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 <linux/acpi.h>
12#include <linux/wait.h>
13#include <linux/slab.h>
14#include <linux/delay.h>
15#include <linux/module.h>
16#include <linux/interrupt.h>
17#include "sbshc.h"
18
19#define PREFIX "ACPI: "
20
21#define ACPI_SMB_HC_CLASS "smbus_host_ctl"
22#define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
23
24struct acpi_smb_hc {
25 struct acpi_ec *ec;
26 struct mutex lock;
27 wait_queue_head_t wait;
28 u8 offset;
29 u8 query_bit;
30 smbus_alarm_callback callback;
31 void *context;
32 bool done;
33};
34
35static int acpi_smbus_hc_add(struct acpi_device *device);
36static int acpi_smbus_hc_remove(struct acpi_device *device);
37
38static const struct acpi_device_id sbs_device_ids[] = {
39 {"ACPI0001", 0},
40 {"ACPI0005", 0},
41 {"", 0},
42};
43
44MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
45
46static struct acpi_driver acpi_smb_hc_driver = {
47 .name = "smbus_hc",
48 .class = ACPI_SMB_HC_CLASS,
49 .ids = sbs_device_ids,
50 .ops = {
51 .add = acpi_smbus_hc_add,
52 .remove = acpi_smbus_hc_remove,
53 },
54};
55
56union acpi_smb_status {
57 u8 raw;
58 struct {
59 u8 status:5;
60 u8 reserved:1;
61 u8 alarm:1;
62 u8 done:1;
63 } fields;
64};
65
66enum acpi_smb_status_codes {
67 SMBUS_OK = 0,
68 SMBUS_UNKNOWN_FAILURE = 0x07,
69 SMBUS_DEVICE_ADDRESS_NACK = 0x10,
70 SMBUS_DEVICE_ERROR = 0x11,
71 SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
72 SMBUS_UNKNOWN_ERROR = 0x13,
73 SMBUS_DEVICE_ACCESS_DENIED = 0x17,
74 SMBUS_TIMEOUT = 0x18,
75 SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
76 SMBUS_BUSY = 0x1a,
77 SMBUS_PEC_ERROR = 0x1f,
78};
79
80enum acpi_smb_offset {
81 ACPI_SMB_PROTOCOL = 0, /* protocol, PEC */
82 ACPI_SMB_STATUS = 1, /* status */
83 ACPI_SMB_ADDRESS = 2, /* address */
84 ACPI_SMB_COMMAND = 3, /* command */
85 ACPI_SMB_DATA = 4, /* 32 data registers */
86 ACPI_SMB_BLOCK_COUNT = 0x24, /* number of data bytes */
87 ACPI_SMB_ALARM_ADDRESS = 0x25, /* alarm address */
88 ACPI_SMB_ALARM_DATA = 0x26, /* 2 bytes alarm data */
89};
90
91static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
92{
93 return ec_read(hc->offset + address, data);
94}
95
96static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
97{
98 return ec_write(hc->offset + address, data);
99}
100
101static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
102{
103 if (wait_event_timeout(hc->wait, hc->done, msecs_to_jiffies(timeout)))
104 return 0;
105 return -ETIME;
106}
107
108static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
109 u8 address, u8 command, u8 *data, u8 length)
110{
111 int ret = -EFAULT, i;
112 u8 temp, sz = 0;
113
114 if (!hc) {
115 printk(KERN_ERR PREFIX "host controller is not configured\n");
116 return ret;
117 }
118
119 mutex_lock(&hc->lock);
120 hc->done = false;
121 if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
122 goto end;
123 if (temp) {
124 ret = -EBUSY;
125 goto end;
126 }
127 smb_hc_write(hc, ACPI_SMB_COMMAND, command);
128 if (!(protocol & 0x01)) {
129 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
130 for (i = 0; i < length; ++i)
131 smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
132 }
133 smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
134 smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
135 /*
136 * Wait for completion. Save the status code, data size,
137 * and data into the return package (if required by the protocol).
