1/*
2 *  max517.c - Support for Maxim MAX517, MAX518 and MAX519
3 *
4 *  Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
5 *
6 *  This program is free software; you can redistribute it and/or modify
7 *  it under the terms of the GNU General Public License as published by
8 *  the Free Software Foundation; either version 2 of the License, or
9 *  (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#include <linux/module.h>
22#include <linux/slab.h>
23#include <linux/jiffies.h>
24#include <linux/i2c.h>
25#include <linux/err.h>
26
27#include <linux/iio/iio.h>
28#include <linux/iio/sysfs.h>
29#include <linux/iio/dac/max517.h>
30
31#define MAX517_DRV_NAME	"max517"
32
33/* Commands */
34#define COMMAND_CHANNEL0	0x00
35#define COMMAND_CHANNEL1	0x01 /* for MAX518 and MAX519 */
36#define COMMAND_PD		0x08 /* Power Down */
37
38enum max517_device_ids {
39	ID_MAX517,
40	ID_MAX518,
41	ID_MAX519,
42	ID_MAX520,
43	ID_MAX521,
44};
45
46struct max517_data {
47	struct i2c_client	*client;
48	unsigned short		vref_mv[8];
49};
50
51/*
52 * channel: bit 0: channel 1
53 *          bit 1: channel 2
54 * (this way, it's possible to set both channels at once)
55 */
56static int max517_set_value(struct iio_dev *indio_dev,
57	long val, int channel)
58{
59	struct max517_data *data = iio_priv(indio_dev);
60	struct i2c_client *client = data->client;
61	u8 outbuf[2];
62	int res;
63
64	if (val < 0 || val > 255)
65		return -EINVAL;
66
67	outbuf[0] = channel;
68	outbuf[1] = val;
69
70	res = i2c_master_send(client, outbuf, 2);
71	if (res < 0)
72		return res;
73	else if (res != 2)
74		return -EIO;
75	else
76		return 0;
77}
78
79static int max517_read_raw(struct iio_dev *indio_dev,
80			   struct iio_chan_spec const *chan,
81			   int *val,
82			   int *val2,
83			   long m)
84{
85	struct max517_data *data = iio_priv(indio_dev);
86
87	switch (m) {
88	case IIO_CHAN_INFO_SCALE:
89		/* Corresponds to Vref / 2^(bits) */
90		*val = data->vref_mv[chan->channel];
91		*val2 = 8;
92		return IIO_VAL_FRACTIONAL_LOG2;
93	default:
94		break;
95	}
96	return -EINVAL;
97}
98
99static int max517_write_raw(struct iio_dev *indio_dev,
100	struct iio_chan_spec const *chan, int val, int val2, long mask)
101{
102	int ret;
103
104	switch (mask) {
105	case IIO_CHAN_INFO_RAW:
106		ret = max517_set_value(indio_dev, val, chan->channel);
107		break;
108	default:
109		ret = -EINVAL;
110		break;
111	}
112
113	return ret;
114}
115
116#ifdef CONFIG_PM_SLEEP
117static int max517_suspend(struct device *dev)
118{
119	u8 outbuf = COMMAND_PD;
120
121	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
122}
123
124static int max517_resume(struct device *dev)
125{
126	u8 outbuf = 0;
127
128	return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
129}
130
131static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
132#define MAX517_PM_OPS (&max517_pm_ops)
133#else
134#define MAX517_PM_OPS NULL
135#endif
136
137static const struct iio_info max517_info = {
138	.read_raw = max517_read_raw,
139	.write_raw = max517_write_raw,
140	.driver_module = THIS_MODULE,
141};
142
143#define MAX517_CHANNEL(chan) {				\
144	.type = IIO_VOLTAGE,				\
145	.indexed = 1,					\
146	.output = 1,					\
147	.channel = (chan),				\
148	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |	\
149	BIT(IIO_CHAN_INFO_SCALE),			\
150}
151
152static const struct iio_chan_spec max517_channels[] = {
153	MAX517_CHANNEL(0),
154	MAX517_CHANNEL(1),
155	MAX517_CHANNEL(2),
156	MAX517_CHANNEL(3),
157	MAX517_CHANNEL(4),
158	MAX517_CHANNEL(5),
159	MAX517_CHANNEL(6),
160	MAX517_CHANNEL(7),
161};
162
163static int max517_probe(struct i2c_client *client,
164			const struct i2c_device_id *id)
165{
166	struct max517_data *data;
167	struct iio_dev *indio_dev;
168	struct max517_platform_data *platform_data = client->dev.platform_data;
169	int chan;
170
171	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
172	if (!indio_dev)
173		return -ENOMEM;
174	data = iio_priv(indio_dev);
175	i2c_set_clientdata(client, indio_dev);
176	data->client = client;
177
178	/* establish that the iio_dev is a child of the i2c device */
179	indio_dev->dev.parent = &client->dev;
180
181	switch (id->driver_data) {
182	case ID_MAX521:
183		indio_dev->num_channels = 8;
184		break;
185	case ID_MAX520:
186		indio_dev->num_channels = 4;
187		break;
188	case ID_MAX519:
189	case ID_MAX518:
190		indio_dev->num_channels = 2;
191		break;
192	default:  /* single channel for MAX517 */
193		indio_dev->num_channels = 1;
194		break;
195	}
196	indio_dev->channels = max517_channels;
197	indio_dev->modes = INDIO_DIRECT_MODE;
198	indio_dev->info = &max517_info;
199
200	/*
201	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
202	 * from platform_data
203	 */
204	for (chan = 0; chan < indio_dev->num_channels; chan++) {
205		if (id->driver_data == ID_MAX518 || !platform_data)
206			data->vref_mv[chan] = 5000; /* mV */
207		else
208			data->vref_mv[chan] = platform_data->vref_mv[chan];
209	}
210
211	return iio_device_register(indio_dev);
212}
213
214static int max517_remove(struct i2c_client *client)
215{
216	iio_device_unregister(i2c_get_clientdata(client));
217	return 0;
218}
219
220static const struct i2c_device_id max517_id[] = {
221	{ "max517", ID_MAX517 },
222	{ "max518", ID_MAX518 },
223	{ "max519", ID_MAX519 },
224	{ "max520", ID_MAX520 },
225	{ "max521", ID_MAX521 },
226	{ }
227};
228MODULE_DEVICE_TABLE(i2c, max517_id);
229
230static struct i2c_driver max517_driver = {
231	.driver = {
232		.name	= MAX517_DRV_NAME,
233		.pm		= MAX517_PM_OPS,
234	},
235	.probe		= max517_probe,
236	.remove		= max517_remove,
237	.id_table	= max517_id,
238};
239module_i2c_driver(max517_driver);
240
241MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
242MODULE_DESCRIPTION("MAX517/518/519/520/521 8-bit DAC");
243MODULE_LICENSE("GPL");
244