2 * SMBus driver for ACPI Embedded Controller (v0.1)
4 * Copyright (c) 2007 Alexey Starikovskiy
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.
11 #include <acpi/acpi_bus.h>
12 #include <acpi/acpi_drivers.h>
13 #include <linux/wait.h>
14 #include <linux/delay.h>
15 #include <linux/interrupt.h>
18 #define PREFIX "ACPI: "
20 #define ACPI_SMB_HC_CLASS "smbus_host_controller"
21 #define ACPI_SMB_HC_DEVICE_NAME "ACPI SMBus HC"
26 wait_queue_head_t wait;
29 smbus_alarm_callback callback;
33 static int acpi_smbus_hc_add(struct acpi_device *device);
34 static int acpi_smbus_hc_remove(struct acpi_device *device, int type);
36 static const struct acpi_device_id sbs_device_ids[] = {
42 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
44 static struct acpi_driver acpi_smb_hc_driver = {
46 .class = ACPI_SMB_HC_CLASS,
47 .ids = sbs_device_ids,
49 .add = acpi_smbus_hc_add,
50 .remove = acpi_smbus_hc_remove,
54 union acpi_smb_status {
64 enum acpi_smb_status_codes {
66 SMBUS_UNKNOWN_FAILURE = 0x07,
67 SMBUS_DEVICE_ADDRESS_NACK = 0x10,
68 SMBUS_DEVICE_ERROR = 0x11,
69 SMBUS_DEVICE_COMMAND_ACCESS_DENIED = 0x12,
70 SMBUS_UNKNOWN_ERROR = 0x13,
71 SMBUS_DEVICE_ACCESS_DENIED = 0x17,
73 SMBUS_HOST_UNSUPPORTED_PROTOCOL = 0x19,
75 SMBUS_PEC_ERROR = 0x1f,
78 enum acpi_smb_offset {
79 ACPI_SMB_PROTOCOL = 0, /* protocol, PEC */
80 ACPI_SMB_STATUS = 1, /* status */
81 ACPI_SMB_ADDRESS = 2, /* address */
82 ACPI_SMB_COMMAND = 3, /* command */
83 ACPI_SMB_DATA = 4, /* 32 data registers */
84 ACPI_SMB_BLOCK_COUNT = 0x24, /* number of data bytes */
85 ACPI_SMB_ALARM_ADDRESS = 0x25, /* alarm address */
86 ACPI_SMB_ALARM_DATA = 0x26, /* 2 bytes alarm data */
89 static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data)
91 return ec_read(hc->offset + address, data);
94 static inline int smb_hc_write(struct acpi_smb_hc *hc, u8 address, u8 data)
96 return ec_write(hc->offset + address, data);
99 static inline int smb_check_done(struct acpi_smb_hc *hc)
101 union acpi_smb_status status = {.raw = 0};
102 smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw);
103 return status.fields.done && (status.fields.status == SMBUS_OK);
106 static int wait_transaction_complete(struct acpi_smb_hc *hc, int timeout)
108 if (wait_event_timeout(hc->wait, smb_check_done(hc),
109 msecs_to_jiffies(timeout)))
112 * After the timeout happens, OS will try to check the status of SMbus.
113 * If the status is what OS expected, it will be regarded as the bogus
116 if (smb_check_done(hc))
122 static int acpi_smbus_transaction(struct acpi_smb_hc *hc, u8 protocol,
123 u8 address, u8 command, u8 *data, u8 length)
125 int ret = -EFAULT, i;
129 printk(KERN_ERR PREFIX "host controller is not configured\n");
133 mutex_lock(&hc->lock);
134 if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp))
140 smb_hc_write(hc, ACPI_SMB_COMMAND, command);
141 if (!(protocol & 0x01)) {
142 smb_hc_write(hc, ACPI_SMB_BLOCK_COUNT, length);
143 for (i = 0; i < length; ++i)
144 smb_hc_write(hc, ACPI_SMB_DATA + i, data[i]);
146 smb_hc_write(hc, ACPI_SMB_ADDRESS, address << 1);
147 smb_hc_write(hc, ACPI_SMB_PROTOCOL, protocol);
149 * Wait for completion. Save the status code, data size,
150 * and data into the return package (if required by the protocol).
