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;
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);
72 if (chip->mode == AD7816_PD) { /* operating mode 2 */
73 gpio_set_value(chip->convert_pin, 1);
74 gpio_set_value(chip->convert_pin, 0);
75 } else { /* operating mode 1 */
76 gpio_set_value(chip->convert_pin, 0);
77 gpio_set_value(chip->convert_pin, 1);
80 while (gpio_get_value(chip->busy_pin))
83 gpio_set_value(chip->rdwr_pin, 0);
84 gpio_set_value(chip->rdwr_pin, 1);
85 ret = spi_read(spi_dev, (u8 *)data, sizeof(*data));
87 dev_err(&spi_dev->dev, "SPI data read error\n");
91 *data = be16_to_cpu(*data);
96 static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
98 struct spi_device *spi_dev = chip->spi_dev;
101 gpio_set_value(chip->rdwr_pin, 1);
102 gpio_set_value(chip->rdwr_pin, 0);
103 ret = spi_write(spi_dev, &data, sizeof(data));
105 dev_err(&spi_dev->dev, "SPI oti data write error\n");
110 static ssize_t ad7816_show_mode(struct device *dev,
111 struct device_attribute *attr,
114 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
115 struct ad7816_chip_info *chip = iio_priv(indio_dev);
118 return sprintf(buf, "power-save\n");
119 return sprintf(buf, "full\n");
122 static ssize_t ad7816_store_mode(struct device *dev,
123 struct device_attribute *attr,
127 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
128 struct ad7816_chip_info *chip = iio_priv(indio_dev);
130 if (strcmp(buf, "full")) {
131 gpio_set_value(chip->rdwr_pin, 1);
132 chip->mode = AD7816_FULL;
134 gpio_set_value(chip->rdwr_pin, 0);
135 chip->mode = AD7816_PD;
141 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
146 static ssize_t ad7816_show_available_modes(struct device *dev,
147 struct device_attribute *attr,
150 return sprintf(buf, "full\npower-save\n");
153 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes,
156 static ssize_t ad7816_show_channel(struct device *dev,
157 struct device_attribute *attr,
160 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
161 struct ad7816_chip_info *chip = iio_priv(indio_dev);
163 return sprintf(buf, "%d\n", chip->channel_id);
166 static ssize_t ad7816_store_channel(struct device *dev,
167 struct device_attribute *attr,
171 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
172 struct ad7816_chip_info *chip = iio_priv(indio_dev);
176 ret = kstrtoul(buf, 10, &data);
180 if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
181 dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
182 data, indio_dev->name);
184 } else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
185 dev_err(&chip->spi_dev->dev,
186 "Invalid channel id %lu for ad7818.\n", data);
188 } else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
189 dev_err(&chip->spi_dev->dev,
190 "Invalid channel id %lu for ad7816.\n", data);
194 chip->channel_id = data;
199 static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
201 ad7816_store_channel,
204 static ssize_t ad7816_show_value(struct device *dev,
205 struct device_attribute *attr,
208 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
209 struct ad7816_chip_info *chip = iio_priv(indio_dev);
214 ret = ad7816_spi_read(chip, &data);
218 data >>= AD7816_VALUE_OFFSET;
220 if (chip->channel_id == 0) {
221 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
222 data &= AD7816_TEMP_FLOAT_MASK;
224 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
225 return sprintf(buf, "%d.%.2d\n", value, data * 25);
227 return sprintf(buf, "%u\n", data);
230 static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
232 static struct attribute *ad7816_attributes[] = {
233 &iio_dev_attr_available_modes.dev_attr.attr,
234 &iio_dev_attr_mode.dev_attr.attr,
235 &iio_dev_attr_channel.dev_attr.attr,
236 &iio_dev_attr_value.dev_attr.attr,
240 static const struct attribute_group ad7816_attribute_group = {
241 .attrs = ad7816_attributes,
245 * temperature bound events
248 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
250 IIO_EV_TYPE_THRESH, \
253 static irqreturn_t ad7816_event_handler(int irq, void *private)
255 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns());
259 static ssize_t ad7816_show_oti(struct device *dev,
260 struct device_attribute *attr,
263 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
264 struct ad7816_chip_info *chip = iio_priv(indio_dev);
267 if (chip->channel_id > AD7816_CS_MAX) {
268 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
270 } else if (chip->channel_id == 0) {
271 value = AD7816_BOUND_VALUE_MIN +
272 (chip->oti_data[chip->channel_id] -
273 AD7816_BOUND_VALUE_BASE);
274 return sprintf(buf, "%d\n", value);
276 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
279 static inline ssize_t ad7816_set_oti(struct device *dev,
280 struct device_attribute *attr,
284 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
285 struct ad7816_chip_info *chip = iio_priv(indio_dev);
290 ret = kstrtol(buf, 10, &value);
294 if (chip->channel_id > AD7816_CS_MAX) {
295 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
297 } else if (chip->channel_id == 0) {
298 if (ret || value < AD7816_BOUND_VALUE_MIN ||
299 value > AD7816_BOUND_VALUE_MAX)
302 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
303 AD7816_BOUND_VALUE_BASE);
305 if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
311 ret = ad7816_spi_write(chip, data);
315 chip->oti_data[chip->channel_id] = data;
320 static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
321 ad7816_show_oti, ad7816_set_oti, 0);
323 static struct attribute *ad7816_event_attributes[] = {
324 &iio_dev_attr_oti.dev_attr.attr,
328 static struct attribute_group ad7816_event_attribute_group = {
329 .attrs = ad7816_event_attributes,
333 static const struct iio_info ad7816_info = {
334 .attrs = &ad7816_attribute_group,
335 .event_attrs = &ad7816_event_attribute_group,
336 .driver_module = THIS_MODULE,
340 * device probe and remove
343 static int ad7816_probe(struct spi_device *spi_dev)
345 struct ad7816_chip_info *chip;
346 struct iio_dev *indio_dev;
347 unsigned short *pins = spi_dev->dev.platform_data;
352 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
356 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
359 chip = iio_priv(indio_dev);
360 /* this is only used for device removal purposes */
361 dev_set_drvdata(&spi_dev->dev, indio_dev);
363 chip->spi_dev = spi_dev;
364 for (i = 0; i <= AD7816_CS_MAX; i++)
365 chip->oti_data[i] = 203;
366 chip->rdwr_pin = pins[0];
367 chip->convert_pin = pins[1];
368 chip->busy_pin = pins[2];
370 ret = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin,
371 spi_get_device_id(spi_dev)->name);
373 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
377 gpio_direction_input(chip->rdwr_pin);
378 ret = devm_gpio_request(&spi_dev->dev, chip->convert_pin,
379 spi_get_device_id(spi_dev)->name);
381 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
385 gpio_direction_input(chip->convert_pin);
386 ret = devm_gpio_request(&spi_dev->dev, chip->busy_pin,
387 spi_get_device_id(spi_dev)->name);
389 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
393 gpio_direction_input(chip->busy_pin);
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;
401 /* Only low trigger is supported in ad7816/7/8 */
402 ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
404 &ad7816_event_handler,
405 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
412 ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
416 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
422 static const struct spi_device_id ad7816_id[] = {
429 MODULE_DEVICE_TABLE(spi, ad7816_id);
431 static struct spi_driver ad7816_driver = {
434 .owner = THIS_MODULE,
436 .probe = ad7816_probe,
437 .id_table = ad7816_id,
439 module_spi_driver(ad7816_driver);
441 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
442 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
443 MODULE_LICENSE("GPL v2");