drivers/w1/slaves/w1_ds28e04.c

   1 /*
   2  *      w1_ds28e04.c - w1 family 1C (DS28E04) driver
   3  *
   4  * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com>
   5  *
   6  * This source code is licensed under the GNU General Public License,
   7  * Version 2. See the file COPYING for more details.
   8  */
   9
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/moduleparam.h>
  13 #include <linux/device.h>
  14 #include <linux/types.h>
  15 #include <linux/delay.h>
  16 #include <linux/slab.h>
  17 #include <linux/crc16.h>
  18 #include <linux/uaccess.h>
  19
  20 #define CRC16_INIT              0
  21 #define CRC16_VALID             0xb001
  22
  23 #include "../w1.h"
  24 #include "../w1_int.h"
  25 #include "../w1_family.h"
  26
  27 MODULE_LICENSE("GPL");
  28 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
  29 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
  30
  31 /* Allow the strong pullup to be disabled, but default to enabled.
  32  * If it was disabled a parasite powered device might not get the required
  33  * current to copy the data from the scratchpad to EEPROM.  If it is enabled
  34  * parasite powered devices have a better chance of getting the current
  35  * required.
  36  */
  37 static int w1_strong_pullup = 1;
  38 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  39
  40 /* enable/disable CRC checking on DS28E04-100 memory accesses */
  41 static char w1_enable_crccheck = 1;
  42
  43 #define W1_EEPROM_SIZE          512
  44 #define W1_PAGE_COUNT           16
  45 #define W1_PAGE_SIZE            32
  46 #define W1_PAGE_BITS            5
  47 #define W1_PAGE_MASK            0x1F
  48
  49 #define W1_F1C_READ_EEPROM      0xF0
  50 #define W1_F1C_WRITE_SCRATCH    0x0F
  51 #define W1_F1C_READ_SCRATCH     0xAA
  52 #define W1_F1C_COPY_SCRATCH     0x55
  53 #define W1_F1C_ACCESS_WRITE     0x5A
  54
  55 #define W1_1C_REG_LOGIC_STATE   0x220
  56
  57 struct w1_f1C_data {
  58         u8      memory[W1_EEPROM_SIZE];
  59         u32     validcrc;
  60 };
  61
  62 /**
  63  * Check the file size bounds and adjusts count as needed.
  64  * This would not be needed if the file size didn't reset to 0 after a write.
  65  */
  66 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size)
  67 {
  68         if (off > size)
  69                 return 0;
  70
  71         if ((off + count) > size)
  72                 return size - off;
  73
  74         return count;
  75 }
  76
  77 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data,
  78                                 int block)
  79 {
  80         u8      wrbuf[3];
  81         int     off = block * W1_PAGE_SIZE;
  82
  83         if (data->validcrc & (1 << block))
  84                 return 0;
  85
  86         if (w1_reset_select_slave(sl)) {
  87                 data->validcrc = 0;
  88                 return -EIO;
  89         }
  90
  91         wrbuf[0] = W1_F1C_READ_EEPROM;
  92         wrbuf[1] = off & 0xff;
  93         wrbuf[2] = off >> 8;
  94         w1_write_block(sl->master, wrbuf, 3);
  95         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  96
  97         /* cache the block if the CRC is valid */
  98         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  99                 data->validcrc |= (1 << block);
 100
 101         return 0;
 102 }
 103
 104 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
 105 {
 106         u8 wrbuf[3];
 107
 108         /* read directly from the EEPROM */
 109         if (w1_reset_select_slave(sl))
 110                 return -EIO;
 111
 112         wrbuf[0] = W1_F1C_READ_EEPROM;
 113         wrbuf[1] = addr & 0xff;
 114         wrbuf[2] = addr >> 8;
 115
 116         w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
 117         return w1_read_block(sl->master, data, len);
 118 }
 119
 120 static ssize_t w1_f1C_read_bin(struct file *filp, struct kobject *kobj,
 121                                struct bin_attribute *bin_attr,
 122                                char *buf, loff_t off, size_t count)
 123 {
 124         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 125         struct w1_f1C_data *data = sl->family_data;
 126         int i, min_page, max_page;
 127
 128         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 129         if (count == 0)
 130                 return 0;
 131
 132         mutex_lock(&sl->master->mutex);
 133
 134         if (w1_enable_crccheck) {
 135                 min_page = (off >> W1_PAGE_BITS);
 136                 max_page = (off + count - 1) >> W1_PAGE_BITS;
 137                 for (i = min_page; i <= max_page; i++) {
 138                         if (w1_f1C_refresh_block(sl, data, i)) {
 139                                 count = -EIO;
 140                                 goto out_up;
 141                         }
 142                 }
 143                 memcpy(buf, &data->memory[off], count);
 144         } else {
 145                 count = w1_f1C_read(sl, off, count, buf);
 146         }
 147
 148 out_up:
 149         mutex_unlock(&sl->master->mutex);
 150
 151         return count;
 152 }
 153
 154 /**
 155  * Writes to the scratchpad and reads it back for verification.
 156  * Then copies the scratchpad to EEPROM.
