1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* |
3 | * maxim_thermocouple.c - Support for Maxim thermocouple chips |
4 | * |
5 | * Copyright (C) 2016-2018 Matt Ranostay |
6 | * Author: <matt.ranostay@konsulko.com> |
7 | */ |
8 | |
9 | #include <linux/init.h> |
10 | #include <linux/mod_devicetable.h> |
11 | #include <linux/module.h> |
12 | #include <linux/mutex.h> |
13 | #include <linux/err.h> |
14 | #include <linux/spi/spi.h> |
15 | #include <linux/iio/iio.h> |
16 | #include <linux/iio/sysfs.h> |
17 | #include <linux/iio/trigger.h> |
18 | #include <linux/iio/buffer.h> |
19 | #include <linux/iio/triggered_buffer.h> |
20 | #include <linux/iio/trigger_consumer.h> |
21 | |
22 | #define MAXIM_THERMOCOUPLE_DRV_NAME "maxim_thermocouple" |
23 | |
24 | enum { |
25 | MAX6675, |
26 | MAX31855, |
27 | MAX31855K, |
28 | MAX31855J, |
29 | MAX31855N, |
30 | MAX31855S, |
31 | MAX31855T, |
32 | MAX31855E, |
33 | MAX31855R, |
34 | }; |
35 | |
36 | static const char maxim_tc_types[] = { |
37 | 'K', '?', 'K', 'J', 'N', 'S', 'T', 'E', 'R' |
38 | }; |
39 | |
40 | static const struct iio_chan_spec max6675_channels[] = { |
41 | { /* thermocouple temperature */ |
42 | .type = IIO_TEMP, |
43 | .info_mask_separate = |
44 | BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | |
45 | BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE), |
46 | .scan_index = 0, |
47 | .scan_type = { |
48 | .sign = 's', |
49 | .realbits = 13, |
50 | .storagebits = 16, |
51 | .shift = 3, |
52 | .endianness = IIO_BE, |
53 | }, |
54 | }, |
55 | IIO_CHAN_SOFT_TIMESTAMP(1), |
56 | }; |
57 | |
58 | static const struct iio_chan_spec max31855_channels[] = { |
59 | { /* thermocouple temperature */ |
60 | .type = IIO_TEMP, |
61 | .address = 2, |
62 | .info_mask_separate = |
63 | BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) | |
64 | BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE), |
65 | .scan_index = 0, |
66 | .scan_type = { |
67 | .sign = 's', |
68 | .realbits = 14, |
69 | .storagebits = 16, |
70 | .shift = 2, |
71 | .endianness = IIO_BE, |
72 | }, |
73 | }, |
74 | { /* cold junction temperature */ |
75 | .type = IIO_TEMP, |
76 | .address = 0, |
77 | .channel2 = IIO_MOD_TEMP_AMBIENT, |
78 | .modified = 1, |
79 | .info_mask_separate = |
80 | BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), |
81 | .scan_index = 1, |
82 | .scan_type = { |
83 | .sign = 's', |
84 | .realbits = 12, |
85 | .storagebits = 16, |
86 | .shift = 4, |
87 | .endianness = IIO_BE, |
88 | }, |
89 | }, |
90 | IIO_CHAN_SOFT_TIMESTAMP(2), |
91 | }; |
92 | |
93 | static const unsigned long max31855_scan_masks[] = {0x3, 0}; |
94 | |
95 | struct maxim_thermocouple_chip { |
96 | const struct iio_chan_spec *channels; |
97 | const unsigned long *scan_masks; |
98 | u8 num_channels; |
99 | u8 read_size; |
100 | |
101 | /* bit-check for valid input */ |
102 | u32 status_bit; |
103 | }; |
104 | |
105 | static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = { |
106 | [MAX6675] = { |
107 | .channels = max6675_channels, |
108 | .num_channels = ARRAY_SIZE(max6675_channels), |
109 | .read_size = 2, |
110 | .status_bit = BIT(2), |
111 | }, |
112 | [MAX31855] = { |
113 | .channels = max31855_channels, |
