drivers/i2c/busses/i2c-taos-evm.c

   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_dbg(&adapter->dev, "Unsupported transaction size %d\n",
 100                         size);
 101                 return -EINVAL;
 102         }
 103
 104         /* Send the transaction to the TAOS EVM */
 105         dev_dbg(&adapter->dev, "Command buffer: %s\n", taos->buffer);
 106         taos->pos = 0;
 107         taos->state = TAOS_STATE_SEND;
 108         serio_write(serio, taos->buffer[0]);
 109         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 110                                          msecs_to_jiffies(250));
 111         if (taos->state != TAOS_STATE_IDLE) {
 112                 dev_err(&adapter->dev, "Transaction failed "
 113                         "(state=%d, pos=%d)\n", taos->state, taos->pos);
 114                 taos->addr = 0;
 115                 return -EIO;
 116         }
 117         taos->addr = addr;
 118
 119         /* Start the transaction and read the answer */
 120         taos->pos = 0;
 121         taos->state = TAOS_STATE_RECV;
 122         serio_write(serio, read_write == I2C_SMBUS_WRITE ? '>' : '<');
 123         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 124                                          msecs_to_jiffies(150));
 125         if (taos->state != TAOS_STATE_IDLE
 126          || taos->pos != 6) {
 127                 dev_err(&adapter->dev, "Transaction timeout (pos=%d)\n",
 128                         taos->pos);
 129                 return -EIO;
 130         }
 131         dev_dbg(&adapter->dev, "Answer buffer: %s\n", taos->buffer);
 132
 133         /* Interpret the returned string */
 134         p = taos->buffer + 2;
 135         p[3] = '\0';
 136         if (!strcmp(p, "NAK"))
 137                 return -ENODEV;
 138
 139         if (read_write == I2C_SMBUS_WRITE) {
 140                 if (!strcmp(p, "ACK"))
 141                         return 0;
 142         } else {
 143                 if (p[0] == 'x') {
 144                         data->byte = simple_strtol(p + 1, NULL, 16);
 145                         return 0;
 146                 }
 147         }
 148
 149         return -EIO;
 150 }
 151
 152 static u32 taos_smbus_func(struct i2c_adapter *adapter)
 153 {
 154         return I2C_FUNC_SMBUS_BYTE | I2C_FUNC_SMBUS_BYTE_DATA;
 155 }
 156
 157 static const struct i2c_algorithm taos_algorithm = {
 158         .smbus_xfer     = taos_smbus_xfer,
 159         .functionality  = taos_smbus_func,
 160 };
 161
 162 static irqreturn_t taos_interrupt(struct serio *serio, unsigned char data,
 163                                   unsigned int flags)
 164 {
 165         struct taos_data *taos = serio_get_drvdata(serio);
 166
 167         switch (taos->state) {
 168         case TAOS_STATE_INIT:
 169                 taos->buffer[taos->pos++] = data;
 170                 if (data == ':'
 171                  || taos->pos == TAOS_BUFFER_SIZE - 1) {
 172                         taos->buffer[taos->pos] = '\0';
 173                         taos->state = TAOS_STATE_IDLE;
 174                         wake_up_interruptible(&wq);
 175                 }
 176                 break;
 177         case TAOS_STATE_SEND:
 178                 if (taos->buffer[++taos->pos])
 179                         serio_write(serio, taos->buffer[taos->pos]);
 180                 else {
 181                         taos->state = TAOS_STATE_IDLE;
 182                         wake_up_interruptible(&wq);
 183                 }
 184                 break;
 185         case TAOS_STATE_RECV:
 186                 taos->buffer[taos->pos++] = data;
 187                 if (data == ']') {
 188                         taos->buffer[taos->pos] = '\0';
 189                         taos->state = TAOS_STATE_IDLE;
 190                         wake_up_interruptible(&wq);
 191                 }
 192                 break;
 193         }
 194
 195         return IRQ_HANDLED;
 196 }
 197
 198 /* Extract the adapter name from the buffer received after reset.
