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 .type = "tsl2550", 55 }; 56 57 /* Instantiate i2c devices based on the adapter name */ 58 static struct i2c_client *taos_instantiate_device(struct i2c_adapter *adapter) 59 { 60 if (!strncmp(adapter->name, "TAOS TSL2550 EVM", 16)) { 61 dev_info(&adapter->dev, "Instantiating device %s at 0x%02x\n", 62 tsl2550_info.driver_name, tsl2550_info.addr); 63 return i2c_new_device(adapter, &tsl2550_info); 64 } 65 66 return NULL; 67 } 68 69 static int taos_smbus_xfer(struct i2c_adapter *adapter, u16 addr, 70 unsigned short flags, char read_write, u8 command, 71 int size, union i2c_smbus_data *data) 72 { 73 struct serio *serio = adapter->algo_data; 74 struct taos_data *taos = serio_get_drvdata(serio); 75 char *p; 76 77 /* Encode our transaction. "@" is for the device address, "$" for the 78 SMBus command and "#" for the data. */ 79 p = taos->buffer; 80 81 /* The device remembers the last used address, no need to send it 82 again if it's the same */ 83 if (addr != taos->addr) 84 p += sprintf(p, "@%02X", addr); 85 86 switch (size) { 87 case I2C_SMBUS_BYTE: 88 if (read_write == I2C_SMBUS_WRITE) 89 sprintf(p, "$#%02X", command); 90 else 91 sprintf(p, "$"); 92 break; 93 case I2C_SMBUS_BYTE_DATA: 94 if (read_write == I2C_SMBUS_WRITE) 95 sprintf(p, "$%02X#%02X", command, data->byte); 96 else 97 sprintf(p, "$%02X", command); 98 break; 99 default: 100 dev_dbg(&adapter->dev, "Unsupported transaction size %d\n", 101 size); 102 return -EINVAL; 103 } 104 105 /* Send the transaction to the TAOS EVM */ 106 dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer); 107 taos->pos = 0; 108 taos->state = TAOS_STATE_SEND; 109 serio_write(serio, taos->buffer[0]); 110 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 111 msecs_to_jiffies(250)); 112 if (taos->state != TAOS_STATE_IDLE) { 113 dev_err(&adapter->dev, "Transaction failed " 114 "(state=%d, pos=%d)\n", taos->state, taos->pos); 115 taos->addr = 0; 116 return -EIO; 117 } 118 taos->addr = addr; 119 120 /* Start the transaction and read the answer */ 121 taos->pos = 0; 122 taos->state = TAOS_STATE_RECV; 123 serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<'); 124 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 125 msecs_to_jiffies(150)); 126 if (taos->state != TAOS_STATE_IDLE 127 || taos->pos != 6) { 128 dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n", 129 taos->pos); 130 return -EIO; 131 } 132 dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer); 133 134 /* Interpret the returned string */ 135 p = taos->buffer + 2; 136 p[3] = '\0'; 137 if (!strcmp(p, "NAK")) 138 return -ENODEV; 139 140 if (read_write == I2C_SMBUS_WRITE) { 141 if (!strcmp(p, "ACK")) 142 return 0; 143 } else { 144 if (p[0] == 'x') { 145 data->byte = simple_strtol(p + 1, NULL, 16); 146 return 0; 147 } 148 } 149 150 return -EIO; 151 } 152 153 static u32 taos_smbus_func(struct i2c_adapter *adapter) 154 { 155 return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA; 156 } 157 158 static const struct i2c_algorithm taos_algorithm = { 159 .smbus_xfer = taos_smbus_xfer, 160 .functionality = taos_smbus_func, 161 }; 162 163 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data, 164 unsigned int flags) 165 { 166 struct taos_data *taos = serio_get_drvdata(serio); 167 168 switch (taos->state) { 169 case TAOS_STATE_INIT: 170 taos->buffer[taos->pos++] = data; 171 if (data == ':' 172 || taos->pos == TAOS_BUFFER_SIZE - 1) { 173 taos->buffer[taos->pos] = '\0'; 174 taos->state = TAOS_STATE_IDLE; 175 wake_up_interruptible(&wq); 176 } 177 break; 178 case TAOS_STATE_SEND: 179 if (taos->buffer[++taos->pos]) 180 serio_write(serio, taos->buffer[taos->pos]); 181 else { 182 taos->state = TAOS_STATE_IDLE; 183 wake_up_interruptible(&wq); 184 } 185 break; 186 case TAOS_STATE_RECV: 187 taos->buffer[taos->pos++] = data; 188 if (data == ']') { 189 taos->buffer[taos->pos] = '\0'; 190 taos->state = TAOS_STATE_IDLE; 191 wake_up_interruptible(&wq); 192 } 193 break; 194 } 195 196 return IRQ_HANDLED; 197 } 198 199 /* Extract the adapter name from the buffer received after reset. 