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/delay.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/libps2.h>
12 #include <linux/i2c.h>
13 #include <linux/serio.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h>
18 struct psmouse_smbus_dev
{
19 struct i2c_board_info board
;
20 struct psmouse
*psmouse
;
21 struct i2c_client
*client
;
22 struct list_head node
;
27 static LIST_HEAD(psmouse_smbus_list
);
28 static DEFINE_MUTEX(psmouse_smbus_mutex
);
30 static struct workqueue_struct
*psmouse_smbus_wq
;
32 static void psmouse_smbus_check_adapter(struct i2c_adapter
*adapter
)
34 struct psmouse_smbus_dev
*smbdev
;
36 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_HOST_NOTIFY
))
39 mutex_lock(&psmouse_smbus_mutex
);
41 list_for_each_entry(smbdev
, &psmouse_smbus_list
, node
) {
49 * Here would be a good place to check if device is actually
50 * present, but it seems that SMBus will not respond unless we
51 * fully reset PS/2 connection. So cross our fingers, and try
52 * to switch over, hopefully our system will not have too many
53 * "host notify" I2C adapters.
55 psmouse_dbg(smbdev
->psmouse
,
56 "SMBus candidate adapter appeared, triggering rescan\n");
57 serio_rescan(smbdev
->psmouse
->ps2dev
.serio
);
60 mutex_unlock(&psmouse_smbus_mutex
);
63 static void psmouse_smbus_detach_i2c_client(struct i2c_client
*client
)
65 struct psmouse_smbus_dev
*smbdev
, *tmp
;
67 mutex_lock(&psmouse_smbus_mutex
);
69 list_for_each_entry_safe(smbdev
, tmp
, &psmouse_smbus_list
, node
) {
70 if (smbdev
->client
!= client
)
73 kfree(client
->dev
.platform_data
);
74 client
->dev
.platform_data
= NULL
;
77 psmouse_dbg(smbdev
->psmouse
,
78 "Marking SMBus companion %s as gone\n",
79 dev_name(&smbdev
->client
->dev
));
81 device_link_remove(&smbdev
->client
->dev
,
82 &smbdev
->psmouse
->ps2dev
.serio
->dev
);
83 serio_rescan(smbdev
->psmouse
->ps2dev
.serio
);
85 list_del(&smbdev
->node
);
90 mutex_unlock(&psmouse_smbus_mutex
);
93 static int psmouse_smbus_notifier_call(struct notifier_block
*nb
,
94 unsigned long action
, void *data
)
96 struct device
*dev
= data
;
99 case BUS_NOTIFY_ADD_DEVICE
:
100 if (dev
->type
== &i2c_adapter_type
)
101 psmouse_smbus_check_adapter(to_i2c_adapter(dev
));
104 case BUS_NOTIFY_REMOVED_DEVICE
:
105 if (dev
->type
== &i2c_client_type
)
106 psmouse_smbus_detach_i2c_client(to_i2c_client(dev
));
113 static struct notifier_block psmouse_smbus_notifier
= {
114 .notifier_call
= psmouse_smbus_notifier_call
,
117 static psmouse_ret_t
psmouse_smbus_process_byte(struct psmouse
*psmouse
)
119 return PSMOUSE_FULL_PACKET
;
122 static void psmouse_activate_smbus_mode(struct psmouse_smbus_dev
*smbdev
)
124 if (smbdev
->need_deactivate
) {
125 psmouse_deactivate(smbdev
->psmouse
);
126 /* Give the device time to switch into SMBus mode */
131 static int psmouse_smbus_reconnect(struct psmouse
*psmouse
)
133 psmouse_activate_smbus_mode(psmouse
->private);
137 struct psmouse_smbus_removal_work
{
138 struct work_struct work
;
139 struct i2c_client
*client
;
142 static void psmouse_smbus_remove_i2c_device(struct work_struct
*work
)
144 struct psmouse_smbus_removal_work
*rwork
=
145 container_of(work
, struct psmouse_smbus_removal_work
, work
);
147 dev_dbg(&rwork
->client
->dev
, "destroying SMBus companion device\n");
148 i2c_unregister_device(rwork
->client
);
154 * This schedules removal of SMBus companion device. We have to do
155 * it in a separate tread to avoid deadlocking on psmouse_mutex in
156 * case the device has a trackstick (which is also driven by psmouse).
