drivers/staging/iio/adc/ad7298.c

   1 /*
   2  * AD7298 digital temperature sensor driver supporting AD7298
   3  *
   4  * Copyright 2010 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/gpio.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/device.h>
  13 #include <linux/kernel.h>
  14 #include <linux/slab.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/list.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/rtc.h>
  19
  20 #include "../iio.h"
  21 #include "../sysfs.h"
  22
  23 /*
  24  * AD7298 command
  25  */
  26 #define AD7298_PD                       0x1
  27 #define AD7298_T_AVG_MASK               0x2
  28 #define AD7298_EXT_REF                  0x4
  29 #define AD7298_T_SENSE_MASK             0x20
  30 #define AD7298_VOLTAGE_MASK             0x3fc0
  31 #define AD7298_VOLTAGE_OFFSET           0x6
  32 #define AD7298_VOLTAGE_LIMIT_COUNT      8
  33 #define AD7298_REPEAT                   0x40
  34 #define AD7298_WRITE                    0x80
  35
  36 /*
  37  * AD7298 value masks
  38  */
  39 #define AD7298_CHANNEL_MASK             0xf000
  40 #define AD7298_VALUE_MASK               0xfff
  41 #define AD7298_T_VALUE_SIGN             0x400
  42 #define AD7298_T_VALUE_FLOAT_OFFSET     2
  43 #define AD7298_T_VALUE_FLOAT_MASK       0x2
  44
  45 /*
  46  * struct ad7298_chip_info - chip specifc information
  47  */
  48
  49 struct ad7298_chip_info {
  50         const char *name;
  51         struct spi_device *spi_dev;
  52         struct iio_dev *indio_dev;
  53         u16 command;
  54         u16 busy_pin;
  55         u8  channels;   /* Active voltage channels */
  56 };
  57
  58 /*
  59  * ad7298 register access by SPI
  60  */
  61 static int ad7298_spi_write(struct ad7298_chip_info *chip, u16 data)
  62 {
  63         struct spi_device *spi_dev = chip->spi_dev;
  64         int ret = 0;
  65
  66         data |= AD7298_WRITE;
  67         data = cpu_to_be16(data);
  68         ret = spi_write(spi_dev, (u8 *)&data, sizeof(data));
  69         if (ret < 0)
  70                 dev_err(&spi_dev->dev, "SPI write error\n");
  71
  72         return ret;
  73 }
  74
  75 static int ad7298_spi_read(struct ad7298_chip_info *chip, u16 mask, u16 *data)
  76 {
  77         struct spi_device *spi_dev = chip->spi_dev;
  78         int ret = 0;
  79         u8 count = chip->channels;
  80         u16 command;
  81         int i;
  82
  83         if (mask & AD7298_T_SENSE_MASK) {
  84                 command = chip->command & ~(AD7298_T_AVG_MASK | AD7298_VOLTAGE_MASK);
  85                 command |= AD7298_T_SENSE_MASK;
  86                 count = 1;
  87         } else if (mask & AD7298_T_AVG_MASK) {
  88                 command = chip->command & ~AD7298_VOLTAGE_MASK;
  89                 command |= AD7298_T_SENSE_MASK | AD7298_T_AVG_MASK;
  90                 count = 2;
  91         } else if (mask & AD7298_VOLTAGE_MASK) {
  92                 command = chip->command & ~(AD7298_T_AVG_MASK | AD7298_T_SENSE_MASK);
  93                 count = chip->channels;
  94         }
  95
  96         ret = ad7298_spi_write(chip, chip->command);
  97         if (ret < 0) {
  98                 dev_err(&spi_dev->dev, "SPI write command error\n");
  99                 return ret;
 100         }
 101
 102         ret = spi_read(spi_dev, (u8 *)&command, sizeof(command));
 103         if (ret < 0) {
 104                 dev_err(&spi_dev->dev, "SPI read error\n");
 105                 return ret;
 106         }
 107
 108         i = 10000;
 109         while (i && gpio_get_value(chip->busy_pin)) {
 110                 cpu_relax();
 111                 i--;
 112         }
 113         if (!i) {
 114                 dev_err(&spi_dev->dev, "Always in busy convertion.\n");
 115                 return -EBUSY;
 116         }
 117
 118         for (i = 0; i < count; i++) {
 119                 ret = spi_read(spi_dev, (u8 *)&data[i], sizeof(data[i]));
 120                 if (ret < 0) {
 121                         dev_err(&spi_dev->dev, "SPI read error\n");
 122                         return ret;
 123                 }
 124                 *data = be16_to_cpu(data[i]);
 125         }
 126
 127         return 0;
 128 }
 129
 130 static ssize_t ad7298_show_mode(struct device *dev,
