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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
/*
* mcp4725.c - Support for Microchip MCP4725
*
* Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
*
* Based on max517 by Roland Stigge <stigge@antcom.de>
*
* This file is subject to the terms and conditions of version 2 of
* the GNU General Public License. See the file COPYING in the main
* directory of this archive for more details.
*
* driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
* (7-bit I2C slave address 0x60, the three LSBs can be configured in
* hardware)
*
* writing the DAC value to EEPROM is not supported
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/dac/mcp4725.h>
#define MCP4725_DRV_NAME "mcp4725"
struct mcp4725_data {
struct i2c_client *client;
u16 vref_mv;
u16 dac_value;
};
#ifdef CONFIG_PM_SLEEP
static int mcp4725_suspend(struct device *dev)
{
u8 outbuf[2];
outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */
outbuf[1] = 0;
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
static int mcp4725_resume(struct device *dev)
{
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct mcp4725_data *data = iio_priv(indio_dev);
u8 outbuf[2];
/* restore previous DAC value */
outbuf[0] = (data->dac_value >> 8) & 0xf;
outbuf[1] = data->dac_value & 0xff;
return i2c_master_send(to_i2c_client(dev), outbuf, 2);
}
static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
#define MCP4725_PM_OPS (&mcp4725_pm_ops)
#else
#define MCP4725_PM_OPS NULL
#endif
static const struct iio_chan_spec mcp4725_channel = {
.type = IIO_VOLTAGE,
.indexed = 1,
.output = 1,
.channel = 0,
.info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT |
IIO_CHAN_INFO_SCALE_SHARED_BIT,
.scan_type = IIO_ST('u', 12, 16, 0),
};
static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
{
struct mcp4725_data *data = iio_priv(indio_dev);
u8 outbuf[2];
int ret;
if (val >= (1 << 12) || val < 0)
return -EINVAL;
outbuf[0] = (val >> 8) & 0xf;
outbuf[1] = val & 0xff;
ret = i2c_master_send(data->client, outbuf, 2);
if (ret < 0)
return ret;
else if (ret != 2)
return -EIO;
else
return 0;
}
static int mcp4725_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct mcp4725_data *data = iio_priv(indio_dev);
unsigned long scale_uv;
switch (mask) {
case IIO_CHAN_INFO_RAW:
*val = data->dac_value;
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
scale_uv = (data->vref_mv * 1000) >> 12;
*val = scale_uv / 1000000;
*val2 = scale_uv % 1000000;
return IIO_VAL_INT_PLUS_MICRO;
}
return -EINVAL;
}
static int mcp4725_write_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct mcp4725_data *data = iio_priv(indio_dev);
int ret;
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = mcp4725_set_value(indio_dev, val);
data->dac_value = val;
break;
default:
ret = -EINVAL;
break;
}
return ret;
}
static const struct iio_info mcp4725_info = {
.read_raw = mcp4725_read_raw,
.write_raw = mcp4725_write_raw,
.driver_module = THIS_MODULE,
};
static int __devinit mcp4725_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct mcp4725_data *data;
struct iio_dev *indio_dev;
struct mcp4725_platform_data *platform_data = client->dev.platform_data;
u8 inbuf[3];
int err;
if (!platform_data || !platform_data->vref_mv) {
dev_err(&client->dev, "invalid platform data");
err = -EINVAL;
goto exit;
}
indio_dev = iio_device_alloc(sizeof(*data));
if (indio_dev == NULL) {
err = -ENOMEM;
goto exit;
}
data = iio_priv(indio_dev);
i2c_set_clientdata(client, indio_dev);
data->client = client;
indio_dev->dev.parent = &client->dev;
indio_dev->info = &mcp4725_info;
indio_dev->channels = &mcp4725_channel;
indio_dev->num_channels = 1;
indio_dev->modes = INDIO_DIRECT_MODE;
data->vref_mv = platform_data->vref_mv;
/* read current DAC value */
err = i2c_master_recv(client, inbuf, 3);
if (err < 0) {
dev_err(&client->dev, "failed to read DAC value");
goto exit_free_device;
}
data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
err = iio_device_register(indio_dev);
if (err)
goto exit_free_device;
dev_info(&client->dev, "MCP4725 DAC registered\n");
return 0;
exit_free_device:
iio_device_free(indio_dev);
exit:
return err;
}
static int __devexit mcp4725_remove(struct i2c_client *client)
{
struct iio_dev *indio_dev = i2c_get_clientdata(client);
iio_device_unregister(indio_dev);
iio_device_free(indio_dev);
return 0;
}
static const struct i2c_device_id mcp4725_id[] = {
{ "mcp4725", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, mcp4725_id);
static struct i2c_driver mcp4725_driver = {
.driver = {
.name = MCP4725_DRV_NAME,
.pm = MCP4725_PM_OPS,
},
.probe = mcp4725_probe,
.remove = __devexit_p(mcp4725_remove),
.id_table = mcp4725_id,
};
module_i2c_driver(mcp4725_driver);
MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("MCP4725 12-bit DAC");
MODULE_LICENSE("GPL");
|
