xref: /openbmc/linux/drivers/iio/adc/ti-adc081c.c (revision 275876e2)
1 /*
2  * Copyright (C) 2012 Avionic Design GmbH
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8 
9 #include <linux/err.h>
10 #include <linux/i2c.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 
14 #include <linux/iio/iio.h>
15 #include <linux/regulator/consumer.h>
16 
17 struct adc081c {
18 	struct i2c_client *i2c;
19 	struct regulator *ref;
20 };
21 
22 #define REG_CONV_RES 0x00
23 
24 static int adc081c_read_raw(struct iio_dev *iio,
25 			    struct iio_chan_spec const *channel, int *value,
26 			    int *shift, long mask)
27 {
28 	struct adc081c *adc = iio_priv(iio);
29 	int err;
30 
31 	switch (mask) {
32 	case IIO_CHAN_INFO_RAW:
33 		err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
34 		if (err < 0)
35 			return err;
36 
37 		*value = (err >> 4) & 0xff;
38 		return IIO_VAL_INT;
39 
40 	case IIO_CHAN_INFO_SCALE:
41 		err = regulator_get_voltage(adc->ref);
42 		if (err < 0)
43 			return err;
44 
45 		*value = err / 1000;
46 		*shift = 8;
47 
48 		return IIO_VAL_FRACTIONAL_LOG2;
49 
50 	default:
51 		break;
52 	}
53 
54 	return -EINVAL;
55 }
56 
57 static const struct iio_chan_spec adc081c_channel = {
58 	.type = IIO_VOLTAGE,
59 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
60 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
61 };
62 
63 static const struct iio_info adc081c_info = {
64 	.read_raw = adc081c_read_raw,
65 	.driver_module = THIS_MODULE,
66 };
67 
68 static int adc081c_probe(struct i2c_client *client,
69 			 const struct i2c_device_id *id)
70 {
71 	struct iio_dev *iio;
72 	struct adc081c *adc;
73 	int err;
74 
75 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
76 		return -ENODEV;
77 
78 	iio = devm_iio_device_alloc(&client->dev, sizeof(*adc));
79 	if (!iio)
80 		return -ENOMEM;
81 
82 	adc = iio_priv(iio);
83 	adc->i2c = client;
84 
85 	adc->ref = devm_regulator_get(&client->dev, "vref");
86 	if (IS_ERR(adc->ref))
87 		return PTR_ERR(adc->ref);
88 
89 	err = regulator_enable(adc->ref);
90 	if (err < 0)
91 		return err;
92 
93 	iio->dev.parent = &client->dev;
94 	iio->name = dev_name(&client->dev);
95 	iio->modes = INDIO_DIRECT_MODE;
96 	iio->info = &adc081c_info;
97 
98 	iio->channels = &adc081c_channel;
99 	iio->num_channels = 1;
100 
101 	err = iio_device_register(iio);
102 	if (err < 0)
103 		goto regulator_disable;
104 
105 	i2c_set_clientdata(client, iio);
106 
107 	return 0;
108 
109 regulator_disable:
110 	regulator_disable(adc->ref);
111 
112 	return err;
113 }
114 
115 static int adc081c_remove(struct i2c_client *client)
116 {
117 	struct iio_dev *iio = i2c_get_clientdata(client);
118 	struct adc081c *adc = iio_priv(iio);
119 
120 	iio_device_unregister(iio);
121 	regulator_disable(adc->ref);
122 
123 	return 0;
124 }
125 
126 static const struct i2c_device_id adc081c_id[] = {
127 	{ "adc081c", 0 },
128 	{ }
129 };
130 MODULE_DEVICE_TABLE(i2c, adc081c_id);
131 
132 #ifdef CONFIG_OF
133 static const struct of_device_id adc081c_of_match[] = {
134 	{ .compatible = "ti,adc081c" },
135 	{ }
136 };
137 MODULE_DEVICE_TABLE(of, adc081c_of_match);
138 #endif
139 
140 static struct i2c_driver adc081c_driver = {
141 	.driver = {
142 		.name = "adc081c",
143 		.owner = THIS_MODULE,
144 		.of_match_table = of_match_ptr(adc081c_of_match),
145 	},
146 	.probe = adc081c_probe,
147 	.remove = adc081c_remove,
148 	.id_table = adc081c_id,
149 };
150 module_i2c_driver(adc081c_driver);
151 
152 MODULE_AUTHOR("Thierry Reding <thierry.reding@avionic-design.de>");
153 MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
154 MODULE_LICENSE("GPL v2");
155