1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * SMBus driver for ACPI Embedded Controller (v0.1)
4 *
5 * Copyright (c) 2007 Alexey Starikovskiy
6 */
7
8 #include <linux/acpi.h>
9 #include <linux/wait.h>
10 #include <linux/slab.h>
11 #include <linux/delay.h>
12 #include <linux/module.h>
13 #include <linux/interrupt.h>
14 #include "sbshc.h"
15
16 #define PREFIX "ACPI: "
17
18 #define ACPI_SMB_HC_CLASS "smbus_host_ctl"
19 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
20
21 struct acpi_smb_hc {
22 struct acpi_ec *ec;
23 struct mutex lock;
24 wait_queue_head_t wait;
25 u8 offset;
26 u8 query_bit;
27 smbus_alarm_callback callback;
28 void *context;
29 bool done;
30 };
31
32 static int acpi_smbus_hc_add(struct acpi_device *device);
33 static int acpi_smbus_hc_remove(struct acpi_device *device);
34
35 static const struct acpi_device_id sbs_device_ids[] = {
36 {"ACPI0001", 0},
37 {"ACPI0005", 0},
38 {"", 0},
39 };
40
41 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
42
43 static struct acpi_driver acpi_smb_hc_driver = {
44 .name = "smbus_hc",
45 .class = ACPI_SMB_HC_CLASS,
46 .ids = sbs_device_ids,
47 .ops = {
48 .add = acpi_smbus_hc_add,
49 .remove = acpi_smbus_hc_remove,
50 },
51 };
52
53 union acpi_smb_status {
54 u8 raw;
55 struct {
56 u8 status:5;
57 u8 reserved:1;
58 u8 alarm:1;
59 u8 done:1;
60 } fields;
61 };
62
63 enum acpi_smb_status_codes {
64 SMBUS_OK = 0,
65 SMBUS_UNKNOWN_FAILURE = 0x07,
66 SMBUS_DEVICE_ADDRESS_NACK = 0x10,
67 SMBUS_DEVICE_ERROR = 0x11,
68 SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
69 SMBUS_UNKNOWN_ERROR = 0x13,
70 SMBUS_DEVICE_ACCESS_DENIED = 0x17,
71 SMBUS_TIMEOUT = 0x18,
72 SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
73 SMBUS_BUSY = 0x1a,
74 SMBUS_PEC_ERROR = 0x1f,
75 };
76
77 enum acpi_smb_offset {
78 ACPI_SMB_PROTOCOL = 0, /* protocol, PEC */
79 ACPI_SMB_STATUS = 1, /* status */
80 ACPI_SMB_ADDRESS = 2, /* address */
81 ACPI_SMB_COMMAND = 3, /* command */
82 ACPI_SMB_DATA = 4, /* 32 data registers */
83 ACPI_SMB_BLOCK_COUNT = 0x24, /* number of data bytes */
84 ACPI_SMB_ALARM_ADDRESS = 0x25, /* alarm address */
85 ACPI_SMB_ALARM_DATA = 0x26, /* 2 bytes alarm data */
86 };
87
smb_hc_read(struct acpi_smb_hc * hc,u8 address,u8 * data)88 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
89 {
90 return ec_read(hc->offset + address, data);
91 }
92
smb_hc_write(struct acpi_smb_hc * hc,u8 address,u8 data)93 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
94 {
95 return ec_write(hc->offset + address, data);
96 }
97
wait_transaction_complete(struct acpi_smb_hc * hc,int timeout)98 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
99 {
100 if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
101 return 0;
102 return -ETIME;
103 }
104
acpi_smbus_transaction(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)105 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
106 u8 address, u8 command, u8 *data, u8 length)
107 {
108 int ret = -EFAULT, i;
109 u8 temp, sz = 0;
110
111 if (!hc) {
112 printk(KERN_ERR PREFIX "host controller is not configured\n");
113 return ret;
114 }
115
116 mutex_lock(&hc->lock);
117 hc->done = false;
118 if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
119 goto end;
120 if (temp) {
121 ret = -EBUSY;
122 goto end;
123 }
124 smb_hc_write(hc, ACPI_SMB_COMMAND, command);
125 if (!(protocol & 0x01)) {
126 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
127 for (i = 0; i < length; ++i)
128 smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
129 }
130 smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
131 smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
132 /*
133 * Wait for completion. Save the status code, data size,
134 * and data into the return package (if required by the protocol).
