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 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 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 } 104 105 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 } 161 162 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); 169 170 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); 177 178 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); 189 190 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); 201 202 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 } 208 209 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); 245 246 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); 283 284 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