kernel/drivers/misc/eeprom/eeprom_93xx46.c

   1 /*
   2  * Driver for 93xx46 EEPROMs
   3  *
   4  * (C) 2011 DENX Software Engineering, Anatolij Gustschin <agust@denx.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/mutex.h>
  16 #include <linux/slab.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/sysfs.h>
  19 #include <linux/eeprom_93xx46.h>
  20
  21 #define OP_START        0x4
  22 #define OP_WRITE        (OP_START | 0x1)
  23 #define OP_READ         (OP_START | 0x2)
  24 #define ADDR_EWDS       0x00
  25 #define ADDR_ERAL       0x20
  26 #define ADDR_EWEN       0x30
  27
  28 struct eeprom_93xx46_dev {
  29         struct spi_device *spi;
  30         struct eeprom_93xx46_platform_data *pdata;
  31         struct bin_attribute bin;
  32         struct mutex lock;
  33         int addrlen;
  34 };
  35
  36 static ssize_t
  37 eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
  38                        struct bin_attribute *bin_attr,
  39                        char *buf, loff_t off, size_t count)
  40 {
  41         struct eeprom_93xx46_dev *edev;
  42         struct device *dev;
  43         struct spi_message m;
  44         struct spi_transfer t[2];
  45         int bits, ret;
  46         u16 cmd_addr;
  47
  48         dev = container_of(kobj, struct device, kobj);
  49         edev = dev_get_drvdata(dev);
  50
  51         cmd_addr = OP_READ << edev->addrlen;
  52
  53         if (edev->addrlen == 7) {
  54                 cmd_addr |= off & 0x7f;
  55                 bits = 10;
  56         } else {
  57                 cmd_addr |= off & 0x3f;
  58                 bits = 9;
  59         }
  60
  61         dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
  62                 cmd_addr, edev->spi->max_speed_hz);
  63
  64         spi_message_init(&m);
  65         memset(t, 0, sizeof(t));
  66
  67         t[0].tx_buf = (char *)&cmd_addr;
  68         t[0].len = 2;
  69         t[0].bits_per_word = bits;
  70         spi_message_add_tail(&t[0], &m);
  71
  72         t[1].rx_buf = buf;
  73         t[1].len = count;
  74         t[1].bits_per_word = 8;
  75         spi_message_add_tail(&t[1], &m);
  76
  77         mutex_lock(&edev->lock);
  78
  79         if (edev->pdata->prepare)
  80                 edev->pdata->prepare(edev);
  81
  82         ret = spi_sync(edev->spi, &m);
  83         /* have to wait at least Tcsl ns */
  84         ndelay(250);
  85         if (ret) {
  86                 dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
  87                         count, (int)off, ret);
  88         }
  89
  90         if (edev->pdata->finish)
  91                 edev->pdata->finish(edev);
  92
  93         mutex_unlock(&edev->lock);
  94         return ret ? : count;
  95 }
  96
  97 static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
  98 {
  99         struct spi_message m;
 100         struct spi_transfer t;
 101         int bits, ret;
 102         u16 cmd_addr;
 103
 104         cmd_addr = OP_START << edev->addrlen;
 105         if (edev->addrlen == 7) {
 106                 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
 107                 bits = 10;
 108         } else {
 109                 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
 110                 bits = 9;
 111         }
 112
 113         dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);
 114
 115         spi_message_init(&m);
 116         memset(&t, 0, sizeof(t));
 117
 118         t.tx_buf = &cmd_addr;
 119         t.len = 2;
 120         t.bits_per_word = bits;
 121         spi_message_add_tail(&t, &m);
 122
 123         mutex_lock(&edev->lock);
 124
 125         if (edev->pdata->prepare)
 126                 edev->pdata->prepare(edev);
 127
 128         ret = spi_sync(edev->spi, &m);
 129         /* have to wait at least Tcsl ns */
 130         ndelay(250);
 131         if (ret)
 132                 dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
 133                         is_on ? "en" : "dis", ret);
 134