 157  * The data must be on one page.
 158  * The master must be locked.
 159  *
 160  * @param sl    The slave structure
 161  * @param addr  Address for the write
 162  * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 163  * @param data  The data to write
 164  * @return      0=Success -1=failure
 165  */
 166 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 167 {
 168         u8 wrbuf[4];
 169         u8 rdbuf[W1_PAGE_SIZE + 3];
 170         u8 es = (addr + len - 1) & 0x1f;
 171         unsigned int tm = 10;
 172         int i;
 173         struct w1_f1C_data *f1C = sl->family_data;
 174
 175         /* Write the data to the scratchpad */
 176         if (w1_reset_select_slave(sl))
 177                 return -1;
 178
 179         wrbuf[0] = W1_F1C_WRITE_SCRATCH;
 180         wrbuf[1] = addr & 0xff;
 181         wrbuf[2] = addr >> 8;
 182
 183         w1_write_block(sl->master, wrbuf, 3);
 184         w1_write_block(sl->master, data, len);
 185
 186         /* Read the scratchpad and verify */
 187         if (w1_reset_select_slave(sl))
 188                 return -1;
 189
 190         w1_write_8(sl->master, W1_F1C_READ_SCRATCH);
 191         w1_read_block(sl->master, rdbuf, len + 3);
 192
 193         /* Compare what was read against the data written */
 194         if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 195             (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 196                 return -1;
 197
 198         /* Copy the scratchpad to EEPROM */
 199         if (w1_reset_select_slave(sl))
 200                 return -1;
 201
 202         wrbuf[0] = W1_F1C_COPY_SCRATCH;
 203         wrbuf[3] = es;
 204
 205         for (i = 0; i < sizeof(wrbuf); ++i) {
 206                 /* issue 10ms strong pullup (or delay) on the last byte
 207                    for writing the data from the scratchpad to EEPROM */
 208                 if (w1_strong_pullup && i == sizeof(wrbuf)-1)
 209                         w1_next_pullup(sl->master, tm);
 210
 211                 w1_write_8(sl->master, wrbuf[i]);
 212         }
 213
 214         if (!w1_strong_pullup)
 215                 msleep(tm);
 216
 217         if (w1_enable_crccheck) {
 218                 /* invalidate cached data */
 219                 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 220         }
 221
 222         /* Reset the bus to wake up the EEPROM (this may not be needed) */
 223         w1_reset_bus(sl->master);
 224
 225         return 0;
 226 }
 227
 228 static ssize_t w1_f1C_write_bin(struct file *filp, struct kobject *kobj,
 229                                struct bin_attribute *bin_attr,
 230                                char *buf, loff_t off, size_t count)
 231
 232 {
 233         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 234         int addr, len, idx;
 235
 236         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 237         if (count == 0)
 238                 return 0;
 239
 240         if (w1_enable_crccheck) {
 241                 /* can only write full blocks in cached mode */
 242                 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 243                         dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 244                                 (int)off, count);
 245                         return -EINVAL;
 246                 }
 247
 248                 /* make sure the block CRCs are valid */
 249                 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 250                         if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE)
 251                                 != CRC16_VALID) {
 252                                 dev_err(&sl->dev, "bad CRC at offset %d\n",
 253                                         (int)off);
 254                                 return -EINVAL;
 255                         }
 256                 }
 257         }
 258
 259         mutex_lock(&sl->master->mutex);
 260
 261         /* Can only write data to one page at a time */
 262         idx = 0;
 263         while (idx < count) {
 264                 addr = off + idx;
 265                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 266                 if (len > (count - idx))
 267                         len = count - idx;
 268
 269                 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) {
 270                         count = -EIO;
 271                         goto out_up;
 272                 }
 273                 idx += len;
 274         }
 275
 276 out_up:
 277         mutex_unlock(&sl->master->mutex);
 278
 279         return count;
 280 }
 281
 282 static ssize_t w1_f1C_read_pio(struct file *filp, struct kobject *kobj,
 283                                struct bin_attribute *bin_attr,
 284                                char *buf, loff_t off, size_t count)
 285
 286 {
 287         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 288         int ret;
 289
 290         /* check arguments */
 291         if (off != 0 || count != 1 || buf == NULL)
 292                 return -EINVAL;
 293
 294         mutex_lock(&sl->master->mutex);
 295         ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
 296         mutex_unlock(&sl->master->mutex);
 297
 298         return ret;
 299 }
 300
 301 static ssize_t w1_f1C_write_pio(struct file *filp, struct kobject *kobj,
