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/consumer.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 {
47 struct spi_device *spi_dev;
48 struct gpio_desc *rdwr_pin;
49 struct gpio_desc *convert_pin;
50 struct gpio_desc *busy_pin;
51 u8 oti_data[AD7816_CS_MAX + 1];
52 u8 channel_id; /* 0 always be temperature */
63 * ad7816 data access by SPI
65 static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
67 struct spi_device *spi_dev = chip->spi_dev;
71 gpiod_set_value(chip->rdwr_pin, 1);
72 gpiod_set_value(chip->rdwr_pin, 0);
73 ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
75 dev_err(&spi_dev->dev, "SPI channel setting error\n");
78 gpiod_set_value(chip->rdwr_pin, 1);
80 if (chip->mode == AD7816_PD) { /* operating mode 2 */
81 gpiod_set_value(chip->convert_pin, 1);
82 gpiod_set_value(chip->convert_pin, 0);
83 } else { /* operating mode 1 */
84 gpiod_set_value(chip->convert_pin, 0);
85 gpiod_set_value(chip->convert_pin, 1);
88 if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
89 while (gpiod_get_value(chip->busy_pin))
93 gpiod_set_value(chip->rdwr_pin, 0);
94 gpiod_set_value(chip->rdwr_pin, 1);
95 ret = spi_read(spi_dev, &buf, sizeof(*data));
97 dev_err(&spi_dev->dev, "SPI data read error\n");
101 *data = be16_to_cpu(buf);
106 static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
108 struct spi_device *spi_dev = chip->spi_dev;
111 gpiod_set_value(chip->rdwr_pin, 1);
112 gpiod_set_value(chip->rdwr_pin, 0);
113 ret = spi_write(spi_dev, &data, sizeof(data));
115 dev_err(&spi_dev->dev, "SPI oti data write error\n");
120 static ssize_t ad7816_show_mode(struct device *dev,
121 struct device_attribute *attr,
124 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
125 struct ad7816_chip_info *chip = iio_priv(indio_dev);
128 return sprintf(buf, "power-save\n");
129 return sprintf(buf, "full\n");
132 static ssize_t ad7816_store_mode(struct device *dev,
133 struct device_attribute *attr,
137 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
138 struct ad7816_chip_info *chip = iio_priv(indio_dev);
140 if (strcmp(buf, "full")) {
141 gpiod_set_value(chip->rdwr_pin, 1);
142 chip->mode = AD7816_FULL;
144 gpiod_set_value(chip->rdwr_pin, 0);
145 chip->mode = AD7816_PD;
151 static IIO_DEVICE_ATTR(mode, 0644,
156 static ssize_t ad7816_show_available_modes(struct device *dev,
157 struct device_attribute *attr,
160 return sprintf(buf, "full\npower-save\n");
163 static IIO_DEVICE_ATTR(available_modes, 0444, ad7816_show_available_modes,
166 static ssize_t ad7816_show_channel(struct device *dev,
167 struct device_attribute *attr,
170 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
171 struct ad7816_chip_info *chip = iio_priv(indio_dev);
173 return sprintf(buf, "%d\n", chip->channel_id);
176 static ssize_t ad7816_store_channel(struct device *dev,
177 struct device_attribute *attr,
181 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
182 struct ad7816_chip_info *chip = iio_priv(indio_dev);
186 ret = kstrtoul(buf, 10, &data);
190 if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
191 dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
192 data, indio_dev->name);
194 } else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
195 dev_err(&chip->spi_dev->dev,
196 "Invalid channel id %lu for ad7818.\n", data);
198 } else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
199 dev_err(&chip->spi_dev->dev,
200 "Invalid channel id %lu for ad7816.\n", data);
204 chip->channel_id = data;
209 static IIO_DEVICE_ATTR(channel, 0644,
211 ad7816_store_channel,
214 static ssize_t ad7816_show_value(struct device *dev,
215 struct device_attribute *attr,
218 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
219 struct ad7816_chip_info *chip = iio_priv(indio_dev);
224 ret = ad7816_spi_read(chip, &data);
228 data >>= AD7816_VALUE_OFFSET;
230 if (chip->channel_id == 0) {
231 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
232 data &= AD7816_TEMP_FLOAT_MASK;
234 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
235 return sprintf(buf, "%d.%.2d\n", value, data * 25);
237 return sprintf(buf, "%u\n", data);
240 static IIO_DEVICE_ATTR(value, 0444, ad7816_show_value, NULL, 0);
242 static struct attribute *ad7816_attributes[] = {
243 &iio_dev_attr_available_modes.dev_attr.attr,
244 &iio_dev_attr_mode.dev_attr.attr,
245 &iio_dev_attr_channel.dev_attr.attr,
