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 #define MAX517_DRV_NAME "max517"
19
20 /* Commands */
21 #define COMMAND_CHANNEL0 0x00
22 #define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
23 #define COMMAND_PD 0x08 /* Power Down */
24
25 enum max517_device_ids {
26 ID_MAX517,
27 ID_MAX518,
28 ID_MAX519,
29 ID_MAX520,
30 ID_MAX521,
31 };
32
33 struct max517_data {
34 struct i2c_client *client;
35 unsigned short vref_mv[8];
36 };
37
38 /*
39 * channel: bit 0: channel 1
40 * bit 1: channel 2
41 * (this way, it's possible to set both channels at once)
42 */
max517_set_value(struct iio_dev * indio_dev,long val,int channel)43 static int max517_set_value(struct iio_dev *indio_dev,
44 long val, int channel)
45 {
46 struct max517_data *data = iio_priv(indio_dev);
47 struct i2c_client *client = data->client;
48 u8 outbuf[2];
49 int res;
50
51 if (val < 0 || val > 255)
52 return -EINVAL;
53
54 outbuf[0] = channel;
55 outbuf[1] = val;
56
57 res = i2c_master_send(client, outbuf, 2);
58 if (res < 0)
59 return res;
60 else if (res != 2)
61 return -EIO;
62 else
63 return 0;
64 }
65
max517_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long m)66 static int max517_read_raw(struct iio_dev *indio_dev,
67 struct iio_chan_spec const *chan,
68 int *val,
69 int *val2,
70 long m)
71 {
72 struct max517_data *data = iio_priv(indio_dev);
73
74 switch (m) {
75 case IIO_CHAN_INFO_SCALE:
76 /* Corresponds to Vref / 2^(bits) */
77 *val = data->vref_mv[chan->channel];
78 *val2 = 8;
79 return IIO_VAL_FRACTIONAL_LOG2;
80 default:
81 break;
82 }
83 return -EINVAL;
84 }
85
max517_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)86 static int max517_write_raw(struct iio_dev *indio_dev,
87 struct iio_chan_spec const *chan, int val, int val2, long mask)
88 {
89 int ret;
90
91 switch (mask) {
92 case IIO_CHAN_INFO_RAW:
93 ret = max517_set_value(indio_dev, val, chan->channel);
94 break;
95 default:
96 ret = -EINVAL;
97 break;
98 }
99
100 return ret;
101 }
102
max517_suspend(struct device * dev)103 static int max517_suspend(struct device *dev)
104 {
105 u8 outbuf = COMMAND_PD;
106
107 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
108 }
109
max517_resume(struct device * dev)110 static int max517_resume(struct device *dev)
111 {
112 u8 outbuf = 0;
113
114 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
115 }
116
117 static DEFINE_SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
118
119 static const struct iio_info max517_info = {
120 .read_raw = max517_read_raw,
121 .write_raw = max517_write_raw,
122 };
123
124 #define MAX517_CHANNEL(chan) { \
125 .type = IIO_VOLTAGE, \
126 .indexed = 1, \
127 .output = 1, \
128 .channel = (chan), \
129 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
130 BIT(IIO_CHAN_INFO_SCALE), \
131 }
132
133 static const struct iio_chan_spec max517_channels[] = {
134 MAX517_CHANNEL(0),
135 MAX517_CHANNEL(1),
136 MAX517_CHANNEL(2),
137 MAX517_CHANNEL(3),
138 MAX517_CHANNEL(4),
139 MAX517_CHANNEL(5),
140 MAX517_CHANNEL(6),
141 MAX517_CHANNEL(7),
142 };
143
max517_probe(struct i2c_client * client)144 static int max517_probe(struct i2c_client *client)
145 {
146 const struct i2c_device_id *id = i2c_client_get_device_id(client);
147 struct max517_data *data;
148 struct iio_dev *indio_dev;
149 struct max517_platform_data *platform_data = client->dev.platform_data;
150 int chan;
151
152 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
153 if (!indio_dev)
154 return -ENOMEM;
155 data = iio_priv(indio_dev);
156 data->client = client;
157
158 switch (id->driver_data) {
159 case ID_MAX521:
160 indio_dev->num_channels = 8;
161 break;
162 case ID_MAX520:
163 indio_dev->num_channels = 4;
164 break;
165 case ID_MAX519:
166 case ID_MAX518:
167 indio_dev->num_channels = 2;
168 break;
169 default: /* single channel for MAX517 */
170 indio_dev->num_channels = 1;
171 break;
172 }
173 indio_dev->channels = max517_channels;
174 indio_dev->modes = INDIO_DIRECT_MODE;
175 indio_dev->info = &max517_info;
176
177 /*
178 * Reference voltage on MAX518 and default is 5V, else take vref_mv
179 * from platform_data
180 */
181 for (chan = 0; chan < indio_dev->num_channels; chan++) {
182 if (id->driver_data == ID_MAX518 || !platform_data)
183 data->vref_mv[chan] = 5000; /* mV */
184 else
185 data->vref_mv[chan] = platform_data->vref_mv[chan];
186 }
187
188 return devm_iio_device_register(&client->dev, indio_dev);
189 }
190
191 static const struct i2c_device_id max517_id[] = {
192 { "max517", ID_MAX517 },
193 { "max518", ID_MAX518 },
194 { "max519", ID_MAX519 },
195 { "max520", ID_MAX520 },
196 { "max521", ID_MAX521 },
197 { }
198 };
199 MODULE_DEVICE_TABLE(i2c, max517_id);
200
201 static struct i2c_driver max517_driver = {
202 .driver = {
203 .name = MAX517_DRV_NAME,
204 .pm = pm_sleep_ptr(&max517_pm_ops),
205 },
206 .probe = max517_probe,
207 .id_table = max517_id,
208 };
209 module_i2c_driver(max517_driver);
210
211 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
212 MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
213 MODULE_LICENSE("GPL");
214
