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