drivers/w1/slaves/w1_ds28e04.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *      w1_ds28e04.c - w1 family 1C (DS28E04) driver
   4  *
   5  * Copyright (c) 2012 Markus Franke <franke.m@sebakmt.com>
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/module.h>
  10 #include <linux/moduleparam.h>
  11 #include <linux/device.h>
  12 #include <linux/types.h>
  13 #include <linux/delay.h>
  14 #include <linux/slab.h>
  15 #include <linux/crc16.h>
  16 #include <linux/uaccess.h>
  17
  18 #define CRC16_INIT              0
  19 #define CRC16_VALID             0xb001
  20
  21 #include <linux/w1.h>
  22
  23 #define W1_FAMILY_DS28E04       0x1C
  24
  25 /* Allow the strong pullup to be disabled, but default to enabled.
  26  * If it was disabled a parasite powered device might not get the required
  27  * current to copy the data from the scratchpad to EEPROM.  If it is enabled
  28  * parasite powered devices have a better chance of getting the current
  29  * required.
  30  */
  31 static int w1_strong_pullup = 1;
  32 module_param_named(strong_pullup, w1_strong_pullup, int, 0);
  33
  34 /* enable/disable CRC checking on DS28E04-100 memory accesses */
  35 static bool w1_enable_crccheck = true;
  36
  37 #define W1_EEPROM_SIZE          512
  38 #define W1_PAGE_COUNT           16
  39 #define W1_PAGE_SIZE            32
  40 #define W1_PAGE_BITS            5
  41 #define W1_PAGE_MASK            0x1F
  42
  43 #define W1_F1C_READ_EEPROM      0xF0
  44 #define W1_F1C_WRITE_SCRATCH    0x0F
  45 #define W1_F1C_READ_SCRATCH     0xAA
  46 #define W1_F1C_COPY_SCRATCH     0x55
  47 #define W1_F1C_ACCESS_WRITE     0x5A
  48
  49 #define W1_1C_REG_LOGIC_STATE   0x220
  50
  51 struct w1_f1C_data {
  52         u8      memory[W1_EEPROM_SIZE];
  53         u32     validcrc;
  54 };
  55
  56 /*
  57  * Check the file size bounds and adjusts count as needed.
  58  * This would not be needed if the file size didn't reset to 0 after a write.
  59  */
  60 static inline size_t w1_f1C_fix_count(loff_t off, size_t count, size_t size)
  61 {
  62         if (off > size)
  63                 return 0;
  64
  65         if ((off + count) > size)
  66                 return size - off;
  67
  68         return count;
  69 }
  70
  71 static int w1_f1C_refresh_block(struct w1_slave *sl, struct w1_f1C_data *data,
  72                                 int block)
  73 {
  74         u8      wrbuf[3];
  75         int     off = block * W1_PAGE_SIZE;
  76
  77         if (data->validcrc & (1 << block))
  78                 return 0;
  79
  80         if (w1_reset_select_slave(sl)) {
  81                 data->validcrc = 0;
  82                 return -EIO;
  83         }
  84
  85         wrbuf[0] = W1_F1C_READ_EEPROM;
  86         wrbuf[1] = off & 0xff;
  87         wrbuf[2] = off >> 8;
  88         w1_write_block(sl->master, wrbuf, 3);
  89         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  90
  91         /* cache the block if the CRC is valid */
  92         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  93                 data->validcrc |= (1 << block);
  94
  95         return 0;
  96 }
  97
  98 static int w1_f1C_read(struct w1_slave *sl, int addr, int len, char *data)
  99 {
 100         u8 wrbuf[3];
 101
 102         /* read directly from the EEPROM */
 103         if (w1_reset_select_slave(sl))
 104                 return -EIO;
 105
 106         wrbuf[0] = W1_F1C_READ_EEPROM;
 107         wrbuf[1] = addr & 0xff;
 108         wrbuf[2] = addr >> 8;
 109
 110         w1_write_block(sl->master, wrbuf, sizeof(wrbuf));
 111         return w1_read_block(sl->master, data, len);
 112 }
 113
 114 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
 115                            struct bin_attribute *bin_attr, char *buf,
 116                            loff_t off, size_t count)
 117 {
 118         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 119         struct w1_f1C_data *data = sl->family_data;
 120         int i, min_page, max_page;
 121
 122         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 123         if (count == 0)
 124                 return 0;
 125
 126         mutex_lock(&sl->master->mutex);
 127
 128         if (w1_enable_crccheck) {
 129                 min_page = (off >> W1_PAGE_BITS);
 130                 max_page = (off + count - 1) >> W1_PAGE_BITS;
 131                 for (i = min_page; i <= max_page; i++) {
 132                         if (w1_f1C_refresh_block(sl, data, i)) {
 133                                 count = -EIO;
 134                                 goto out_up;
 135                         }
 136                 }
 137                 memcpy(buf, &data->memory[off], count);
 138         } else {
 139                 count = w1_f1C_read(sl, off, count, buf);
 140         }
 141
 142 out_up:
 143         mutex_unlock(&sl->master->mutex);
 144
 145         return count;
 146 }
 147
 148 /**
 149  * w1_f1C_write() - Writes to the scratchpad and reads it back for verification.
