1 /*
2  * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
3  *
4  * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
5  *
6  * This file is subject to the terms and conditions of version 2 of
7  * the GNU General Public License.  See the file COPYING in the main
8  * directory of this archive for more details.
9  *
10  * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
11  *
12  * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
13  *
14  * TODO: sleep mode, configuration EEPROM
15  */
16 
17 #include <linux/err.h>
18 #include <linux/i2c.h>
19 #include <linux/module.h>
20 
21 #include <linux/iio/iio.h>
22 
23 #define MLX90614_OP_RAM 0x00
24 
25 /* RAM offsets with 16-bit data, MSB first */
26 #define MLX90614_TA 0x06 /* ambient temperature */
27 #define MLX90614_TOBJ1 0x07 /* object temperature */
28 
29 struct mlx90614_data {
30 	struct i2c_client *client;
31 };
32 
33 static int mlx90614_read_raw(struct iio_dev *indio_dev,
34 			    struct iio_chan_spec const *channel, int *val,
35 			    int *val2, long mask)
36 {
37 	struct mlx90614_data *data = iio_priv(indio_dev);
38 	s32 ret;
39 
40 	switch (mask) {
41 	case IIO_CHAN_INFO_RAW: /* 0.02K / LSB */
42 		switch (channel->channel2) {
43 		case IIO_MOD_TEMP_AMBIENT:
44 			ret = i2c_smbus_read_word_data(data->client,
45 			    MLX90614_OP_RAM | MLX90614_TA);
46 			if (ret < 0)
47 				return ret;
48 			break;
49 		case IIO_MOD_TEMP_OBJECT:
50 			ret = i2c_smbus_read_word_data(data->client,
51 			    MLX90614_OP_RAM | MLX90614_TOBJ1);
52 			if (ret < 0)
53 				return ret;
54 			break;
55 		default:
56 			return -EINVAL;
57 		}
58 		*val = ret;
59 		return IIO_VAL_INT;
60 	case IIO_CHAN_INFO_OFFSET:
61 		*val = 13657;
62 		*val2 = 500000;
63 		return IIO_VAL_INT_PLUS_MICRO;
64 	case IIO_CHAN_INFO_SCALE:
65 		*val = 20;
66 		return IIO_VAL_INT;
67 	default:
68 		return -EINVAL;
69 	}
70 }
71 
72 static const struct iio_chan_spec mlx90614_channels[] = {
73 	{
74 		.type = IIO_TEMP,
75 		.modified = 1,
76 		.channel2 = IIO_MOD_TEMP_AMBIENT,
77 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
78 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
79 		    BIT(IIO_CHAN_INFO_SCALE),
80 	},
81 	{
82 		.type = IIO_TEMP,
83 		.modified = 1,
84 		.channel2 = IIO_MOD_TEMP_OBJECT,
85 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
86 		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_OFFSET) |
87 		    BIT(IIO_CHAN_INFO_SCALE),
88 	},
89 };
90 
91 static const struct iio_info mlx90614_info = {
92 	.read_raw = mlx90614_read_raw,
93 	.driver_module = THIS_MODULE,
94 };
95 
96 static int mlx90614_probe(struct i2c_client *client,
97 			 const struct i2c_device_id *id)
98 {
99 	struct iio_dev *indio_dev;
100 	struct mlx90614_data *data;
101 
102 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
103 		return -ENODEV;
104 
105 	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
106 	if (!indio_dev)
107 		return -ENOMEM;
108 
109 	data = iio_priv(indio_dev);
110 	i2c_set_clientdata(client, indio_dev);
111 	data->client = client;
112 
113 	indio_dev->dev.parent = &client->dev;
114 	indio_dev->name = id->name;
115 	indio_dev->modes = INDIO_DIRECT_MODE;
116 	indio_dev->info = &mlx90614_info;
117 
118 	indio_dev->channels = mlx90614_channels;
119 	indio_dev->num_channels = ARRAY_SIZE(mlx90614_channels);
120 
121 	return iio_device_register(indio_dev);
122 }
123 
124 static int mlx90614_remove(struct i2c_client *client)
125 {
126 	iio_device_unregister(i2c_get_clientdata(client));
127 
128 	return 0;
129 }
130 
131 static const struct i2c_device_id mlx90614_id[] = {
132 	{ "mlx90614", 0 },
133 	{ }
134 };
135 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
136 
137 static struct i2c_driver mlx90614_driver = {
138 	.driver = {
139 		.name	= "mlx90614",
140 		.owner	= THIS_MODULE,
141 	},
142 	.probe = mlx90614_probe,
143 	.remove = mlx90614_remove,
144 	.id_table = mlx90614_id,
145 };
146 module_i2c_driver(mlx90614_driver);
147 
148 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
149 MODULE_DESCRIPTION("Melexis MLX90614 contactless IR temperature sensor driver");
150 MODULE_LICENSE("GPL");
151