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 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
  33
  34 #define W1_EEPROM_SIZE          512
  35 #define W1_PAGE_COUNT           16
  36 #define W1_PAGE_SIZE            32
  37 #define W1_PAGE_BITS            5
  38 #define W1_PAGE_MASK            0x1F
  39
  40 #define W1_F23_TIME             300
  41
  42 #define W1_F23_READ_EEPROM      0xF0
  43 #define W1_F23_WRITE_SCRATCH    0x0F
  44 #define W1_F23_READ_SCRATCH     0xAA
  45 #define W1_F23_COPY_SCRATCH     0x55
  46
  47 struct w1_f23_data {
  48         u8      memory[W1_EEPROM_SIZE];
  49         u32     validcrc;
  50 };
  51
  52 /**
  53  * Check the file size bounds and adjusts count as needed.
  54  * This would not be needed if the file size didn't reset to 0 after a write.
  55  */
  56 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
  57 {
  58         if (off > size)
  59                 return 0;
  60
  61         if ((off + count) > size)
  62                 return (size - off);
  63
  64         return count;
  65 }
  66
  67 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
  68 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
  69                                 int block)
  70 {
  71         u8      wrbuf[3];
  72         int     off = block * W1_PAGE_SIZE;
  73
  74         if (data->validcrc & (1 << block))
  75                 return 0;
  76
  77         if (w1_reset_select_slave(sl)) {
  78                 data->validcrc = 0;
  79                 return -EIO;
  80         }
  81
  82         wrbuf[0] = W1_F23_READ_EEPROM;
  83         wrbuf[1] = off & 0xff;
  84         wrbuf[2] = off >> 8;
  85         w1_write_block(sl->master, wrbuf, 3);
  86         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  87
  88         /* cache the block if the CRC is valid */
  89         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  90                 data->validcrc |= (1 << block);
  91
  92         return 0;
  93 }
  94 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
  95
  96 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
  97                            struct bin_attribute *bin_attr, char *buf,
  98                            loff_t off, size_t count)
  99 {
 100         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 101 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 102         struct w1_f23_data *data = sl->family_data;
 103         int i, min_page, max_page;
 104 #else
 105         u8 wrbuf[3];
 106 #endif
 107
 108         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 109                 return 0;
 110
 111         mutex_lock(&sl->master->bus_mutex);
 112
 113 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 114
 115         min_page = (off >> W1_PAGE_BITS);
 116         max_page = (off + count - 1) >> W1_PAGE_BITS;
 117         for (i = min_page; i <= max_page; i++) {
 118                 if (w1_f23_refresh_block(sl, data, i)) {
 119                         count = -EIO;
 120                         goto out_up;
 121                 }
 122         }
 123         memcpy(buf, &data->memory[off], count);
 124
 125 #else   /* CONFIG_W1_SLAVE_DS2433_CRC */
 126
 127         /* read directly from the EEPROM */
 128         if (w1_reset_select_slave(sl)) {
 129                 count = -EIO;
 130                 goto out_up;
 131         }
 132
 133         wrbuf[0] = W1_F23_READ_EEPROM;
 134         wrbuf[1] = off & 0xff;
 135         wrbuf[2] = off >> 8;
 136         w1_write_block(sl->master, wrbuf, 3);
 137         w1_read_block(sl->master, buf, count);
 138
 139 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 140
 141 out_up:
 142         mutex_unlock(&sl->master->bus_mutex);
 143
 144         return count;
 145 }
 146
 147 /**
 148  * Writes to the scratchpad and reads it back for verification.
 149  * Then copies the scratchpad to EEPROM.
 150  * The data must be on one page.
 151  * The master must be locked.
