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9#include <linux/module.h>
10#include <linux/init.h>
11#include <linux/mutex.h>
12#include <linux/err.h>
13#include <linux/of.h>
14#include <linux/of_device.h>
15#include <linux/spi/spi.h>
16#include <linux/iio/iio.h>
17#include <linux/iio/sysfs.h>
18#include <linux/iio/trigger.h>
19#include <linux/iio/buffer.h>
20#include <linux/iio/triggered_buffer.h>
21#include <linux/iio/trigger_consumer.h>
22
23#define MAXIM_THERMOCOUPLE_DRV_NAME "maxim_thermocouple"
24
25enum {
26 MAX6675,
27 MAX31855,
28 MAX31855K,
29 MAX31855J,
30 MAX31855N,
31 MAX31855S,
32 MAX31855T,
33 MAX31855E,
34 MAX31855R,
35};
36
37static const char maxim_tc_types[] = {
38 'K', '?', 'K', 'J', 'N', 'S', 'T', 'E', 'R'
39};
40
41static const struct iio_chan_spec max6675_channels[] = {
42 {
43 .type = IIO_TEMP,
44 .info_mask_separate =
45 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
46 BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
47 .scan_index = 0,
48 .scan_type = {
49 .sign = 's',
50 .realbits = 13,
51 .storagebits = 16,
52 .shift = 3,
53 .endianness = IIO_BE,
54 },
55 },
56 IIO_CHAN_SOFT_TIMESTAMP(1),
57};
58
59static const struct iio_chan_spec max31855_channels[] = {
60 {
61 .type = IIO_TEMP,
62 .address = 2,
63 .info_mask_separate =
64 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
65 BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
66 .scan_index = 0,
67 .scan_type = {
68 .sign = 's',
69 .realbits = 14,
70 .storagebits = 16,
71 .shift = 2,
72 .endianness = IIO_BE,
73 },
74 },
75 {
76 .type = IIO_TEMP,
77 .address = 0,
78 .channel2 = IIO_MOD_TEMP_AMBIENT,
79 .modified = 1,
80 .info_mask_separate =
81 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
82 .scan_index = 1,
83 .scan_type = {
84 .sign = 's',
85 .realbits = 12,
86 .storagebits = 16,
87 .shift = 4,
88 .endianness = IIO_BE,
89 },
90 },
91 IIO_CHAN_SOFT_TIMESTAMP(2),
92};
93
94static const unsigned long max31855_scan_masks[] = {0x3, 0};
95
96struct maxim_thermocouple_chip {
97 const struct iio_chan_spec *channels;
98 const unsigned long *scan_masks;
99 u8 num_channels;
100 u8 read_size;
101
102
103 u32 status_bit;
104};
105
106static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
107 [MAX6675] = {
108 .channels = max6675_channels,
109 .num_channels = ARRAY_SIZE(max6675_channels),
110 .read_size = 2,
111 .status_bit = BIT(2),
112 },
113 [MAX31855] = {
114 .channels = max31855_channels,
115 .num_channels = ARRAY_SIZE(max31855_channels),
116 .read_size = 4,
117 .scan_masks = max31855_scan_masks,
118 .status_bit = BIT(16),
119 },
120};
121
122struct maxim_thermocouple_data {
123 struct spi_device *spi;
124 const struct maxim_thermocouple_chip *chip;
125
126 u8 buffer[16] ____cacheline_aligned;
127 char tc_type;
128};
129
130static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,
131 struct iio_chan_spec const *chan, int *val)
132{
133 unsigned int storage_bytes = data->chip->read_size;
134 unsigned int shift = chan->scan_type.shift + (chan->address * 8);
135 __be16 buf16;
136 __be32 buf32;
137 int ret;
138
139 switch (storage_bytes) {
140 case 2:
141 ret = spi_read(data->spi, (void *)&buf16, storage_bytes);
142 *val = be16_to_cpu(buf16);
143 break;
144 case 4:
145 ret = spi_read(data->spi, (void *)&buf32, storage_bytes);
146 *val = be32_to_cpu(buf32);
147 break;
148 default:
149 ret = -EINVAL;
150 }
151
152 if (ret)
153 return ret;
154
155
156 if (*val & data->chip->status_bit)
157 return -EINVAL;
158
159 *val = sign_extend32(*val >> shift, chan->scan_type.realbits - 1);
160
161 return 0;
162}
163
164static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private)
165{
166 struct iio_poll_func *pf = private;
167 struct iio_dev *indio_dev = pf->indio_dev;
168 struct maxim_thermocouple_data *data = iio_priv(indio_dev);
169 int ret;
170
171 ret = spi_read(data->spi, data->buffer, data->chip->read_size);
