xref: /openbmc/linux/drivers/iio/temperature/tsys01.c (revision 7cf15f42)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * tsys01.c - Support for Measurement-Specialties tsys01 temperature sensor
4  *
5  * Copyright (c) 2015 Measurement-Specialties
6  *
7  * Datasheet:
8  *  http://www.meas-spec.com/downloads/TSYS01_Digital_Temperature_Sensor.pdf
9  */
10 
11 #include <linux/iio/iio.h>
12 #include <linux/iio/sysfs.h>
13 #include <linux/device.h>
14 #include <linux/mutex.h>
15 #include <linux/module.h>
16 #include <linux/mod_devicetable.h>
17 #include <linux/init.h>
18 #include <linux/kernel.h>
19 #include <linux/stat.h>
20 #include "../common/ms_sensors/ms_sensors_i2c.h"
21 
22 /* TSYS01 Commands */
23 #define TSYS01_RESET				0x1E
24 #define TSYS01_CONVERSION_START			0x48
25 #define TSYS01_ADC_READ				0x00
26 #define TSYS01_PROM_READ			0xA0
27 
28 #define TSYS01_PROM_WORDS_NB			8
29 
30 struct tsys01_dev {
31 	void *client;
32 	struct mutex lock; /* lock during conversion */
33 
34 	int (*reset)(void *cli, u8 cmd, unsigned int delay);
35 	int (*convert_and_read)(void *cli, u8 conv, u8 rd,
36 				unsigned int delay, u32 *adc);
37 	int (*read_prom_word)(void *cli, int cmd, u16 *word);
38 
39 	u16 prom[TSYS01_PROM_WORDS_NB];
40 };
41 
42 /* Multiplication coefficients for temperature computation */
43 static const int coeff_mul[] = { -1500000, 1000000, -2000000,
44 				 4000000, -2000000 };
45 
tsys01_read_temperature(struct iio_dev * indio_dev,s32 * temperature)46 static int tsys01_read_temperature(struct iio_dev *indio_dev,
47 				   s32 *temperature)
48 {
49 	int ret, i;
50 	u32 adc;
51 	s64 temp = 0;
52 	struct tsys01_dev *dev_data = iio_priv(indio_dev);
53 
54 	mutex_lock(&dev_data->lock);
55 	ret = dev_data->convert_and_read(dev_data->client,
56 					 TSYS01_CONVERSION_START,
57 					 TSYS01_ADC_READ, 9000, &adc);
58 	mutex_unlock(&dev_data->lock);
59 	if (ret)
60 		return ret;
61 
62 	adc >>= 8;
63 
64 	/* Temperature algorithm */
65 	for (i = 4; i > 0; i--) {
66 		temp += coeff_mul[i] *
67 			(s64)dev_data->prom[5 - i];
68 		temp *= (s64)adc;
69 		temp = div64_s64(temp, 100000);
70 	}
71 	temp *= 10;
72 	temp += coeff_mul[0] * (s64)dev_data->prom[5];
73 	temp = div64_s64(temp, 100000);
74 
75 	*temperature = temp;
76 
77 	return 0;
78 }
79 
tsys01_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * channel,int * val,int * val2,long mask)80 static int tsys01_read_raw(struct iio_dev *indio_dev,
81 			   struct iio_chan_spec const *channel, int *val,
82 			   int *val2, long mask)
83 {
84 	int ret;
85 	s32 temperature;
86 
87 	switch (mask) {
88 	case IIO_CHAN_INFO_PROCESSED:
89 		switch (channel->type) {
90 		case IIO_TEMP:	/* in milli °C */
91 			ret = tsys01_read_temperature(indio_dev, &temperature);
92 			if (ret)
93 				return ret;
94 			*val = temperature;
95 
96 			return IIO_VAL_INT;
97 		default:
98 			return -EINVAL;
99 		}
100 	default:
101 		return -EINVAL;
102 	}
103 }
104 
105 static const struct iio_chan_spec tsys01_channels[] = {
106 	{
107 		.type = IIO_TEMP,
108 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
109 	}
110 };
111 
112 static const struct iio_info tsys01_info = {
113 	.read_raw = tsys01_read_raw,
114 };
115 
tsys01_crc_valid(u16 * n_prom)116 static bool tsys01_crc_valid(u16 *n_prom)
117 {
118 	u8 cnt;
119 	u8 sum = 0;
120 
121 	for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