 131                 struct device_attribute *attr,
 132                 char *buf)
 133 {
 134         struct iio_dev *dev_info = dev_get_drvdata(dev);
 135         struct ad7298_chip_info *chip = dev_info->dev_data;
 136
 137         if (chip->command & AD7298_REPEAT)
 138                 return sprintf(buf, "repeat\n");
 139         else
 140                 return sprintf(buf, "normal\n");
 141 }
 142
 143 static ssize_t ad7298_store_mode(struct device *dev,
 144                 struct device_attribute *attr,
 145                 const char *buf,
 146                 size_t len)
 147 {
 148         struct iio_dev *dev_info = dev_get_drvdata(dev);
 149         struct ad7298_chip_info *chip = dev_info->dev_data;
 150
 151         if (strcmp(buf, "repeat"))
 152                 chip->command |= AD7298_REPEAT;
 153         else
 154                 chip->command &= (~AD7298_REPEAT);
 155
 156         return 1;
 157 }
 158
 159 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
 160                 ad7298_show_mode,
 161                 ad7298_store_mode,
 162                 0);
 163
 164 static ssize_t ad7298_show_available_modes(struct device *dev,
 165                 struct device_attribute *attr,
 166                 char *buf)
 167 {
 168         return sprintf(buf, "normal\nrepeat\n");
 169 }
 170
 171 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7298_show_available_modes, NULL, 0);
 172
 173 static ssize_t ad7298_store_reset(struct device *dev,
 174                 struct device_attribute *attr,
 175                 const char *buf,
 176                 size_t len)
 177 {
 178         struct iio_dev *dev_info = dev_get_drvdata(dev);
 179         struct ad7298_chip_info *chip = dev_info->dev_data;
 180         u16 command;
 181         int ret;
 182
 183         command = chip->command & ~AD7298_PD;
 184
 185         ret = ad7298_spi_write(chip, command);
 186         if (ret)
 187                 return -EIO;
 188
 189         command = chip->command | AD7298_PD;
 190
 191         ret = ad7298_spi_write(chip, command);
 192         if (ret)
 193                 return -EIO;
 194
 195         return len;
 196 }
 197
 198 static IIO_DEVICE_ATTR(reset, S_IWUSR,
 199                 NULL,
 200                 ad7298_store_reset,
 201                 0);
 202
 203 static ssize_t ad7298_show_ext_ref(struct device *dev,
 204                 struct device_attribute *attr,
 205                 char *buf)
 206 {
 207         struct iio_dev *dev_info = dev_get_drvdata(dev);
 208         struct ad7298_chip_info *chip = dev_info->dev_data;
 209
 210         return sprintf(buf, "%d\n", !!(chip->command & AD7298_EXT_REF));
 211 }
 212
 213 static ssize_t ad7298_store_ext_ref(struct device *dev,
 214                 struct device_attribute *attr,
 215                 const char *buf,
 216                 size_t len)
 217 {
 218         struct iio_dev *dev_info = dev_get_drvdata(dev);
 219         struct ad7298_chip_info *chip = dev_info->dev_data;
 220         u16 command;
 221         int ret;
 222
 223         command = chip->command & (~AD7298_EXT_REF);
 224         if (strcmp(buf, "1"))
 225                 command |= AD7298_EXT_REF;
 226
 227         ret = ad7298_spi_write(chip, command);
 228         if (ret)
 229                 return -EIO;
 230
 231         chip->command = command;
 232
 233         return len;
 234 }
 235
 236 static IIO_DEVICE_ATTR(ext_ref, S_IRUGO | S_IWUSR,
 237                 ad7298_show_ext_ref,
 238                 ad7298_store_ext_ref,
 239                 0);
 240
 241 static ssize_t ad7298_show_t_sense(struct device *dev,
 242                 struct device_attribute *attr,
 243                 char *buf)
 244 {
 245         struct iio_dev *dev_info = dev_get_drvdata(dev);
 246         struct ad7298_chip_info *chip = dev_info->dev_data;
 247         u16 data;
 248         char sign = ' ';
 249         int ret;
 250
 251         ret = ad7298_spi_read(chip, AD7298_T_SENSE_MASK, &data);
 252         if (ret)
 253                 return -EIO;
 254
 255         if (data & AD7298_T_VALUE_SIGN) {
 256                 /* convert supplement to positive value */
 257                 data = (AD7298_T_VALUE_SIGN << 1) - data;