135 */
136 ret = wait_transaction_complete(hc, 1000);
137 if (ret || !(protocol & 0x01))
138 goto end;
139 switch (protocol) {
140 case SMBUS_RECEIVE_BYTE:
141 case SMBUS_READ_BYTE:
142 sz = 1;
143 break;
144 case SMBUS_READ_WORD:
145 sz = 2;
146 break;
147 case SMBUS_READ_BLOCK:
148 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
149 ret = -EFAULT;
150 goto end;
151 }
152 sz &= 0x1f;
153 break;
154 }
155 for (i = 0; i < sz; ++i)
156 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
157 end:
158 mutex_unlock(&hc->lock);
159 return ret;
160 }
161
acpi_smbus_read(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data)162 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
163 u8 command, u8 *data)
164 {
165 return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
166 }
167
168 EXPORT_SYMBOL_GPL(acpi_smbus_read);
169
acpi_smbus_write(struct acpi_smb_hc * hc,u8 protocol,u8 address,u8 command,u8 * data,u8 length)170 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
171 u8 command, u8 *data, u8 length)
172 {
173 return acpi_smbus_transaction(hc, protocol, address, command, data, length);
174 }
175
176 EXPORT_SYMBOL_GPL(acpi_smbus_write);
177
acpi_smbus_register_callback(struct acpi_smb_hc * hc,smbus_alarm_callback callback,void * context)178 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
179 smbus_alarm_callback callback, void *context)
180 {
181 mutex_lock(&hc->lock);
182 hc->callback = callback;
183 hc->context = context;
184 mutex_unlock(&hc->lock);
185 return 0;
186 }
187
188 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
189
acpi_smbus_unregister_callback(struct acpi_smb_hc * hc)190 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
191 {
192 mutex_lock(&hc->lock);
193 hc->callback = NULL;
194 hc->context = NULL;
195 mutex_unlock(&hc->lock);
196 acpi_os_wait_events_complete();
197 return 0;
198 }
199
200 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
201
acpi_smbus_callback(void * context)202 static inline void acpi_smbus_callback(void *context)
203 {
204 struct acpi_smb_hc *hc = context;
205 if (hc->callback)
206 hc->callback(hc->context);
207 }
208
smbus_alarm(void * context)209 static int smbus_alarm(void *context)
210 {
211 struct acpi_smb_hc *hc = context;
212 union acpi_smb_status status;
213 u8 address;
214 if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
215 return 0;
216 /* Check if it is only a completion notify */
217 if (status.fields.done && status.fields.status == SMBUS_OK) {
218 hc->done = true;
219 wake_up(&hc->wait);
220 }
221 if (!status.fields.alarm)
222 return 0;
223 mutex_lock(&hc->lock);
224 smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
225 status.fields.alarm = 0;
226 smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
227 /* We are only interested in events coming from known devices */
228 switch (address >> 1) {
229 case ACPI_SBS_CHARGER:
230 case ACPI_SBS_MANAGER:
231 case ACPI_SBS_BATTERY:
232 acpi_os_execute(OSL_NOTIFY_HANDLER,
233 acpi_smbus_callback, hc);
234 default:;
235 }
236 mutex_unlock(&hc->lock);
237 return 0;
238 }
239
240 typedef int (*acpi_ec_query_func) (void *data);
241
242 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
243 acpi_handle handle, acpi_ec_query_func func,
244 void *data);
245
acpi_smbus_hc_add(struct acpi_device * device)246 static int acpi_smbus_hc_add(struct acpi_device *device)
247 {
248 int status;
249 unsigned long long val;
250 struct acpi_smb_hc *hc;
251
252 if (!device)
253 return -EINVAL;
254
255 status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
256 if (ACPI_FAILURE(status)) {
257 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
258 return -EIO;
259 }
260
261 strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
262 strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
263
264 hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
265 if (!hc)
266 return -ENOMEM;
267 mutex_init(&hc->lock);
268 init_waitqueue_head(&hc->wait);
269
270 hc->ec = acpi_driver_data(device->parent);
271 hc->offset = (val >> 8) & 0xff;
272 hc->query_bit = val & 0xff;
273 device->driver_data = hc;
274
275 acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
276 dev_info(&device->dev, "SBS HC: offset = 0x%0x, query_bit = 0x%0x\n",
277 hc->offset, hc->query_bit);
278
279 return 0;
280 }
281
282 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
283
acpi_smbus_hc_remove(struct acpi_device * device)284 static int acpi_smbus_hc_remove(struct acpi_device *device)
285 {
286 struct acpi_smb_hc *hc;
287
288 if (!device)
289 return -EINVAL;
290
291 hc = acpi_driver_data(device);
292 acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
293 acpi_os_wait_events_complete();
294 kfree(hc);
295 device->driver_data = NULL;
296 return 0;
297 }
298
299 module_acpi_driver(acpi_smb_hc_driver);
300
301 MODULE_LICENSE("GPL");
302 MODULE_AUTHOR("Alexey Starikovskiy");
303 MODULE_DESCRIPTION("ACPI SMBus HC driver");
304