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/init.h>
  15 #include <linux/module.h>
  16 #include <linux/mutex.h>
  17 #include <linux/slab.h>
  18 #include <linux/spi/spi.h>
  19 #include <linux/sysfs.h>
  20 #include <linux/eeprom_93xx46.h>
  21
  22 #define OP_START        0x4
  23 #define OP_WRITE        (OP_START | 0x1)
  24 #define OP_READ         (OP_START | 0x2)
  25 #define ADDR_EWDS       0x00
  26 #define ADDR_ERAL       0x20
  27 #define ADDR_EWEN       0x30
  28
  29 struct eeprom_93xx46_dev {
  30         struct spi_device *spi;
  31         struct eeprom_93xx46_platform_data *pdata;
  32         struct bin_attribute bin;
  33         struct mutex lock;
  34         int addrlen;
  35 };
  36
  37 static ssize_t
  38 eeprom_93xx46_bin_read(struct file *filp, struct kobject *kobj,
  39                        struct bin_attribute *bin_attr,
  40                        char *buf, loff_t off, size_t count)
  41 {
  42         struct eeprom_93xx46_dev *edev;
  43         struct device *dev;
  44         struct spi_message m;
  45         struct spi_transfer t[2];
  46         int bits, ret;
  47         u16 cmd_addr;
  48
  49         dev = container_of(kobj, struct device, kobj);
  50         edev = dev_get_drvdata(dev);
  51
  52         if (unlikely(off >= edev->bin.size))
  53                 return 0;
  54         if ((off + count) > edev->bin.size)
  55                 count = edev->bin.size - off;
  56         if (unlikely(!count))
  57                 return count;
  58
  59         cmd_addr = OP_READ << edev->addrlen;
  60
  61         if (edev->addrlen == 7) {
  62                 cmd_addr |= off & 0x7f;
  63                 bits = 10;
  64         } else {
  65                 cmd_addr |= off & 0x3f;
  66                 bits = 9;
  67         }
  68
  69         dev_dbg(&edev->spi->dev, "read cmd 0x%x, %d Hz\n",
  70                 cmd_addr, edev->spi->max_speed_hz);
  71
  72         spi_message_init(&m);
  73         memset(t, 0, sizeof(t));
  74
  75         t[0].tx_buf = (char *)&cmd_addr;
  76         t[0].len = 2;
  77         t[0].bits_per_word = bits;
  78         spi_message_add_tail(&t[0], &m);
  79
  80         t[1].rx_buf = buf;
  81         t[1].len = count;
  82         t[1].bits_per_word = 8;
  83         spi_message_add_tail(&t[1], &m);
  84
  85         mutex_lock(&edev->lock);
  86
  87         if (edev->pdata->prepare)
  88                 edev->pdata->prepare(edev);
  89
  90         ret = spi_sync(edev->spi, &m);
  91         /* have to wait at least Tcsl ns */
  92         ndelay(250);
  93         if (ret) {
  94                 dev_err(&edev->spi->dev, "read %zu bytes at %d: err. %d\n",
  95                         count, (int)off, ret);
  96         }
  97
  98         if (edev->pdata->finish)
  99                 edev->pdata->finish(edev);
 100
 101         mutex_unlock(&edev->lock);
 102         return ret ? : count;
 103 }
 104
 105 static int eeprom_93xx46_ew(struct eeprom_93xx46_dev *edev, int is_on)
 106 {
 107         struct spi_message m;
 108         struct spi_transfer t;
 109         int bits, ret;
 110         u16 cmd_addr;
 111
 112         cmd_addr = OP_START << edev->addrlen;
 113         if (edev->addrlen == 7) {
 114                 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS) << 1;
 115                 bits = 10;
 116         } else {
 117                 cmd_addr |= (is_on ? ADDR_EWEN : ADDR_EWDS);
 118                 bits = 9;
 119         }
 120
 121         dev_dbg(&edev->spi->dev, "ew cmd 0x%04x\n", cmd_addr);
 122
 123         spi_message_init(&m);
 124         memset(&t, 0, sizeof(t));
 125
 126         t.tx_buf = &cmd_addr;
 127         t.len = 2;
 128         t.bits_per_word = bits;
 129         spi_message_add_tail(&t, &m);
 130
 131         mutex_lock(&edev->lock);
 132
 133         if (edev->pdata->prepare)
 134                 edev->pdata->prepare(edev);
 135
 136         ret = spi_sync(edev->spi, &m);
 137         /* have to wait at least Tcsl ns */
 138         ndelay(250);
 139         if (ret)
 140                 dev_err(&edev->spi->dev, "erase/write %sable error %d\n",
 141                         is_on ? "en" : "dis", ret);
 142
 143         if (edev->pdata->finish)
 144                 edev->pdata->finish(edev);
 145
 146         mutex_unlock(&edev->lock);
