1 /*
2 * SMBus driver for ACPI Embedded Controller (v0.1)
3 *
4 * Copyright (c) 2007 Alexey Starikovskiy
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation version 2.
9 */
10
11 #include <acpi/acpi_bus.h>
12 #include <acpi/acpi_drivers.h>
13 #include <acpi/actypes.h>
14 #include <linux/wait.h>
15 #include <linux/delay.h>
16 #include <linux/interrupt.h>
17 #include "sbshc.h"
18
19 #define ACPI_SMB_HC_CLASS "smbus_host_controller"
20 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
21
22 struct acpi_smb_hc {
23 struct acpi_ec *ec;
24 struct mutex lock;
25 wait_queue_head_t wait;
26 u8 offset;
27 u8 query_bit;
28 smbus_alarm_callback callback;
29 void *context;
30 };
31
32 static int acpi_smbus_hc_add(struct acpi_device *device);
33 static int acpi_smbus_hc_remove(struct acpi_device *device, int type);
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
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
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
98 static inline int smb_check_done(struct acpi_smb_hc *hc)
99 {
100 union acpi_smb_status status = {.raw = 0};
101 smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
102 return status.fields.done && (status.fields.status == SMBUS_OK);
103 }
104
105 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
106 {
107 if (wait_event_timeout(hc->wait, smb_check_done(hc),
108 msecs_to_jiffies(timeout)))
109 return 0;
110 else
111 return -ETIME;
112 }
113
114 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
115 u8 address, u8 command, u8 *data, u8 length)
116 {
117 int ret = -EFAULT, i;
118 u8 temp, sz = 0;
119
120 if (!hc) {
121 printk(KERN_ERR PREFIX "host controller is not configured\n");
122 return ret;
123 }
124
125 mutex_lock(&hc->lock);
126 if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
127 goto end;
128 if (temp) {
129 ret = -EBUSY;
130 goto end;
131 }
132 smb_hc_write(hc, ACPI_SMB_COMMAND, command);
133 if (!(protocol & 0x01)) {
134 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
135 for (i = 0; i < length; ++i)
136 smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
137 }
138 smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
139 smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
140 /*
141 * Wait for completion. Save the status code, data size,
142 * and data into the return package (if required by the protocol).
143 */
144 ret = wait_transaction_complete(hc, 1000);
145 if (ret || !(protocol & 0x01))
146 goto end;
147 switch (protocol) {
148 case SMBUS_RECEIVE_BYTE:
149 case SMBUS_READ_BYTE:
150 sz = 1;
151 break;
152 case SMBUS_READ_WORD:
153 sz = 2;
154 break;
155 case SMBUS_READ_BLOCK:
156 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
157 ret = -EFAULT;
158 goto end;
159 }
160 sz &= 0x1f;
161 break;
162 }
163 for (i = 0; i < sz; ++i)
164 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
165 end:
166 mutex_unlock(&hc->lock);
167 return ret;
168 }
169
170 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
171 u8 command, u8 *data)
172 {
173 return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
174 }
175
176 EXPORT_SYMBOL_GPL(acpi_smbus_read);
177
178 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
179 u8 command, u8 *data, u8 length)
180 {
181 return acpi_smbus_transaction(hc, protocol, address, command, data, length);
182 }
183
184 EXPORT_SYMBOL_GPL(acpi_smbus_write);
185
186 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
187 smbus_alarm_callback callback, void *context)
188 {
189 mutex_lock(&hc->lock);
190 hc->callback = callback;
191 hc->context = context;
192 mutex_unlock(&hc->lock);
193 return 0;
194 }
195
196 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
197
198 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
199 {
200 mutex_lock(&hc->lock);
201 hc->callback = NULL;
202 hc->context = NULL;
203 mutex_unlock(&hc->lock);
204 return 0;
205 }
206
207 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
208
209 static inline void acpi_smbus_callback(void *context)
210 {
211 struct acpi_smb_hc *hc = context;
212 if (hc->callback)
213 hc->callback(hc->context);
214 }
215
216 static int smbus_alarm(void *context)
217 {
218 struct acpi_smb_hc *hc = context;
219 union acpi_smb_status status;
220 u8 address;
221 if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
222 return 0;
223 /* Check if it is only a completion notify */
224 if (status.fields.done)
225 wake_up(&hc->wait);
226 if (!status.fields.alarm)
227 return 0;
228 mutex_lock(&hc->lock);
229 smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
230 status.fields.alarm = 0;
231 smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
232 /* We are only interested in events coming from known devices */
233 switch (address >> 1) {
234 case ACPI_SBS_CHARGER:
235 case ACPI_SBS_MANAGER:
236 case ACPI_SBS_BATTERY:
237 acpi_os_execute(OSL_GPE_HANDLER,
238 acpi_smbus_callback, hc);
239 default:;
240 }
241 mutex_unlock(&hc->lock);
242 return 0;
243 }
244
245 typedef int (*acpi_ec_query_func) (void *data);
246
247 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
248 acpi_handle handle, acpi_ec_query_func func,
249 void *data);
250
251 static int acpi_smbus_hc_add(struct acpi_device *device)
252 {
253 int status;
254 unsigned long val;
255 struct acpi_smb_hc *hc;
256
257 if (!device)
258 return -EINVAL;
259
260 status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
261 if (ACPI_FAILURE(status)) {
262 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
263 return -EIO;
264 }
265
266 strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
267 strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
268
269 hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
270 if (!hc)
271 return -ENOMEM;
272 mutex_init(&hc->lock);
273 init_waitqueue_head(&hc->wait);
274
275 hc->ec = acpi_driver_data(device->parent);
276 hc->offset = (val >> 8) & 0xff;
277 hc->query_bit = val & 0xff;
278 acpi_driver_data(device) = hc;
279
280 acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
281 printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
282 hc->ec, hc->offset, hc->query_bit);
283
284 return 0;
285 }
286
287 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
288
289 static int acpi_smbus_hc_remove(struct acpi_device *device, int type)
290 {
291 struct acpi_smb_hc *hc;
292
293 if (!device)
294 return -EINVAL;
295
296 hc = acpi_driver_data(device);
297 acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
298 kfree(hc);
299 acpi_driver_data(device) = NULL;
300 return 0;
301 }
302
303 static int __init acpi_smb_hc_init(void)
304 {
305 int result;
306
307 result = acpi_bus_register_driver(&acpi_smb_hc_driver);
308 if (result < 0)
309 return -ENODEV;
310 return 0;
311 }
312
313 static void __exit acpi_smb_hc_exit(void)
314 {
315 acpi_bus_unregister_driver(&acpi_smb_hc_driver);
316 }
317
318 module_init(acpi_smb_hc_init);
319 module_exit(acpi_smb_hc_exit);
320
321 MODULE_LICENSE("GPL");
322 MODULE_AUTHOR("Alexey Starikovskiy");
323 MODULE_DESCRIPTION("ACPI SMBus HC driver");
324
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