drivers/w1/slaves/w1_ds2433.c

   1 /*
   2  *      w1_ds2433.c - w1 family 23 (DS2433) driver
   3  *
   4  * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.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 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
  18 #include <linux/crc16.h>
  19
  20 #define CRC16_INIT              0
  21 #define CRC16_VALID             0xb001
  22
  23 #endif
  24
  25 #include "../w1.h"
  26 #include "../w1_int.h"
  27 #include "../w1_family.h"
  28
  29 MODULE_LICENSE("GPL");
  30 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
  31 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
  32
  33 #define W1_EEPROM_SIZE          512
  34 #define W1_PAGE_COUNT           16
  35 #define W1_PAGE_SIZE            32
  36 #define W1_PAGE_BITS            5
  37 #define W1_PAGE_MASK            0x1F
  38
  39 #define W1_F23_TIME             300
  40
  41 #define W1_F23_READ_EEPROM      0xF0
  42 #define W1_F23_WRITE_SCRATCH    0x0F
  43 #define W1_F23_READ_SCRATCH     0xAA
  44 #define W1_F23_COPY_SCRATCH     0x55
  45
  46 struct w1_f23_data {
  47         u8      memory[W1_EEPROM_SIZE];
  48         u32     validcrc;
  49 };
  50
  51 /**
  52  * Check the file size bounds and adjusts count as needed.
  53  * This would not be needed if the file size didn't reset to 0 after a write.
  54  */
  55 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
  56 {
  57         if (off > size)
  58                 return 0;
  59
  60         if ((off + count) > size)
  61                 return (size - off);
  62
  63         return count;
  64 }
  65
  66 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
  67 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
  68                                 int block)
  69 {
  70         u8      wrbuf[3];
  71         int     off = block * W1_PAGE_SIZE;
  72
  73         if (data->validcrc & (1 << block))
  74                 return 0;
  75
  76         if (w1_reset_select_slave(sl)) {
  77                 data->validcrc = 0;
  78                 return -EIO;
  79         }
  80
  81         wrbuf[0] = W1_F23_READ_EEPROM;
  82         wrbuf[1] = off & 0xff;
  83         wrbuf[2] = off >> 8;
  84         w1_write_block(sl->master, wrbuf, 3);
  85         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  86
  87         /* cache the block if the CRC is valid */
  88         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  89                 data->validcrc |= (1 << block);
  90
  91         return 0;
  92 }
  93 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
  94
  95 static ssize_t w1_f23_read_bin(struct file *filp, struct kobject *kobj,
  96                                struct bin_attribute *bin_attr,
  97                                char *buf, loff_t off, size_t count)
  98 {
  99         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 100 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 101         struct w1_f23_data *data = sl->family_data;
 102         int i, min_page, max_page;
 103 #else
 104         u8 wrbuf[3];
 105 #endif
 106
 107         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 108                 return 0;
 109
 110         mutex_lock(&sl->master->mutex);
 111
 112 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 113
 114         min_page = (off >> W1_PAGE_BITS);
 115         max_page = (off + count - 1) >> W1_PAGE_BITS;
 116         for (i = min_page; i <= max_page; i++) {
 117                 if (w1_f23_refresh_block(sl, data, i)) {
 118                         count = -EIO;
 119                         goto out_up;
 120                 }
 121         }
 122         memcpy(buf, &data->memory[off], count);
 123
 124 #else   /* CONFIG_W1_SLAVE_DS2433_CRC */
 125
 126         /* read directly from the EEPROM */
 127         if (w1_reset_select_slave(sl)) {
 128                 count = -EIO;
 129                 goto out_up;
 130         }
 131
 132         wrbuf[0] = W1_F23_READ_EEPROM;
 133         wrbuf[1] = off & 0xff;
 134         wrbuf[2] = off >> 8;
 135         w1_write_block(sl->master, wrbuf, 3);
 136         w1_read_block(sl->master, buf, count);
 137
 138 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 139
 140 out_up:
 141         mutex_unlock(&sl->master->mutex);
 142
 143         return count;
 144 }
 145
 146 /**
 147  * Writes to the scratchpad and reads it back for verification.
 148  * Then copies the scratchpad to EEPROM.
 149  * The data must be on one page.
 150  * The master must be locked.