 147         return ret;
 148 }
 149
 150 static ssize_t
 151 eeprom_93xx46_write_word(struct eeprom_93xx46_dev *edev,
 152                          const char *buf, unsigned off)
 153 {
 154         struct spi_message m;
 155         struct spi_transfer t[2];
 156         int bits, data_len, ret;
 157         u16 cmd_addr;
 158
 159         cmd_addr = OP_WRITE << edev->addrlen;
 160
 161         if (edev->addrlen == 7) {
 162                 cmd_addr |= off & 0x7f;
 163                 bits = 10;
 164                 data_len = 1;
 165         } else {
 166                 cmd_addr |= off & 0x3f;
 167                 bits = 9;
 168                 data_len = 2;
 169         }
 170
 171         dev_dbg(&edev->spi->dev, "write cmd 0x%x\n", cmd_addr);
 172
 173         spi_message_init(&m);
 174         memset(t, 0, sizeof(t));
 175
 176         t[0].tx_buf = (char *)&cmd_addr;
 177         t[0].len = 2;
 178         t[0].bits_per_word = bits;
 179         spi_message_add_tail(&t[0], &m);
 180
 181         t[1].tx_buf = buf;
 182         t[1].len = data_len;
 183         t[1].bits_per_word = 8;
 184         spi_message_add_tail(&t[1], &m);
 185
 186         ret = spi_sync(edev->spi, &m);
 187         /* have to wait program cycle time Twc ms */
 188         mdelay(6);
 189         return ret;
 190 }
 191
 192 static ssize_t
 193 eeprom_93xx46_bin_write(struct file *filp, struct kobject *kobj,
 194                         struct bin_attribute *bin_attr,
 195                         char *buf, loff_t off, size_t count)
 196 {
 197         struct eeprom_93xx46_dev *edev;
 198         struct device *dev;
 199         int i, ret, step = 1;
 200
 201         dev = container_of(kobj, struct device, kobj);
 202         edev = dev_get_drvdata(dev);
 203
 204         if (unlikely(off >= edev->bin.size))
 205                 return 0;
 206         if ((off + count) > edev->bin.size)
 207                 count = edev->bin.size - off;
 208         if (unlikely(!count))
 209                 return count;
 210
 211         /* only write even number of bytes on 16-bit devices */
 212         if (edev->addrlen == 6) {
 213                 step = 2;
 214                 count &= ~1;
 215         }
 216
 217         /* erase/write enable */
 218         ret = eeprom_93xx46_ew(edev, 1);
 219         if (ret)
 220                 return ret;
 221
 222         mutex_lock(&edev->lock);
 223
 224         if (edev->pdata->prepare)
 225                 edev->pdata->prepare(edev);
 226
 227         for (i = 0; i < count; i += step) {
 228                 ret = eeprom_93xx46_write_word(edev, &buf[i], off + i);
 229                 if (ret) {
 230                         dev_err(&edev->spi->dev, "write failed at %d: %d\n",
 231                                 (int)off + i, ret);
 232                         break;
 233                 }
 234         }
 235
 236         if (edev->pdata->finish)
 237                 edev->pdata->finish(edev);
 238
 239         mutex_unlock(&edev->lock);
 240
 241         /* erase/write disable */
 242         eeprom_93xx46_ew(edev, 0);
 243         return ret ? : count;
 244 }
 245
 246 static int eeprom_93xx46_eral(struct eeprom_93xx46_dev *edev)
 247 {
 248         struct eeprom_93xx46_platform_data *pd = edev->pdata;
 249         struct spi_message m;
 250         struct spi_transfer t;
 251         int bits, ret;
 252         u16 cmd_addr;
 253
 254         cmd_addr = OP_START << edev->addrlen;
 255         if (edev->addrlen == 7) {
 256                 cmd_addr |= ADDR_ERAL << 1;
 257                 bits = 10;
 258         } else {
 259                 cmd_addr |= ADDR_ERAL;
 260                 bits = 9;
 261         }
 262
 263         spi_message_init(&m);
 264         memset(&t, 0, sizeof(t));
 265
 266         t.tx_buf = &cmd_addr;
 267         t.len = 2;
 268         t.bits_per_word = bits;
 269         spi_message_add_tail(&t, &m);
 270
 271         mutex_lock(&edev->lock);
 272
 273         if (edev->pdata->prepare)
 274                 edev->pdata->prepare(edev);
 275
 276         ret = spi_sync(edev->spi, &m);
 277         if (ret)
 278                 dev_err(&edev->spi->dev, "erase error %d\n", ret);
 279         /* have to wait erase cycle time Tec ms */
 280         mdelay(6);
 281
 282         if (pd->finish)
 283                 pd->finish(edev);
