LXR linux/drivers/w1/slaves/w1

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