2 * AD7816 digital temperature sensor driver supporting AD7816/7/8
4 * Copyright 2010 Analog Devices Inc.
6 * Licensed under the GPL-2 or later.
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>
24 #define AD7816_FULL 0x1
26 #define AD7816_CS_MASK 0x7
27 #define AD7816_CS_MAX 0x4
30 * AD7816 temperature masks
32 #define AD7816_VALUE_OFFSET 6
33 #define AD7816_BOUND_VALUE_BASE 0x8
34 #define AD7816_BOUND_VALUE_MIN -95
35 #define AD7816_BOUND_VALUE_MAX 152
36 #define AD7816_TEMP_FLOAT_OFFSET 2
37 #define AD7816_TEMP_FLOAT_MASK 0x3
41 * struct ad7816_chip_info - chip specifc information
44 struct ad7816_chip_info {
45 struct spi_device *spi_dev;
46 struct iio_dev *indio_dev;
50 u8 oti_data[AD7816_CS_MAX+1];
51 u8 channel_id; /* 0 always be temperature */
56 * ad7816 data access by SPI
58 static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
60 struct spi_device *spi_dev = chip->spi_dev;
63 gpio_set_value(chip->rdwr_pin, 1);
64 gpio_set_value(chip->rdwr_pin, 0);
65 ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
67 dev_err(&spi_dev->dev, "SPI channel setting error\n");
70 gpio_set_value(chip->rdwr_pin, 1);
73 if (chip->mode == AD7816_PD) { /* operating mode 2 */
74 gpio_set_value(chip->convert_pin, 1);
75 gpio_set_value(chip->convert_pin, 0);
76 } else { /* operating mode 1 */
77 gpio_set_value(chip->convert_pin, 0);
78 gpio_set_value(chip->convert_pin, 1);
81 while (gpio_get_value(chip->busy_pin))
84 gpio_set_value(chip->rdwr_pin, 0);
85 gpio_set_value(chip->rdwr_pin, 1);
86 ret = spi_read(spi_dev, (u8 *)data, sizeof(*data));
88 dev_err(&spi_dev->dev, "SPI data read error\n");
92 *data = be16_to_cpu(*data);
97 static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
99 struct spi_device *spi_dev = chip->spi_dev;
102 gpio_set_value(chip->rdwr_pin, 1);
103 gpio_set_value(chip->rdwr_pin, 0);
104 ret = spi_write(spi_dev, &data, sizeof(data));
106 dev_err(&spi_dev->dev, "SPI oti data write error\n");
111 static ssize_t ad7816_show_mode(struct device *dev,
112 struct device_attribute *attr,
115 struct iio_dev *dev_info = dev_get_drvdata(dev);
116 struct ad7816_chip_info *chip = dev_info->dev_data;
119 return sprintf(buf, "power-save\n");
121 return sprintf(buf, "full\n");
124 static ssize_t ad7816_store_mode(struct device *dev,
125 struct device_attribute *attr,
129 struct iio_dev *dev_info = dev_get_drvdata(dev);
130 struct ad7816_chip_info *chip = dev_info->dev_data;
132 if (strcmp(buf, "full")) {
133 gpio_set_value(chip->rdwr_pin, 1);
134 chip->mode = AD7816_FULL;
136 gpio_set_value(chip->rdwr_pin, 0);
137 chip->mode = AD7816_PD;
143 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
148 static ssize_t ad7816_show_available_modes(struct device *dev,
149 struct device_attribute *attr,
152 return sprintf(buf, "full\npower-save\n");
155 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, NULL, 0);
157 static ssize_t ad7816_show_channel(struct device *dev,
158 struct device_attribute *attr,
161 struct iio_dev *dev_info = dev_get_drvdata(dev);
162 struct ad7816_chip_info *chip = dev_info->dev_data;
164 return sprintf(buf, "%d\n", chip->channel_id);
167 static ssize_t ad7816_store_channel(struct device *dev,
168 struct device_attribute *attr,
172 struct iio_dev *dev_info = dev_get_drvdata(dev);
173 struct ad7816_chip_info *chip = dev_info->dev_data;
177 ret = strict_strtoul(buf, 10, &data);
