1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Maxim Integrated MAX5432-MAX5435 digital potentiometer driver
* Copyright (C) 2019 Martin Kaiser <martin@kaiser.cx>
*
* Datasheet:
* https://datasheets.maximintegrated.com/en/ds/MAX5432-MAX5435.pdf
*/
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/limits.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
/* All chip variants have 32 wiper positions. */
#define MAX5432_MAX_POS 31
#define MAX5432_OHM_50K (50 * 1000)
#define MAX5432_OHM_100K (100 * 1000)
/* Update the volatile (currently active) setting. */
#define MAX5432_CMD_VREG 0x11
struct max5432_data {
struct i2c_client *client;
unsigned long ohm;
};
static const struct iio_chan_spec max5432_channels[] = {
{
.type = IIO_RESISTANCE,
.indexed = 1,
.output = 1,
.channel = 0,
.address = MAX5432_CMD_VREG,
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
}
};
static int max5432_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct max5432_data *data = iio_priv(indio_dev);
if (mask != IIO_CHAN_INFO_SCALE)
return -EINVAL;
if (unlikely(data->ohm > INT_MAX))
return -ERANGE;
*val = data->ohm;
*val2 = MAX5432_MAX_POS;
return IIO_VAL_FRACTIONAL;
}
static int max5432_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct max5432_data *data = iio_priv(indio_dev);
u8 data_byte;
if (mask != IIO_CHAN_INFO_RAW)
return -EINVAL;
if (val < 0 || val > MAX5432_MAX_POS)
return -EINVAL;
if (val2 != 0)
return -EINVAL;
/* Wiper position is in bits D7-D3. (D2-D0 are don't care bits.) */
data_byte = val << 3;
return i2c_smbus_write_byte_data(data->client, chan->address,
data_byte);
}
static const struct iio_info max5432_info = {
.read_raw = max5432_read_raw,
.write_raw = max5432_write_raw,
};
static int max5432_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct iio_dev *indio_dev;
struct max5432_data *data;
indio_dev = devm_iio_device_alloc(dev, sizeof(struct max5432_data));
if (!indio_dev)
return -ENOMEM;
i2c_set_clientdata(client, indio_dev);
data = iio_priv(indio_dev);
data->client = client;
data->ohm = (unsigned long)of_device_get_match_data(dev);
indio_dev->dev.parent = dev;
indio_dev->info = &max5432_info;
indio_dev->channels = max5432_channels;
indio_dev->num_channels = ARRAY_SIZE(max5432_channels);
indio_dev->name = client->name;
return devm_iio_device_register(dev, indio_dev);
}
static const struct of_device_id max5432_dt_ids[] = {
{ .compatible = "maxim,max5432", .data = (void *)MAX5432_OHM_50K },
{ .compatible = "maxim,max5433", .data = (void *)MAX5432_OHM_100K },
{ .compatible = "maxim,max5434", .data = (void *)MAX5432_OHM_50K },
{ .compatible = "maxim,max5435", .data = (void *)MAX5432_OHM_100K },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, max5432_dt_ids);
static struct i2c_driver max5432_driver = {
.driver = {
.name = "max5432",
.of_match_table = of_match_ptr(max5432_dt_ids),
},
.probe = max5432_probe,
};
module_i2c_driver(max5432_driver);
MODULE_AUTHOR("Martin Kaiser <martin@kaiser.cx>");
MODULE_DESCRIPTION("max5432-max5435 digital potentiometers");
MODULE_LICENSE("GPL v2");
|
