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 | */ |
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(desc: chip->rdwr_pin, value: 1); |
71 | gpiod_set_value(desc: chip->rdwr_pin, value: 0); |
72 | ret = spi_write(spi: spi_dev, buf: &chip->channel_id, len: 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(desc: chip->rdwr_pin, value: 1); |
78 | |
79 | if (chip->mode == AD7816_PD) { /* operating mode 2 */ |
80 | gpiod_set_value(desc: chip->convert_pin, value: 1); |
81 | gpiod_set_value(desc: chip->convert_pin, value: 0); |
82 | } else { /* operating mode 1 */ |
83 | gpiod_set_value(desc: chip->convert_pin, value: 0); |
84 | gpiod_set_value(desc: chip->convert_pin, value: 1); |
85 | } |
86 | |
87 | if (chip->id == ID_AD7816 || chip->id == ID_AD7817) { |
88 | while (gpiod_get_value(desc: chip->busy_pin)) |
89 | cpu_relax(); |
90 | } |
91 | |
92 | gpiod_set_value(desc: chip->rdwr_pin, value: 0); |
93 | gpiod_set_value(desc: chip->rdwr_pin, value: 1); |
94 | ret = spi_read(spi: spi_dev, buf: &buf, len: 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 | |
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(desc: chip->rdwr_pin, value: 1); |
111 | gpiod_set_value(desc: chip->rdwr_pin, value: 0); |
112 | ret = spi_write(spi: spi_dev, buf: &data, len: sizeof(data)); |
113 | if (ret < 0) |
114 | dev_err(&spi_dev->dev, "SPI oti data write error\n" ); |
115 | |
116 | return ret; |
117 | } |
118 | |
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, fmt: "power-save\n" ); |
128 | return sprintf(buf, fmt: "full\n" ); |
129 | } |
130 | |
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(desc: chip->rdwr_pin, value: 1); |
141 | chip->mode = AD7816_FULL; |
142 | } else { |
143 | gpiod_set_value(desc: chip->rdwr_pin, value: 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 | |
155 | static ssize_t ad7816_show_available_modes(struct device *dev, |
156 | struct device_attribute *attr, |
157 | char *buf) |
158 | { |
159 | return sprintf(buf, fmt: "full\npower-save\n" ); |
160 | } |
161 | |
162 | static IIO_DEVICE_ATTR(available_modes, 0444, ad7816_show_available_modes, |
163 | NULL, 0); |
164 | |
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, fmt: "%d\n" , chip->channel_id); |
173 | } |
174 | |
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(s: buf, base: 10, res: &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 | |
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: &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, fmt: "%d.%.2d\n" , value, data * 25); |
235 | } |
236 | return sprintf(buf, fmt: "%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 | |
262 | static irqreturn_t ad7816_event_handler(int irq, void *private) |
263 | { |
264 | iio_push_event(indio_dev: private, IIO_EVENT_CODE_AD7816_OTI, |
265 | timestamp: iio_get_time_ns(indio_dev: private)); |
266 | return IRQ_HANDLED; |
267 | } |
268 | |
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, fmt: "%d\n" , value); |
285 | } |
286 | return sprintf(buf, fmt: "%u\n" , chip->oti_data[chip->channel_id]); |
287 | } |
288 | |
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(s: buf, base: 10, res: &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 | |
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(parent: &spi_dev->dev, sizeof_priv: 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(dev: &spi_dev->dev, data: 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(sdev: spi_dev)->driver_data; |
370 | chip->rdwr_pin = devm_gpiod_get(dev: &spi_dev->dev, con_id: "rdwr" , flags: GPIOD_OUT_HIGH); |
371 | if (IS_ERR(ptr: chip->rdwr_pin)) { |
372 | ret = PTR_ERR(ptr: 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(dev: &spi_dev->dev, con_id: "convert" , |
378 | flags: GPIOD_OUT_HIGH); |
379 | if (IS_ERR(ptr: chip->convert_pin)) { |
380 | ret = PTR_ERR(ptr: 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(dev: &spi_dev->dev, con_id: "busy" , |
387 | flags: GPIOD_IN); |
388 | if (IS_ERR(ptr: chip->busy_pin)) { |
389 | ret = PTR_ERR(ptr: 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(sdev: spi_dev)->name; |
397 | indio_dev->info = &ad7816_info; |
398 | indio_dev->modes = INDIO_DIRECT_MODE; |
399 | |
400 | if (spi_dev->irq) { |
401 | /* Only low trigger is supported in ad7816/7/8 */ |
402 | ret = devm_request_threaded_irq(dev: &spi_dev->dev, irq: spi_dev->irq, |
403 | NULL, |
404 | thread_fn: &ad7816_event_handler, |
405 | IRQF_TRIGGER_LOW | IRQF_ONESHOT, |
406 | devname: indio_dev->name, |
407 | dev_id: indio_dev); |
408 | if (ret) |
409 | return ret; |
410 | } |
411 | |
412 | ret = devm_iio_device_register(&spi_dev->dev, indio_dev); |
413 | if (ret) |
414 | return ret; |
415 | |
416 | dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n" , |
417 | indio_dev->name); |
418 | |
419 | return 0; |
420 | } |
421 | |
422 | static const struct of_device_id ad7816_of_match[] = { |
423 | { .compatible = "adi,ad7816" , }, |
424 | { .compatible = "adi,ad7817" , }, |
425 | { .compatible = "adi,ad7818" , }, |
426 | { } |
427 | }; |
428 | MODULE_DEVICE_TABLE(of, ad7816_of_match); |
429 | |
430 | static const struct spi_device_id ad7816_id[] = { |
431 | { "ad7816" , ID_AD7816 }, |
432 | { "ad7817" , ID_AD7817 }, |
433 | { "ad7818" , ID_AD7818 }, |
434 | {} |
435 | }; |
436 | |
437 | MODULE_DEVICE_TABLE(spi, ad7816_id); |
438 | |
439 | static struct spi_driver ad7816_driver = { |
440 | .driver = { |
441 | .name = "ad7816" , |
442 | .of_match_table = ad7816_of_match, |
443 | }, |
444 | .probe = ad7816_probe, |
445 | .id_table = ad7816_id, |
446 | }; |
447 | module_spi_driver(ad7816_driver); |
448 | |
449 | MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>" ); |
450 | MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver" ); |
451 | MODULE_LICENSE("GPL v2" ); |
452 | |