181 if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
182 dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
183 data, dev_info->name);
185 } else if (strcmp(dev_info->name, "ad7818") == 0 && data > 1) {
186 dev_err(&chip->spi_dev->dev,
187 "Invalid channel id %lu for ad7818.\n", data);
189 } else if (strcmp(dev_info->name, "ad7816") == 0 && data > 0) {
190 dev_err(&chip->spi_dev->dev,
191 "Invalid channel id %lu for ad7816.\n", data);
195 chip->channel_id = data;
200 static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
202 ad7816_store_channel,
206 static ssize_t ad7816_show_value(struct device *dev,
207 struct device_attribute *attr,
210 struct iio_dev *dev_info = dev_get_drvdata(dev);
211 struct ad7816_chip_info *chip = dev_info->dev_data;
216 ret = ad7816_spi_read(chip, &data);
220 data >>= AD7816_VALUE_OFFSET;
222 if (chip->channel_id == 0) {
223 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
224 data &= AD7816_TEMP_FLOAT_MASK;
226 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
227 return sprintf(buf, "%d.%.2d\n", value, data * 25);
229 return sprintf(buf, "%u\n", data);
232 static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
234 static struct attribute *ad7816_attributes[] = {
235 &iio_dev_attr_available_modes.dev_attr.attr,
236 &iio_dev_attr_mode.dev_attr.attr,
237 &iio_dev_attr_channel.dev_attr.attr,
238 &iio_dev_attr_value.dev_attr.attr,
242 static const struct attribute_group ad7816_attribute_group = {
243 .attrs = ad7816_attributes,
247 * temperature bound events
250 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_EV_CLASS_TEMP, \
252 IIO_EV_TYPE_THRESH, \
255 static irqreturn_t ad7816_event_handler(int irq, void *private)
257 iio_push_event(private, 0,
258 IIO_EVENT_CODE_AD7816_OTI,
263 static ssize_t ad7816_show_oti(struct device *dev,
264 struct device_attribute *attr,
267 struct iio_dev *dev_info = dev_get_drvdata(dev);
268 struct ad7816_chip_info *chip = dev_info->dev_data;
271 if (chip->channel_id > AD7816_CS_MAX) {
272 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
274 } else if (chip->channel_id == 0) {
275 value = AD7816_BOUND_VALUE_MIN +
276 (chip->oti_data[chip->channel_id] -
277 AD7816_BOUND_VALUE_BASE);
278 return sprintf(buf, "%d\n", value);
280 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
283 static inline ssize_t ad7816_set_oti(struct device *dev,
284 struct device_attribute *attr,
288 struct iio_dev *dev_info = dev_get_drvdata(dev);
289 struct ad7816_chip_info *chip = dev_info->dev_data;
294 ret = strict_strtol(buf, 10, &value);
296 if (chip->channel_id > AD7816_CS_MAX) {
297 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
299 } else if (chip->channel_id == 0) {
300 if (ret || value < AD7816_BOUND_VALUE_MIN ||
301 value > AD7816_BOUND_VALUE_MAX)
304 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
305 AD7816_BOUND_VALUE_BASE);
307 if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
313 ret = ad7816_spi_write(chip, data);
317 chip->oti_data[chip->channel_id] = data;
322 static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
323 ad7816_show_oti, ad7816_set_oti, 0);
325 static struct attribute *ad7816_event_attributes[] = {
326 &iio_dev_attr_oti.dev_attr.attr,
330 static struct attribute_group ad7816_event_attribute_group = {
331 .attrs = ad7816_event_attributes,
334 static const struct iio_info ad7816_info = {
335 .attrs = &ad7816_attribute_group,