138 */
139 ret = wait_transaction_complete(hc, 1000);
140 if (ret || !(protocol & 0x01))
141 goto end;
142 switch (protocol) {
143 case SMBUS_RECEIVE_BYTE:
144 case SMBUS_READ_BYTE:
145 sz = 1;
146 break;
147 case SMBUS_READ_WORD:
148 sz = 2;
149 break;
150 case SMBUS_READ_BLOCK:
151 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
152 ret = -EFAULT;
153 goto end;
154 }
155 sz &= 0x1f;
156 break;
157 }
158 for (i = 0; i < sz; ++i)
159 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
160 end:
161 mutex_unlock(&hc->lock);
162 return ret;
163}
164
165int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
166 u8 command, u8 *data)
167{
168 return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
169}
170
171EXPORT_SYMBOL_GPL(acpi_smbus_read);
172
173int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
174 u8 command, u8 *data, u8 length)
175{
176 return acpi_smbus_transaction(hc, protocol, address, command, data, length);
177}
178
179EXPORT_SYMBOL_GPL(acpi_smbus_write);
180
181int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
182 smbus_alarm_callback callback, void *context)
183{
184 mutex_lock(&hc->lock);
185 hc->callback = callback;
186 hc->context = context;
187 mutex_unlock(&hc->lock);
188 return 0;
189}
190
191EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
192
193int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
194{
195 mutex_lock(&hc->lock);
196 hc->callback = NULL;
197 hc->context = NULL;
198 mutex_unlock(&hc->lock);
199 acpi_os_wait_events_complete();
200 return 0;
201}
202
203EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
204
205static inline void acpi_smbus_callback(void *context)
206{
207 struct acpi_smb_hc *hc = context;
208 if (hc->callback)
209 hc->callback(hc->context);
210}
211
212static int smbus_alarm(void *context)
213{
214 struct acpi_smb_hc *hc = context;
215 union acpi_smb_status status;
216 u8 address;
217 if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
218 return 0;
219 /* Check if it is only a completion notify */
220 if (status.fields.done && status.fields.status == SMBUS_OK) {
221 hc->done = true;
222 wake_up(&hc->wait);
223 }
224 if (!status.fields.alarm)
225 return 0;
226 mutex_lock(&hc->lock);
227 smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
228 status.fields.alarm = 0;
229 smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
230 /* We are only interested in events coming from known devices */
231 switch (address >> 1) {
232 case ACPI_SBS_CHARGER:
233 case ACPI_SBS_MANAGER:
234 case ACPI_SBS_BATTERY:
235 acpi_os_execute(OSL_NOTIFY_HANDLER,
236 acpi_smbus_callback, hc);
237 default:;
238 }
239 mutex_unlock(&hc->lock);
240 return 0;
241}
242
243typedef int (*acpi_ec_query_func) (void *data);
244
245extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
246 acpi_handle handle, acpi_ec_query_func func,
247 void *data);
248
249static int acpi_smbus_hc_add(struct acpi_device *device)
250{
251 int status;
252 unsigned long long val;
253 struct acpi_smb_hc *hc;
254
255 if (!device)
256 return -EINVAL;
257
258 status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
259 if (ACPI_FAILURE(status)) {
260 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
261 return -EIO;
262 }
263
264 strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
265 strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
266
267 hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
268 if (!hc)
269 return -ENOMEM;
270 mutex_init(&hc->lock);
271 init_waitqueue_head(&hc->wait);
272
273 hc->ec = acpi_driver_data(device->parent);
274 hc->offset = (val >> 8) & 0xff;
275 hc->query_bit = val & 0xff;
276 device->driver_data = hc;
277
278 acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
279 dev_info(&device->dev, "SBS HC: offset = 0x%0x, query_bit = 0x%0x\n",
280 hc->offset, hc->query_bit);
281
282 return 0;
283}
284
285extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
286
287static int acpi_smbus_hc_remove(struct acpi_device *device)
288{
289 struct acpi_smb_hc *hc;
290
291 if (!device)
292 return -EINVAL;
293
294 hc = acpi_driver_data(device);
295 acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
296 acpi_os_wait_events_complete();
297 kfree(hc);
298 device->driver_data = NULL;
299 return 0;
300}
301
302module_acpi_driver(acpi_smb_hc_driver);
303
304MODULE_LICENSE("GPL");
305MODULE_AUTHOR("Alexey Starikovskiy");
306MODULE_DESCRIPTION("ACPI SMBus HC driver");
307