 151  *
 152  * @param sl    The slave structure
 153  * @param addr  Address for the write
 154  * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 155  * @param data  The data to write
 156  * @return      0=Success -1=failure
 157  */
 158 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 159 {
 160 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 161         struct w1_f23_data *f23 = sl->family_data;
 162 #endif
 163         u8 wrbuf[4];
 164         u8 rdbuf[W1_PAGE_SIZE + 3];
 165         u8 es = (addr + len - 1) & 0x1f;
 166
 167         /* Write the data to the scratchpad */
 168         if (w1_reset_select_slave(sl))
 169                 return -1;
 170
 171         wrbuf[0] = W1_F23_WRITE_SCRATCH;
 172         wrbuf[1] = addr & 0xff;
 173         wrbuf[2] = addr >> 8;
 174
 175         w1_write_block(sl->master, wrbuf, 3);
 176         w1_write_block(sl->master, data, len);
 177
 178         /* Read the scratchpad and verify */
 179         if (w1_reset_select_slave(sl))
 180                 return -1;
 181
 182         w1_write_8(sl->master, W1_F23_READ_SCRATCH);
 183         w1_read_block(sl->master, rdbuf, len + 3);
 184
 185         /* Compare what was read against the data written */
 186         if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 187             (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 188                 return -1;
 189
 190         /* Copy the scratchpad to EEPROM */
 191         if (w1_reset_select_slave(sl))
 192                 return -1;
 193
 194         wrbuf[0] = W1_F23_COPY_SCRATCH;
 195         wrbuf[3] = es;
 196         w1_write_block(sl->master, wrbuf, 4);
 197
 198         /* Sleep for 5 ms to wait for the write to complete */
 199         msleep(5);
 200
 201         /* Reset the bus to wake up the EEPROM (this may not be needed) */
 202         w1_reset_bus(sl->master);
 203 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 204         f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 205 #endif
 206         return 0;
 207 }
 208
 209 static ssize_t w1_f23_write_bin(struct file *filp, struct kobject *kobj,
 210                                 struct bin_attribute *bin_attr,
 211                                 char *buf, loff_t off, size_t count)
 212 {
 213         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 214         int addr, len, idx;
 215
 216         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 217                 return 0;
 218
 219 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 220         /* can only write full blocks in cached mode */
 221         if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 222                 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 223                         (int)off, count);
 224                 return -EINVAL;
 225         }
 226
 227         /* make sure the block CRCs are valid */
 228         for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 229                 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
 230                         dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
 231                         return -EINVAL;
 232                 }
 233         }
 234 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 235
 236         mutex_lock(&sl->master->mutex);
 237
 238         /* Can only write data to one page at a time */
 239         idx = 0;
 240         while (idx < count) {
 241                 addr = off + idx;
 242                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 243                 if (len > (count - idx))
 244                         len = count - idx;
 245
 246                 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
 247                         count = -EIO;
 248                         goto out_up;
 249                 }
 250                 idx += len;
 251         }
 252
 253 out_up:
 254         mutex_unlock(&sl->master->mutex);
 255
 256         return count;
 257 }
 258
 259 static struct bin_attribute w1_f23_bin_attr = {
 260         .attr = {
 261                 .name = "eeprom",
 262                 .mode = S_IRUGO | S_IWUSR,
 263         },
 264         .size = W1_EEPROM_SIZE,
 265         .read = w1_f23_read_bin,
 266         .write = w1_f23_write_bin,
 267 };
 268
 269 static int w1_f23_add_slave(struct w1_slave *sl)
 270 {
 271         int err;
 272 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 273         struct w1_f23_data *data;
 274
 275         data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
 276         if (!data)
 277                 return -ENOMEM;
 278         sl->family_data = data;
 279
 280 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 281
 282         err = sysfs_create_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
 283
 284 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 285         if (err)
 286                 kfree(data);
 287 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 288
 289         return err;
 290 }
 291
 292 static void w1_f23_remove_slave(struct w1_slave *sl)
 293 {
 294 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 295         kfree(sl->family_data);
 296         sl->family_data = NULL;
 297 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 298         sysfs_remove_bin_file(&sl->dev.kobj, &w1_f23_bin_attr);
 299 }
 300
 301 static struct w1_family_ops w1_f23_fops = {
 302         .add_slave      = w1_f23_add_slave,
 303         .remove_slave   = w1_f23_remove_slave,
 304 };
 305
 306 static struct w1_family w1_family_23 = {
 307         .fid = W1_EEPROM_DS2433,
 308         .fops = &w1_f23_fops,
 309 };
 310
 311 static int __init w1_f23_init(void)
 312 {
 313         return w1_register_family(&w1_family_23);
 314 }
 315
 316 static void __exit w1_f23_fini(void)
 317 {
 318         w1_unregister_family(&w1_family_23);
 319 }
 320
 321 module_init(w1_f23_init);
 322 module_exit(w1_f23_fini);