1 /* 2 * Driver for the TAOS evaluation modules 3 * These devices include an I2C master which can be controlled over the 4 * serial port. 5 * 6 * Copyright (C) 2007 Jean Delvare <khali@linux-fr.org> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; version 2 of the License. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #include <linux/delay.h> 23 #include <linux/module.h> 24 #include <linux/slab.h> 25 #include <linux/interrupt.h> 26 #include <linux/input.h> 27 #include <linux/serio.h> 28 #include <linux/init.h> 29 #include <linux/i2c.h> 30 31 #define TAOS_BUFFER_SIZE 63 32 33 #define TAOS_STATE_INIT 0 34 #define TAOS_STATE_IDLE 1 35 #define TAOS_STATE_SEND 2 36 #define TAOS_STATE_RECV 3 37 38 #define TAOS_CMD_RESET 0x12 39 40 static DECLARE_WAIT_QUEUE_HEAD(wq); 41 42 struct taos_data { 43 struct i2c_adapter adapter; 44 struct i2c_client *client; 45 int state; 46 u8 addr; /* last used address */ 47 unsigned char buffer[TAOS_BUFFER_SIZE]; 48 unsigned int pos; /* position inside the buffer */ 49 }; 50 51 /* TAOS TSL2550 EVM */ 52 static struct i2c_board_info tsl2550_info = { 53 I2C_BOARD_INFO("tsl2550", 0x39), 54 }; 55 56 /* Instantiate i2c devices based on the adapter name */ 57 static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) 58 { 59 if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { 60 dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", 61 tsl2550_info.type, tsl2550_info.addr); 62 return i2c_new_device(adapter, &tsl2550_info); 63 } 64 65 return NULL; 66 } 67 68 static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 69 unsigned short flags, char read_write, u8 command, 70 int size, union i2c_smbus_data *data) 71 { 72 struct serio *serio = adapter->algo_data; 73 struct taos_data *taos = serio_get_drvdata(serio); 74 char *p; 75 76 /* Encode our transaction. "@" is for the device address, "$" for the 77 SMBus command and "#" for the data. */ 78 p = taos->buffer; 79 80 /* The device remembers the last used address, no need to send it 81 again if it's the same */ 82 if (addr != taos->addr) 83 p += sprintf(p, "@%02X", addr); 84 85 switch (size) { 86 case I2C_SMBUS_BYTE: 87 if (read_write == I2C_SMBUS_WRITE) 88 sprintf(p, "$#%02X", command); 89 else 90 sprintf(p, "$"); 91 break; 92 case I2C_SMBUS_BYTE_DATA: 93 if (read_write == I2C_SMBUS_WRITE) 94 sprintf(p, "$%02X#%02X", command, data->byte); 95 else 96 sprintf(p, "$%02X", command); 97 break; 98 default: 99 dev_warn(&adapter->dev, "Unsupported transaction %d\n", size); 100 return -EOPNOTSUPP; 101 } 102 103 /* Send the transaction to the TAOS EVM */ 104 dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); 105 taos->pos = 0; 106 taos->state = TAOS_STATE_SEND; 107 serio_write(serio, taos->buffer[0]); 108 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 109 msecs_to_jiffies(250)); 110 if (taos->state != TAOS_STATE_IDLE) { 111 dev_err(&adapter->dev, "Transaction failed " 112 "(state=%d, pos=%d)\n", taos->state, taos->pos); 113 taos->addr = 0; 114 return -EIO; 115 } 116 taos->addr = addr; 117 118 /* Start the transaction and read the answer */ 119 taos->pos = 0; 120 taos->state = TAOS_STATE_RECV; 121 serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); 122 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 123 msecs_to_jiffies(150)); 124 if (taos->state != TAOS_STATE_IDLE 125 || taos->pos != 6) { 126 dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", 127 taos->pos); 128 return -EIO; 129 } 130 dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); 131 132 /* Interpret the returned string */ 133 p = taos->buffer + 2; 134 p[3] = '\0'; 135 if (!strcmp(p, "NAK")) 136 return -ENODEV; 137 138 if (read_write == I2C_SMBUS_WRITE) { 139 if (!strcmp(p, "ACK")) 140 return 0; 141 } else { 142 if (p[0] == 'x') { 143 data->byte = simple_strtol(p + 1, NULL, 16); 144 return 0; 145 } 146 } 147 148 return -EIO; 149 } 150 151 static u32 taos_smbus_func(struct i2c_adapter *adapter) 152 { 153 return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; 154 } 155 156 static const struct i2c_algorithm taos_algorithm = { 157 .smbus_xfer = taos_smbus_xfer, 158 .functionality = taos_smbus_func, 159 }; 160 