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
43 * struct ad7816_chip_info - chip specifc information
46 struct ad7816_chip_info {
47 struct spi_device *spi_dev;
51 u8 oti_data[AD7816_CS_MAX+1];
52 u8 channel_id; /* 0 always be temperature */
57 * ad7816 data access by SPI
59 static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
61 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);
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);
82 while (gpio_get_value(chip->busy_pin))
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));
89 dev_err(&spi_dev->dev, "SPI data read error\n");
93 *data = be16_to_cpu(*data);
98 static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
100 struct spi_device *spi_dev = chip->spi_dev;
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));
107 dev_err(&spi_dev->dev, "SPI oti data write error\n");
112 static ssize_t ad7816_show_mode(struct device *dev,
113 struct device_attribute *attr,
116 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
117 struct ad7816_chip_info *chip = iio_priv(indio_dev);
120 return sprintf(buf, "power-save\n");
122 return sprintf(buf, "full\n");
125 static ssize_t ad7816_store_mode(struct device *dev,
126 struct device_attribute *attr,
130 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
131 struct ad7816_chip_info *chip = iio_priv(indio_dev);
133 if (strcmp(buf, "full")) {
134 gpio_set_value(chip->rdwr_pin, 1);
135 chip->mode = AD7816_FULL;
137 gpio_set_value(chip->rdwr_pin, 0);
138 chip->mode = AD7816_PD;
144 static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR,
149 static ssize_t ad7816_show_available_modes(struct device *dev,
150 struct device_attribute *attr,
153 return sprintf(buf, "full\npower-save\n");
156 static IIO_DEVICE_ATTR(available_modes, S_IRUGO, ad7816_show_available_modes, NULL, 0);
158 static ssize_t ad7816_show_channel(struct device *dev,
159 struct device_attribute *attr,
162 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
163 struct ad7816_chip_info *chip = iio_priv(indio_dev);
165 return sprintf(buf, "%d\n", chip->channel_id);
168 static ssize_t ad7816_store_channel(struct device *dev,
169 struct device_attribute *attr,
173 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
174 struct ad7816_chip_info *chip = iio_priv(indio_dev);
178 ret = kstrtoul(buf, 10, &data);
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);
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);
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);
196 chip->channel_id = data;
201 static IIO_DEVICE_ATTR(channel, S_IRUGO | S_IWUSR,
203 ad7816_store_channel,
207 static ssize_t ad7816_show_value(struct device *dev,
208 struct device_attribute *attr,
211 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
212 struct ad7816_chip_info *chip = iio_priv(indio_dev);
217 ret = ad7816_spi_read(chip, &data);
221 data >>= AD7816_VALUE_OFFSET;
223 if (chip->channel_id == 0) {
224 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
225 data &= AD7816_TEMP_FLOAT_MASK;
227 data = (1 << AD7816_TEMP_FLOAT_OFFSET) - data;
228 return sprintf(buf, "%d.%.2d\n", value, data * 25);
230 return sprintf(buf, "%u\n", data);
233 static IIO_DEVICE_ATTR(value, S_IRUGO, ad7816_show_value, NULL, 0);
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,
243 static const struct attribute_group ad7816_attribute_group = {
244 .attrs = ad7816_attributes,
248 * temperature bound events
251 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
253 IIO_EV_TYPE_THRESH, \
256 static irqreturn_t ad7816_event_handler(int irq, void *private)
258 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI, iio_get_time_ns());
262 static ssize_t ad7816_show_oti(struct device *dev,
263 struct device_attribute *attr,
266 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
267 struct ad7816_chip_info *chip = iio_priv(indio_dev);
270 if (chip->channel_id > AD7816_CS_MAX) {
271 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
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);
279 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
282 static inline ssize_t ad7816_set_oti(struct device *dev,
283 struct device_attribute *attr,
287 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
288 struct ad7816_chip_info *chip = iio_priv(indio_dev);
293 ret = kstrtol(buf, 10, &value);
297 if (chip->channel_id > AD7816_CS_MAX) {
298 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
300 } else if (chip->channel_id == 0) {
301 if (ret || value < AD7816_BOUND_VALUE_MIN ||
302 value > AD7816_BOUND_VALUE_MAX)
305 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
306 AD7816_BOUND_VALUE_BASE);
308 if (ret || value < AD7816_BOUND_VALUE_BASE || value > 255)
314 ret = ad7816_spi_write(chip, data);
318 chip->oti_data[chip->channel_id] = data;
323 static IIO_DEVICE_ATTR(oti, S_IRUGO | S_IWUSR,
324 ad7816_show_oti, ad7816_set_oti, 0);
326 static struct attribute *ad7816_event_attributes[] = {
327 &iio_dev_attr_oti.dev_attr.attr,
331 static struct attribute_group ad7816_event_attribute_group = {
332 .attrs = ad7816_event_attributes,
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,
343 * device probe and remove
346 static int ad7816_probe(struct spi_device *spi_dev)
348 struct ad7816_chip_info *chip;
349 struct iio_dev *indio_dev;
350 unsigned short *pins = spi_dev->dev.platform_data;
355 dev_err(&spi_dev->dev, "No necessary GPIO platform data.\n");
359 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
362 chip = iio_priv(indio_dev);
363 /* this is only used for device removal purposes */
364 dev_set_drvdata(&spi_dev->dev, indio_dev);
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];
373 ret = devm_gpio_request(&spi_dev->dev, chip->rdwr_pin,
374 spi_get_device_id(spi_dev)->name);
376 dev_err(&spi_dev->dev, "Fail to request rdwr gpio PIN %d.\n",
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);
384 dev_err(&spi_dev->dev, "Fail to request convert gpio PIN %d.\n",
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);
392 dev_err(&spi_dev->dev, "Fail to request busy gpio PIN %d.\n",
396 gpio_direction_input(chip->busy_pin);
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 spi_device_id ad7816_id[] = {
432 MODULE_DEVICE_TABLE(spi, ad7816_id);
434 static struct spi_driver ad7816_driver = {
437 .owner = THIS_MODULE,
439 .probe = ad7816_probe,
440 .id_table = ad7816_id,
442 module_spi_driver(ad7816_driver);
444 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
445 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital"
446 " temperature sensor driver");
447 MODULE_LICENSE("GPL v2");