114 | .num_channels = ARRAY_SIZE(max31855_channels), |
115 | .read_size = 4, |
116 | .scan_masks = max31855_scan_masks, |
117 | .status_bit = BIT(16), |
118 | }, |
119 | }; |
120 | |
121 | struct maxim_thermocouple_data { |
122 | struct spi_device *spi; |
123 | const struct maxim_thermocouple_chip *chip; |
124 | |
125 | u8 buffer[16] __aligned(IIO_DMA_MINALIGN); |
126 | char tc_type; |
127 | }; |
128 | |
129 | static int maxim_thermocouple_read(struct maxim_thermocouple_data *data, |
130 | struct iio_chan_spec const *chan, int *val) |
131 | { |
132 | unsigned int storage_bytes = data->chip->read_size; |
133 | unsigned int shift = chan->scan_type.shift + (chan->address * 8); |
134 | __be16 buf16; |
135 | __be32 buf32; |
136 | int ret; |
137 | |
138 | switch (storage_bytes) { |
139 | case 2: |
140 | ret = spi_read(spi: data->spi, buf: (void *)&buf16, len: storage_bytes); |
141 | *val = be16_to_cpu(buf16); |
142 | break; |
143 | case 4: |
144 | ret = spi_read(spi: data->spi, buf: (void *)&buf32, len: storage_bytes); |
145 | *val = be32_to_cpu(buf32); |
146 | break; |
147 | default: |
148 | ret = -EINVAL; |
149 | } |
150 | |
151 | if (ret) |
152 | return ret; |
153 | |
154 | /* check to be sure this is a valid reading */ |
155 | if (*val & data->chip->status_bit) |
156 | return -EINVAL; |
157 | |
158 | *val = sign_extend32(value: *val >> shift, index: chan->scan_type.realbits - 1); |
159 | |
160 | return 0; |
161 | } |
162 | |
163 | static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private) |
164 | { |
165 | struct iio_poll_func *pf = private; |
166 | struct iio_dev *indio_dev = pf->indio_dev; |
167 | struct maxim_thermocouple_data *data = iio_priv(indio_dev); |
168 | int ret; |
169 | |
170 | ret = spi_read(spi: data->spi, buf: data->buffer, len: data->chip->read_size); |
171 | if (!ret) { |
172 | iio_push_to_buffers_with_timestamp(indio_dev, data: data->buffer, |
173 | timestamp: iio_get_time_ns(indio_dev)); |
174 | } |
175 | |
176 | iio_trigger_notify_done(trig: indio_dev->trig); |
177 | |
178 | return IRQ_HANDLED; |
179 | } |
180 | |
181 | static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev, |
182 | struct iio_chan_spec const *chan, |
183 | int *val, int *val2, long mask) |
184 | { |
185 | struct maxim_thermocouple_data *data = iio_priv(indio_dev); |
186 | int ret = -EINVAL; |
187 | |
188 | switch (mask) { |
189 | case IIO_CHAN_INFO_RAW: |
190 | ret = iio_device_claim_direct_mode(indio_dev); |
191 | if (ret) |
192 | return ret; |
193 | |
194 | ret = maxim_thermocouple_read(data, chan, val); |
195 | iio_device_release_direct_mode(indio_dev); |
196 | |
197 | if (!ret) |
198 | return IIO_VAL_INT; |
199 | |
200 | break; |
201 | case IIO_CHAN_INFO_SCALE: |
202 | switch (chan->channel2) { |
203 | case IIO_MOD_TEMP_AMBIENT: |
204 | *val = 62; |
205 | *val2 = 500000; /* 1000 * 0.0625 */ |
206 | ret = IIO_VAL_INT_PLUS_MICRO; |
207 | break; |
208 | default: |
209 | *val = 250; /* 1000 * 0.25 */ |
210 | ret = IIO_VAL_INT; |
211 | } |
212 | break; |
213 | case IIO_CHAN_INFO_THERMOCOUPLE_TYPE: |
214 | *val = data->tc_type; |
215 | ret = IIO_VAL_CHAR; |
216 | break; |
217 | } |
218 | |
219 | return ret; |