 302                                 struct bin_attribute *bin_attr,
 303                                 char *buf, loff_t off, size_t count)
 304
 305 {
 306         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 307         u8 wrbuf[3];
 308         u8 ack;
 309
 310         /* check arguments */
 311         if (off != 0 || count != 1 || buf == NULL)
 312                 return -EINVAL;
 313
 314         mutex_lock(&sl->master->mutex);
 315
 316         /* Write the PIO data */
 317         if (w1_reset_select_slave(sl)) {
 318                 mutex_unlock(&sl->master->mutex);
 319                 return -1;
 320         }
 321
 322         /* set bit 7..2 to value '1' */
 323         *buf = *buf | 0xFC;
 324
 325         wrbuf[0] = W1_F1C_ACCESS_WRITE;
 326         wrbuf[1] = *buf;
 327         wrbuf[2] = ~(*buf);
 328         w1_write_block(sl->master, wrbuf, 3);
 329
 330         w1_read_block(sl->master, &ack, sizeof(ack));
 331
 332         mutex_unlock(&sl->master->mutex);
 333
 334         /* check for acknowledgement */
 335         if (ack != 0xAA)
 336                 return -EIO;
 337
 338         return count;
 339 }
 340
 341 static ssize_t w1_f1C_show_crccheck(struct device *dev,
 342                                     struct device_attribute *attr, char *buf)
 343 {
 344         if (put_user(w1_enable_crccheck + 0x30, buf))
 345                 return -EFAULT;
 346
 347         return sizeof(w1_enable_crccheck);
 348 }
 349
 350 static ssize_t w1_f1C_store_crccheck(struct device *dev,
 351                                      struct device_attribute *attr,
 352                                      const char *buf, size_t count)
 353 {
 354         char val;
 355
 356         if (count != 1 || !buf)
 357                 return -EINVAL;
 358
 359         if (get_user(val, buf))
 360                 return -EFAULT;
 361
 362         /* convert to decimal */
 363         val = val - 0x30;
 364         if (val != 0 && val != 1)
 365                 return -EINVAL;
 366
 367         /* set the new value */
 368         w1_enable_crccheck = val;
 369
 370         return sizeof(w1_enable_crccheck);
 371 }
 372
 373 #define NB_SYSFS_BIN_FILES 2
 374 static struct bin_attribute w1_f1C_bin_attr[NB_SYSFS_BIN_FILES] = {
 375         {
 376                 .attr = {
 377                         .name = "eeprom",
 378                         .mode = S_IRUGO | S_IWUSR,
 379                 },
 380                 .size = W1_EEPROM_SIZE,
 381                 .read = w1_f1C_read_bin,
 382                 .write = w1_f1C_write_bin,
 383         },
 384         {
 385                 .attr = {
 386                         .name = "pio",
 387                         .mode = S_IRUGO | S_IWUSR,
 388                 },
 389                 .size = 1,
 390                 .read = w1_f1C_read_pio,
 391                 .write = w1_f1C_write_pio,
 392         }
 393 };
 394
 395 static DEVICE_ATTR(crccheck, S_IWUSR | S_IRUGO,
 396                    w1_f1C_show_crccheck, w1_f1C_store_crccheck);
 397
 398 static int w1_f1C_add_slave(struct w1_slave *sl)
 399 {
 400         int err = 0;
 401         int i;
 402         struct w1_f1C_data *data = NULL;
 403
 404         if (w1_enable_crccheck) {
 405                 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL);
 406                 if (!data)
 407                         return -ENOMEM;
 408                 sl->family_data = data;
 409         }
 410
 411         /* create binary sysfs attributes */
 412         for (i = 0; i < NB_SYSFS_BIN_FILES && !err; ++i)
 413                 err = sysfs_create_bin_file(
 414                         &sl->dev.kobj, &(w1_f1C_bin_attr[i]));
 415
 416         if (!err) {
 417                 /* create device attributes */
 418                 err = device_create_file(&sl->dev, &dev_attr_crccheck);
 419         }
 420
 421         if (err) {
 422                 /* remove binary sysfs attributes */
 423                 for (i = 0; i < NB_SYSFS_BIN_FILES; ++i)
 424                         sysfs_remove_bin_file(
 425                                 &sl->dev.kobj, &(w1_f1C_bin_attr[i]));
 426
 427                 kfree(data);
 428         }
 429
 430         return err;
 431 }
 432
 433 static void w1_f1C_remove_slave(struct w1_slave *sl)
 434 {
 435         int i;
 436
 437         kfree(sl->family_data);
 438         sl->family_data = NULL;
 439
 440         /* remove device attributes */
 441         device_remove_file(&sl->dev, &dev_attr_crccheck);
 442
 443         /* remove binary sysfs attributes */
 444         for (i = 0; i < NB_SYSFS_BIN_FILES; ++i)
 445                 sysfs_remove_bin_file(&sl->dev.kobj, &(w1_f1C_bin_attr[i]));
 446 }
 447
 448 static struct w1_family_ops w1_f1C_fops = {
 449         .add_slave      = w1_f1C_add_slave,
 450         .remove_slave   = w1_f1C_remove_slave,
 451 };
 452
 453 static struct w1_family w1_family_1C = {
 454         .fid = W1_FAMILY_DS28E04,
 455         .fops = &w1_f1C_fops,
 456 };
 457
 458 static int __init w1_f1C_init(void)
 459 {
 460         return w1_register_family(&w1_family_1C);
 461 }
 462
 463 static void __exit w1_f1C_fini(void)
 464 {
 465         w1_unregister_family(&w1_family_1C);
 466 }
 467
 468 module_init(w1_f1C_init);
 469 module_exit(w1_f1C_fini);