200 The buffer is modified and a pointer inside the buffer is returned. */ 201 static char *taos_adapter_name(char *buffer) 202 { 203 char *start, *end; 204 205 start = strstr(buffer, "TAOS "); 206 if (!start) 207 return NULL; 208 209 end = strchr(start, '\r'); 210 if (!end) 211 return NULL; 212 *end = '\0'; 213 214 return start; 215 } 216 217 static int taos_connect(struct serio *serio, struct serio_driver *drv) 218 { 219 struct taos_data *taos; 220 struct i2c_adapter *adapter; 221 char *name; 222 int err; 223 224 taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL); 225 if (!taos) { 226 err = -ENOMEM; 227 goto exit; 228 } 229 taos->state = TAOS_STATE_INIT; 230 serio_set_drvdata(serio, taos); 231 232 err = serio_open(serio, drv); 233 if (err) 234 goto exit_kfree; 235 236 adapter = &taos->adapter; 237 adapter->owner = THIS_MODULE; 238 adapter->algo = &taos_algorithm; 239 adapter->algo_data = serio; 240 adapter->dev.parent = &serio->dev; 241 242 /* Reset the TAOS evaluation module to identify it */ 243 serio_write(serio, TAOS_CMD_RESET); 244 wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE, 245 msecs_to_jiffies(2000)); 246 247 if (taos->state != TAOS_STATE_IDLE) { 248 err = -ENODEV; 249 dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, " 250 "pos=%d)\n", taos->state, taos->pos); 251 goto exit_close; 252 } 253 254 name = taos_adapter_name(taos->buffer); 255 if (!name) { 256 err = -ENODEV; 257 dev_err(&serio->dev, "TAOS EVM identification failed\n"); 258 goto exit_close; 259 } 260 strlcpy(adapter->name, name, sizeof(adapter->name)); 261 262 err = i2c_add_adapter(adapter); 263 if (err) 264 goto exit_close; 265 dev_dbg(&serio->dev, "Connected to TAOS EVM\n"); 266 267 taos->client = taos_instantiate_device(adapter); 268 return 0; 269 270 exit_close: 271 serio_close(serio); 272 exit_kfree: 273 serio_set_drvdata(serio, NULL); 274 kfree(taos); 275 exit: 276 return err; 277 } 278 279 static void taos_disconnect(struct serio *serio) 280 { 281 struct taos_data *taos = serio_get_drvdata(serio); 282 283 if (taos->client) 284 i2c_unregister_device(taos->client); 285 i2c_del_adapter(&taos->adapter); 286 serio_close(serio); 287 serio_set_drvdata(serio, NULL); 288 kfree(taos); 289 290 dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n"); 291 } 292 293 static struct serio_device_id taos_serio_ids[] = { 294 { 295 .type = SERIO_RS232, 296 .proto = SERIO_TAOSEVM, 297 .id = SERIO_ANY, 298 .extra = SERIO_ANY, 299 }, 300 { 0 } 301 }; 302 MODULE_DEVICE_TABLE(serio, taos_serio_ids); 303 304 static struct serio_driver taos_drv = { 305 .driver = { 306 .name = "taos-evm", 307 }, 308 .description = "TAOS evaluation module driver", 309 .id_table = taos_serio_ids, 310 .connect = taos_connect, 311 .disconnect = taos_disconnect, 312 .interrupt = taos_interrupt, 313 }; 314 315 static int __init taos_init(void) 316 { 317 return serio_register_driver(&taos_drv); 318 } 319 320 static void __exit taos_exit(void) 321 { 322 serio_unregister_driver(&taos_drv); 323 } 324 325 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>"); 326 MODULE_DESCRIPTION("TAOS evaluation module driver"); 327 MODULE_LICENSE("GPL"); 328 329 module_init(taos_init); 330 module_exit(taos_exit); 331