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17#include <linux/module.h>
18#include <linux/init.h>
19#include <linux/mutex.h>
20#include <linux/err.h>
21#include <linux/spi/spi.h>
22#include <linux/iio/iio.h>
23#include <linux/iio/trigger.h>
24#include <linux/iio/buffer.h>
25#include <linux/iio/triggered_buffer.h>
26#include <linux/iio/trigger_consumer.h>
27
28#define MAXIM_THERMOCOUPLE_DRV_NAME "maxim_thermocouple"
29
30enum {
31 MAX6675,
32 MAX31855,
33};
34
35static const struct iio_chan_spec max6675_channels[] = {
36 {
37 .type = IIO_TEMP,
38 .info_mask_separate =
39 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
40 .scan_index = 0,
41 .scan_type = {
42 .sign = 's',
43 .realbits = 13,
44 .storagebits = 16,
45 .shift = 3,
46 .endianness = IIO_BE,
47 },
48 },
49 IIO_CHAN_SOFT_TIMESTAMP(1),
50};
51
52static const struct iio_chan_spec max31855_channels[] = {
53 {
54 .type = IIO_TEMP,
55 .address = 2,
56 .info_mask_separate =
57 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
58 .scan_index = 0,
59 .scan_type = {
60 .sign = 's',
61 .realbits = 14,
62 .storagebits = 16,
63 .shift = 2,
64 .endianness = IIO_BE,
65 },
66 },
67 {
68 .type = IIO_TEMP,
69 .address = 0,
70 .channel2 = IIO_MOD_TEMP_AMBIENT,
71 .modified = 1,
72 .info_mask_separate =
73 BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
74 .scan_index = 1,
75 .scan_type = {
76 .sign = 's',
77 .realbits = 12,
78 .storagebits = 16,
79 .shift = 4,
80 .endianness = IIO_BE,
81 },
82 },
83 IIO_CHAN_SOFT_TIMESTAMP(2),
84};
85
86static const unsigned long max31855_scan_masks[] = {0x3, 0};
87
88struct maxim_thermocouple_chip {
89 const struct iio_chan_spec *channels;
90 const unsigned long *scan_masks;
91 u8 num_channels;
92 u8 read_size;
93
94
95 u32 status_bit;
96};
97
98static const struct maxim_thermocouple_chip maxim_thermocouple_chips[] = {
99 [MAX6675] = {
100 .channels = max6675_channels,
101 .num_channels = ARRAY_SIZE(max6675_channels),
102 .read_size = 2,
103 .status_bit = BIT(2),
104 },
105 [MAX31855] = {
106 .channels = max31855_channels,
107 .num_channels = ARRAY_SIZE(max31855_channels),
108 .read_size = 4,
109 .scan_masks = max31855_scan_masks,
110 .status_bit = BIT(16),
111 },
112};
113
114struct maxim_thermocouple_data {
115 struct spi_device *spi;
116 const struct maxim_thermocouple_chip *chip;
117
118 u8 buffer[16] ____cacheline_aligned;
119};
120
121static int maxim_thermocouple_read(struct maxim_thermocouple_data *data,
122 struct iio_chan_spec const *chan, int *val)
123{
124 unsigned int storage_bytes = data->chip->read_size;
125 unsigned int shift = chan->scan_type.shift + (chan->address * 8);
126 __be16 buf16;
127 __be32 buf32;
128 int ret;
129
130 switch (storage_bytes) {
131 case 2:
132 ret = spi_read(data->spi, (void *)&buf16, storage_bytes);
133 *val = be16_to_cpu(buf16);
134 break;
135 case 4:
136 ret = spi_read(data->spi, (void *)&buf32, storage_bytes);
137 *val = be32_to_cpu(buf32);
138 break;
139 default:
140 ret = -EINVAL;
141 }
142
143 if (ret)
144 return ret;
145
146
147 if (*val & data->chip->status_bit)
148 return -EINVAL;
149
150 *val = sign_extend32(*val >> shift, chan->scan_type.realbits - 1);
151
152 return 0;
153}
154
155static irqreturn_t maxim_thermocouple_trigger_handler(int irq, void *private)
156{
157 struct iio_poll_func *pf = private;