 199    The buffer is modified and a pointer inside the buffer is returned. */
 200 static char *taos_adapter_name(char *buffer)
 201 {
 202         char *start, *end;
 203
 204         start = strstr(buffer, "TAOS ");
 205         if (!start)
 206                 return NULL;
 207
 208         end = strchr(start, '\r');
 209         if (!end)
 210                 return NULL;
 211         *end = '\0';
 212
 213         return start;
 214 }
 215
 216 static int taos_connect(struct serio *serio, struct serio_driver *drv)
 217 {
 218         struct taos_data *taos;
 219         struct i2c_adapter *adapter;
 220         char *name;
 221         int err;
 222
 223         taos = kzalloc(sizeof(struct taos_data), GFP_KERNEL);
 224         if (!taos) {
 225                 err = -ENOMEM;
 226                 goto exit;
 227         }
 228         taos->state = TAOS_STATE_INIT;
 229         serio_set_drvdata(serio, taos);
 230
 231         err = serio_open(serio, drv);
 232         if (err)
 233                 goto exit_kfree;
 234
 235         adapter = &taos->adapter;
 236         adapter->owner = THIS_MODULE;
 237         adapter->algo = &taos_algorithm;
 238         adapter->algo_data = serio;
 239         adapter->dev.parent = &serio->dev;
 240
 241         /* Reset the TAOS evaluation module to identify it */
 242         serio_write(serio, TAOS_CMD_RESET);
 243         wait_event_interruptible_timeout(wq, taos->state == TAOS_STATE_IDLE,
 244                                          msecs_to_jiffies(2000));
 245
 246         if (taos->state != TAOS_STATE_IDLE) {
 247                 err = -ENODEV;
 248                 dev_dbg(&serio->dev, "TAOS EVM reset failed (state=%d, "
 249                         "pos=%d)\n", taos->state, taos->pos);
 250                 goto exit_close;
 251         }
 252
 253         name = taos_adapter_name(taos->buffer);
 254         if (!name) {
 255                 err = -ENODEV;
 256                 dev_err(&serio->dev, "TAOS EVM identification failed\n");
 257                 goto exit_close;
 258         }
 259         strlcpy(adapter->name, name, sizeof(adapter->name));
 260
 261         err = i2c_add_adapter(adapter);
 262         if (err)
 263                 goto exit_close;
 264         dev_dbg(&serio->dev, "Connected to TAOS EVM\n");
 265
 266         taos->client = taos_instantiate_device(adapter);
 267         return 0;
 268
 269  exit_close:
 270         serio_close(serio);
 271  exit_kfree:
 272         serio_set_drvdata(serio, NULL);
 273         kfree(taos);
 274  exit:
 275         return err;
 276 }
 277
 278 static void taos_disconnect(struct serio *serio)
 279 {
 280         struct taos_data *taos = serio_get_drvdata(serio);
 281
 282         if (taos->client)
 283                 i2c_unregister_device(taos->client);
 284         i2c_del_adapter(&taos->adapter);
 285         serio_close(serio);
 286         serio_set_drvdata(serio, NULL);
 287         kfree(taos);
 288
 289         dev_dbg(&serio->dev, "Disconnected from TAOS EVM\n");
 290 }
 291
 292 static struct serio_device_id taos_serio_ids[] = {
 293         {
 294                 .type   = SERIO_RS232,
 295                 .proto  = SERIO_TAOSEVM,
 296                 .id     = SERIO_ANY,
 297                 .extra  = SERIO_ANY,
 298         },
 299         { 0 }
 300 };
 301 MODULE_DEVICE_TABLE(serio, taos_serio_ids);
 302
 303 static struct serio_driver taos_drv = {
 304         .driver         = {
 305                 .name   = "taos-evm",
 306         },
 307         .description    = "TAOS evaluation module driver",
 308         .id_table       = taos_serio_ids,
 309         .connect        = taos_connect,
 310         .disconnect     = taos_disconnect,
 311         .interrupt      = taos_interrupt,
 312 };
 313
 314 static int __init taos_init(void)
 315 {
 316         return serio_register_driver(&taos_drv);
 317 }
 318
 319 static void __exit taos_exit(void)
 320 {
 321         serio_unregister_driver(&taos_drv);
 322 }
 323
 324 MODULE_AUTHOR("Jean Delvare <khali@linux-fr.org>");
 325 MODULE_DESCRIPTION("TAOS evaluation module driver");
 326 MODULE_LICENSE("GPL");
 327
 328 module_init(taos_init);
 329 module_exit(taos_exit);