1/* 2 * AD7816 digital temperature sensor driver supporting AD7816/7/8 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/device.h> 12#include <linux/kernel.h> 13#include <linux/slab.h> 14#include <linux/sysfs.h> 15#include <linux/list.h> 16#include <linux/spi/spi.h> 17#include <linux/module.h> 18 19#include "../iio.h" 20#include "../sysfs.h" 21#include "../events.h" 22 23/* 24 * AD7816 config masks 25 */ 26#define AD7816_FULL 0x1 27#define AD7816_PD 0x2 28#define AD7816_CS_MASK 0x7 29#define AD7816_CS_MAX 0x4 30 31/* 32 * AD7816 temperature masks 33 */ 34#define AD7816_VALUE_OFFSET 6 35#define AD7816_BOUND_VALUE_BASE 0x8 36#define AD7816_BOUND_VALUE_MIN -95 37#define AD7816_BOUND_VALUE_MAX 152 38#define AD7816_TEMP_FLOAT_OFFSET 2 39#define AD7816_TEMP_FLOAT_MASK 0x3 40 41 42/* 43 * struct ad7816_chip_info - chip specifc information 44 */ 45 46struct ad7816_chip_info { 47 struct spi_device *spi_dev; 48 u16 rdwr_pin; 49 u16 convert_pin; 50 u16 busy_pin; 51 u8 oti_data[AD7816_CS_MAX+1]; 52 u8 channel_id; /* 0 always be temperature */ 53 u8 mode; 54}; 55 56/* 57 * ad7816 data access by SPI 58 */ 59static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data) 60{ 61 struct spi_device *spi_dev = chip->spi_dev; 62 int ret = 0; 63 64 gpio_set_value(chip->rdwr_pin, 1); 65 gpio_set_value(chip->rdwr_pin, 0); 66 ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id)); 67 if (ret < 0) { 68 dev_err(&spi_dev->dev, "SPI channel setting error\n"); 69 return ret; 70 } 71 gpio_set_value(chip->rdwr_pin, 1); 72 73 74 if (chip->mode == AD7816_PD) { /* operating mode 2 */ 75 gpio_set_value(chip->convert_pin, 1); 76 gpio_set_value(chip->convert_pin, 0); 77 } else { /* operating mode 1 */ 78 gpio_set_value(chip->convert_pin, 0); 79 gpio_set_value(chip->convert_pin, 1); 80 } 81 82 while (gpio_get_value(chip->busy_pin)) 83 cpu_relax(); 84 85 gpio_set_value(chip->rdwr_pin, 0); 86 gpio_set_value(chip->rdwr_pin, 1); 87 ret = spi_read(spi_dev, (u8 *)data, sizeof(*data)); 88 if (ret < 0) { 89 dev_err(&spi_dev->dev, "SPI data read error\n"); 90 return ret; 91 } 92 93 *data = be16_to_cpu(*data); 94 95 return ret; 96} 97 98static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data) 99{ 100 struct spi_device *spi_dev = chip->spi_dev; 101 int ret = 0; 102 103 gpio_set_value(chip->rdwr_pin, 1); 104 gpio_set_value(chip->rdwr_pin, 0); 105 ret = spi_write(spi_dev, &data, sizeof(data)); 106 if (ret < 0) 107 dev_err(&spi_dev->dev, "SPI oti data write error\n"); 108 109 return ret; 110} 111 112static ssize_t ad7816_show_mode(struct device *dev, 113 struct device_attribute *attr, 114 char *buf) 115{ 116 struct iio_dev *indio_dev = dev_get_drvdata(dev); 117 struct ad7816_chip_info *chip = iio_priv(indio_dev); 118 119 if (chip->mode) 120 return sprintf(buf, "power-save\n"); 121 else 122 return sprintf(buf, "full\n"); 123} 124 125static ssize_t ad7816_store_mode(struct device *dev, 126 struct device_attribute *attr, 127 const char *buf, 128 size_t len) 129{ 130 struct iio_dev *indio_dev = dev_get_drvdata(dev); 131 struct ad7816_chip_info *chip = iio_priv(indio_dev); 132 133 if (strcmp(buf, "full")) { 134 gpio_set_value(chip->rdwr_pin, 1); 135 chip->mode = AD7816_FULL; 136 } else { 137 gpio_set_value(chip->rdwr_pin, 0); 138 chip->mode = AD7816_PD; 139 } 140 141 return len; 142} 143 144static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, 145 ad7816_show_mode, 146 ad7816_store_mode, 147 0); 148 149static ssize_t ad7816_show_available_modes(struct device *dev, 150 struct device_attribute *attr, 151 char *buf) 152{ 153 return sprintf(buf, "full\npower-save\n"); 154} 155 156static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, NULL, 0); 157 158static ssize_t ad7816_show_channel(struct device *dev, 159 struct device_attribute *attr, 160 char *buf) 161{ 162 struct iio_dev *indio_dev = dev_get_drvdata(dev); 163 struct ad7816_chip_info *chip = iio_priv(indio_dev); 164 165 return sprintf(buf, "%d\n", chip->channel_id); 166} 167 168static ssize_t ad7816_store_channel(struct device *dev, 169 struct device_attribute *attr, 170 const char *buf, 171 size_t len) 172{ 173 struct iio_dev *indio_dev = dev_get_drvdata(dev); 174 struct ad7816_chip_info *chip = iio_priv(indio_dev); 175 unsigned long data; 176 int ret; 177 178 ret = strict_strtoul(buf, 10, &data); 179 if (ret) 180 return -EINVAL; 181 182 if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) { 183 dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n", 184 data, indio_dev->name); 185 return -EINVAL; 186 } else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) { 187 dev_err(&chip->spi_dev->dev, 188 "Invalid channel id %lu for ad7818.