 258                 sign = '-';
 259         }
 260
 261         return sprintf(buf, "%c%d.%.2d\n", sign,
 262                 (data >> AD7298_T_VALUE_FLOAT_OFFSET),
 263                 (data & AD7298_T_VALUE_FLOAT_MASK) * 25);
 264 }
 265
 266 static IIO_DEVICE_ATTR(t_sense, S_IRUGO, ad7298_show_t_sense, NULL, 0);
 267
 268 static ssize_t ad7298_show_t_average(struct device *dev,
 269                 struct device_attribute *attr,
 270                 char *buf)
 271 {
 272         struct iio_dev *dev_info = dev_get_drvdata(dev);
 273         struct ad7298_chip_info *chip = dev_info->dev_data;
 274         u16 data[2];
 275         char sign = ' ';
 276         int ret;
 277
 278         ret = ad7298_spi_read(chip, AD7298_T_AVG_MASK, data);
 279         if (ret)
 280                 return -EIO;
 281
 282         if (data[1] & AD7298_T_VALUE_SIGN) {
 283                 /* convert supplement to positive value */
 284                 data[1] = (AD7298_T_VALUE_SIGN << 1) - data[1];
 285                 sign = '-';
 286         }
 287
 288         return sprintf(buf, "%c%d.%.2d\n", sign,
 289                 (data[1] >> AD7298_T_VALUE_FLOAT_OFFSET),
 290                 (data[1] & AD7298_T_VALUE_FLOAT_MASK) * 25);
 291 }
 292
 293 static IIO_DEVICE_ATTR(t_average, S_IRUGO, ad7298_show_t_average, NULL, 0);
 294
 295 static ssize_t ad7298_show_voltage(struct device *dev,
 296                 struct device_attribute *attr,
 297                 char *buf)
 298 {
 299         struct iio_dev *dev_info = dev_get_drvdata(dev);
 300         struct ad7298_chip_info *chip = dev_info->dev_data;
 301         u16 data[AD7298_VOLTAGE_LIMIT_COUNT];
 302         int i, size, ret;
 303
 304         ret = ad7298_spi_read(chip, AD7298_VOLTAGE_MASK, data);
 305         if (ret)
 306                 return -EIO;
 307
 308         for (i = 0; i < AD7298_VOLTAGE_LIMIT_COUNT; i++) {
 309                 if (chip->command & (AD7298_T_SENSE_MASK << i)) {
 310                         ret = sprintf(buf, "channel[%d]=%d\n", i,
 311                                         data[i] & AD7298_VALUE_MASK);
 312                         if (ret < 0)
 313                                 break;
 314                         buf += ret;
 315                         size += ret;
 316                 }
 317         }
 318
 319         return size;
 320 }
 321
 322 static IIO_DEVICE_ATTR(voltage, S_IRUGO, ad7298_show_voltage, NULL, 0);
 323
 324 static ssize_t ad7298_show_channel_mask(struct device *dev,
 325                 struct device_attribute *attr,
 326                 char *buf)
 327 {
 328         struct iio_dev *dev_info = dev_get_drvdata(dev);
 329         struct ad7298_chip_info *chip = dev_info->dev_data;
 330
 331         return sprintf(buf, "0x%x\n", (chip->command & AD7298_VOLTAGE_MASK) >>
 332                         AD7298_VOLTAGE_OFFSET);
 333 }
 334
 335 static ssize_t ad7298_store_channel_mask(struct device *dev,
 336                 struct device_attribute *attr,
 337                 const char *buf,
 338                 size_t len)
 339 {
 340         struct iio_dev *dev_info = dev_get_drvdata(dev);
 341         struct ad7298_chip_info *chip = dev_info->dev_data;
 342         unsigned long data;
 343         int i, ret;
 344
 345         ret = strict_strtoul(buf, 16, &data);
 346         if (ret || data > 0xff)
 347                 return -EINVAL;
 348
 349         chip->command &= (~AD7298_VOLTAGE_MASK);
 350         chip->command |= data << AD7298_VOLTAGE_OFFSET;
 351
 352         for (i = 0, chip->channels = 0; i < AD7298_VOLTAGE_LIMIT_COUNT; i++) {
 353                 if (chip->command & (AD7298_T_SENSE_MASK << i))
 354                         chip->channels++;
 355         }
 356
 357         return ret;
 358 }
 359
 360 static IIO_DEVICE_ATTR(channel_mask, S_IRUGO | S_IWUSR,
 361                 ad7298_show_channel_mask,
 362                 ad7298_store_channel_mask,
 363                 0);
 364
 365 static ssize_t ad7298_show_name(struct device *dev,
 366                 struct device_attribute *attr,
 367                 char *buf)
 368 {
 369         struct iio_dev *dev_info = dev_get_drvdata(dev);
 370         struct ad7298_chip_info *chip = dev_info->dev_data;
