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 <linux/w1.h>
  26
  27 #define W1_EEPROM_DS2433        0x23
  28
  29 #define W1_EEPROM_SIZE          512
  30 #define W1_PAGE_COUNT           16
  31 #define W1_PAGE_SIZE            32
  32 #define W1_PAGE_BITS            5
  33 #define W1_PAGE_MASK            0x1F
  34
  35 #define W1_F23_TIME             300
  36
  37 #define W1_F23_READ_EEPROM      0xF0
  38 #define W1_F23_WRITE_SCRATCH    0x0F
  39 #define W1_F23_READ_SCRATCH     0xAA
  40 #define W1_F23_COPY_SCRATCH     0x55
  41
  42 struct w1_f23_data {
  43         u8      memory[W1_EEPROM_SIZE];
  44         u32     validcrc;
  45 };
  46
  47 /**
  48  * Check the file size bounds and adjusts count as needed.
  49  * This would not be needed if the file size didn't reset to 0 after a write.
  50  */
  51 static inline size_t w1_f23_fix_count(loff_t off, size_t count, size_t size)
  52 {
  53         if (off > size)
  54                 return 0;
  55
  56         if ((off + count) > size)
  57                 return (size - off);
  58
  59         return count;
  60 }
  61
  62 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
  63 static int w1_f23_refresh_block(struct w1_slave *sl, struct w1_f23_data *data,
  64                                 int block)
  65 {
  66         u8      wrbuf[3];
  67         int     off = block * W1_PAGE_SIZE;
  68
  69         if (data->validcrc & (1 << block))
  70                 return 0;
  71
  72         if (w1_reset_select_slave(sl)) {
  73                 data->validcrc = 0;
  74                 return -EIO;
  75         }
  76
  77         wrbuf[0] = W1_F23_READ_EEPROM;
  78         wrbuf[1] = off & 0xff;
  79         wrbuf[2] = off >> 8;
  80         w1_write_block(sl->master, wrbuf, 3);
  81         w1_read_block(sl->master, &data->memory[off], W1_PAGE_SIZE);
  82
  83         /* cache the block if the CRC is valid */
  84         if (crc16(CRC16_INIT, &data->memory[off], W1_PAGE_SIZE) == CRC16_VALID)
  85                 data->validcrc |= (1 << block);
  86
  87         return 0;
  88 }
  89 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
  90
  91 static ssize_t eeprom_read(struct file *filp, struct kobject *kobj,
  92                            struct bin_attribute *bin_attr, char *buf,
  93                            loff_t off, size_t count)
  94 {
  95         struct w1_slave *sl = kobj_to_w1_slave(kobj);
  96 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
  97         struct w1_f23_data *data = sl->family_data;
  98         int i, min_page, max_page;
  99 #else
 100         u8 wrbuf[3];
 101 #endif
 102
 103         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 104                 return 0;
 105
 106         mutex_lock(&sl->master->bus_mutex);
 107
 108 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 109
 110         min_page = (off >> W1_PAGE_BITS);
 111         max_page = (off + count - 1) >> W1_PAGE_BITS;
 112         for (i = min_page; i <= max_page; i++) {
 113                 if (w1_f23_refresh_block(sl, data, i)) {
 114                         count = -EIO;
 115                         goto out_up;
 116                 }
 117         }
 118         memcpy(buf, &data->memory[off], count);
 119
 120 #else   /* CONFIG_W1_SLAVE_DS2433_CRC */
 121
 122         /* read directly from the EEPROM */
 123         if (w1_reset_select_slave(sl)) {
 124                 count = -EIO;
 125                 goto out_up;
 126         }
 127
 128         wrbuf[0] = W1_F23_READ_EEPROM;
 129         wrbuf[1] = off & 0xff;
 130         wrbuf[2] = off >> 8;
 131         w1_write_block(sl->master, wrbuf, 3);
 132         w1_read_block(sl->master, buf, count);
 133
 134 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 135
 136 out_up:
 137         mutex_unlock(&sl->master->bus_mutex);
 138
 139         return count;
 140 }
 141
 142 /**
 143  * Writes to the scratchpad and reads it back for verification.
 144  * Then copies the scratchpad to EEPROM.
 145  * The data must be on one page.
 146  * The master must be locked.