 150  * @sl:         The slave structure
 151  * @addr:       Address for the write
 152  * @len:        length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 153  * @data:       The data to write
 154  *
 155  * Then copies the scratchpad to EEPROM.
 156  * The data must be on one page.
 157  * The master must be locked.
 158  *
 159  * Return:      0=Success, -1=failure
 160  */
 161 static int w1_f1C_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 162 {
 163         u8 wrbuf[4];
 164         u8 rdbuf[W1_PAGE_SIZE + 3];
 165         u8 es = (addr + len - 1) & 0x1f;
 166         unsigned int tm = 10;
 167         int i;
 168         struct w1_f1C_data *f1C = sl->family_data;
 169
 170         /* Write the data to the scratchpad */
 171         if (w1_reset_select_slave(sl))
 172                 return -1;
 173
 174         wrbuf[0] = W1_F1C_WRITE_SCRATCH;
 175         wrbuf[1] = addr & 0xff;
 176         wrbuf[2] = addr >> 8;
 177
 178         w1_write_block(sl->master, wrbuf, 3);
 179         w1_write_block(sl->master, data, len);
 180
 181         /* Read the scratchpad and verify */
 182         if (w1_reset_select_slave(sl))
 183                 return -1;
 184
 185         w1_write_8(sl->master, W1_F1C_READ_SCRATCH);
 186         w1_read_block(sl->master, rdbuf, len + 3);
 187
 188         /* Compare what was read against the data written */
 189         if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 190             (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 191                 return -1;
 192
 193         /* Copy the scratchpad to EEPROM */
 194         if (w1_reset_select_slave(sl))
 195                 return -1;
 196
 197         wrbuf[0] = W1_F1C_COPY_SCRATCH;
 198         wrbuf[3] = es;
 199
 200         for (i = 0; i < sizeof(wrbuf); ++i) {
 201                 /*
 202                  * issue 10ms strong pullup (or delay) on the last byte
 203                  * for writing the data from the scratchpad to EEPROM
 204                  */
 205                 if (w1_strong_pullup && i == sizeof(wrbuf)-1)
 206                         w1_next_pullup(sl->master, tm);
 207
 208                 w1_write_8(sl->master, wrbuf[i]);
 209         }
 210
 211         if (!w1_strong_pullup)
 212                 msleep(tm);
 213
 214         if (w1_enable_crccheck) {
 215                 /* invalidate cached data */
 216                 f1C->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 217         }
 218
 219         /* Reset the bus to wake up the EEPROM (this may not be needed) */
 220         w1_reset_bus(sl->master);
 221
 222         return 0;
 223 }
 224
 225 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 226                             struct bin_attribute *bin_attr, char *buf,
 227                             loff_t off, size_t count)
 228
 229 {
 230         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 231         int addr, len, idx;
 232
 233         count = w1_f1C_fix_count(off, count, W1_EEPROM_SIZE);
 234         if (count == 0)
 235                 return 0;
 236
 237         if (w1_enable_crccheck) {
 238                 /* can only write full blocks in cached mode */
 239                 if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 240                         dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 241                                 (int)off, count);
 242                         return -EINVAL;
 243                 }
 244
 245                 /* make sure the block CRCs are valid */
 246                 for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 247                         if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE)
 248                                 != CRC16_VALID) {
 249                                 dev_err(&sl->dev, "bad CRC at offset %d\n",
 250                                         (int)off);
 251                                 return -EINVAL;
 252                         }
 253                 }
 254         }
 255
 256         mutex_lock(&sl->master->mutex);
 257
 258         /* Can only write data to one page at a time */
 259         idx = 0;
 260         while (idx < count) {
 261                 addr = off + idx;
 262                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 263                 if (len > (count - idx))
 264                         len = count - idx;
 265
 266                 if (w1_f1C_write(sl, addr, len, &buf[idx]) < 0) {
 267                         count = -EIO;
