1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * AD7816 digital temperature sensor driver supporting AD7816/7/8
4 *
5 * Copyright 2010 Analog Devices Inc.
6 */
7
8 #include <linux/interrupt.h>
9 #include <linux/gpio/consumer.h>
10 #include <linux/device.h>
11 #include <linux/kernel.h>
12 #include <linux/slab.h>
13 #include <linux/sysfs.h>
14 #include <linux/list.h>
15 #include <linux/spi/spi.h>
16 #include <linux/module.h>
17
18 #include <linux/iio/iio.h>
19 #include <linux/iio/sysfs.h>
20 #include <linux/iio/events.h>
21
22 /*
23 * AD7816 config masks
24 */
25 #define AD7816_FULL 0x1
26 #define AD7816_PD 0x2
27 #define AD7816_CS_MASK 0x7
28 #define AD7816_CS_MAX 0x4
29
30 /*
31 * AD7816 temperature masks
32 */
33 #define AD7816_VALUE_OFFSET 6
34 #define AD7816_BOUND_VALUE_BASE 0x8
35 #define AD7816_BOUND_VALUE_MIN -95
36 #define AD7816_BOUND_VALUE_MAX 152
37 #define AD7816_TEMP_FLOAT_OFFSET 2
38 #define AD7816_TEMP_FLOAT_MASK 0x3
39
40 /*
41 * struct ad7816_chip_info - chip specific information
42 */
43
44 struct ad7816_chip_info {
45 kernel_ulong_t id;
46 struct spi_device *spi_dev;
47 struct gpio_desc *rdwr_pin;
48 struct gpio_desc *convert_pin;
49 struct gpio_desc *busy_pin;
50 u8 oti_data[AD7816_CS_MAX + 1];
51 u8 channel_id; /* 0 always be temperature */
52 u8 mode;
53 };
54
55 enum ad7816_type {
56 ID_AD7816,
57 ID_AD7817,
58 ID_AD7818,
59 };
60
61 /*
62 * ad7816 data access by SPI
63 */
ad7816_spi_read(struct ad7816_chip_info * chip,u16 * data)64 static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
65 {
66 struct spi_device *spi_dev = chip->spi_dev;
67 int ret;
68 __be16 buf;
69
70 gpiod_set_value(chip->rdwr_pin, 1);
71 gpiod_set_value(chip->rdwr_pin, 0);
72 ret = spi_write(spi_dev, &chip->channel_id, sizeof(chip->channel_id));
73 if (ret < 0) {
74 dev_err(&spi_dev->dev, "SPI channel setting error\n");
75 return ret;
76 }
77 gpiod_set_value(chip->rdwr_pin, 1);
78
79 if (chip->mode == AD7816_PD) { /* operating mode 2 */
80 gpiod_set_value(chip->convert_pin, 1);
81 gpiod_set_value(chip->convert_pin, 0);
82 } else { /* operating mode 1 */
83 gpiod_set_value(chip->convert_pin, 0);
84 gpiod_set_value(chip->convert_pin, 1);
85 }
86
87 if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
88 while (gpiod_get_value(chip->busy_pin))
89 cpu_relax();
90 }
91
92 gpiod_set_value(chip->rdwr_pin, 0);
93 gpiod_set_value(chip->rdwr_pin, 1);
94 ret = spi_read(spi_dev, &buf, sizeof(*data));
95 if (ret < 0) {
96 dev_err(&spi_dev->dev, "SPI data read error\n");
97 return ret;
98 }
99
100 *data = be16_to_cpu(buf);
101
102 return ret;
103 }
104
ad7816_spi_write(struct ad7816_chip_info * chip,u8 data)105 static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
106 {
107 struct spi_device *spi_dev = chip->spi_dev;
108 int ret;
109
110 gpiod_set_value(chip->rdwr_pin, 1);
111 gpiod_set_value(chip->rdwr_pin, 0);
112 ret = spi_write(spi_dev, &data, sizeof(data));
113 if (ret < 0)
114 dev_err(&spi_dev->dev, "SPI oti data write error\n");
115
116 return ret;
117 }
118
ad7816_show_mode(struct device * dev,struct device_attribute * attr,char * buf)119 static ssize_t ad7816_show_mode(struct device *dev,
120 struct device_attribute *attr,
121 char *buf)
122 {
123 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
124 struct ad7816_chip_info *chip = iio_priv(indio_dev);
125
126 if (chip->mode)
127 return sprintf(buf, "power-save\n");
128 return sprintf(buf, "full\n");
129 }
130
ad7816_store_mode(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)131 static ssize_t ad7816_store_mode(struct device *dev,
132 struct device_attribute *attr,
133 const char *buf,
134 size_t len)
135 {
136 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
137 struct ad7816_chip_info *chip = iio_priv(indio_dev);
138
139 if (strcmp(buf, "full")) {
140 gpiod_set_value(chip->rdwr_pin, 1);
141 chip->mode = AD7816_FULL;
142 } else {
143 gpiod_set_value(chip->rdwr_pin, 0);
144 chip->mode = AD7816_PD;
145 }
146
147 return len;
148 }
149
150 static IIO_DEVICE_ATTR(mode, 0644,
151 ad7816_show_mode,
152 ad7816_store_mode,
153 0);
154
ad7816_show_available_modes(struct device * dev,struct device_attribute * attr,char * buf)155 static ssize_t ad7816_show_available_modes(struct device *dev,