158 * Note that this may be racing with i2c adapter removal, but we
159 * can't do anything about that: i2c automatically destroys clients
160 * attached to an adapter that is being removed. This has to be
163 static void psmouse_smbus_schedule_remove(struct i2c_client
*client
)
165 struct psmouse_smbus_removal_work
*rwork
;
167 rwork
= kzalloc(sizeof(*rwork
), GFP_KERNEL
);
169 INIT_WORK(&rwork
->work
, psmouse_smbus_remove_i2c_device
);
170 rwork
->client
= client
;
172 queue_work(psmouse_smbus_wq
, &rwork
->work
);
176 static void psmouse_smbus_disconnect(struct psmouse
*psmouse
)
178 struct psmouse_smbus_dev
*smbdev
= psmouse
->private;
180 mutex_lock(&psmouse_smbus_mutex
);
183 list_del(&smbdev
->node
);
187 device_link_remove(&smbdev
->client
->dev
,
188 &psmouse
->ps2dev
.serio
->dev
);
189 psmouse_dbg(smbdev
->psmouse
,
190 "posting removal request for SMBus companion %s\n",
191 dev_name(&smbdev
->client
->dev
));
192 psmouse_smbus_schedule_remove(smbdev
->client
);
195 mutex_unlock(&psmouse_smbus_mutex
);
197 psmouse
->private = NULL
;
200 static int psmouse_smbus_create_companion(struct device
*dev
, void *data
)
202 struct psmouse_smbus_dev
*smbdev
= data
;
203 unsigned short addr_list
[] = { smbdev
->board
.addr
, I2C_CLIENT_END
};
204 struct i2c_adapter
*adapter
;
205 struct i2c_client
*client
;
207 adapter
= i2c_verify_adapter(dev
);
211 if (!i2c_check_functionality(adapter
, I2C_FUNC_SMBUS_HOST_NOTIFY
))
214 client
= i2c_new_scanned_device(adapter
, &smbdev
->board
,
219 /* We have our(?) device, stop iterating i2c bus. */
220 smbdev
->client
= client
;
224 void psmouse_smbus_cleanup(struct psmouse
*psmouse
)
226 struct psmouse_smbus_dev
*smbdev
, *tmp
;
228 mutex_lock(&psmouse_smbus_mutex
);
230 list_for_each_entry_safe(smbdev
, tmp
, &psmouse_smbus_list
, node
) {
231 if (psmouse
== smbdev
->psmouse
) {
232 list_del(&smbdev
->node
);
237 mutex_unlock(&psmouse_smbus_mutex
);
240 int psmouse_smbus_init(struct psmouse
*psmouse
,
241 const struct i2c_board_info
*board
,
242 const void *pdata
, size_t pdata_size
,
243 bool need_deactivate
,
244 bool leave_breadcrumbs
)
246 struct psmouse_smbus_dev
*smbdev
;
249 smbdev
= kzalloc(sizeof(*smbdev
), GFP_KERNEL
);
253 smbdev
->psmouse
= psmouse
;
254 smbdev
->board
= *board
;
255 smbdev
->need_deactivate
= need_deactivate
;
258 smbdev
->board
.platform_data
= kmemdup(pdata
, pdata_size
,
260 if (!smbdev
->board
.platform_data
) {
266 psmouse_activate_smbus_mode(smbdev
);
268 psmouse
->private = smbdev
;
269 psmouse
->protocol_handler
= psmouse_smbus_process_byte
;
270 psmouse
->reconnect
= psmouse_smbus_reconnect
;
271 psmouse
->fast_reconnect
= psmouse_smbus_reconnect
;
272 psmouse
->disconnect
= psmouse_smbus_disconnect
;
273 psmouse
->resync_time
= 0;
275 mutex_lock(&psmouse_smbus_mutex
);
276 list_add_tail(&smbdev
->node
, &psmouse_smbus_list
);
277 mutex_unlock(&psmouse_smbus_mutex
);
279 /* Bind to already existing adapters right away */
280 error
= i2c_for_each_dev(smbdev
, psmouse_smbus_create_companion
);
282 if (smbdev
->client
) {
283 /* We have our companion device */
284 if (!device_link_add(&smbdev
->client
->dev
,
285 &psmouse
->ps2dev
.serio
->dev
,
287 psmouse_warn(psmouse
,
288 "failed to set up link with iSMBus companion %s\n",
289 dev_name(&smbdev
->client
->dev
));
294 * If we did not create i2c device we will not need platform
295 * data even if we are leaving breadcrumbs.
297 kfree(smbdev
->board
.platform_data
);
298 smbdev
->board
.platform_data
= NULL
;
300 if (error
< 0 || !leave_breadcrumbs
) {
301 mutex_lock(&psmouse_smbus_mutex
);
302 list_del(&smbdev
->node
);
303 mutex_unlock(&psmouse_smbus_mutex
);
308 return error
< 0 ? error
: -EAGAIN
;
311 int __init
psmouse_smbus_module_init(void)
315 psmouse_smbus_wq
= alloc_workqueue("psmouse-smbus", 0, 0);
316 if (!psmouse_smbus_wq
)
319 error
= bus_register_notifier(&i2c_bus_type
, &psmouse_smbus_notifier
);
321 pr_err("failed to register i2c bus notifier: %d\n", error
);
322 destroy_workqueue(psmouse_smbus_wq
);
329 void psmouse_smbus_module_exit(void)
331 bus_unregister_notifier(&i2c_bus_type
, &psmouse_smbus_notifier
);
332 destroy_workqueue(psmouse_smbus_wq
);