246 &iio_dev_attr_value.dev_attr.attr,
250 static const struct attribute_group ad7816_attribute_group = {
251 .attrs = ad7816_attributes,
255 * temperature bound events
258 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
260 IIO_EV_TYPE_THRESH, \
263 static irqreturn_t ad7816_event_handler(int irq, void *private)
265 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI,
266 iio_get_time_ns(private));
270 static ssize_t ad7816_show_oti(struct device *dev,
271 struct device_attribute *attr,
274 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
275 struct ad7816_chip_info *chip = iio_priv(indio_dev);
278 if (chip->channel_id > AD7816_CS_MAX) {
279 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
281 } else if (chip->channel_id == 0) {
282 value = AD7816_BOUND_VALUE_MIN +
283 (chip->oti_data[chip->channel_id] -
284 AD7816_BOUND_VALUE_BASE);
285 return sprintf(buf, "%d\n", value);
287 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
290 static inline ssize_t ad7816_set_oti(struct device *dev,
291 struct device_attribute *attr,
295 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
296 struct ad7816_chip_info *chip = iio_priv(indio_dev);
301 ret = kstrtol(buf, 10, &value);
305 if (chip->channel_id > AD7816_CS_MAX) {
306 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
308 } else if (chip->channel_id == 0) {
309 if (value < AD7816_BOUND_VALUE_MIN ||
310 value > AD7816_BOUND_VALUE_MAX)
313 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
314 AD7816_BOUND_VALUE_BASE);
316 if (value < AD7816_BOUND_VALUE_BASE || value > 255)
322 ret = ad7816_spi_write(chip, data);
326 chip->oti_data[chip->channel_id] = data;
331 static IIO_DEVICE_ATTR(oti, 0644,
332 ad7816_show_oti, ad7816_set_oti, 0);
334 static struct attribute *ad7816_event_attributes[] = {
335 &iio_dev_attr_oti.dev_attr.attr,
339 static const struct attribute_group ad7816_event_attribute_group = {
340 .attrs = ad7816_event_attributes,
344 static const struct iio_info ad7816_info = {
345 .attrs = &ad7816_attribute_group,
346 .event_attrs = &ad7816_event_attribute_group,
350 * device probe and remove
353 static int ad7816_probe(struct spi_device *spi_dev)
355 struct ad7816_chip_info *chip;
356 struct iio_dev *indio_dev;
360 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
363 chip = iio_priv(indio_dev);
364 /* this is only used for device removal purposes */
365 dev_set_drvdata(&spi_dev->dev, indio_dev);
367 chip->spi_dev = spi_dev;
368 for (i = 0; i <= AD7816_CS_MAX; i++)
369 chip->oti_data[i] = 203;
371 chip->id = spi_get_device_id(spi_dev)->driver_data;
372 chip->rdwr_pin = devm_gpiod_get(&spi_dev->dev, "rdwr", GPIOD_OUT_HIGH);
373 if (IS_ERR(chip->rdwr_pin)) {
374 ret = PTR_ERR(chip->rdwr_pin);
375 dev_err(&spi_dev->dev, "Failed to request rdwr GPIO: %d\n",
379 chip->convert_pin = devm_gpiod_get(&spi_dev->dev, "convert",
381 if (IS_ERR(chip->convert_pin)) {
382 ret = PTR_ERR(chip->convert_pin);
383 dev_err(&spi_dev->dev, "Failed to request convert GPIO: %d\n",
387 if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
388 chip->busy_pin = devm_gpiod_get(&spi_dev->dev, "busy",
390 if (IS_ERR(chip->busy_pin)) {
391 ret = PTR_ERR(chip->busy_pin);
392 dev_err(&spi_dev->dev, "Failed to request busy GPIO: %d\n",
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;
404 /* Only low trigger is supported in ad7816/7/8 */
405 ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
407 &ad7816_event_handler,
408 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
415 ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
419 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
425 static const struct of_device_id ad7816_of_match[] = {
426 { .compatible = "adi,ad7816", },
427 { .compatible = "adi,ad7817", },
428 { .compatible = "adi,ad7818", },
431 MODULE_DEVICE_TABLE(of, ad7816_of_match);
433 static const struct spi_device_id ad7816_id[] = {
434 { "ad7816", ID_AD7816 },
435 { "ad7817", ID_AD7817 },
436 { "ad7818", ID_AD7818 },
440 MODULE_DEVICE_TABLE(spi, ad7816_id);
442 static struct spi_driver ad7816_driver = {
445 .of_match_table = ad7816_of_match,
447 .probe = ad7816_probe,
448 .id_table = ad7816_id,
450 module_spi_driver(ad7816_driver);
452 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
453 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
454 MODULE_LICENSE("GPL v2");