172 if (!ret) {
173 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
174 iio_get_time_ns(indio_dev));
175 }
176
177 iio_trigger_notify_done(indio_dev->trig);
178
179 return IRQ_HANDLED;
180}
181
182static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev,
183 struct iio_chan_spec const *chan,
184 int *val, int *val2, long mask)
185{
186 struct maxim_thermocouple_data *data = iio_priv(indio_dev);
187 int ret = -EINVAL;
188
189 switch (mask) {
190 case IIO_CHAN_INFO_RAW:
191 ret = iio_device_claim_direct_mode(indio_dev);
192 if (ret)
193 return ret;
194
195 ret = maxim_thermocouple_read(data, chan, val);
196 iio_device_release_direct_mode(indio_dev);
197
198 if (!ret)
199 return IIO_VAL_INT;
200
201 break;
202 case IIO_CHAN_INFO_SCALE:
203 switch (chan->channel2) {
204 case IIO_MOD_TEMP_AMBIENT:
205 *val = 62;
206 *val2 = 500000;
207 ret = IIO_VAL_INT_PLUS_MICRO;
208 break;
209 default:
210 *val = 250;
211 ret = IIO_VAL_INT;
212 }
213 break;
214 case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
215 *val = data->tc_type;
216 ret = IIO_VAL_CHAR;
217 break;
218 }
219
220 return ret;
221}
222
223static const struct iio_info maxim_thermocouple_info = {
224 .read_raw = maxim_thermocouple_read_raw,
225};
226
227static int maxim_thermocouple_probe(struct spi_device *spi)
228{
229 const struct spi_device_id *id = spi_get_device_id(spi);
230 struct iio_dev *indio_dev;
231 struct maxim_thermocouple_data *data;
232 const int chip_type = (id->driver_data == MAX6675) ? MAX6675 : MAX31855;
233 const struct maxim_thermocouple_chip *chip =
234 &maxim_thermocouple_chips[chip_type];
235 int ret;
236
237 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
238 if (!indio_dev)
239 return -ENOMEM;
240
241 indio_dev->info = &maxim_thermocouple_info;
242 indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME;
243 indio_dev->channels = chip->channels;
244 indio_dev->available_scan_masks = chip->scan_masks;
245 indio_dev->num_channels = chip->num_channels;
246 indio_dev->modes = INDIO_DIRECT_MODE;
247
248 data = iio_priv(indio_dev);
249 data->spi = spi;
250 data->chip = chip;
251 data->tc_type = maxim_tc_types[id->driver_data];
252
253 ret = devm_iio_triggered_buffer_setup(&spi->dev,
254 indio_dev, NULL,
255 maxim_thermocouple_trigger_handler, NULL);
256 if (ret)
257 return ret;
258
259 if (id->driver_data == MAX31855)
260 dev_warn(&spi->dev, "generic max31855 ID is deprecated\nplease use more specific part type");
261
262 return devm_iio_device_register(&spi->dev, indio_dev);
263}
264
265static const struct spi_device_id maxim_thermocouple_id[] = {
266 {"max6675", MAX6675},
267 {"max31855", MAX31855},
268 {"max31855k", MAX31855K},
269 {"max31855j", MAX31855J},
270 {"max31855n", MAX31855N},
271 {"max31855s", MAX31855S},
272 {"max31855t", MAX31855T},
273 {"max31855e", MAX31855E},
274 {"max31855r", MAX31855R},
275 {},
276};
277MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id);
278
279static const struct of_device_id maxim_thermocouple_of_match[] = {
280 { .compatible = "maxim,max6675" },
281 { .compatible = "maxim,max31855" },
282 { .compatible = "maxim,max31855k" },
283 { .compatible = "maxim,max31855j" },
284 { .compatible = "maxim,max31855n" },
285 { .compatible = "maxim,max31855s" },
286 { .compatible = "maxim,max31855t" },
287 { .compatible = "maxim,max31855e" },
288 { .compatible = "maxim,max31855r" },
289 { },
290};
291MODULE_DEVICE_TABLE(of, maxim_thermocouple_of_match);
292
293static struct spi_driver maxim_thermocouple_driver = {
294 .driver = {
295 .name = MAXIM_THERMOCOUPLE_DRV_NAME,
296 .of_match_table = maxim_thermocouple_of_match,
297 },
298 .probe = maxim_thermocouple_probe,
299 .id_table = maxim_thermocouple_id,
300};
301module_spi_driver(maxim_thermocouple_driver);
302
303MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
304MODULE_DESCRIPTION("Maxim thermocouple sensors");
305MODULE_LICENSE("GPL");
306