\n", data); 189 return -EINVAL; 190 } else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) { 191 dev_err(&chip->spi_dev->dev, 192 "Invalid channel id %lu for ad7816.\n", data); 193 return -EINVAL; 194 } 195 196 chip->channel_id = data; 197 198 return len; 199} 200 201static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR, 202 ad7816_show_channel, 203 ad7816_store_channel, 204 0); 205 206 207static ssize_t ad7816_show_value(struct device *dev, 208 struct device_attribute *attr, 209 char *buf) 210{ 211 struct iio_dev *indio_dev = dev_get_drvdata(dev); 212 struct ad7816_chip_info *chip = iio_priv(indio_dev); 213 u16 data; 214 s8 value; 215 int ret; 216 217 ret = ad7816_spi_read(chip, &data); 218 if (ret) 219 return -EIO; 220 221 data >>= AD7816_VALUE_OFFSET; 222 223 if (chip->channel_id == 0) { 224 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103); 225 data &= AD7816_TEMP_FLOAT_MASK; 226 if (value < 0) 227 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data; 228 return sprintf(buf, "%d.%.2d\n", value, data * 25); 229 } else 230 return sprintf(buf, "%u\n", data); 231} 232 233static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0); 234 235static struct attribute *ad7816_attributes[] = { 236 &iio_dev_attr_available_modes.dev_attr.attr, 237 &iio_dev_attr_mode.dev_attr.attr, 238 &iio_dev_attr_channel.dev_attr.attr, 239 &iio_dev_attr_value.dev_attr.attr, 240 NULL, 241}; 242 243static const struct attribute_group ad7816_attribute_group = { 244 .attrs = ad7816_attributes, 245}; 246 247/* 248 * temperature bound events 249 */ 250 251#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \ 252 0, \ 253 IIO_EV_TYPE_THRESH, \ 254 IIO_EV_DIR_FALLING) 255 256static irqreturn_t ad7816_event_handler(int irq, void *private) 257{ 258 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns()); 259 return IRQ_HANDLED; 260} 261 262static ssize_t ad7816_show_oti(struct device *dev, 263 struct device_attribute *attr, 264 char *buf) 265{ 266 struct iio_dev *indio_dev = dev_get_drvdata(dev); 267 struct ad7816_chip_info *chip = iio_priv(indio_dev); 268 int value; 269 270 if (chip->channel_id > AD7816_CS_MAX) { 271 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id); 272 return -EINVAL; 273 } else if (chip->channel_id == 0) { 274 value = AD7816_BOUND_VALUE_MIN + 275 (chip->oti_data[chip->channel_id] - 276 AD7816_BOUND_VALUE_BASE); 277 return sprintf(buf, "%d\n", value); 278 } else 279 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]); 280} 281 282static inline ssize_t ad7816_set_oti(struct device *dev, 283 struct device_attribute *attr, 284 const char *buf, 285 size_t len) 286{ 287 struct iio_dev *indio_dev = dev_get_drvdata(dev); 288 struct ad7816_chip_info *chip = iio_priv(indio_dev); 289 long value; 290 u8 data; 291 int ret; 292 293 ret = strict_strtol(buf, 10, &value); 294 295 if (chip->channel_id > AD7816_CS_MAX) { 296 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id); 297 return -EINVAL; 298 } else if (chip->channel_id == 0) { 299 if (ret || value < AD7816_BOUND_VALUE_MIN || 300 value > AD7816_BOUND_VALUE_MAX) 301 return -EINVAL; 302 303 data = (u8)(value - AD7816_BOUND_VALUE_MIN + 304 AD7816_BOUND_VALUE_BASE); 305 } else { 306 if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255) 307 return -EINVAL; 308 309 data = (u8)value; 310 } 311 312 ret = ad7816_spi_write(chip, data); 313 if (ret) 314 return -EIO; 315 316 chip->oti_data[chip->channel_id] = data; 317 318 return len; 319} 320 321static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR, 322 ad7816_show_oti, ad7816_set_oti, 