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 <linux/iio/iio.h> 20 #include <linux/iio/sysfs.h> 21 #include <linux/iio/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 specific information 44 */ 45 46 struct 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 */ 59 static 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 98 static 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 } 111 112 static ssize_t ad7816_show_mode(struct device *dev, 113 struct device_attribute *attr, 114 char *buf) 115 { 116 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 117 struct ad7816_chip_info *chip = iio_priv(indio_dev); 118 119 if (chip->mode) 120 return sprintf(buf, "power-save\n"); 121 return sprintf(buf, "full\n"); 122 } 123 124 static ssize_t ad7816_store_mode(struct device *dev, 125 struct device_attribute *attr, 126 const char *buf, 127 size_t len) 128 { 129 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 130 struct ad7816_chip_info *chip = iio_priv(indio_dev); 131 132 if (strcmp(buf, "full")) { 133 gpio_set_value(chip->rdwr_pin, 1); 134 chip->mode = AD7816_FULL; 135 } else { 136 gpio_set_value(chip->rdwr_pin, 0); 137 chip->mode = AD7816_PD; 138 } 139 140 return len; 141 } 142 143 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, 144 ad7816_show_mode, 145 ad7816_store_mode, 146 0); 147 148 static ssize_t ad7816_show_available_modes(struct device *dev, 149 struct device_attribute *attr, 150 char *buf) 151 { 152 return sprintf(buf, "full\npower-save\n"); 153 } 154 155 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, 156 NULL, 0); 157 158 static ssize_t ad7816_show_channel(struct device *dev, 159 struct device_attribute *attr, 160 char *buf) 161 { 162 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 163 struct ad7816_chip_info *chip = iio_priv(indio_dev); 164 165 return sprintf(buf, "%d\n", chip->channel_id); 166 } 167 168 static 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_to_iio_dev(dev); 174 struct ad7816_chip_info *chip = iio_priv(indio_dev); 175 unsigned long data; 176 int ret; 177 178 ret = kstrtoul(buf, 10, &data); 179 if (ret) 180 return ret; 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 } 200 201 static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR, 202 ad7816_show_channel, 203 ad7816_store_channel, 204 0); 205 206 207 static ssize_t ad7816_show_value(struct device *dev, 208 struct device_attribute *attr, 209 char *buf) 210 { 211 struct iio_dev *indio_dev = dev_to_iio_dev(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 } 230 return sprintf(buf, "%u\n", data); 231 } 232 233 static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0); 234 235 static 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 }; 242 243 static 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) 255 256 static 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 } 261 262 static ssize_t ad7816_show_oti(struct device *dev, 263 struct device_attribute *attr, 264 char *buf) 265 { 266 struct iio_dev *indio_dev = dev_to_iio_dev(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 } 279 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]); 280 } 281 282 static 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_to_iio_dev(dev); 288 struct ad7816_chip_info *chip = iio_priv(indio_dev); 289 long value; 290 u8 data; 291 int ret; 292 293 ret = kstrtol(buf, 10, &value); 294 if (ret) 295 return ret; 296 297 if (chip->channel_id > AD7816_CS_MAX) { 298 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id); 299 return -EINVAL; 300 } else if (chip->channel_id == 0) { 301 if (ret || value < AD7816_BOUND_VALUE_MIN || 302 value > AD7816_BOUND_VALUE_MAX) 303 return -EINVAL; 304 305 data = (u8)(value - AD7816_BOUND_VALUE_MIN + 306 AD7816_BOUND_VALUE_BASE); 307 } else { 308 if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255) 309 return -EINVAL; 310 311 data = (u8)value; 312 } 313 314 ret = ad7816_spi_write(chip, data); 315 if (ret) 316 return -EIO; 317 318 chip->oti_data[chip->channel_id] = data; 319 320 return len; 321 } 322 323 static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR, 324 ad7816_show_oti, ad7816_set_oti, 0); 325 326 static struct attribute *ad7816_event_attributes[] = { 327 &iio_dev_attr_oti.dev_attr.attr, 328 NULL, 329 }; 330 331 static struct attribute_group ad7816_event_attribute_group = { 332 .attrs = ad7816_event_attributes, 333 .name = "events", 334 }; 335 336 static const struct iio_info ad7816_info = { 337 .attrs = &ad7816_attribute_group, 338 .event_attrs = &ad7816_event_attribute_group, 339 .driver_module = THIS_MODULE, 340 }; 341 342 /* 343 * device probe and remove 344 */ 345 346 static int ad7816_probe(struct spi_device *spi_dev) 347 { 348 struct ad7816_chip_info *chip; 349 struct iio_dev *indio_dev; 350 unsigned short *pins = spi_dev->dev.platform_data; 351 int ret = 0; 352 int i; 353 354 if (!pins) { 355 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n"); 356 return -EINVAL; 357 } 358 359 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip)); 360 if (!indio_dev) 361 return -ENOMEM; 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 = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin, 374 spi_get_device_id(spi_dev)->name); 375 if (ret) { 376 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n", 377 chip->rdwr_pin); 378 return ret; 379 } 380 gpio_direction_input(chip->rdwr_pin); 381 ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin, 382 spi_get_device_id(spi_dev)->name); 383 if (ret) { 384 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n", 385 chip->convert_pin); 386 return ret; 387 } 388 gpio_direction_input(chip->convert_pin); 389 ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin, 390 spi_get_device_id(spi_dev)->name); 391 if (ret) { 392 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n", 393 chip->busy_pin); 394 return ret; 395 } 396 gpio_direction_input(chip->busy_pin); 397 398 indio_dev->name = spi_get_device_id(spi_dev)->name; 399 indio_dev->dev.parent = &spi_dev->dev; 400 indio_dev->info = &ad7816_info; 401 indio_dev->modes = INDIO_DIRECT_MODE; 402 403 if (spi_dev->irq) { 404 /* Only low trigger is supported in ad7816/7/8 */ 405 ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq, 406 NULL, 407 &ad7816_event_handler, 408 IRQF_TRIGGER_LOW | IRQF_ONESHOT, 409 indio_dev->name, 410 indio_dev); 411 if (ret) 412 return ret; 413 } 414 415 ret = devm_iio_device_register(&spi_dev->dev, indio_dev); 416 if (ret) 417 return ret; 418 419 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n", 420 indio_dev->name); 421 422 return 0; 423 } 424 425 static const struct spi_device_id ad7816_id[] = { 426 { "ad7816", 0 }, 427 { "ad7817", 0 }, 428 { "ad7818", 0 }, 429 {} 430 }; 431 432 MODULE_DEVICE_TABLE(spi, ad7816_id); 433 434 static struct spi_driver ad7816_driver = { 435 .driver = { 436 .name = "ad7816", 437 .owner = THIS_MODULE, 438 }, 439 .probe = ad7816_probe, 440 .id_table = ad7816_id, 441 }; 442 module_spi_driver(ad7816_driver); 443 444 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>"); 445 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver"); 446 MODULE_LICENSE("GPL v2"); 447