LXR linux/drivers/w1/slaves/w1

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *      w1_ds2433.c - w1 family 23 (DS2433) driver
   4 *
   5 * Copyright (c) 2005 Ben Gardner <bgardner@wabtec.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#ifdef CONFIG_W1_SLAVE_DS2433_CRC
  16#include <linux/crc16.h>
  17
  18#define CRC16_INIT              0
  19#define CRC16_VALID             0xb001
  20
  21#endif
  22
  23#include <linux/w1.h>
  24
  25#define W1_EEPROM_DS2433        0x23
  26
  27#define W1_EEPROM_SIZE          512
  28#define W1_PAGE_COUNT           16
  29#define W1_PAGE_SIZE            32
  30#define W1_PAGE_BITS            5
  31#define W1_PAGE_MASK            0x1F
  32
  33#define W1_F23_TIME             300
  34
  35#define W1_F23_READ_EEPROM      0xF0
  36#define W1_F23_WRITE_SCRATCH    0x0F
  37#define W1_F23_READ_SCRATCH     0xAA
  38#define W1_F23_COPY_SCRATCH     0x55
  39
  40struct w1_f23_data {
  41        u8      memory[W1_EEPROM_SIZE];
  42        u32     validcrc;
  43};
  44
  45/**
  46 * Check the file size bounds and adjusts count as needed.
  47 * This would not be needed if the file size didn't reset to 0 after a write.
  48 */
  49static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
  50{
  51        if (off > size)
  52                return 0;
  53
  54        if ((off + count) > size)
  55                return (size - off);
  56
  57        return count;
  58}
  59
  60#ifdef CONFIG_W1_SLAVE_DS2433_CRC
  61static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
  62                                int block)
  63{
  64        u8      wrbuf[3];
  65        int     off = block * W1_PAGE_SIZE;
  66
  67        if (data->validcrc & (1 << block))
  68                return 0;
  69
  70        if (w1_reset_select_slave(sl)) {
  71                data->validcrc = 0;
  72                return -EIO;
  73        }
  74
  75        wrbuf[0] = W1_F23_READ_EEPROM;
  76        wrbuf[1] = off & 0xff;
  77        wrbuf[2] = off >> 8;
  78        w1_write_block(sl->master, wrbuf, 3);
  79        w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  80
  81        /* cache the block if the CRC is valid */
  82        if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  83                data->validcrc |= (1 << block);
  84
  85        return 0;
  86}
  87#endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
  88
  89static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
  90                           struct bin_attribute *bin_attr, char *buf,
  91                           loff_t off, size_t count)
  92{
  93        struct w1_slave *sl = kobj_to_w1_slave(kobj);
  94#ifdef CONFIG_W1_SLAVE_DS2433_CRC
  95        struct w1_f23_data *data = sl->family_data;
  96        int i, min_page, max_page;
  97#else
  98        u8 wrbuf[3];
  99#endif
 100
 101        if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 102                return 0;
 103
 104        mutex_lock(&sl->master->bus_mutex);
 105
 106#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 107
 108        min_page = (off >> W1_PAGE_BITS);
 109        max_page = (off + count - 1) >> W1_PAGE_BITS;
 110        for (i = min_page; i <= max_page; i++) {
 111                if (w1_f23_refresh_block(sl, data, i)) {
 112                        count = -EIO;
 113                        goto out_up;
 114                }
 115        }
 116        memcpy(buf, &data->memory[off], count);
 117
 118#else   /* CONFIG_W1_SLAVE_DS2433_CRC */
 119
 120        /* read directly from the EEPROM */
 121        if (w1_reset_select_slave(sl)) {
 122                count = -EIO;
 123                goto out_up;
 124        }
 125
 126        wrbuf[0] = W1_F23_READ_EEPROM;
 127        wrbuf[1] = off & 0xff;
 128        wrbuf[2] = off >> 8;
 129        w1_write_block(sl->master, wrbuf, 3);
 130        w1_read_block(sl->master, buf, count);
 131
 132#endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 133
 134out_up:
 135        mutex_unlock(&sl->master->bus_mutex);
 136
 137        return count;
 138}
 139
 140/**
 141 * Writes to the scratchpad and reads it back for verification.
