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