 147  *
 148  * @param sl    The slave structure
 149  * @param addr  Address for the write
 150  * @param len   length must be <= (W1_PAGE_SIZE - (addr & W1_PAGE_MASK))
 151  * @param data  The data to write
 152  * @return      0=Success -1=failure
 153  */
 154 static int w1_f23_write(struct w1_slave *sl, int addr, int len, const u8 *data)
 155 {
 156 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 157         struct w1_f23_data *f23 = sl->family_data;
 158 #endif
 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 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 200         f23->validcrc &= ~(1 << (addr >> W1_PAGE_BITS));
 201 #endif
 202         return 0;
 203 }
 204
 205 static ssize_t eeprom_write(struct file *filp, struct kobject *kobj,
 206                             struct bin_attribute *bin_attr, char *buf,
 207                             loff_t off, size_t count)
 208 {
 209         struct w1_slave *sl = kobj_to_w1_slave(kobj);
 210         int addr, len, idx;
 211
 212         if ((count = w1_f23_fix_count(off, count, W1_EEPROM_SIZE)) == 0)
 213                 return 0;
 214
 215 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 216         /* can only write full blocks in cached mode */
 217         if ((off & W1_PAGE_MASK) || (count & W1_PAGE_MASK)) {
 218                 dev_err(&sl->dev, "invalid offset/count off=%d cnt=%zd\n",
 219                         (int)off, count);
 220                 return -EINVAL;
 221         }
 222
 223         /* make sure the block CRCs are valid */
 224         for (idx = 0; idx < count; idx += W1_PAGE_SIZE) {
 225                 if (crc16(CRC16_INIT, &buf[idx], W1_PAGE_SIZE) != CRC16_VALID) {
 226                         dev_err(&sl->dev, "bad CRC at offset %d\n", (int)off);
 227                         return -EINVAL;
 228                 }
 229         }
 230 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 231
 232         mutex_lock(&sl->master->bus_mutex);
 233
 234         /* Can only write data to one page at a time */
 235         idx = 0;
 236         while (idx < count) {
 237                 addr = off + idx;
 238                 len = W1_PAGE_SIZE - (addr & W1_PAGE_MASK);
 239                 if (len > (count - idx))
 240                         len = count - idx;
 241
 242                 if (w1_f23_write(sl, addr, len, &buf[idx]) < 0) {
 243                         count = -EIO;
 244                         goto out_up;
 245                 }
 246                 idx += len;
 247         }
 248
 249 out_up:
 250         mutex_unlock(&sl->master->bus_mutex);
 251
 252         return count;
 253 }
 254
 255 static BIN_ATTR_RW(eeprom, W1_EEPROM_SIZE);
 256
 257 static struct bin_attribute *w1_f23_bin_attributes[] = {
 258         &bin_attr_eeprom,
 259         NULL,
 260 };
 261
 262 static const struct attribute_group w1_f23_group = {
 263         .bin_attrs = w1_f23_bin_attributes,
 264 };
 265
 266 static const struct attribute_group *w1_f23_groups[] = {
 267         &w1_f23_group,
 268         NULL,
 269 };
 270
 271 static int w1_f23_add_slave(struct w1_slave *sl)
 272 {
 273 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 274         struct w1_f23_data *data;
 275
 276         data = kzalloc(sizeof(struct w1_f23_data), GFP_KERNEL);
 277         if (!data)
 278                 return -ENOMEM;
 279         sl->family_data = data;
 280
 281 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 282         return 0;
 283 }
 284
 285 static void w1_f23_remove_slave(struct w1_slave *sl)
 286 {
 287 #ifdef CONFIG_W1_SLAVE_DS2433_CRC
 288         kfree(sl->family_data);
 289         sl->family_data = NULL;
 290 #endif  /* CONFIG_W1_SLAVE_DS2433_CRC */
 291 }
 292
 293 static struct w1_family_ops w1_f23_fops = {
 294         .add_slave      = w1_f23_add_slave,
 295         .remove_slave   = w1_f23_remove_slave,
 296         .groups         = w1_f23_groups,
 297 };
 298
 299 static struct w1_family w1_family_23 = {
 300         .fid = W1_EEPROM_DS2433,
 301         .fops = &w1_f23_fops,
 302 };
 303 module_w1_family(w1_family_23);
 304
 305 MODULE_AUTHOR("Ben Gardner <bgardner@wabtec.com>");
 306 MODULE_DESCRIPTION("w1 family 23 driver for DS2433, 4kb EEPROM");
 307 MODULE_LICENSE("GPL");
 308 MODULE_ALIAS("w1-family-" __stringify(W1_EEPROM_DS2433));