tjh.dev
Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * max517.c - Support for Maxim MAX517, MAX518 and MAX519
4 *
5 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
6 */
7
8#include <linux/module.h>
9#include <linux/slab.h>
10#include <linux/jiffies.h>
11#include <linux/i2c.h>
12#include <linux/err.h>
13
14#include <linux/iio/iio.h>
15#include <linux/iio/sysfs.h>
16#include <linux/iio/dac/max517.h>
17
18/* Commands */
19#define COMMAND_CHANNEL0 0x00
20#define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
21#define COMMAND_PD 0x08 /* Power Down */
22
23enum max517_device_ids {
24 ID_MAX517,
25 ID_MAX518,
26 ID_MAX519,
27 ID_MAX520,
28 ID_MAX521,
29};
30
31struct max517_data {
32 struct i2c_client *client;
33 unsigned short vref_mv[8];
34};
35
36/*
37 * channel: bit 0: channel 1
38 * bit 1: channel 2
39 * (this way, it's possible to set both channels at once)
40 */
41static int max517_set_value(struct iio_dev *indio_dev,
42 long val, int channel)
43{
44 struct max517_data *data = iio_priv(indio_dev);
45 struct i2c_client *client = data->client;
46 u8 outbuf[2];
47 int res;
48
49 if (val < 0 || val > 255)
50 return -EINVAL;
51
52 outbuf[0] = channel;
53 outbuf[1] = val;
54
55 res = i2c_master_send(client, outbuf, 2);
56 if (res < 0)
57 return res;
58 else if (res != 2)
59 return -EIO;
60 else
61 return 0;
62}
63
64static int max517_read_raw(struct iio_dev *indio_dev,
65 struct iio_chan_spec const *chan,
66 int *val,
67 int *val2,
68 long m)
69{
70 struct max517_data *data = iio_priv(indio_dev);
71
72 switch (m) {
73 case IIO_CHAN_INFO_SCALE:
74 /* Corresponds to Vref / 2^(bits) */
75 *val = data->vref_mv[chan->channel];
76 *val2 = 8;
77 return IIO_VAL_FRACTIONAL_LOG2;
78 default:
79 break;
80 }
81 return -EINVAL;
82}
83
84static int max517_write_raw(struct iio_dev *indio_dev,
85 struct iio_chan_spec const *chan, int val, int val2, long mask)
86{
87 int ret;
88
89 switch (mask) {
90 case IIO_CHAN_INFO_RAW:
91 ret = max517_set_value(indio_dev, val, chan->channel);
92 break;
93 default:
94 ret = -EINVAL;
95 break;
96 }
97
98 return ret;
99}
100
101static int max517_suspend(struct device *dev)
102{
103 u8 outbuf = COMMAND_PD;
104
105 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
106}
107
108static int max517_resume(struct device *dev)
109{
110 u8 outbuf = 0;
111
112 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
113}
114
115static DEFINE_SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
116
117static const struct iio_info max517_info = {
118 .read_raw = max517_read_raw,
119 .write_raw = max517_write_raw,
120};
121
122#define MAX517_CHANNEL(chan) { \
123 .type = IIO_VOLTAGE, \
124 .indexed = 1, \
125 .output = 1, \
126 .channel = (chan), \
127 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
128 BIT(IIO_CHAN_INFO_SCALE), \
129}
130
131static const struct iio_chan_spec max517_channels[] = {
132 MAX517_CHANNEL(0),
133 MAX517_CHANNEL(1),
134 MAX517_CHANNEL(2),
135 MAX517_CHANNEL(3),
136 MAX517_CHANNEL(4),
137 MAX517_CHANNEL(5),
138 MAX517_CHANNEL(6),
139 MAX517_CHANNEL(7),
140};
141
142static int max517_probe(struct i2c_client *client)
143{
144 const struct max517_platform_data *platform_data = dev_get_platdata(&client->dev);
145 const struct i2c_device_id *id = i2c_client_get_device_id(client);
146 struct max517_data *data;
147 struct iio_dev *indio_dev;
148 int chan;
149
150 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
151 if (!indio_dev)
152 return -ENOMEM;
153 data = iio_priv(indio_dev);
154 data->client = client;
155
156 switch (id->driver_data) {
157 case ID_MAX521:
158 indio_dev->num_channels = 8;
159 break;
160 case ID_MAX520:
161 indio_dev->num_channels = 4;
162 break;
163 case ID_MAX519:
164 case ID_MAX518:
165 indio_dev->num_channels = 2;
166 break;
167 default: /* single channel for MAX517 */
168 indio_dev->num_channels = 1;
169 break;
170 }
171 indio_dev->channels = max517_channels;
172 indio_dev->modes = INDIO_DIRECT_MODE;
173 indio_dev->info = &max517_info;
174
175 /*
176 * Reference voltage on MAX518 and default is 5V, else take vref_mv
177 * from platform_data
178 */
179 for (chan = 0; chan < indio_dev->num_channels; chan++) {
180 if (id->driver_data == ID_MAX518 || !platform_data)
181 data->vref_mv[chan] = 5000; /* mV */
182 else
183 data->vref_mv[chan] = platform_data->vref_mv[chan];
184 }
185
186 return devm_iio_device_register(&client->dev, indio_dev);
187}
188
189static const struct i2c_device_id max517_id[] = {
190 { "max517", ID_MAX517 },
191 { "max518", ID_MAX518 },
192 { "max519", ID_MAX519 },
193 { "max520", ID_MAX520 },
194 { "max521", ID_MAX521 },
195 { }
196};
197MODULE_DEVICE_TABLE(i2c, max517_id);
198
199static struct i2c_driver max517_driver = {
200 .driver = {
201 .name = "max517",
202 .pm = pm_sleep_ptr(&max517_pm_ops),
203 },
204 .probe = max517_probe,
205 .id_table = max517_id,
206};
207module_i2c_driver(max517_driver);
208
209MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
210MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
211MODULE_LICENSE("GPL");