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 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));
  31
  32 /* Allow the strong pullup to be disabled, but default to enabled.
  33  * If it was disabled a parasite powered device might not get the required
  34  * current to copy the data from the scratchpad to EEPROM.  If it is enabled
  35  * parasite powered devices have a better chance of getting the current
  36  * required.
  37  */
  38 static int w1_strong_pullup = 1;
  39 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  40
  41 /* enable/disable CRC checking on DS28E04-100 memory accesses */
  42 static char w1_enable_crccheck = 1;
  43
  44 #define W1_EEPROM_SIZE          512
  45 #define W1_PAGE_COUNT           16
  46 #define W1_PAGE_SIZE            32
  47 #define W1_PAGE_BITS            5
  48 #define W1_PAGE_MASK            0x1F
  49
  50 #define W1_F1C_READ_EEPROM      0xF0
  51 #define W1_F1C_WRITE_SCRATCH    0x0F
  52 #define W1_F1C_READ_SCRATCH     0xAA
  53 #define W1_F1C_COPY_SCRATCH     0x55
  54 #define W1_F1C_ACCESS_WRITE     0x5A
  55
  56 #define W1_1C_REG_LOGIC_STATE   0x220
  57
  58 struct w1_f1C_data {
  59         u8      memory[W1_EEPROM_SIZE];
  60         u32     validcrc;
  61 };
  62
  63 /**
  64  * Check the file size bounds and adjusts count as needed.
  65  * This would not be needed if the file size didn't reset to 0 after a write.
  66  */
  67 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size)
  68 {
  69         if (off > size)
  70                 return 0;
  71
  72         if ((off + count) > size)
  73                 return size - off;
  74
  75         return count;
  76 }
  77
  78 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data,
  79                                 int block)
  80 {
  81         u8      wrbuf[3];
  82         int     off = block * W1_PAGE_SIZE;
  83
  84         if (data->validcrc & (1 << block))
  85                 return 0;
  86
  87         if (w1_reset_select_slave(sl)) {
  88                 data->validcrc = 0;
  89                 return -EIO;
  90         }
  91
  92         wrbuf[0] = W1_F1C_READ_EEPROM;
  93         wrbuf[1] = off & 0xff;
  94         wrbuf[2] = off >> 8;
  95         w1_write_block(sl->master, wrbuf, 3);
  96         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  97
  98         /* cache the block if the CRC is valid */
  99         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
 100                 data->validcrc |= (1 << block);
 101
 102         return 0;
 103 }
 104
 105 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
 106 {
 107         u8 wrbuf[3];
 108
 109         /* read directly from the EEPROM */
 110         if (w1_reset_select_slave(sl))
 111                 return -EIO;
 112
 113         wrbuf[0] = W1_F1C_READ_EEPROM;
 114         wrbuf[1] = addr & 0xff;
 115         wrbuf[2] = addr >> 8;
 116
 117         w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
 118         return w1_read_block(sl->master, data, len);
 119 }
 120
 121 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
 122                            struct bin_attribute *bin_attr, char *buf,
 123                            loff_t off, size_t count)
 124 {
 125         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 126         struct w1_f1C_data *data = sl->family_data;
 127         int i, min_page, max_page;
 128
 129         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 130         if (count == 0)
 131                 return 0;
 132
 133         mutex_lock(&sl->master->mutex);
 134
 135         if (w1_enable_crccheck) {
 136                 min_page = (off >> W1_PAGE_BITS);
 137                 max_page = (off + count - 1) >> W1_PAGE_BITS;
 138                 for (i = min_page; i <= max_page; i++) {
 139                         if (w1_f1C_refresh_block(sl, data, i)) {
 140                                 count = -EIO;
 141                                 goto out_up;
 142                         }
 143                 }
 144                 memcpy(buf, &data->memory[off], count);
 145         } else {
 146                 count = w1_f1C_read(sl, off, count, buf);
 147         }
 148
 149 out_up:
 150         mutex_unlock(&sl->master->mutex);
 151
 152         return count;
 153 }
 154
 155 /**
 156  * Writes to the scratchpad and reads it back for verification.
 157  * Then copies the scratchpad to EEPROM.