 268                         goto out_up;
 269                 }
 270                 idx += len;
 271         }
 272
 273 out_up:
 274         mutex_unlock(&sl->master->mutex);
 275
 276         return count;
 277 }
 278
 279 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 280
 281 static ssize_t pio_read(struct file *filp, struct kobject *kobj,
 282                         struct bin_attribute *bin_attr, char *buf, loff_t off,
 283                         size_t count)
 284
 285 {
 286         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 287         int ret;
 288
 289         /* check arguments */
 290         if (off != 0 || count != 1 || buf == NULL)
 291                 return -EINVAL;
 292
 293         mutex_lock(&sl->master->mutex);
 294         ret = w1_f1C_read(sl, W1_1C_REG_LOGIC_STATE, count, buf);
 295         mutex_unlock(&sl->master->mutex);
 296
 297         return ret;
 298 }
 299
 300 static ssize_t pio_write(struct file *filp, struct kobject *kobj,
 301                          struct bin_attribute *bin_attr, char *buf, loff_t off,
 302                          size_t count)
 303
 304 {
 305         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 306         u8 wrbuf[3];
 307         u8 ack;
 308
 309         /* check arguments */
 310         if (off != 0 || count != 1 || buf == NULL)
 311                 return -EINVAL;
 312
 313         mutex_lock(&sl->master->mutex);
 314
 315         /* Write the PIO data */
 316         if (w1_reset_select_slave(sl)) {
 317                 mutex_unlock(&sl->master->mutex);
 318                 return -1;
 319         }
 320
 321         /* set bit 7..2 to value '1' */
 322         *buf = *buf | 0xFC;
 323
 324         wrbuf[0] = W1_F1C_ACCESS_WRITE;
 325         wrbuf[1] = *buf;
 326         wrbuf[2] = ~(*buf);
 327         w1_write_block(sl->master, wrbuf, 3);
 328
 329         w1_read_block(sl->master, &ack, sizeof(ack));
 330
 331         mutex_unlock(&sl->master->mutex);
 332
 333         /* check for acknowledgement */
 334         if (ack != 0xAA)
 335                 return -EIO;
 336
 337         return count;
 338 }
 339
 340 static BIN_ATTR_RW(pio, 1);
 341
 342 static ssize_t crccheck_show(struct device *dev, struct device_attribute *attr,
 343                              char *buf)
 344 {
 345         return sysfs_emit(buf, "%d\n", w1_enable_crccheck);
 346 }
 347
 348 static ssize_t crccheck_store(struct device *dev, struct device_attribute *attr,
 349                               const char *buf, size_t count)
 350 {
 351         int err = kstrtobool(buf, &w1_enable_crccheck);
 352
 353         if (err)
 354                 return err;
 355
 356         return count;
 357 }
 358
 359 static DEVICE_ATTR_RW(crccheck);
 360
 361 static struct attribute *w1_f1C_attrs[] = {
 362         &dev_attr_crccheck.attr,
 363         NULL,
 364 };
 365
 366 static struct bin_attribute *w1_f1C_bin_attrs[] = {
 367         &bin_attr_eeprom,
 368         &bin_attr_pio,
 369         NULL,
 370 };
 371
 372 static const struct attribute_group w1_f1C_group = {
 373         .attrs          = w1_f1C_attrs,
 374         .bin_attrs      = w1_f1C_bin_attrs,
 375 };
 376
 377 static const struct attribute_group *w1_f1C_groups[] = {
 378         &w1_f1C_group,
 379         NULL,
 380 };
 381
 382 static int w1_f1C_add_slave(struct w1_slave *sl)
 383 {
 384         struct w1_f1C_data *data = NULL;
 385
 386         if (w1_enable_crccheck) {
 387                 data = kzalloc(sizeof(struct w1_f1C_data), GFP_KERNEL);
 388                 if (!data)
 389                         return -ENOMEM;
 390                 sl->family_data = data;
 391         }
 392
 393         return 0;
 394 }
 395
 396 static void w1_f1C_remove_slave(struct w1_slave *sl)
 397 {
 398         kfree(sl->family_data);
 399         sl->family_data = NULL;
 400 }
 401
 402 static const struct w1_family_ops w1_f1C_fops = {
 403         .add_slave      = w1_f1C_add_slave,
 404         .remove_slave   = w1_f1C_remove_slave,
 405         .groups         = w1_f1C_groups,
 406 };
 407
 408 static struct w1_family w1_family_1C = {
 409         .fid = W1_FAMILY_DS28E04,
 410         .fops = &w1_f1C_fops,
 411 };
 412 module_w1_family(w1_family_1C);
 413
 414 MODULE_AUTHOR("Markus Franke <franke.m@sebakmt.com>, <franm@hrz.tu-chemnitz.de>");
 415 MODULE_DESCRIPTION("w1 family 1C driver for DS28E04, 4kb EEPROM and PIO");
 416 MODULE_LICENSE("GPL");
 417 MODULE_ALIAS("w1-family-" __stringify(W1_FAMILY_DS28E04));