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>
17 #include <linux/module.h>
19 #include <linux/iio/iio.h>
20 #include <linux/iio/sysfs.h>
21 #include <linux/iio/events.h>
26 #define AD7816_FULL 0x1
28 #define AD7816_CS_MASK 0x7
29 #define AD7816_CS_MAX 0x4
32 * AD7816 temperature masks
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
42 * struct ad7816_chip_info - chip specific information
45 struct ad7816_chip_info {
46 struct spi_device *spi_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;
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));
68 dev_err(&spi_dev->dev, "SPI channel setting error\n");
71 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, &buf, sizeof(*data));
88 dev_err(&spi_dev->dev, "SPI data read error\n");
92 *data = be16_to_cpu(buf);
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 *indio_dev = dev_to_iio_dev(dev);
116 struct ad7816_chip_info *chip = iio_priv(indio_dev);
119 return sprintf(buf, "power-save\n");
120 return sprintf(buf, "full\n");
123 static ssize_t ad7816_store_mode(struct device *dev,
124 struct device_attribute *attr,
128 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
129 struct ad7816_chip_info *chip = iio_priv(indio_dev);
131 if (strcmp(buf, "full")) {
132 gpio_set_value(chip->rdwr_pin, 1);
133 chip->mode = AD7816_FULL;
135 gpio_set_value(chip->rdwr_pin, 0);
136 chip->mode = AD7816_PD;
142 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
147 static ssize_t ad7816_show_available_modes(struct device *dev,
148 struct device_attribute *attr,
151 return sprintf(buf, "full\npower-save\n");
154 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes,
157 static ssize_t ad7816_show_channel(struct device *dev,
158 struct device_attribute *attr,
161 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
162 struct ad7816_chip_info *chip = iio_priv(indio_dev);
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 *indio_dev = dev_to_iio_dev(dev);
173 struct ad7816_chip_info *chip = iio_priv(indio_dev);
177 ret = kstrtoul(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, indio_dev->name);
185 } else if (strcmp(indio_dev->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(indio_dev->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,
205 static ssize_t ad7816_show_value(struct device *dev,
206 struct device_attribute *attr,
209 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
210 struct ad7816_chip_info *chip = iio_priv(indio_dev);
215 ret = ad7816_spi_read(chip, &data);
219 data >>= AD7816_VALUE_OFFSET;
221 if (chip->channel_id == 0) {
222 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
223 data &= AD7816_TEMP_FLOAT_MASK;
225 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
226 return sprintf(buf, "%d.%.2d\n", value, data * 25);
228 return sprintf(buf, "%u\n", data);
231 static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
233 static struct attribute *ad7816_attributes[] = {
234 &iio_dev_attr_available_modes.dev_attr.attr,
235 &iio_dev_attr_mode.dev_attr.attr,
236 &iio_dev_attr_channel.dev_attr.attr,
237 &iio_dev_attr_value.dev_attr.attr,
241 static const struct attribute_group ad7816_attribute_group = {
242 .attrs = ad7816_attributes,
246 * temperature bound events
249 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
251 IIO_EV_TYPE_THRESH, \
254 static irqreturn_t ad7816_event_handler(int irq, void *private)
256 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns());
260 static ssize_t ad7816_show_oti(struct device *dev,
261 struct device_attribute *attr,
264 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
265 struct ad7816_chip_info *chip = iio_priv(indio_dev);
268 if (chip->channel_id > AD7816_CS_MAX) {
269 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
271 } else if (chip->channel_id == 0) {
272 value = AD7816_BOUND_VALUE_MIN +
273 (chip->oti_data[chip->channel_id] -
274 AD7816_BOUND_VALUE_BASE);
275 return sprintf(buf, "%d\n", value);
277 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
280 static inline ssize_t ad7816_set_oti(struct device *dev,
281 struct device_attribute *attr,
285 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
286 struct ad7816_chip_info *chip = iio_priv(indio_dev);
291 ret = kstrtol(buf, 10, &value);
295 if (chip->channel_id > AD7816_CS_MAX) {
296 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
298 } else if (chip->channel_id == 0) {
299 if (value < AD7816_BOUND_VALUE_MIN ||
300 value > AD7816_BOUND_VALUE_MAX)
303 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
304 AD7816_BOUND_VALUE_BASE);
306 if (value < AD7816_BOUND_VALUE_BASE || value > 255)
312 ret = ad7816_spi_write(chip, data);
316 chip->oti_data[chip->channel_id] = data;
321 static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
322 ad7816_show_oti, ad7816_set_oti, 0);
324 static struct attribute *ad7816_event_attributes[] = {
325 &iio_dev_attr_oti.dev_attr.attr,
329 static struct attribute_group ad7816_event_attribute_group = {
330 .attrs = ad7816_event_attributes,
334 static const struct iio_info ad7816_info = {
335 .attrs = &ad7816_attribute_group,
336 .event_attrs = &ad7816_event_attribute_group,
337 .driver_module = THIS_MODULE,
341 * device probe and remove
344 static int ad7816_probe(struct spi_device *spi_dev)
346 struct ad7816_chip_info *chip;
347 struct iio_dev *indio_dev;
348 unsigned short *pins = dev_get_platdata(&spi_dev->dev);
353 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
357 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
360 chip = iio_priv(indio_dev);
361 /* this is only used for device removal purposes */
362 dev_set_drvdata(&spi_dev->dev, indio_dev);
364 chip->spi_dev = spi_dev;
365 for (i = 0; i <= AD7816_CS_MAX; i++)
366 chip->oti_data[i] = 203;
367 chip->rdwr_pin = pins[0];
368 chip->convert_pin = pins[1];
369 chip->busy_pin = pins[2];
371 ret = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin,
372 spi_get_device_id(spi_dev)->name);
374 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
378 gpio_direction_input(chip->rdwr_pin);
379 ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin,
380 spi_get_device_id(spi_dev)->name);
382 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
386 gpio_direction_input(chip->convert_pin);
387 ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin,
388 spi_get_device_id(spi_dev)->name);
390 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
394 gpio_direction_input(chip->busy_pin);
396 indio_dev->name = spi_get_device_id(spi_dev)->name;
397 indio_dev->dev.parent = &spi_dev->dev;
398 indio_dev->info = &ad7816_info;
399 indio_dev->modes = INDIO_DIRECT_MODE;
402 /* Only low trigger is supported in ad7816/7/8 */
403 ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
405 &ad7816_event_handler,
406 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
413 ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
417 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
423 static const struct spi_device_id ad7816_id[] = {
430 MODULE_DEVICE_TABLE(spi, ad7816_id);
432 static struct spi_driver ad7816_driver = {
436 .probe = ad7816_probe,
437 .id_table = ad7816_id,
439 module_spi_driver(ad7816_driver);
442 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
443 MODULE_LICENSE("GPL v2");