 158  * The data must be on one page.
 159  * The master must be locked.
 160  *
 161  * @param sl    The slave structure
 162  * @param addr  Address for the write
 163  * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 164  * @param data  The data to write
 165  * @return      0=Success -1=failure
 166  */
 167 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 168 {
 169         u8 wrbuf[4];
 170         u8 rdbuf[W1_PAGE_SIZE + 3];
 171         u8 es = (addr + len - 1) & 0x1f;
 172         unsigned int tm = 10;
 173         int i;
 174         struct w1_f1C_data *f1C = sl->family_data;
 175
 176         /* Write the data to the scratchpad */
 177         if (w1_reset_select_slave(sl))
 178                 return -1;
 179
 180         wrbuf[0] = W1_F1C_WRITE_SCRATCH;
 181         wrbuf[1] = addr & 0xff;
 182         wrbuf[2] = addr >> 8;
 183
 184         w1_write_block(sl->master, wrbuf, 3);
 185         w1_write_block(sl->master, data, len);
 186
 187         /* Read the scratchpad and verify */
 188         if (w1_reset_select_slave(sl))
 189                 return -1;
 190
 191         w1_write_8(sl->master, W1_F1C_READ_SCRATCH);
 192         w1_read_block(sl->master, rdbuf, len + 3);
 193
 194         /* Compare what was read against the data written */
 195         if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 196             (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 197                 return -1;
 198
 199         /* Copy the scratchpad to EEPROM */
 200         if (w1_reset_select_slave(sl))
 201                 return -1;
 202
 203         wrbuf[0] = W1_F1C_COPY_SCRATCH;
 204         wrbuf[3] = es;
 205
 206         for (i = 0; i < sizeof(wrbuf); ++i) {
 207                 /* issue 10ms strong pullup (or delay) on the last byte
 208                    for writing the data from the scratchpad to EEPROM */
 209                 if (w1_strong_pullup && i == sizeof(wrbuf)-1)
 210                         w1_next_pullup(sl->master, tm);
 211
 212                 w1_write_8(sl->master, wrbuf[i]);
 213         }
 214
 215         if (!w1_strong_pullup)
 216                 msleep(tm);
 217
 218         if (w1_enable_crccheck) {
 219                 /* invalidate cached data */
 220                 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 221         }
 222
 223         /* Reset the bus to wake up the EEPROM (this may not be needed) */
 224         w1_reset_bus(sl->master);
 225
 226         return 0;
 227 }
 228
 229 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 230                             struct bin_attribute *bin_attr, char *buf,
 231                             loff_t off, size_t count)
 232
 233 {
 234         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 235         int addr, len, idx;
 236
 237         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 238         if (count == 0)
 239                 return 0;
 240
 241         if (w1_enable_crccheck) {
 242                 /* can only write full blocks in cached mode */
 243                 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 244                         dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 245                                 (int)off, count);
 246                         return -EINVAL;
 247                 }
 248
 249                 /* make sure the block CRCs are valid */
 250                 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 251                         if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE)
 252                                 != CRC16_VALID) {
 253                                 dev_err(&sl->dev, "bad CRC at offset %d\n",
 254                                         (int)off);
 255                                 return -EINVAL;
 256                         }
 257                 }
 258         }
 259
 260         mutex_lock(&sl->master->mutex);
 261
 262         /* Can only write data to one page at a time */
 263         idx = 0;
 264         while (idx < count) {
 265                 addr = off + idx;
 266                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 267                 if (len > (count - idx))
 268                         len = count - idx;
 269
 270                 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) {
 271                         count = -EIO;
 272                         goto out_up;
 273                 }
 274                 idx += len;