152 ret = wait_transaction_complete(hc, 1000);
153 if (ret || !(protocol & 0x01))
156 case SMBUS_RECEIVE_BYTE:
157 case SMBUS_READ_BYTE:
160 case SMBUS_READ_WORD:
163 case SMBUS_READ_BLOCK:
164 if (smb_hc_read(hc, ACPI_SMB_BLOCK_COUNT, &sz)) {
171 for (i = 0; i < sz; ++i)
172 smb_hc_read(hc, ACPI_SMB_DATA + i, &data[i]);
174 mutex_unlock(&hc->lock);
178 int acpi_smbus_read(struct acpi_smb_hc *hc, u8 protocol, u8 address,
179 u8 command, u8 *data)
181 return acpi_smbus_transaction(hc, protocol, address, command, data, 0);
184 EXPORT_SYMBOL_GPL(acpi_smbus_read);
186 int acpi_smbus_write(struct acpi_smb_hc *hc, u8 protocol, u8 address,
187 u8 command, u8 *data, u8 length)
189 return acpi_smbus_transaction(hc, protocol, address, command, data, length);
192 EXPORT_SYMBOL_GPL(acpi_smbus_write);
194 int acpi_smbus_register_callback(struct acpi_smb_hc *hc,
195 smbus_alarm_callback callback, void *context)
197 mutex_lock(&hc->lock);
198 hc->callback = callback;
199 hc->context = context;
200 mutex_unlock(&hc->lock);
204 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
206 int acpi_smbus_unregister_callback(struct acpi_smb_hc *hc)
208 mutex_lock(&hc->lock);
211 mutex_unlock(&hc->lock);
215 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
217 static inline void acpi_smbus_callback(void *context)
219 struct acpi_smb_hc *hc = context;
221 hc->callback(hc->context);
224 static int smbus_alarm(void *context)
226 struct acpi_smb_hc *hc = context;
227 union acpi_smb_status status;
229 if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
231 /* Check if it is only a completion notify */
232 if (status.fields.done)
234 if (!status.fields.alarm)
236 mutex_lock(&hc->lock);
237 smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
238 status.fields.alarm = 0;
239 smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
240 /* We are only interested in events coming from known devices */
241 switch (address >> 1) {
242 case ACPI_SBS_CHARGER:
243 case ACPI_SBS_MANAGER:
244 case ACPI_SBS_BATTERY:
245 acpi_os_execute(OSL_NOTIFY_HANDLER,
246 acpi_smbus_callback, hc);
249 mutex_unlock(&hc->lock);
253 typedef int (*acpi_ec_query_func) (void *data);
255 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
256 acpi_handle handle, acpi_ec_query_func func,
259 static int acpi_smbus_hc_add(struct acpi_device *device)
262 unsigned long long val;
263 struct acpi_smb_hc *hc;
268 status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
269 if (ACPI_FAILURE(status)) {
270 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
274 strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
275 strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
277 hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
280 mutex_init(&hc->lock);
281 init_waitqueue_head(&hc->wait);
283 hc->ec = acpi_driver_data(device->parent);
284 hc->offset = (val >> 8) & 0xff;
285 hc->query_bit = val & 0xff;
286 device->driver_data = hc;
288 acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
289 printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
290 hc->ec, hc->offset, hc->query_bit);
295 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
297 static int acpi_smbus_hc_remove(struct acpi_device *device, int type)
299 struct acpi_smb_hc *hc;
304 hc = acpi_driver_data(device);
305 acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
307 device->driver_data = NULL;
311 static int __init acpi_smb_hc_init(void)
315 result = acpi_bus_register_driver(&acpi_smb_hc_driver);
321 static void __exit acpi_smb_hc_exit(void)
323 acpi_bus_unregister_driver(&acpi_smb_hc_driver);
326 module_init(acpi_smb_hc_init);
327 module_exit(acpi_smb_hc_exit);
329 MODULE_LICENSE("GPL");
330 MODULE_AUTHOR("Alexey Starikovskiy");
331 MODULE_DESCRIPTION("ACPI SMBus HC driver");