156 struct device_attribute *attr,
157 char *buf)
158 {
159 return sprintf(buf, "full\npower-save\n");
160 }
161
162 static IIO_DEVICE_ATTR(available_modes, 0444, ad7816_show_available_modes,
163 NULL, 0);
164
ad7816_show_channel(struct device * dev,struct device_attribute * attr,char * buf)165 static ssize_t ad7816_show_channel(struct device *dev,
166 struct device_attribute *attr,
167 char *buf)
168 {
169 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
170 struct ad7816_chip_info *chip = iio_priv(indio_dev);
171
172 return sprintf(buf, "%d\n", chip->channel_id);
173 }
174
ad7816_store_channel(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)175 static ssize_t ad7816_store_channel(struct device *dev,
176 struct device_attribute *attr,
177 const char *buf,
178 size_t len)
179 {
180 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
181 struct ad7816_chip_info *chip = iio_priv(indio_dev);
182 unsigned long data;
183 int ret;
184
185 ret = kstrtoul(buf, 10, &data);
186 if (ret)
187 return ret;
188
189 if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
190 dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
191 data, indio_dev->name);
192 return -EINVAL;
193 } else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
194 dev_err(&chip->spi_dev->dev,
195 "Invalid channel id %lu for ad7818.\n", data);
196 return -EINVAL;
197 } else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
198 dev_err(&chip->spi_dev->dev,
199 "Invalid channel id %lu for ad7816.\n", data);
200 return -EINVAL;
201 }
202
203 chip->channel_id = data;
204
205 return len;
206 }
207
208 static IIO_DEVICE_ATTR(channel, 0644,
209 ad7816_show_channel,
210 ad7816_store_channel,
211 0);
212
ad7816_show_value(struct device * dev,struct device_attribute * attr,char * buf)213 static ssize_t ad7816_show_value(struct device *dev,
214 struct device_attribute *attr,
215 char *buf)
216 {
217 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
218 struct ad7816_chip_info *chip = iio_priv(indio_dev);
219 u16 data;
220 s8 value;
221 int ret;
222
223 ret = ad7816_spi_read(chip, &data);
224 if (ret)
225 return -EIO;
226
227 data >>= AD7816_VALUE_OFFSET;
228
229 if (chip->channel_id == 0) {
230 value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
231 data &= AD7816_TEMP_FLOAT_MASK;
232 if (value < 0)
233 data = BIT(AD7816_TEMP_FLOAT_OFFSET) - data;
234 return sprintf(buf, "%d.%.2d\n", value, data * 25);
235 }
236 return sprintf(buf, "%u\n", data);
237 }
238
239 static IIO_DEVICE_ATTR(value, 0444, ad7816_show_value, NULL, 0);
240
241 static struct attribute *ad7816_attributes[] = {
242 &iio_dev_attr_available_modes.dev_attr.attr,
243 &iio_dev_attr_mode.dev_attr.attr,
244 &iio_dev_attr_channel.dev_attr.attr,
245 &iio_dev_attr_value.dev_attr.attr,
246 NULL,
247 };
248
249 static const struct attribute_group ad7816_attribute_group = {
250 .attrs = ad7816_attributes,
251 };
252
253 /*
254 * temperature bound events
255 */
256
257 #define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP, \
258 0, \
259 IIO_EV_TYPE_THRESH, \
260 IIO_EV_DIR_FALLING)
261
ad7816_event_handler(int irq,void * private)262 static irqreturn_t ad7816_event_handler(int irq, void *private)
263 {
264 iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI,
265 iio_get_time_ns(private));
266 return IRQ_HANDLED;
267 }
268
ad7816_show_oti(struct device * dev,struct device_attribute * attr,char * buf)269 static ssize_t ad7816_show_oti(struct device *dev,
270 struct device_attribute *attr,
271 char *buf)
272 {
273 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
274 struct ad7816_chip_info *chip = iio_priv(indio_dev);
275 int value;
276
277 if (chip->channel_id > AD7816_CS_MAX) {
278 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
279 return -EINVAL;
280 } else if (chip->channel_id == 0) {
281 value = AD7816_BOUND_VALUE_MIN +
282 (chip->oti_data[chip->channel_id] -
283 AD7816_BOUND_VALUE_BASE);
284 return sprintf(buf, "%d\n", value);
285 }
286 return sprintf(buf, "%u\n", chip->oti_data[chip->channel_id]);
287 }
288
ad7816_set_oti(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)289 static inline ssize_t ad7816_set_oti(struct device *dev,
290 struct device_attribute *attr,