 275         }
 276
 277 out_up:
 278         mutex_unlock(&sl->master->mutex);
 279
 280         return count;
 281 }
 282
 283 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 284
 285 static ssize_t pio_read(struct file *filp, struct kobject *kobj,
 286                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 287                         size_t count)
 288
 289 {
 290         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 291         int ret;
 292
 293         /* check arguments */
 294         if (off != 0 || count != 1 || buf == NULL)
 295                 return -EINVAL;
 296
 297         mutex_lock(&sl->master->mutex);
 298         ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
 299         mutex_unlock(&sl->master->mutex);
 300
 301         return ret;
 302 }
 303
 304 static ssize_t pio_write(struct file *filp, struct kobject *kobj,
 305                          struct bin_attribute *bin_attr, char *buf, loff_t off,
 306                          size_t count)
 307
 308 {
 309         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 310         u8 wrbuf[3];
 311         u8 ack;
 312
 313         /* check arguments */
 314         if (off != 0 || count != 1 || buf == NULL)
 315                 return -EINVAL;
 316
 317         mutex_lock(&sl->master->mutex);
 318
 319         /* Write the PIO data */
 320         if (w1_reset_select_slave(sl)) {
 321                 mutex_unlock(&sl->master->mutex);
 322                 return -1;
 323         }
 324
 325         /* set bit 7..2 to value '1' */
 326         *buf = *buf | 0xFC;
 327
 328         wrbuf[0] = W1_F1C_ACCESS_WRITE;
 329         wrbuf[1] = *buf;
 330         wrbuf[2] = ~(*buf);
 331         w1_write_block(sl->master, wrbuf, 3);
 332
 333         w1_read_block(sl->master, &ack, sizeof(ack));
 334
 335         mutex_unlock(&sl->master->mutex);
 336
 337         /* check for acknowledgement */
 338         if (ack != 0xAA)
 339                 return -EIO;
 340
 341         return count;
 342 }
 343
 344 static BIN_ATTR_RW(pio, 1);
 345
 346 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr,
 347                              char *buf)
 348 {
 349         if (put_user(w1_enable_crccheck + 0x30, buf))
 350                 return -EFAULT;
 351
 352         return sizeof(w1_enable_crccheck);
 353 }
 354
 355 static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
 356                               const char *buf, size_t count)
 357 {
 358         char val;
 359
 360         if (count != 1 || !buf)
 361                 return -EINVAL;
 362
 363         if (get_user(val, buf))
 364                 return -EFAULT;
 365
 366         /* convert to decimal */
 367         val = val - 0x30;
 368         if (val != 0 && val != 1)
 369                 return -EINVAL;
 370
 371         /* set the new value */
 372         w1_enable_crccheck = val;
 373
 374         return sizeof(w1_enable_crccheck);
 375 }
 376
 377 static DEVICE_ATTR_RW(crccheck);
 378
 379 static struct attribute *w1_f1C_attrs[] = {
 380         &dev_attr_crccheck.attr,
 381         NULL,
 382 };
 383
 384 static struct bin_attribute *w1_f1C_bin_attrs[] = {
 385         &bin_attr_eeprom,
 386         &bin_attr_pio,
 387         NULL,
 388 };
 389
 390 static const struct attribute_group w1_f1C_group = {
 391         .attrs          = w1_f1C_attrs,
 392         .bin_attrs      = w1_f1C_bin_attrs,
 393 };
 394
 395 static const struct attribute_group *w1_f1C_groups[] = {
 396         &w1_f1C_group,
 397         NULL,
 398 };
 399
 400 static int w1_f1C_add_slave(struct w1_slave *sl)
 401 {
 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         return 0;
 412 }
 413
 414 static void w1_f1C_remove_slave(struct w1_slave *sl)
 415 {
 416         kfree(sl->family_data);
 417         sl->family_data = NULL;
 418 }
 419
 420 static struct w1_family_ops w1_f1C_fops = {
 421         .add_slave      = w1_f1C_add_slave,
 422         .remove_slave   = w1_f1C_remove_slave,
 423         .groups         = w1_f1C_groups,
 424 };
 425
 426 static struct w1_family w1_family_1C = {
 427         .fid = W1_FAMILY_DS28E04,
 428         .fops = &w1_f1C_fops,
 429 };
 430
 431 static int __init w1_f1C_init(void)
 432 {
 433         return w1_register_family(&w1_family_1C);
 434 }
 435
 436 static void __exit w1_f1C_fini(void)
 437 {
 438         w1_unregister_family(&w1_family_1C);
 439 }
 440
 441 module_init(w1_f1C_init);
 442 module_exit(w1_f1C_fini);