 135         if (edev->pdata->finish)
 136                 edev->pdata->finish(edev);
 137
 138         mutex_unlock(&edev->lock);
 139         return ret;
 140 }
 141
 142 static ssize_t
 143 eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
 144                          const char *buf, unsigned off)
 145 {
 146         struct spi_message m;
 147         struct spi_transfer t[2];
 148         int bits, data_len, ret;
 149         u16 cmd_addr;
 150
 151         cmd_addr = OP_WRITE << edev->addrlen;
 152
 153         if (edev->addrlen == 7) {
 154                 cmd_addr |= off & 0x7f;
 155                 bits = 10;
 156                 data_len = 1;
 157         } else {
 158                 cmd_addr |= off & 0x3f;
 159                 bits = 9;
 160                 data_len = 2;
 161         }
 162
 163         dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
 164
 165         spi_message_init(&m);
 166         memset(t, 0, sizeof(t));
 167
 168         t[0].tx_buf = (char *)&cmd_addr;
 169         t[0].len = 2;
 170         t[0].bits_per_word = bits;
 171         spi_message_add_tail(&t[0], &m);
 172
 173         t[1].tx_buf = buf;
 174         t[1].len = data_len;
 175         t[1].bits_per_word = 8;
 176         spi_message_add_tail(&t[1], &m);
 177
 178         ret = spi_sync(edev->spi, &m);
 179         /* have to wait program cycle time Twc ms */
 180         mdelay(6);
 181         return ret;
 182 }
 183
 184 static ssize_t
 185 eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
 186                         struct bin_attribute *bin_attr,
 187                         char *buf, loff_t off, size_t count)
 188 {
 189         struct eeprom_93xx46_dev *edev;
 190         struct device *dev;
 191         int i, ret, step = 1;
 192
 193         dev = container_of(kobj, struct device, kobj);
 194         edev = dev_get_drvdata(dev);
 195
 196         /* only write even number of bytes on 16-bit devices */
 197         if (edev->addrlen == 6) {
 198                 step = 2;
 199                 count &= ~1;
 200         }
 201
 202         /* erase/write enable */
 203         ret = eeprom_93xx46_ew(edev, 1);
 204         if (ret)
 205                 return ret;
 206
 207         mutex_lock(&edev->lock);
 208
 209         if (edev->pdata->prepare)
 210                 edev->pdata->prepare(edev);
 211
 212         for (i = 0; i < count; i += step) {
 213                 ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
 214                 if (ret) {
 215                         dev_err(&edev->spi->dev, "write failed at %d: %d\n",
 216                                 (int)off + i, ret);
 217                         break;
 218                 }
 219         }
 220
 221         if (edev->pdata->finish)
 222                 edev->pdata->finish(edev);
 223
 224         mutex_unlock(&edev->lock);
 225
 226         /* erase/write disable */
 227         eeprom_93xx46_ew(edev, 0);
 228         return ret ? : count;
 229 }
 230
 231 static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
 232 {
 233         struct eeprom_93xx46_platform_data *pd = edev->pdata;
 234         struct spi_message m;
 235         struct spi_transfer t;
 236         int bits, ret;
 237         u16 cmd_addr;
 238
 239         cmd_addr = OP_START << edev->addrlen;
 240         if (edev->addrlen == 7) {
 241                 cmd_addr |= ADDR_ERAL << 1;
 242                 bits = 10;
 243         } else {
 244                 cmd_addr |= ADDR_ERAL;
 245                 bits = 9;
 246         }
 247
 248         spi_message_init(&m);
 249         memset(&t, 0, sizeof(t));
 250
 251         t.tx_buf = &cmd_addr;
 252         t.len = 2;
 253         t.bits_per_word = bits;
 254         spi_message_add_tail(&t, &m);
 255
 256         mutex_lock(&edev->lock);
 257
 258         if (edev->pdata->prepare)
 259                 edev->pdata->prepare(edev);
 260
 261         ret = spi_sync(edev->spi, &m);
 262         if (ret)
 263                 dev_err(&edev->spi->dev, "erase error %d\n", ret);