 142 * Then copies the scratchpad to EEPROM.
 143 * The data must be on one page.
 144 * The master must be locked.
 145 *
 146 * @param sl    The slave structure
 147 * @param addr  Address for the write
 148 * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 149 * @param data  The data to write
 150 * @return      0=Success -1=failure
 151 */
 152static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 153{
 154#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 155        struct w1_f23_data *f23 = sl->family_data;
 156#endif
 157        u8 wrbuf[4];
 158        u8 rdbuf[W1_PAGE_SIZE + 3];
 159        u8 es = (addr + len - 1) & 0x1f;
 160
 161        /* Write the data to the scratchpad */
 162        if (w1_reset_select_slave(sl))
 163                return -1;
 164
 165        wrbuf[0] = W1_F23_WRITE_SCRATCH;
 166        wrbuf[1] = addr & 0xff;
 167        wrbuf[2] = addr >> 8;
 168
 169        w1_write_block(sl->master, wrbuf, 3);
 170        w1_write_block(sl->master, data, len);
 171
 172        /* Read the scratchpad and verify */
 173        if (w1_reset_select_slave(sl))
 174                return -1;
 175
 176        w1_write_8(sl->master, W1_F23_READ_SCRATCH);
 177        w1_read_block(sl->master, rdbuf, len + 3);
 178
 179        /* Compare what was read against the data written */
 180        if ((rdbuf[0] != wrbuf[1]) || (rdbuf[1] != wrbuf[2]) ||
 181            (rdbuf[2] != es) || (memcmp(data, &rdbuf[3], len) != 0))
 182                return -1;
 183
 184        /* Copy the scratchpad to EEPROM */
 185        if (w1_reset_select_slave(sl))
 186                return -1;
 187
 188        wrbuf[0] = W1_F23_COPY_SCRATCH;
 189        wrbuf[3] = es;
 190        w1_write_block(sl->master, wrbuf, 4);
 191
 192        /* Sleep for 5 ms to wait for the write to complete */
 193        msleep(5);
 194
 195        /* Reset the bus to wake up the EEPROM (this may not be needed) */
 196        w1_reset_bus(sl->master);
 197#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 198        f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 199#endif
 200        return 0;
 201}
 202
 203static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 204                            struct bin_attribute *bin_attr, char *buf,
 205                            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->bus_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->bus_mutex);
 249
 250        return count;
 251}
 252
 253static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 254
 255static struct bin_attribute *w1_f23_bin_attributes[] = {
 256        &bin_attr_eeprom,
 257        NULL,
 258};
 259
 260static const struct attribute_group w1_f23_group = {
 261        .bin_attrs = w1_f23_bin_attributes,
 262};
 263
 264static const struct attribute_group *w1_f23_groups[] = {
 265        &w1_f23_group,
 266        NULL,
 267};
 268
 269static int w1_f23_add_slave(struct w1_slave *sl)
 270{
 271#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 272        struct w1_f23_data *data;
 273
 274        data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
 275        if (!data)
 276                return -ENOMEM;
 277        sl->family_data = data;
 278
 279#endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 280        return 0;
 281}
 282
 283static void w1_f23_remove_slave(struct w1_slave *sl)
 284{
 285#ifdef CONFIG_W1_SLAVE_DS2433_CRC
 286        kfree(sl->family_data);
 287        sl->family_data = NULL;
 288#endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 289}
 290
 291static struct w1_family_ops w1_f23_fops = {
 292        .add_slave      = w1_f23_add_slave,
 293        .remove_slave   = w1_f23_remove_slave,
 294        .groups         = w1_f23_groups,
 295};
 296
 297static struct w1_family w1_family_23 = {
 298        .fid = W1_EEPROM_DS2433,
 299        .fops = &w1_f23_fops,
 300};
 301module_w1_family(w1_family_23);
 302
 303MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 304MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
 305MODULE_LICENSE("GPL");
 306MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));
 307