0); 323 324static struct attribute *ad7816_event_attributes[] = { 325 &iio_dev_attr_oti.dev_attr.attr, 326 NULL, 327}; 328 329static struct attribute_group ad7816_event_attribute_group = { 330 .attrs = ad7816_event_attributes, 331 .name = "events", 332}; 333 334static const struct iio_info ad7816_info = { 335 .attrs = &ad7816_attribute_group, 336 .event_attrs = &ad7816_event_attribute_group, 337 .driver_module = THIS_MODULE, 338}; 339 340/* 341 * device probe and remove 342 */ 343 344static int __devinit ad7816_probe(struct spi_device *spi_dev) 345{ 346 struct ad7816_chip_info *chip; 347 struct iio_dev *indio_dev; 348 unsigned short *pins = spi_dev->dev.platform_data; 349 int ret = 0; 350 int i; 351 352 if (!pins) { 353 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n"); 354 return -EINVAL; 355 } 356 357 indio_dev = iio_allocate_device(sizeof(*chip)); 358 if (indio_dev == NULL) { 359 ret = -ENOMEM; 360 goto error_ret; 361 } 362 chip = iio_priv(indio_dev); 363 /* this is only used for device removal purposes */ 364 dev_set_drvdata(&spi_dev->dev, indio_dev); 365 366 chip->spi_dev = spi_dev; 367 for (i = 0; i <= AD7816_CS_MAX; i++) 368 chip->oti_data[i] = 203; 369 chip->rdwr_pin = pins[0]; 370 chip->convert_pin = pins[1]; 371 chip->busy_pin = pins[2]; 372 373 ret = gpio_request(chip->rdwr_pin, spi_get_device_id(spi_dev)->name); 374 if (ret) { 375 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n", 376 chip->rdwr_pin); 377 goto error_free_device; 378 } 379 gpio_direction_input(chip->rdwr_pin); 380 ret = gpio_request(chip->convert_pin, spi_get_device_id(spi_dev)->name); 381 if (ret) { 382 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n", 383 chip->convert_pin); 384 goto error_free_gpio_rdwr; 385 } 386 gpio_direction_input(chip->convert_pin); 387 ret = gpio_request(chip->busy_pin, spi_get_device_id(spi_dev)->name); 388 if (ret) { 389 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n", 390 chip->busy_pin); 391 goto error_free_gpio_convert; 392 } 393 gpio_direction_input(chip->busy_pin); 394 395 indio_dev->name = spi_get_device_id(spi_dev)->name; 396 indio_dev->dev.parent = &spi_dev->dev; 397 indio_dev->info = &ad7816_info; 398 indio_dev->modes = INDIO_DIRECT_MODE; 399 400 if (spi_dev->irq) { 401 /* Only low trigger is supported in ad7816/7/8 */ 402 ret = request_threaded_irq(spi_dev->irq, 403 NULL, 404 &ad7816_event_handler, 405 IRQF_TRIGGER_LOW, 406 indio_dev->name, 407 indio_dev); 408 if (ret) 409 goto error_free_gpio; 410 } 411 412 ret = iio_device_register(indio_dev); 413 if (ret) 414 goto error_free_irq; 415 416 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n", 417 indio_dev->name); 418 419 return 0; 420error_free_irq: 421 free_irq(spi_dev->irq, indio_dev); 422error_free_gpio: 423 gpio_free(chip->busy_pin); 424error_free_gpio_convert: 425 gpio_free(chip->convert_pin); 426error_free_gpio_rdwr: 427 gpio_free(chip->rdwr_pin); 428error_free_device: 429 iio_free_device(indio_dev); 430error_ret: 431 return ret; 432} 433 434static int __devexit ad7816_remove(struct spi_device *spi_dev) 435{ 436 struct iio_dev *indio_dev = dev_get_drvdata(&spi_dev->dev); 437 struct ad7816_chip_info *chip = iio_priv(indio_dev); 438 439 iio_device_unregister(indio_dev); 440 dev_set_drvdata(&spi_dev->dev, NULL); 441 if (spi_dev->irq) 442 free_irq(spi_dev->irq, indio_dev); 443 gpio_free(chip->busy_pin); 444 gpio_free(chip->convert_pin); 445 gpio_free(chip->rdwr_pin); 446 iio_free_device(indio_dev); 447 448 return 0; 449} 450 451static const struct spi_device_id ad7816_id[] = { 452 { "ad7816", 0 }, 453 { "ad7817", 0 }, 454 { "ad7818", 0 }, 455 {} 456}; 457 458MODULE_DEVICE_TABLE(spi, ad7816_id); 459 460static struct spi_driver ad7816_driver = { 461 .driver = { 462 .name = "ad7816", 463 .owner = THIS_MODULE, 464 }, 465 .probe = ad7816_probe, 466 .remove = __devexit_p(ad7816_remove), 467 .id_table = ad7816_id, 468}; 469module_spi_driver(ad7816_driver); 470 471MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 472MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital" 473 " temperature sensor driver"); 474MODULE_LICENSE("GPL v2"); 475