336 .num_interrupt_lines = 1,
337 .event_attrs = &ad7816_event_attribute_group,
338 .driver_module = THIS_MODULE,
342 * device probe and remove
345 static int __devinit ad7816_probe(struct spi_device *spi_dev)
347 struct ad7816_chip_info *chip;
348 unsigned short *pins = spi_dev->dev.platform_data;
353 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
357 chip = kzalloc(sizeof(struct ad7816_chip_info), GFP_KERNEL);
362 /* this is only used for device removal purposes */
363 dev_set_drvdata(&spi_dev->dev, chip);
365 chip->spi_dev = spi_dev;
366 for (i = 0; i <= AD7816_CS_MAX; i++)
367 chip->oti_data[i] = 203;
368 chip->rdwr_pin = pins[0];
369 chip->convert_pin = pins[1];
370 chip->busy_pin = pins[2];
372 ret = gpio_request(chip->rdwr_pin, spi_get_device_id(spi_dev)->name);
374 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
376 goto error_free_chip;
378 gpio_direction_input(chip->rdwr_pin);
379 ret = gpio_request(chip->convert_pin, spi_get_device_id(spi_dev)->name);
381 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
383 goto error_free_gpio_rdwr;
385 gpio_direction_input(chip->convert_pin);
386 ret = gpio_request(chip->busy_pin, spi_get_device_id(spi_dev)->name);
388 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
390 goto error_free_gpio_convert;
392 gpio_direction_input(chip->busy_pin);
394 chip->indio_dev = iio_allocate_device(0);
395 if (chip->indio_dev == NULL) {
397 goto error_free_gpio;
399 chip->indio_dev->name = spi_get_device_id(spi_dev)->name;
400 chip->indio_dev->dev.parent = &spi_dev->dev;
401 chip->indio_dev->info = &ad7816_info;
402 chip->indio_dev->dev_data = (void *)chip;
403 chip->indio_dev->modes = INDIO_DIRECT_MODE;
405 ret = iio_device_register(chip->indio_dev);
410 /* Only low trigger is supported in ad7816/7/8 */
411 ret = request_threaded_irq(spi_dev->irq,
413 &ad7816_event_handler,
415 chip->indio_dev->name,
418 goto error_unreg_dev;
421 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
422 chip->indio_dev->name);
427 iio_device_unregister(chip->indio_dev);
429 iio_free_device(chip->indio_dev);
431 gpio_free(chip->busy_pin);
432 error_free_gpio_convert:
433 gpio_free(chip->convert_pin);
434 error_free_gpio_rdwr:
435 gpio_free(chip->rdwr_pin);
442 static int __devexit ad7816_remove(struct spi_device *spi_dev)
444 struct ad7816_chip_info *chip = dev_get_drvdata(&spi_dev->dev);
445 struct iio_dev *indio_dev = chip->indio_dev;
447 dev_set_drvdata(&spi_dev->dev, NULL);
449 free_irq(spi_dev->irq, indio_dev);
450 iio_device_unregister(indio_dev);
451 iio_free_device(chip->indio_dev);
452 gpio_free(chip->busy_pin);
453 gpio_free(chip->convert_pin);
454 gpio_free(chip->rdwr_pin);
460 static const struct spi_device_id ad7816_id[] = {
467 MODULE_DEVICE_TABLE(spi, ad7816_id);
469 static struct spi_driver ad7816_driver = {
472 .bus = &spi_bus_type,
473 .owner = THIS_MODULE,
475 .probe = ad7816_probe,
476 .remove = __devexit_p(ad7816_remove),
477 .id_table = ad7816_id,
480 static __init int ad7816_init(void)
482 return spi_register_driver(&ad7816_driver);
485 static __exit void ad7816_exit(void)
487 spi_unregister_driver(&ad7816_driver);
490 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
491 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital"
492 " temperature sensor driver");
493 MODULE_LICENSE("GPL v2");
495 module_init(ad7816_init);
496 module_exit(ad7816_exit);