 152  *
 153  * @param sl    The slave structure
 154  * @param addr  Address for the write
 155  * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 156  * @param data  The data to write
 157  * @return      0=Success -1=failure
 158  */
 159 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 160 {
 161 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 162         struct w1_f23_data *f23 = sl->family_data;
 163 #endif
 164         u8 wrbuf[4];
 165         u8 rdbuf[W1_PAGE_SIZE + 3];
 166         u8 es = (addr + len - 1) & 0x1f;
 167
 168         /* Write the data to the scratchpad */
 169         if (w1_reset_select_slave(sl))
 170                 return -1;
 171
 172         wrbuf[0] = W1_F23_WRITE_SCRATCH;
 173         wrbuf[1] = addr & 0xff;
 174         wrbuf[2] = addr >> 8;
 175
 176         w1_write_block(sl->master, wrbuf, 3);
 177         w1_write_block(sl->master, data, len);
 178
 179         /* Read the scratchpad and verify */
 180         if (w1_reset_select_slave(sl))
 181                 return -1;
 182
 183         w1_write_8(sl->master, W1_F23_READ_SCRATCH);
 184         w1_read_block(sl->master, rdbuf, len + 3);
 185
 186         /* Compare what was read against the data written */
 187         if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 188             (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 189                 return -1;
 190
 191         /* Copy the scratchpad to EEPROM */
 192         if (w1_reset_select_slave(sl))
 193                 return -1;
 194
 195         wrbuf[0] = W1_F23_COPY_SCRATCH;
 196         wrbuf[3] = es;
 197         w1_write_block(sl->master, wrbuf, 4);
 198
 199         /* Sleep for 5 ms to wait for the write to complete */
 200         msleep(5);
 201
 202         /* Reset the bus to wake up the EEPROM (this may not be needed) */
 203         w1_reset_bus(sl->master);
 204 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 205         f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 206 #endif
 207         return 0;
 208 }
 209
 210 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 211                             struct bin_attribute *bin_attr, char *buf,
 212                             loff_t off, size_t count)
 213 {
 214         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 215         int addr, len, idx;
 216
 217         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 218                 return 0;
 219
 220 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 221         /* can only write full blocks in cached mode */
 222         if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 223                 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 224                         (int)off, count);
 225                 return -EINVAL;
 226         }
 227
 228         /* make sure the block CRCs are valid */
 229         for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 230                 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
 231                         dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
 232                         return -EINVAL;
 233                 }
 234         }
 235 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 236
 237         mutex_lock(&sl->master->bus_mutex);
 238
 239         /* Can only write data to one page at a time */
 240         idx = 0;
 241         while (idx < count) {
 242                 addr = off + idx;
 243                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 244                 if (len > (count - idx))
 245                         len = count - idx;
 246
 247                 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
 248                         count = -EIO;
 249                         goto out_up;
 250                 }
 251                 idx += len;
 252         }
 253
 254 out_up:
 255         mutex_unlock(&sl->master->bus_mutex);
 256
 257         return count;
 258 }
 259
 260 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 261
 262 static struct bin_attribute *w1_f23_bin_attributes[] = {
 263         &bin_attr_eeprom,
 264         NULL,
 265 };
 266
 267 static const struct attribute_group w1_f23_group = {
 268         .bin_attrs = w1_f23_bin_attributes,
 269 };
 270
 271 static const struct attribute_group *w1_f23_groups[] = {
 272         &w1_f23_group,
 273         NULL,
 274 };
 275
 276 static int w1_f23_add_slave(struct w1_slave *sl)
 277 {
 278 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 279         struct w1_f23_data *data;
 280
 281         data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
 282         if (!data)
 283                 return -ENOMEM;
 284         sl->family_data = data;
 285
 286 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 287         return 0;
 288 }
 289
 290 static void w1_f23_remove_slave(struct w1_slave *sl)
 291 {
 292 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 293         kfree(sl->family_data);
 294         sl->family_data = NULL;
 295 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 296 }
 297
 298 static struct w1_family_ops w1_f23_fops = {
 299         .add_slave      = w1_f23_add_slave,
 300         .remove_slave   = w1_f23_remove_slave,
 301         .groups         = w1_f23_groups,
 302 };
 303
 304 static struct w1_family w1_family_23 = {
 305         .fid = W1_EEPROM_DS2433,
 306         .fops = &w1_f23_fops,
 307 };
 308
 309 static int __init w1_f23_init(void)
 310 {
 311         return w1_register_family(&w1_family_23);
 312 }
 313
 314 static void __exit w1_f23_fini(void)
 315 {
 316         w1_unregister_family(&w1_family_23);
 317 }
 318
 319 module_init(w1_f23_init);
 320 module_exit(w1_f23_fini);