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
 30struct 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 */
 43static const int coeff_mul[] = { -1500000, 1000000, -2000000,
 44				 4000000, -2000000 };
 45
 46static 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
 80static 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
105static 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
112static const struct iio_info tsys01_info = {
113	.read_raw = tsys01_read_raw,
114};
115
116static 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
127static 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
155static 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
179static 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
208static const struct i2c_device_id tsys01_id[] = {
209	{"tsys01", 0},
210	{}
211};
212MODULE_DEVICE_TABLE(i2c, tsys01_id);
213
214static const struct of_device_id tsys01_of_match[] = {
215	{ .compatible = "meas,tsys01", },
216	{ },
217};
218MODULE_DEVICE_TABLE(of, tsys01_of_match);
219
220static 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
229module_i2c_driver(tsys01_driver);
230
231MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
232MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
233MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
234MODULE_LICENSE("GPL v2");
235MODULE_IMPORT_NS(IIO_MEAS_SPEC_SENSORS);