drivers/w1/slaves/w1_ds2433.c

   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
  40 struct 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  */
  49 static 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
  61 static 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
  89 static 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
 134 out_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  */
 152 static 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
 203 static 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
 247 out_up:
 248         mutex_unlock(&sl->master->bus_mutex);
 249
 250         return count;
 251 }
 252
 253 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 254
 255 static struct bin_attribute *w1_f23_bin_attributes[] = {
 256         &bin_attr_eeprom,
 257         NULL,
 258 };
 259
 260 static const struct attribute_group w1_f23_group = {
 261         .bin_attrs = w1_f23_bin_attributes,
 262 };
 263
 264 static const struct attribute_group *w1_f23_groups[] = {
 265         &w1_f23_group,
 266         NULL,
 267 };
 268
 269 static 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
 283 static 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
 291 static const 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
 297 static struct w1_family w1_family_23 = {
 298         .fid = W1_EEPROM_DS2433,
 299         .fops = &w1_f23_fops,
 300 };
 301 module_w1_family(w1_family_23);
 302
 303 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 304 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
 305 MODULE_LICENSE("GPL");
 306 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));