122 		sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));
123 
124 	return (sum == 0);
125 }
126 
tsys01_read_prom(struct iio_dev * indio_dev)127 static int tsys01_read_prom(struct iio_dev *indio_dev)
128 {
129 	int i, ret;
130 	struct tsys01_dev *dev_data = iio_priv(indio_dev);
131 	char buf[7 * TSYS01_PROM_WORDS_NB + 1];
132 	char *ptr = buf;
133 
134 	for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) {
135 		ret = dev_data->read_prom_word(dev_data->client,
136 					       TSYS01_PROM_READ + (i << 1),
137 					       &dev_data->prom[i]);
138 		if (ret)
139 			return ret;
140 
141 		ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]);
142 		ptr += ret;
143 	}
144 
145 	if (!tsys01_crc_valid(dev_data->prom)) {
146 		dev_err(&indio_dev->dev, "prom crc check error\n");
147 		return -ENODEV;
148 	}
149 	*ptr = 0;
150 	dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf);
151 
152 	return 0;
153 }
154 
tsys01_probe(struct iio_dev * indio_dev,struct device * dev)155 static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev)
156 {
157 	int ret;
158 	struct tsys01_dev *dev_data = iio_priv(indio_dev);
159 
160 	mutex_init(&dev_data->lock);
161 
162 	indio_dev->info = &tsys01_info;
163 	indio_dev->name = dev->driver->name;
164 	indio_dev->modes = INDIO_DIRECT_MODE;
165 	indio_dev->channels = tsys01_channels;
166 	indio_dev->num_channels = ARRAY_SIZE(tsys01_channels);
167 
168 	ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000);
169 	if (ret)
170 		return ret;
171 
172 	ret = tsys01_read_prom(indio_dev);
173 	if (ret)
174 		return ret;
175 
176 	return devm_iio_device_register(dev, indio_dev);
177 }
178 
tsys01_i2c_probe(struct i2c_client * client)179 static int tsys01_i2c_probe(struct i2c_client *client)
180 {
181 	struct tsys01_dev *dev_data;
182 	struct iio_dev *indio_dev;
183 
184 	if (!i2c_check_functionality(client->adapter,
185 				     I2C_FUNC_SMBUS_WORD_DATA |
186 				     I2C_FUNC_SMBUS_WRITE_BYTE |
187 				     I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
188 		dev_err(&client->dev,
189 			"Adapter does not support some i2c transaction\n");
190 		return -EOPNOTSUPP;
191 	}
192 
193 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
194 	if (!indio_dev)
195 		return -ENOMEM;
196 
197 	dev_data = iio_priv(indio_dev);
198 	dev_data->client = client;
199 	dev_data->reset = ms_sensors_reset;
200 	dev_data->read_prom_word = ms_sensors_read_prom_word;
201 	dev_data->convert_and_read = ms_sensors_convert_and_read;
202 
203 	i2c_set_clientdata(client, indio_dev);
204 
205 	return tsys01_probe(indio_dev, &client->dev);
206 }
207 
208 static const struct i2c_device_id tsys01_id[] = {
209 	{"tsys01", 0},
210 	{}
211 };
212 MODULE_DEVICE_TABLE(i2c, tsys01_id);
213 
214 static const struct of_device_id tsys01_of_match[] = {
215 	{ .compatible = "meas,tsys01", },
216 	{ },
217 };
218 MODULE_DEVICE_TABLE(of, tsys01_of_match);
219 
220 static struct i2c_driver tsys01_driver = {
221 	.probe = tsys01_i2c_probe,
222 	.id_table = tsys01_id,
223 	.driver = {
224 		   .name = "tsys01",
225 		   .of_match_table = tsys01_of_match,
226 		   },
227 };
228 
229 module_i2c_driver(tsys01_driver);
230 
231 MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
232 MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
233 MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
234 MODULE_LICENSE("GPL v2");
235 MODULE_IMPORT_NS(IIO_MEAS_SPEC_SENSORS);
236