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Linux/drivers/acpi/sbshc.c

  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 
 24 struct 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 
 35 static int acpi_smbus_hc_add(struct acpi_device *device);
 36 static int acpi_smbus_hc_remove(struct acpi_device *device);
 37 
 38 static const struct acpi_device_id sbs_device_ids[] = {
 39         {"ACPI0001", 0},
 40         {"ACPI0005", 0},
 41         {"", 0},
 42 };
 43 
 44 MODULE_DEVICE_TABLE(acpi, sbs_device_ids);
 45 
 46 static 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 
 56 union 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 
 66 enum 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 
 80 enum 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 
 91 static 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 
 96 static 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 
101 static 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 
108 static 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 
165 int 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 
171 EXPORT_SYMBOL_GPL(acpi_smbus_read);
172 
173 int 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 
179 EXPORT_SYMBOL_GPL(acpi_smbus_write);
180 
181 int 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 
191 EXPORT_SYMBOL_GPL(acpi_smbus_register_callback);
192 
193 int 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         return 0;
200 }
201 
202 EXPORT_SYMBOL_GPL(acpi_smbus_unregister_callback);
203 
204 static inline void acpi_smbus_callback(void *context)
205 {
206         struct acpi_smb_hc *hc = context;
207         if (hc->callback)
208                 hc->callback(hc->context);
209 }
210 
211 static int smbus_alarm(void *context)
212 {
213         struct acpi_smb_hc *hc = context;
214         union acpi_smb_status status;
215         u8 address;
216         if (smb_hc_read(hc, ACPI_SMB_STATUS, &status.raw))
217                 return 0;
218         /* Check if it is only a completion notify */
219         if (status.fields.done && status.fields.status == SMBUS_OK) {
220                 hc->done = true;
221                 wake_up(&hc->wait);
222         }
223         if (!status.fields.alarm)
224                 return 0;
225         mutex_lock(&hc->lock);
226         smb_hc_read(hc, ACPI_SMB_ALARM_ADDRESS, &address);
227         status.fields.alarm = 0;
228         smb_hc_write(hc, ACPI_SMB_STATUS, status.raw);
229         /* We are only interested in events coming from known devices */
230         switch (address >> 1) {
231                 case ACPI_SBS_CHARGER:
232                 case ACPI_SBS_MANAGER:
233                 case ACPI_SBS_BATTERY:
234                         acpi_os_execute(OSL_NOTIFY_HANDLER,
235                                         acpi_smbus_callback, hc);
236                 default:;
237         }
238         mutex_unlock(&hc->lock);
239         return 0;
240 }
241 
242 typedef int (*acpi_ec_query_func) (void *data);
243 
244 extern int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit,
245                               acpi_handle handle, acpi_ec_query_func func,
246                               void *data);
247 
248 static int acpi_smbus_hc_add(struct acpi_device *device)
249 {
250         int status;
251         unsigned long long val;
252         struct acpi_smb_hc *hc;
253 
254         if (!device)
255                 return -EINVAL;
256 
257         status = acpi_evaluate_integer(device->handle, "_EC", NULL, &val);
258         if (ACPI_FAILURE(status)) {
259                 printk(KERN_ERR PREFIX "error obtaining _EC.\n");
260                 return -EIO;
261         }
262 
263         strcpy(acpi_device_name(device), ACPI_SMB_HC_DEVICE_NAME);
264         strcpy(acpi_device_class(device), ACPI_SMB_HC_CLASS);
265 
266         hc = kzalloc(sizeof(struct acpi_smb_hc), GFP_KERNEL);
267         if (!hc)
268                 return -ENOMEM;
269         mutex_init(&hc->lock);
270         init_waitqueue_head(&hc->wait);
271 
272         hc->ec = acpi_driver_data(device->parent);
273         hc->offset = (val >> 8) & 0xff;
274         hc->query_bit = val & 0xff;
275         device->driver_data = hc;
276 
277         acpi_ec_add_query_handler(hc->ec, hc->query_bit, NULL, smbus_alarm, hc);
278         printk(KERN_INFO PREFIX "SBS HC: EC = 0x%p, offset = 0x%0x, query_bit = 0x%0x\n",
279                 hc->ec, hc->offset, hc->query_bit);
280 
281         return 0;
282 }
283 
284 extern void acpi_ec_remove_query_handler(struct acpi_ec *ec, u8 query_bit);
285 
286 static int acpi_smbus_hc_remove(struct acpi_device *device)
287 {
288         struct acpi_smb_hc *hc;
289 
290         if (!device)
291                 return -EINVAL;
292 
293         hc = acpi_driver_data(device);
294         acpi_ec_remove_query_handler(hc->ec, hc->query_bit);
295         kfree(hc);
296         device->driver_data = NULL;
297         return 0;
298 }
299 
300 module_acpi_driver(acpi_smb_hc_driver);
301 
302 MODULE_LICENSE("GPL");
303 MODULE_AUTHOR("Alexey Starikovskiy");
304 MODULE_DESCRIPTION("ACPI SMBus HC driver");
305 

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