158 struct iio_dev *indio_dev = pf->indio_dev;
159 struct maxim_thermocouple_data *data = iio_priv(indio_dev);
160 int ret;
161
162 ret = spi_read(data->spi, data->buffer, data->chip->read_size);
163 if (!ret) {
164 iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
165 iio_get_time_ns(indio_dev));
166 }
167
168 iio_trigger_notify_done(indio_dev->trig);
169
170 return IRQ_HANDLED;
171}
172
173static int maxim_thermocouple_read_raw(struct iio_dev *indio_dev,
174 struct iio_chan_spec const *chan,
175 int *val, int *val2, long mask)
176{
177 struct maxim_thermocouple_data *data = iio_priv(indio_dev);
178 int ret = -EINVAL;
179
180 switch (mask) {
181 case IIO_CHAN_INFO_RAW:
182 ret = iio_device_claim_direct_mode(indio_dev);
183 if (ret)
184 return ret;
185
186 ret = maxim_thermocouple_read(data, chan, val);
187 iio_device_release_direct_mode(indio_dev);
188
189 if (!ret)
190 return IIO_VAL_INT;
191
192 break;
193 case IIO_CHAN_INFO_SCALE:
194 switch (chan->channel2) {
195 case IIO_MOD_TEMP_AMBIENT:
196 *val = 62;
197 *val2 = 500000;
198 ret = IIO_VAL_INT_PLUS_MICRO;
199 break;
200 default:
201 *val = 250;
202 ret = IIO_VAL_INT;
203 };
204 break;
205 }
206
207 return ret;
208}
209
210static const struct iio_info maxim_thermocouple_info = {
211 .driver_module = THIS_MODULE,
212 .read_raw = maxim_thermocouple_read_raw,
213};
214
215static int maxim_thermocouple_probe(struct spi_device *spi)
216{
217 const struct spi_device_id *id = spi_get_device_id(spi);
218 struct iio_dev *indio_dev;
219 struct maxim_thermocouple_data *data;
220 const struct maxim_thermocouple_chip *chip =
221 &maxim_thermocouple_chips[id->driver_data];
222 int ret;
223
224 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
225 if (!indio_dev)
226 return -ENOMEM;
227
228 indio_dev->info = &maxim_thermocouple_info;
229 indio_dev->name = MAXIM_THERMOCOUPLE_DRV_NAME;
230 indio_dev->channels = chip->channels;
231 indio_dev->available_scan_masks = chip->scan_masks;
232 indio_dev->num_channels = chip->num_channels;
233 indio_dev->modes = INDIO_DIRECT_MODE;
234
235 data = iio_priv(indio_dev);
236 data->spi = spi;
237 data->chip = chip;
238
239 ret = iio_triggered_buffer_setup(indio_dev, NULL,
240 maxim_thermocouple_trigger_handler, NULL);
241 if (ret)
242 return ret;
243
244 ret = iio_device_register(indio_dev);
245 if (ret)
246 goto error_unreg_buffer;
247
248 return 0;
249
250error_unreg_buffer:
251 iio_triggered_buffer_cleanup(indio_dev);
252
253 return ret;
254}
255
256static int maxim_thermocouple_remove(struct spi_device *spi)
257{
258 struct iio_dev *indio_dev = spi_get_drvdata(spi);
259
260 iio_device_unregister(indio_dev);
261 iio_triggered_buffer_cleanup(indio_dev);
262
263 return 0;
264}
265
266static const struct spi_device_id maxim_thermocouple_id[] = {
267 {"max6675", MAX6675},
268 {"max31855", MAX31855},
269 {},
270};
271MODULE_DEVICE_TABLE(spi, maxim_thermocouple_id);
272
273static struct spi_driver maxim_thermocouple_driver = {
274 .driver = {
275 .name = MAXIM_THERMOCOUPLE_DRV_NAME,
276 },
277 .probe = maxim_thermocouple_probe,
278 .remove = maxim_thermocouple_remove,
279 .id_table = maxim_thermocouple_id,
280};
281module_spi_driver(maxim_thermocouple_driver);
282
283MODULE_AUTHOR("Matt Ranostay <mranostay@gmail.com>");
284MODULE_DESCRIPTION("Maxim thermocouple sensors");
285MODULE_LICENSE("GPL");
286