161 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, 162 unsigned int flags) 163 { 164 struct taos_data *taos = serio_get_drvdata(serio); 165 166 switch (taos->state) { 167 case TAOS_STATE_INIT: 168 taos->buffer[taos->pos++] = data; 169 if (data == ':' 170 || taos->pos == TAOS_BUFFER_SIZE - 1) { 171 taos->buffer[taos->pos] = '\0'; 172 taos->state = TAOS_STATE_IDLE; 173 wake_up_interruptible(&wq); 174 } 175 break; 176 case TAOS_STATE_SEND: 177 if (taos->buffer[++taos->pos]) 178 serio_write(serio, taos->buffer[taos->pos]); 179 else { 180 taos->state = TAOS_STATE_IDLE; 181 wake_up_interruptible(&wq); 182 } 183 break; 184 case TAOS_STATE_RECV: 185 taos->buffer[taos->pos++] = data; 186 if (data == ']') { 187 taos->buffer[taos->pos] = '\0'; 188 taos->state = TAOS_STATE_IDLE; 189 wake_up_interruptible(&wq); 190 } 191 break; 192 } 193 194 return IRQ_HANDLED; 195 } 196 197 /* Extract the adapter name from the buffer received after reset. 198 The buffer is modified and a pointer inside the buffer is returned. */ 199 static char *taos_adapter_name(char *buffer) 200 { 201 char *start, *end; 202 203 start = strstr(buffer, "TAOS "); 204 if (!start) 205 return NULL; 206 207 end = strchr(start, '\r'); 208 if (!end) 209 return NULL; 210 *end = '\0'; 211 212 return start; 213 } 214 215 static int taos_connect(struct serio *serio, struct serio_driver *drv) 216 { 217 struct taos_data *taos; 218 struct i2c_adapter *adapter; 219 char *name; 220 int err; 221 222 taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); 223 if (!taos) { 224 err = -ENOMEM; 225 goto exit; 226 } 227 taos->state = TAOS_STATE_INIT; 228 serio_set_drvdata(serio, taos); 229 230 err = serio_open(serio, drv); 231 if (err) 232 goto exit_kfree; 233 234 adapter = &taos->adapter; 235 adapter->owner = THIS_MODULE; 236 adapter->algo = &taos_algorithm; 237 adapter->algo_data = serio; 238 adapter->dev.parent = &serio->dev; 239 240 /* Reset the TAOS evaluation module to identify it */ 241 serio_write(serio, TAOS_CMD_RESET); 242 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 243 msecs_to_jiffies(2000)); 244 245 if (taos->state != TAOS_STATE_IDLE) { 246 err = -ENODEV; 247 dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, " 248 "pos=%d)\n", taos->state, taos->pos); 249 goto exit_close; 250 } 251 252 name = taos_adapter_name(taos->buffer); 253 if (!name) { 254 err = -ENODEV; 255 dev_err(&serio->dev, "TAOS EVM identification failed\n"); 256 goto exit_close; 257 } 258 strlcpy(adapter->name, name, sizeof(adapter->name)); 259 260 err = i2c_add_adapter(adapter); 261 if (err) 262 goto exit_close; 263 dev_dbg(&serio->dev, "Connected to TAOS EVM\n"); 264 265 taos->client = taos_instantiate_device(adapter); 266 return 0; 267 268 exit_close: 269 serio_close(serio); 270 exit_kfree: 271 serio_set_drvdata(serio, NULL); 272 kfree(taos); 273 exit: 274 return err; 275 } 276 277 static void taos_disconnect(struct serio *serio) 278 { 279 struct taos_data *taos = serio_get_drvdata(serio); 280 281 if (taos->client) 282 i2c_unregister_device(taos->client); 283 i2c_del_adapter(&taos->adapter); 284 serio_close(serio); 285 serio_set_drvdata(serio, NULL); 286 kfree(taos); 287 288 dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n"); 289 } 290 291 static struct serio_device_id taos_serio_ids[] = { 292 { 293 .type = SERIO_RS232, 294 .proto = SERIO_TAOSEVM, 295 .id = SERIO_ANY, 296 .extra = SERIO_ANY, 297 }, 298 { 0 } 299 }; 300 MODULE_DEVICE_TABLE(serio, taos_serio_ids); 301 302 static struct serio_driver taos_drv = { 303 .driver = { 304 .name = "taos-evm", 305 }, 306 .description = "TAOS evaluation module driver", 307 .id_table = taos_serio_ids, 308 .connect = taos_connect, 309 .disconnect = taos_disconnect, 310 .interrupt = taos_interrupt, 311 }; 312 313 static int __init taos_init(void) 314 { 315 return serio_register_driver(&taos_drv); 316 } 317 318 static void __exit taos_exit(void) 319 { 320 serio_unregister_driver(&taos_drv); 321 } 322 323 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 324 MODULE_DESCRIPTION("TAOS evaluation module driver"); 325 MODULE_LICENSE("GPL"); 326 327 module_init(taos_init); 328 module_exit(taos_exit); 329