291 const char *buf,
292 size_t len)
293 {
294 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
295 struct ad7816_chip_info *chip = iio_priv(indio_dev);
296 long value;
297 u8 data;
298 int ret;
299
300 ret = kstrtol(buf, 10, &value);
301 if (ret)
302 return ret;
303
304 if (chip->channel_id > AD7816_CS_MAX) {
305 dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
306 return -EINVAL;
307 } else if (chip->channel_id == 0) {
308 if (value < AD7816_BOUND_VALUE_MIN ||
309 value > AD7816_BOUND_VALUE_MAX)
310 return -EINVAL;
311
312 data = (u8)(value - AD7816_BOUND_VALUE_MIN +
313 AD7816_BOUND_VALUE_BASE);
314 } else {
315 if (value < AD7816_BOUND_VALUE_BASE || value > 255)
316 return -EINVAL;
317
318 data = (u8)value;
319 }
320
321 ret = ad7816_spi_write(chip, data);
322 if (ret)
323 return -EIO;
324
325 chip->oti_data[chip->channel_id] = data;
326
327 return len;
328 }
329
330 static IIO_DEVICE_ATTR(oti, 0644,
331 ad7816_show_oti, ad7816_set_oti, 0);
332
333 static struct attribute *ad7816_event_attributes[] = {
334 &iio_dev_attr_oti.dev_attr.attr,
335 NULL,
336 };
337
338 static const struct attribute_group ad7816_event_attribute_group = {
339 .attrs = ad7816_event_attributes,
340 .name = "events",
341 };
342
343 static const struct iio_info ad7816_info = {
344 .attrs = &ad7816_attribute_group,
345 .event_attrs = &ad7816_event_attribute_group,
346 };
347
348 /*
349 * device probe and remove
350 */
351
ad7816_probe(struct spi_device * spi_dev)352 static int ad7816_probe(struct spi_device *spi_dev)
353 {
354 struct ad7816_chip_info *chip;
355 struct iio_dev *indio_dev;
356 int i, ret;
357
358 indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
359 if (!indio_dev)
360 return -ENOMEM;
361 chip = iio_priv(indio_dev);
362 /* this is only used for device removal purposes */
363 dev_set_drvdata(&spi_dev->dev, indio_dev);
364
365 chip->spi_dev = spi_dev;
366 for (i = 0; i <= AD7816_CS_MAX; i++)
367 chip->oti_data[i] = 203;
368
369 chip->id = spi_get_device_id(spi_dev)->driver_data;
370 chip->rdwr_pin = devm_gpiod_get(&spi_dev->dev, "rdwr", GPIOD_OUT_HIGH);
371 if (IS_ERR(chip->rdwr_pin)) {
372 ret = PTR_ERR(chip->rdwr_pin);
373 dev_err(&spi_dev->dev, "Failed to request rdwr GPIO: %d\n",
374 ret);
375 return ret;
376 }
377 chip->convert_pin = devm_gpiod_get(&spi_dev->dev, "convert",
378 GPIOD_OUT_HIGH);
379 if (IS_ERR(chip->convert_pin)) {
380 ret = PTR_ERR(chip->convert_pin);
381 dev_err(&spi_dev->dev, "Failed to request convert GPIO: %d\n",
382 ret);
383 return ret;
384 }
385 if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
386 chip->busy_pin = devm_gpiod_get(&spi_dev->dev, "busy",
387 GPIOD_IN);
388 if (IS_ERR(chip->busy_pin)) {
389 ret = PTR_ERR(chip->busy_pin);
390 dev_err(&spi_dev->dev, "Failed to request busy GPIO: %d\n",
391 ret);
392 return ret;
393 }
394 }
395
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;
400
401 if (spi_dev->irq) {
402 /* Only low trigger is supported in ad7816/7/8 */
403 ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
404 NULL,
405 &ad7816_event_handler,
406 IRQF_TRIGGER_LOW | IRQF_ONESHOT,
407 indio_dev->name,
408 indio_dev);
409 if (ret)
410 return ret;
411 }
412
413 ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
414 if (ret)
415 return ret;
416
417 dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
418 indio_dev->name);
419
420 return 0;
421 }
422
423 static const struct of_device_id ad7816_of_match[] = {
424 { .compatible = "adi,ad7816", },
425 { .compatible = "adi,ad7817", },
426 { .compatible = "adi,ad7818", },
427 { }
428 };
429 MODULE_DEVICE_TABLE(of, ad7816_of_match);
430
431 static const struct spi_device_id ad7816_id[] = {
432 { "ad7816", ID_AD7816 },
433 { "ad7817", ID_AD7817 },
434 { "ad7818", ID_AD7818 },
435 {}
436 };
437
438 MODULE_DEVICE_TABLE(spi, ad7816_id);
439
440 static struct spi_driver ad7816_driver = {
441 .driver = {
442 .name = "ad7816",
443 .of_match_table = ad7816_of_match,
444 },
445 .probe = ad7816_probe,
446 .id_table = ad7816_id,
447 };
448 module_spi_driver(ad7816_driver);
449
450 MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
451 MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
452 MODULE_LICENSE("GPL v2");
453
