUS_NOTIFY_ADD_DEVICE:
99 if (dev->type == &i2c_adapter_type)
100 psmouse_smbus_check_adapter(to_i2c_adapter(dev));
103 case BUS_NOTIFY_REMOVED_DEVICE:
104 if (dev->type == &i2c_client_type)
105 psmouse_smbus_detach_i2c_client(to_i2c_client(dev));
112 static struct notifier_block psmouse_smbus_notifier = {
113 .notifier_call = psmouse_smbus_notifier_call,
116 static psmouse_ret_t psmouse_smbus_process_byte(struct psmouse *psmouse)
118 return PSMOUSE_FULL_PACKET;
121 static int psmouse_smbus_reconnect(struct psmouse *psmouse)
123 struct psmouse_smbus_dev *smbdev = psmouse->private;
125 if (smbdev->need_deactivate)
126 psmouse_deactivate(psmouse);
131 struct psmouse_smbus_removal_work {
132 struct work_struct work;
133 struct i2c_client *client;
136 static void psmouse_smbus_remove_i2c_device(struct work_struct *work)
138 struct psmouse_smbus_removal_work *rwork =
139 container_of(work, struct psmouse_smbus_removal_work, work);
141 dev_dbg(&rwork->client->dev, "destroying SMBus companion device\n");
142 i2c_unregister_device(rwork->client);
148 * This schedules removal of SMBus companion device. We have to do
149 * it in a separate tread to avoid deadlocking on psmouse_mutex in
150 * case the device has a trackstick (which is also driven by psmouse).
152 * Note that this may be racing with i2c adapter removal, but we
153 * can't do anything about that: i2c automatically destroys clients
154 * attached to an adapter that is being removed. This has to be
157 static void psmouse_smbus_schedule_remove(struct i2c_client *client)
159 struct psmouse_smbus_removal_work *rwork;
161 rwork = kzalloc(sizeof(*rwork), GFP_KERNEL);
163 INIT_WORK(&rwork->work, psmouse_smbus_remove_i2c_device);
164 rwork->client = client;
166 queue_work(psmouse_smbus_wq, &rwork->work);
170 static void psmouse_smbus_disconnect(struct psmouse *psmouse)
172 struct psmouse_smbus_dev *smbdev = psmouse->private;
174 mutex_lock(&psmouse_smbus_mutex);
177 list_del(&smbdev->node);
181 device_link_remove(&smbdev->client->dev,
182 &psmouse->ps2dev.serio->dev);
183 psmouse_dbg(smbdev->psmouse,
184 "posting removal request for SMBus companion %s\n",
185 dev_name(&smbdev->client->dev));
186 psmouse_smbus_schedule_remove(smbdev->client);
189 mutex_unlock(&psmouse_smbus_mutex);
191 psmouse->private = NULL;
194 static int psmouse_smbus_create_companion(struct device *dev, void *data)
196 struct psmouse_smbus_dev *smbdev = data;
197 unsigned short addr_list[] = { smbdev->board.addr, I2C_CLIENT_END };
198 struct i2c_adapter *adapter;
199 struct i2c_client *client;
201 adapter = i2c_verify_adapter(dev);
205 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_HOST_NOTIFY))
208 client = i2c_new_scanned_device(adapter, &smbdev->board,
213 /* We have our(?) device, stop iterating i2c bus. */
214 smbdev->client = client;
218 void psmouse_smbus_cleanup(struct psmouse *psmouse)
220 struct psmouse_smbus_dev *smbdev, *tmp;
222 mutex_lock(&psmouse_smbus_mutex);
224 list_for_each_entry_safe(smbdev, tmp, &psmouse_smbus_list, node) {
225 if (psmouse == smbdev->psmouse) {
226 list_del(&smbdev->node);
231 mutex_unlock(&psmouse_smbus_mutex);
234 int psmouse_smbus_init(struct psmouse *psmouse,
235 const struct i2c_board_info *board,
236 const void *pdata, size_t pdata_size,
237 bool need_deactivate,
238 bool leave_breadcrumbs)
240 struct psmouse_smbus_dev *smbdev;
243 smbdev = kzalloc(sizeof(*smbdev), GFP_KERNEL);
247 smbdev->psmouse = psmouse;
248 smbdev->board = *board;
249 smbdev->need_deactivate = need_deactivate;
252 smbdev->board.platform_data = kmemdup(pdata, pdata_size,
254 if (!smbdev->board.platform_data) {
261 psmouse_deactivate(psmouse);
263 psmouse->private = smbdev;
264 psmouse->protocol_handler = psmouse_smbus_process_byte;
265 psmouse->reconnect = psmouse_smbus_reconnect;
266 psmouse->fast_reconnect = psmouse_smbus_reconnect;
267 psmouse->disconnect = psmouse_smbus_disconnect;
268 psmouse->resync_time = 0;
270 mutex_lock(&psmouse_smbus_mutex);
271 list_add_tail(&smbdev->node, &psmouse_smbus_list);
272 mutex_unlock(&psmouse_smbus_mutex);
274 /* Bind to already existing adapters right away */
275 error = i2c_for_each_dev(smbdev, psmouse_smbus_create_companion);
277 if (smbdev->client) {
278 /* We have our companion device */
279 if (!device_link_add(&smbdev->client->dev,
280 &psmouse->ps2dev.serio->dev,
282 psmouse_warn(psmouse,
283 "failed to set up link with iSMBus companion %s\n",
284 dev_name(&smbdev->client->dev));
289 * If we did not create i2c device we will not need platform
290 * data even if we are leaving breadcrumbs.
292 kfree(smbdev->board.platform_data);
293 smbdev->board.platform_data = NULL;
295 if (error < 0 || !leave_breadcrumbs) {
296 mutex_lock(&psmouse_smbus_mutex);
297 list_del(&smbdev->node);
298 mutex_unlock(&psmouse_smbus_mutex);
303 return error < 0 ? error : -EAGAIN;
306 int __init psmouse_smbus_module_init(void)
310 psmouse_smbus_wq = alloc_workqueue("psmouse-smbus", 0, 0);
311 if (!psmouse_smbus_wq)
314 error = bus_register_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
316 pr_err("failed to register i2c bus notifier: %d\n", error);
317 destroy_workqueue(psmouse_smbus_wq);
324 void psmouse_smbus_module_exit(void)
326 bus_unregister_notifier(&i2c_bus_type, &psmouse_smbus_notifier);
327 destroy_workqueue(psmouse_smbus_wq);