 284
 285         mutex_unlock(&edev->lock);
 286         return ret;
 287 }
 288
 289 static ssize_t eeprom_93xx46_store_erase(struct device *dev,
 290                                          struct device_attribute *attr,
 291                                          const char *buf, size_t count)
 292 {
 293         struct eeprom_93xx46_dev *edev = dev_get_drvdata(dev);
 294         int erase = 0, ret;
 295
 296         sscanf(buf, "%d", &erase);
 297         if (erase) {
 298                 ret = eeprom_93xx46_ew(edev, 1);
 299                 if (ret)
 300                         return ret;
 301                 ret = eeprom_93xx46_eral(edev);
 302                 if (ret)
 303                         return ret;
 304                 ret = eeprom_93xx46_ew(edev, 0);
 305                 if (ret)
 306                         return ret;
 307         }
 308         return count;
 309 }
 310 static DEVICE_ATTR(erase, S_IWUSR, NULL, eeprom_93xx46_store_erase);
 311
 312 static int __devinit eeprom_93xx46_probe(struct spi_device *spi)
 313 {
 314         struct eeprom_93xx46_platform_data *pd;
 315         struct eeprom_93xx46_dev *edev;
 316         int err;
 317
 318         pd = spi->dev.platform_data;
 319         if (!pd) {
 320                 dev_err(&spi->dev, "missing platform data\n");
 321                 return -ENODEV;
 322         }
 323
 324         edev = kzalloc(sizeof(*edev), GFP_KERNEL);
 325         if (!edev)
 326                 return -ENOMEM;
 327
 328         if (pd->flags & EE_ADDR8)
 329                 edev->addrlen = 7;
 330         else if (pd->flags & EE_ADDR16)
 331                 edev->addrlen = 6;
 332         else {
 333                 dev_err(&spi->dev, "unspecified address type\n");
 334                 err = -EINVAL;
 335                 goto fail;
 336         }
 337
 338         mutex_init(&edev->lock);
 339
 340         edev->spi = spi_dev_get(spi);
 341         edev->pdata = pd;
 342
 343         sysfs_bin_attr_init(&edev->bin);
 344         edev->bin.attr.name = "eeprom";
 345         edev->bin.attr.mode = S_IRUSR;
 346         edev->bin.read = eeprom_93xx46_bin_read;
 347         edev->bin.size = 128;
 348         if (!(pd->flags & EE_READONLY)) {
 349                 edev->bin.write = eeprom_93xx46_bin_write;
 350                 edev->bin.attr.mode |= S_IWUSR;
 351         }
 352
 353         err = sysfs_create_bin_file(&spi->dev.kobj, &edev->bin);
 354         if (err)
 355                 goto fail;
 356
 357         dev_info(&spi->dev, "%d-bit eeprom %s\n",
 358                 (pd->flags & EE_ADDR8) ? 8 : 16,
 359                 (pd->flags & EE_READONLY) ? "(readonly)" : "");
 360
 361         if (!(pd->flags & EE_READONLY)) {
 362                 if (device_create_file(&spi->dev, &dev_attr_erase))
 363                         dev_err(&spi->dev, "can't create erase interface\n");
 364         }
 365
 366         dev_set_drvdata(&spi->dev, edev);
 367         return 0;
 368 fail:
 369         kfree(edev);
 370         return err;
 371 }
 372
 373 static int __devexit eeprom_93xx46_remove(struct spi_device *spi)
 374 {
 375         struct eeprom_93xx46_dev *edev = dev_get_drvdata(&spi->dev);
 376
 377         if (!(edev->pdata->flags & EE_READONLY))
 378                 device_remove_file(&spi->dev, &dev_attr_erase);
 379
 380         sysfs_remove_bin_file(&spi->dev.kobj, &edev->bin);
 381         dev_set_drvdata(&spi->dev, NULL);
 382         kfree(edev);
 383         return 0;
 384 }
 385
 386 static struct spi_driver eeprom_93xx46_driver = {
 387         .driver = {
 388                 .name   = "93xx46",
 389                 .owner  = THIS_MODULE,
 390         },
 391         .probe          = eeprom_93xx46_probe,
 392         .remove         = __devexit_p(eeprom_93xx46_remove),
 393 };
 394
 395 static int __init eeprom_93xx46_init(void)
 396 {
 397         return spi_register_driver(&eeprom_93xx46_driver);
 398 }
 399 module_init(eeprom_93xx46_init);
 400
 401 static void __exit eeprom_93xx46_exit(void)
 402 {
 403         spi_unregister_driver(&eeprom_93xx46_driver);
 404 }
 405 module_exit(eeprom_93xx46_exit);
 406
 407 MODULE_LICENSE("GPL");
 408 MODULE_DESCRIPTION("Driver for 93xx46 EEPROMs");
 409 MODULE_AUTHOR("Anatolij Gustschin <agust@denx.de>");
 410 MODULE_ALIAS("spi:93xx46");