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#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
  29MODULE_LICENSE("GPL");
  30MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
  31MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
  32MODULE_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
  47struct 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 */
  56static 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
  68static 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
  96static 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
 141out_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 */
 159static 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
 210static 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
 254out_up:
 255        mutex_unlock(&sl->master->bus_mutex);
 256
 257        return count;
 258}
 259
 260static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 261
 262static struct bin_attribute *w1_f23_bin_attributes[] = {
 263        &bin_attr_eeprom,
 264        NULL,
 265};
 266
 267static const struct attribute_group w1_f23_group = {
 268        .bin_attrs = w1_f23_bin_attributes,
 269};
 270
 271static const struct attribute_group *w1_f23_groups[] = {
 272        &w1_f23_group,
 273        NULL,
 274};
 275
 276static 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
 290static 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
 298static 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
 304static struct w1_family w1_family_23 = {
 305        .fid = W1_EEPROM_DS2433,
 306        .fops = &w1_f23_fops,
 307};
 308
 309static int __init w1_f23_init(void)
 310{
 311        return w1_register_family(&w1_family_23);
 312}
 313
 314static void __exit w1_f23_fini(void)
 315{
 316        w1_unregister_family(&w1_family_23);
 317}
 318
 319module_init(w1_f23_init);
 320module_exit(w1_f23_fini);
 321