xref: /openbmc/linux/drivers/iio/dac/max517.c (revision b755c25f)
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  */
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 
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 
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 
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 
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 
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