t5403.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * t5403.c - Support for EPCOS T5403 pressure/temperature sensor
  4 *
  5 * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
  6 *
  7 * (7-bit I2C slave address 0x77)
  8 *
  9 * TODO: end-of-conversion irq
 10 */
 11
 12#include <linux/module.h>
 13#include <linux/i2c.h>
 14#include <linux/iio/iio.h>
 15#include <linux/iio/sysfs.h>
 16#include <linux/delay.h>
 17
 18#define T5403_DATA 0xf5 /* data, LSB first, 16 bit */
 19#define T5403_CALIB_DATA 0x8e /* 10 calibration coeff., LSB first, 16 bit */
 20#define T5403_SLAVE_ADDR 0x88 /* I2C slave address, 0x77 */
 21#define T5403_COMMAND 0xf1
 22
 23/* command bits */
 24#define T5403_MODE_SHIFT 3 /* conversion time: 2, 8, 16, 66 ms */
 25#define T5403_PT BIT(1) /* 0 .. pressure, 1 .. temperature measurement */
 26#define T5403_SCO BIT(0) /* start conversion */
 27
 28#define T5403_MODE_LOW 0
 29#define T5403_MODE_STANDARD 1
 30#define T5403_MODE_HIGH 2
 31#define T5403_MODE_ULTRA_HIGH 3
 32
 33#define T5403_I2C_MASK (~BIT(7))
 34#define T5403_I2C_ADDR 0x77
 35
 36static const int t5403_pressure_conv_ms[] = {2, 8, 16, 66};
 37
 38struct t5403_data {
 39	struct i2c_client *client;
 40	struct mutex lock;
 41	int mode;
 42	__le16 c[10];
 43};
 44
 45#define T5403_C_U16(i) le16_to_cpu(data->c[(i) - 1])
 46#define T5403_C(i) sign_extend32(T5403_C_U16(i), 15)
 47
 48static int t5403_read(struct t5403_data *data, bool pressure)
 49{
 50	int wait_time = 3;  /* wakeup time in ms */
 51
 52	int ret = i2c_smbus_write_byte_data(data->client, T5403_COMMAND,
 53		(pressure ? (data->mode << T5403_MODE_SHIFT) : T5403_PT) |
 54		T5403_SCO);
 55	if (ret < 0)
 56		return ret;
 57
 58	wait_time += pressure ? t5403_pressure_conv_ms[data->mode] : 2;
 59
 60	msleep(wait_time);
 61
 62	return i2c_smbus_read_word_data(data->client, T5403_DATA);
 63}
 64
 65static int t5403_comp_pressure(struct t5403_data *data, int *val, int *val2)
 66{
 67	int ret;
 68	s16 t_r;
 69	u16 p_r;
 70	s32 S, O, X;
 71
 72	mutex_lock(&data->lock);
 73
 74	ret = t5403_read(data, false);
 75	if (ret < 0)
 76		goto done;
 77	t_r = ret;
 78
 79	ret = t5403_read(data, true);
 80	if (ret < 0)
 81		goto done;
 82	p_r = ret;
 83
 84	/* see EPCOS application note */
 85	S = T5403_C_U16(3) + (s32) T5403_C_U16(4) * t_r / 0x20000 +
 86		T5403_C(5) * t_r / 0x8000 * t_r / 0x80000 +
 87		T5403_C(9) * t_r / 0x8000 * t_r / 0x8000 * t_r / 0x10000;
 88
 89	O = T5403_C(6) * 0x4000 + T5403_C(7) * t_r / 8 +
 90		T5403_C(8) * t_r / 0x8000 * t_r / 16 +
 91		T5403_C(9) * t_r / 0x8000 * t_r / 0x10000 * t_r;
 92
 93	X = (S * p_r + O) / 0x4000;
 94
 95	X += ((X - 75000) * (X - 75000) / 0x10000 - 9537) *
 96	    T5403_C(10) / 0x10000;
 97
 98	*val = X / 1000;
 99	*val2 = (X % 1000) * 1000;
100
101done:
102	mutex_unlock(&data->lock);
103	return ret;
104}
105
106static int t5403_comp_temp(struct t5403_data *data, int *val)
107{
108	int ret;
109	s16 t_r;
110
111	mutex_lock(&data->lock);
112	ret = t5403_read(data, false);
113	if (ret < 0)
114		goto done;
115	t_r = ret;
116
117	/* see EPCOS application note */
118	*val = ((s32) T5403_C_U16(1) * t_r / 0x100 +
119		(s32) T5403_C_U16(2) * 0x40) * 1000 / 0x10000;
120
121done:
122	mutex_unlock(&data->lock);
123	return ret;
124}
125
126static int t5403_read_raw(struct iio_dev *indio_dev,
127			  struct iio_chan_spec const *chan,
128			  int *val, int *val2, long mask)
129{
130	struct t5403_data *data = iio_priv(indio_dev);
131	int ret;
132
133	switch (mask) {
134	case IIO_CHAN_INFO_PROCESSED:
135		switch (chan->type) {
