1 /*
2  * MS5611 pressure and temperature sensor driver (I2C bus)
3  *
4  * Copyright (c) Tomasz Duszynski <tduszyns@gmail.com>
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  *
10  * 7-bit I2C slave addresses:
11  *
12  * 0x77 (CSB pin low)
13  * 0x76 (CSB pin high)
14  *
15  */
16 
17 #include <linux/delay.h>
18 #include <linux/i2c.h>
19 #include <linux/module.h>
20 
21 #include "ms5611.h"
22 
23 static int ms5611_i2c_reset(struct device *dev)
24 {
25 	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
26 
27 	return i2c_smbus_write_byte(st->client, MS5611_RESET);
28 }
29 
30 static int ms5611_i2c_read_prom_word(struct device *dev, int index, u16 *word)
31 {
32 	int ret;
33 	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
34 
35 	ret = i2c_smbus_read_word_swapped(st->client,
36 			MS5611_READ_PROM_WORD + (index << 1));
37 	if (ret < 0)
38 		return ret;
39 
40 	*word = ret;
41 
42 	return 0;
43 }
44 
45 static int ms5611_i2c_read_adc(struct ms5611_state *st, s32 *val)
46 {
47 	int ret;
48 	u8 buf[3];
49 
50 	ret = i2c_smbus_read_i2c_block_data(st->client, MS5611_READ_ADC,
51 					    3, buf);
52 	if (ret < 0)
53 		return ret;
54 
55 	*val = (buf[0] << 16) | (buf[1] << 8) | buf[2];
56 
57 	return 0;
58 }
59 
60 static int ms5611_i2c_read_adc_temp_and_pressure(struct device *dev,
61 						 s32 *temp, s32 *pressure)
62 {
63 	int ret;
64 	struct ms5611_state *st = iio_priv(dev_to_iio_dev(dev));
65 
66 	ret = i2c_smbus_write_byte(st->client, MS5611_START_TEMP_CONV);
67 	if (ret < 0)
68 		return ret;
69 
70 	usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
71 
72 	ret = ms5611_i2c_read_adc(st, temp);
73 	if (ret < 0)
74 		return ret;
75 
76 	ret = i2c_smbus_write_byte(st->client, MS5611_START_PRESSURE_CONV);
77 	if (ret < 0)
78 		return ret;
79 
80 	usleep_range(MS5611_CONV_TIME_MIN, MS5611_CONV_TIME_MAX);
81 
82 	return ms5611_i2c_read_adc(st, pressure);
83 }
84 
85 static int ms5611_i2c_probe(struct i2c_client *client,
86 			    const struct i2c_device_id *id)
87 {
88 	struct ms5611_state *st;
89 	struct iio_dev *indio_dev;
90 
91 	if (!i2c_check_functionality(client->adapter,
92 				     I2C_FUNC_SMBUS_WRITE_BYTE |
93 				     I2C_FUNC_SMBUS_READ_WORD_DATA |
94 				     I2C_FUNC_SMBUS_READ_I2C_BLOCK))
95 		return -ENODEV;
96 
97 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*st));
98 	if (!indio_dev)
99 		return -ENOMEM;
100 
101 	st = iio_priv(indio_dev);
102 	st->reset = ms5611_i2c_reset;
103 	st->read_prom_word = ms5611_i2c_read_prom_word;
104 	st->read_adc_temp_and_pressure = ms5611_i2c_read_adc_temp_and_pressure;
105 	st->client = client;
106 
107 	return ms5611_probe(indio_dev, &client->dev, id->driver_data);
108 }
109 
110 static const struct i2c_device_id ms5611_id[] = {
111 	{ "ms5611", MS5611 },
112 	{ "ms5607", MS5607 },
113 	{ }
114 };
115 MODULE_DEVICE_TABLE(i2c, ms5611_id);
116 
117 static struct i2c_driver ms5611_driver = {
118 	.driver = {
119 		.name = "ms5611",
120 	},
121 	.id_table = ms5611_id,
122 	.probe = ms5611_i2c_probe,
123 };
124 module_i2c_driver(ms5611_driver);
125 
126 MODULE_AUTHOR("Tomasz Duszynski <tduszyns@gmail.com>");
127 MODULE_DESCRIPTION("MS5611 i2c driver");
128 MODULE_LICENSE("GPL v2");
129