summaryrefslogtreecommitdiff
path: root/drivers/iio/temperature/tsys01.c
blob: 3e60c6189d98b8d30d1f4d4c32186eeae1e62276 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
/*
 * tsys01.c - Support for Measurement-Specialties tsys01 temperature sensor
 *
 * Copyright (c) 2015 Measurement-Specialties
 *
 * Licensed under the GPL-2.
 *
 * Datasheet:
 *  http://www.meas-spec.com/downloads/TSYS01_Digital_Temperature_Sensor.pdf
 */

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/stat.h>
#include "../common/ms_sensors/ms_sensors_i2c.h"

/* TSYS01 Commands */
#define TSYS01_RESET				0x1E
#define TSYS01_CONVERSION_START			0x48
#define TSYS01_ADC_READ				0x00
#define TSYS01_PROM_READ			0xA0

#define TSYS01_PROM_WORDS_NB			8

struct tsys01_dev {
	void *client;
	struct mutex lock; /* lock during conversion */

	int (*reset)(void *cli, u8 cmd, unsigned int delay);
	int (*convert_and_read)(void *cli, u8 conv, u8 rd,
				unsigned int delay, u32 *adc);
	int (*read_prom_word)(void *cli, int cmd, u16 *word);

	u16 prom[TSYS01_PROM_WORDS_NB];
};

/* Multiplication coefficients for temperature computation */
static const int coeff_mul[] = { -1500000, 1000000, -2000000,
				 4000000, -2000000 };

static int tsys01_read_temperature(struct iio_dev *indio_dev,
				   s32 *temperature)
{
	int ret, i;
	u32 adc;
	s64 temp = 0;
	struct tsys01_dev *dev_data = iio_priv(indio_dev);

	mutex_lock(&dev_data->lock);
	ret = dev_data->convert_and_read(dev_data->client,
					 TSYS01_CONVERSION_START,
					 TSYS01_ADC_READ, 9000, &adc);
	mutex_unlock(&dev_data->lock);
	if (ret)
		return ret;

	adc >>= 8;

	/* Temperature algorithm */
	for (i = 4; i > 0; i--) {
		temp += coeff_mul[i] *
			(s64)dev_data->prom[5 - i];
		temp *= (s64)adc;
		temp = div64_s64(temp, 100000);
	}
	temp *= 10;
	temp += coeff_mul[0] * (s64)dev_data->prom[5];
	temp = div64_s64(temp, 100000);

	*temperature = temp;

	return 0;
}

static int tsys01_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *channel, int *val,
			   int *val2, long mask)
{
	int ret;
	s32 temperature;

	switch (mask) {
	case IIO_CHAN_INFO_PROCESSED:
		switch (channel->type) {
		case IIO_TEMP:	/* in milli °C */
			ret = tsys01_read_temperature(indio_dev, &temperature);
			if (ret)
				return ret;
			*val = temperature;

			return IIO_VAL_INT;
		default:
			return -EINVAL;
		}
	default:
		return -EINVAL;
	}
}

static const struct iio_chan_spec tsys01_channels[] = {
	{
		.type = IIO_TEMP,
		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
	}
};

static const struct iio_info tsys01_info = {
	.read_raw = tsys01_read_raw,
	.driver_module = THIS_MODULE,
};

static bool tsys01_crc_valid(u16 *n_prom)
{
	u8 cnt;
	u8 sum = 0;

	for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
		sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));

	return (sum == 0);
}

static int tsys01_read_prom(struct iio_dev *indio_dev)
{
	int i, ret;
	struct tsys01_dev *dev_data = iio_priv(indio_dev);
	char buf[7 * TSYS01_PROM_WORDS_NB + 1];
	char *ptr = buf;

	for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) {
		ret = dev_data->read_prom_word(dev_data->client,
					       TSYS01_PROM_READ + (i << 1),
					       &dev_data->prom[i]);
		if (ret)
			return ret;

		ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]);
		ptr += ret;
	}

	if (!tsys01_crc_valid(dev_data->prom)) {
		dev_err(&indio_dev->dev, "prom crc check error\n");
		return -ENODEV;
	}
	*ptr = 0;
	dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf);

	return 0;
}

static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev)
{
	int ret;
	struct tsys01_dev *dev_data = iio_priv(indio_dev);

	mutex_init(&dev_data->lock);

	indio_dev->info = &tsys01_info;
	indio_dev->name = dev->driver->name;
	indio_dev->dev.parent = dev;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->channels = tsys01_channels;
	indio_dev->num_channels = ARRAY_SIZE(tsys01_channels);

	ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000);
	if (ret)
		return ret;

	ret = tsys01_read_prom(indio_dev);
	if (ret)
		return ret;

	return devm_iio_device_register(dev, indio_dev);
}

static int tsys01_i2c_probe(struct i2c_client *client,
			    const struct i2c_device_id *id)
{
	struct tsys01_dev *dev_data;
	struct iio_dev *indio_dev;

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_WORD_DATA |
				     I2C_FUNC_SMBUS_WRITE_BYTE |
				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
		dev_err(&client->dev,
			"Adapter does not support some i2c transaction\n");
		return -EOPNOTSUPP;
	}

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
	if (!indio_dev)
		return -ENOMEM;

	dev_data = iio_priv(indio_dev);
	dev_data->client = client;
	dev_data->reset = ms_sensors_reset;
	dev_data->read_prom_word = ms_sensors_read_prom_word;
	dev_data->convert_and_read = ms_sensors_convert_and_read;

	i2c_set_clientdata(client, indio_dev);

	return tsys01_probe(indio_dev, &client->dev);
}

static const struct i2c_device_id tsys01_id[] = {
	{"tsys01", 0},
	{}
};
MODULE_DEVICE_TABLE(i2c, tsys01_id);

static struct i2c_driver tsys01_driver = {
	.probe = tsys01_i2c_probe,
	.id_table = tsys01_id,
	.driver = {
		   .name = "tsys01",
		   },
};

module_i2c_driver(tsys01_driver);

MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
MODULE_LICENSE("GPL v2");