220 | } |
221 | |
222 | static const struct iio_info maxim_thermocouple_info = { |
223 | .read_raw = maxim_thermocouple_read_raw, |
224 | }; |
225 | |
226 | static int maxim_thermocouple_probe(struct spi_device *spi) |
227 | { |
228 | const struct spi_device_id *id = spi_get_device_id(sdev: spi); |
229 | struct iio_dev *indio_dev; |
230 | struct maxim_thermocouple_data *data; |
231 | const int chip_type = (id->driver_data == MAX6675) ? MAX6675 : MAX31855; |
232 | const struct maxim_thermocouple_chip *chip = |
233 | &maxim_thermocouple_chips[chip_type]; |
234 | int ret; |
235 | |
236 | indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*data)); |
237 | if (!indio_dev) |
238 | return -ENOMEM; |
239 | |
240 | indio_dev->info = &maxim_thermocouple_info; |
241 | indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME; |
242 | indio_dev->channels = chip->channels; |
243 | indio_dev->available_scan_masks = chip->scan_masks; |
244 | indio_dev->num_channels = chip->num_channels; |
245 | indio_dev->modes = INDIO_DIRECT_MODE; |
246 | |
247 | data = iio_priv(indio_dev); |
248 | data->spi = spi; |
249 | data->chip = chip; |
250 | data->tc_type = maxim_tc_types[id->driver_data]; |
251 | |
252 | ret = devm_iio_triggered_buffer_setup(&spi->dev, |
253 | indio_dev, NULL, |
254 | maxim_thermocouple_trigger_handler, NULL); |
255 | if (ret) |
256 | return ret; |
257 | |
258 | if (id->driver_data == MAX31855) |
259 | dev_warn(&spi->dev, "generic max31855 ID is deprecated\nplease use more specific part type" ); |
260 | |
261 | return devm_iio_device_register(&spi->dev, indio_dev); |
262 | } |
263 | |
264 | static const struct spi_device_id maxim_thermocouple_id[] = { |
265 | {"max6675" , MAX6675}, |
266 | {"max31855" , MAX31855}, |
267 | {"max31855k" , MAX31855K}, |
268 | {"max31855j" , MAX31855J}, |
269 | {"max31855n" , MAX31855N}, |
270 | {"max31855s" , MAX31855S}, |
271 | {"max31855t" , MAX31855T}, |
272 | {"max31855e" , MAX31855E}, |
273 | {"max31855r" , MAX31855R}, |
274 | {}, |
275 | }; |
276 | MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id); |
277 | |
278 | static const struct of_device_id maxim_thermocouple_of_match[] = { |
279 | { .compatible = "maxim,max6675" }, |
280 | { .compatible = "maxim,max31855" }, |
281 | { .compatible = "maxim,max31855k" }, |
282 | { .compatible = "maxim,max31855j" }, |
283 | { .compatible = "maxim,max31855n" }, |
284 | { .compatible = "maxim,max31855s" }, |
285 | { .compatible = "maxim,max31855t" }, |
286 | { .compatible = "maxim,max31855e" }, |
287 | { .compatible = "maxim,max31855r" }, |
288 | { }, |
289 | }; |
290 | MODULE_DEVICE_TABLE(of, maxim_thermocouple_of_match); |
291 | |
292 | static struct spi_driver maxim_thermocouple_driver = { |
293 | .driver = { |
294 | .name = MAXIM_THERMOCOUPLE_DRV_NAME, |
295 | .of_match_table = maxim_thermocouple_of_match, |
296 | }, |
297 | .probe = maxim_thermocouple_probe, |
298 | .id_table = maxim_thermocouple_id, |
299 | }; |
300 | module_spi_driver(maxim_thermocouple_driver); |
301 | |
302 | MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>" ); |
303 | MODULE_DESCRIPTION("Maxim thermocouple sensors" ); |
304 | MODULE_LICENSE("GPL" ); |
305 | |