 264         /* have to wait erase cycle time Tec ms */
 265         mdelay(6);
 266
 267         if (pd->finish)
 268                 pd->finish(edev);
 269
 270         mutex_unlock(&edev->lock);
 271         return ret;
 272 }
 273
 274 static ssize_t eeprom_93xx46_store_erase(struct device *dev,
 275                                          struct device_attribute *attr,
 276                                          const char *buf, size_t count)
 277 {
 278         struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
 279         int erase = 0, ret;
 280
 281         sscanf(buf, "%d", &erase);
 282         if (erase) {
 283                 ret = eeprom_93xx46_ew(edev, 1);
 284                 if (ret)
 285                         return ret;
 286                 ret = eeprom_93xx46_eral(edev);
 287                 if (ret)
 288                         return ret;
 289                 ret = eeprom_93xx46_ew(edev, 0);
 290                 if (ret)
 291                         return ret;
 292         }
 293         return count;
 294 }
 295 static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
 296
 297 static int eeprom_93xx46_probe(struct spi_device *spi)
 298 {
 299         struct eeprom_93xx46_platform_data *pd;
 300         struct eeprom_93xx46_dev *edev;
 301         int err;
 302
 303         pd = spi->dev.platform_data;
 304         if (!pd) {
 305                 dev_err(&spi->dev, "missing platform data\n");
 306                 return -ENODEV;
 307         }
 308
 309         edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 310         if (!edev)
 311                 return -ENOMEM;
 312
 313         if (pd->flags & EE_ADDR8)
 314                 edev->addrlen = 7;
 315         else if (pd->flags & EE_ADDR16)
 316                 edev->addrlen = 6;
 317         else {
 318                 dev_err(&spi->dev, "unspecified address type\n");
 319                 err = -EINVAL;
 320                 goto fail;
 321         }
 322
 323         mutex_init(&edev->lock);
 324
 325         edev->spi = spi_dev_get(spi);
 326         edev->pdata = pd;
 327
 328         sysfs_bin_attr_init(&edev->bin);
 329         edev->bin.attr.name = "eeprom";
 330         edev->bin.attr.mode = S_IRUSR;
 331         edev->bin.read = eeprom_93xx46_bin_read;
 332         edev->bin.size = 128;
 333         if (!(pd->flags & EE_READONLY)) {
 334                 edev->bin.write = eeprom_93xx46_bin_write;
 335                 edev->bin.attr.mode |= S_IWUSR;
 336         }
 337
 338         err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
 339         if (err)
 340                 goto fail;
 341
 342         dev_info(&spi->dev, "%d-bit eeprom %s\n",
 343                 (pd->flags & EE_ADDR8) ? 8 : 16,
 344                 (pd->flags & EE_READONLY) ? "(readonly)" : "");
 345
 346         if (!(pd->flags & EE_READONLY)) {
 347                 if (device_create_file(&spi->dev, &dev_attr_erase))
 348                         dev_err(&spi->dev, "can't create erase interface\n");
 349         }
 350
 351         spi_set_drvdata(spi, edev);
 352         return 0;
 353 fail:
 354         kfree(edev);
 355         return err;
 356 }
 357
 358 static int eeprom_93xx46_remove(struct spi_device *spi)
 359 {
 360         struct eeprom_93xx46_dev *edev = spi_get_drvdata(spi);
 361
 362         if (!(edev->pdata->flags & EE_READONLY))
 363                 device_remove_file(&spi->dev, &dev_attr_erase);
 364
 365         sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
 366         kfree(edev);
 367         return 0;
 368 }
 369
 370 static struct spi_driver eeprom_93xx46_driver = {
 371         .driver = {
 372                 .name   = "93xx46",
 373         },
 374         .probe          = eeprom_93xx46_probe,
 375         .remove         = eeprom_93xx46_remove,
 376 };
 377
 378 module_spi_driver(eeprom_93xx46_driver);
 379
 380 MODULE_LICENSE("GPL");
 381 MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
 382 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
 383 MODULE_ALIAS("spi:93xx46");