 371         return sprintf(buf, "%s\n", chip->name);
 372 }
 373
 374 static IIO_DEVICE_ATTR(name, S_IRUGO, ad7298_show_name, NULL, 0);
 375
 376 static struct attribute *ad7298_attributes[] = {
 377         &iio_dev_attr_available_modes.dev_attr.attr,
 378         &iio_dev_attr_mode.dev_attr.attr,
 379         &iio_dev_attr_reset.dev_attr.attr,
 380         &iio_dev_attr_ext_ref.dev_attr.attr,
 381         &iio_dev_attr_t_sense.dev_attr.attr,
 382         &iio_dev_attr_t_average.dev_attr.attr,
 383         &iio_dev_attr_voltage.dev_attr.attr,
 384         &iio_dev_attr_channel_mask.dev_attr.attr,
 385         &iio_dev_attr_name.dev_attr.attr,
 386         NULL,
 387 };
 388
 389 static const struct attribute_group ad7298_attribute_group = {
 390         .attrs = ad7298_attributes,
 391 };
 392
 393 /*
 394  * device probe and remove
 395  */
 396 static int __devinit ad7298_probe(struct spi_device *spi_dev)
 397 {
 398         struct ad7298_chip_info *chip;
 399         unsigned short *pins = spi_dev->dev.platform_data;
 400         int ret = 0;
 401
 402         chip = kzalloc(sizeof(struct ad7298_chip_info), GFP_KERNEL);
 403
 404         if (chip == NULL)
 405                 return -ENOMEM;
 406
 407         /* this is only used for device removal purposes */
 408         dev_set_drvdata(&spi_dev->dev, chip);
 409
 410         chip->spi_dev = spi_dev;
 411         chip->name = spi_dev->modalias;
 412         chip->busy_pin = pins[0];
 413
 414         ret = gpio_request(chip->busy_pin, chip->name);
 415         if (ret) {
 416                 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
 417                         chip->busy_pin);
 418                 goto error_free_chip;
 419         }
 420         gpio_direction_input(chip->busy_pin);
 421
 422         chip->indio_dev = iio_allocate_device();
 423         if (chip->indio_dev == NULL) {
 424                 ret = -ENOMEM;
 425                 goto error_free_gpio;
 426         }
 427
 428         chip->indio_dev->dev.parent = &spi_dev->dev;
 429         chip->indio_dev->attrs = &ad7298_attribute_group;
 430         chip->indio_dev->dev_data = (void *)chip;
 431         chip->indio_dev->driver_module = THIS_MODULE;
 432         chip->indio_dev->modes = INDIO_DIRECT_MODE;
 433
 434         ret = iio_device_register(chip->indio_dev);
 435         if (ret)
 436                 goto error_free_dev;
 437
 438         dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
 439                          chip->name);
 440
 441         return 0;
 442
 443 error_free_dev:
 444         iio_free_device(chip->indio_dev);
 445 error_free_gpio:
 446         gpio_free(chip->busy_pin);
 447 error_free_chip:
 448         kfree(chip);
 449
 450         return ret;
 451 }
 452
 453 static int __devexit ad7298_remove(struct spi_device *spi_dev)
 454 {
 455         struct ad7298_chip_info *chip = dev_get_drvdata(&spi_dev->dev);
 456         struct iio_dev *indio_dev = chip->indio_dev;
 457
 458         dev_set_drvdata(&spi_dev->dev, NULL);
 459         iio_device_unregister(indio_dev);
 460         iio_free_device(chip->indio_dev);
 461         gpio_free(chip->busy_pin);
 462         kfree(chip);
 463
 464         return 0;
 465 }
 466
 467 static const struct spi_device_id ad7298_id[] = {
 468         { "ad7298", 0 },
 469         {}
 470 };
 471
 472 MODULE_DEVICE_TABLE(spi, ad7298_id);
 473
 474 static struct spi_driver ad7298_driver = {
 475         .driver = {
 476                 .name = "ad7298",
 477                 .bus = &spi_bus_type,
 478                 .owner = THIS_MODULE,
 479         },
 480         .probe = ad7298_probe,
 481         .remove = __devexit_p(ad7298_remove),
 482         .id_table = ad7298_id,
 483 };
 484
 485 static __init int ad7298_init(void)
 486 {
 487         return spi_register_driver(&ad7298_driver);
 488 }
 489
 490 static __exit void ad7298_exit(void)
 491 {
 492         spi_unregister_driver(&ad7298_driver);
 493 }
 494
 495 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
 496 MODULE_DESCRIPTION("Analog Devices AD7298 digital"
 497                         " temperature sensor and ADC driver");
 498 MODULE_LICENSE("GPL v2");
 499
 500 module_init(ad7298_init);
 501 module_exit(ad7298_exit);