136		case IIO_PRESSURE:
137			ret = t5403_comp_pressure(data, val, val2);
138			if (ret < 0)
139				return ret;
140			return IIO_VAL_INT_PLUS_MICRO;
141		case IIO_TEMP:
142			ret = t5403_comp_temp(data, val);
143			if (ret < 0)
144				return ret;
145			return IIO_VAL_INT;
146		default:
147			return -EINVAL;
148	    }
149	case IIO_CHAN_INFO_INT_TIME:
150		*val = 0;
151		*val2 = t5403_pressure_conv_ms[data->mode] * 1000;
152		return IIO_VAL_INT_PLUS_MICRO;
153	default:
154		return -EINVAL;
155	}
156}
157
158static int t5403_write_raw(struct iio_dev *indio_dev,
159			   struct iio_chan_spec const *chan,
160			   int val, int val2, long mask)
161{
162	struct t5403_data *data = iio_priv(indio_dev);
163	int i;
164
165	switch (mask) {
166	case IIO_CHAN_INFO_INT_TIME:
167		if (val != 0)
168			return -EINVAL;
169		for (i = 0; i < ARRAY_SIZE(t5403_pressure_conv_ms); i++)
170			if (val2 == t5403_pressure_conv_ms[i] * 1000) {
171				mutex_lock(&data->lock);
172				data->mode = i;
173				mutex_unlock(&data->lock);
174				return 0;
175			}
176		return -EINVAL;
177	default:
178		return -EINVAL;
179	}
180}
181
182static const struct iio_chan_spec t5403_channels[] = {
183	{
184		.type = IIO_PRESSURE,
185		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
186		    BIT(IIO_CHAN_INFO_INT_TIME),
187	},
188	{
189		.type = IIO_TEMP,
190		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
191	},
192};
193
194static IIO_CONST_ATTR_INT_TIME_AVAIL("0.002 0.008 0.016 0.066");
195
196static struct attribute *t5403_attributes[] = {
197	&iio_const_attr_integration_time_available.dev_attr.attr,
198	NULL
199};
200
201static const struct attribute_group t5403_attribute_group = {
202	.attrs = t5403_attributes,
203};
204
205static const struct iio_info t5403_info = {
206	.read_raw = &t5403_read_raw,
207	.write_raw = &t5403_write_raw,
208	.attrs = &t5403_attribute_group,
209};
210
211static int t5403_probe(struct i2c_client *client)
212{
213	const struct i2c_device_id *id = i2c_client_get_device_id(client);
214	struct t5403_data *data;
215	struct iio_dev *indio_dev;
216	int ret;
217
218	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA |
219	    I2C_FUNC_SMBUS_I2C_BLOCK))
220		return -EOPNOTSUPP;
221
222	ret = i2c_smbus_read_byte_data(client, T5403_SLAVE_ADDR);
223	if (ret < 0)
224		return ret;
225	if ((ret & T5403_I2C_MASK) != T5403_I2C_ADDR)
226		return -ENODEV;
227
228	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
229	if (!indio_dev)
230		return -ENOMEM;
231
232	data = iio_priv(indio_dev);
233	data->client = client;
234	mutex_init(&data->lock);
235
236	i2c_set_clientdata(client, indio_dev);
237	indio_dev->info = &t5403_info;
238	indio_dev->name = id->name;
239	indio_dev->modes = INDIO_DIRECT_MODE;
240	indio_dev->channels = t5403_channels;
241	indio_dev->num_channels = ARRAY_SIZE(t5403_channels);
242
243	data->mode = T5403_MODE_STANDARD;
244
245	ret = i2c_smbus_read_i2c_block_data(data->client, T5403_CALIB_DATA,
246	    sizeof(data->c), (u8 *) data->c);
247	if (ret < 0)
248		return ret;
249
250	return devm_iio_device_register(&client->dev, indio_dev);
251}
252
253static const struct i2c_device_id t5403_id[] = {
254	{ "t5403" },
255	{ }
256};
257MODULE_DEVICE_TABLE(i2c, t5403_id);
258
259static struct i2c_driver t5403_driver = {
260	.driver = {
261		.name	= "t5403",
262	},
263	.probe = t5403_probe,
264	.id_table = t5403_id,
265};
266module_i2c_driver(t5403_driver);
267
268MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
269MODULE_DESCRIPTION("EPCOS T5403 pressure/temperature sensor driver");
270MODULE_LICENSE("GPL");