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/init.h>
23#include <linux/slab.h>
24#include <linux/jiffies.h>
25#include <linux/i2c.h>
26#include <linux/err.h>
27
28#include "../iio.h"
29#include "../sysfs.h"
30#include "dac.h"
31
32#include "max517.h"
33
34#define MAX517_DRV_NAME	"max517"
35
36/* Commands */
37#define COMMAND_CHANNEL0	0x00
38#define COMMAND_CHANNEL1	0x01 /* for MAX518 and MAX519 */
39#define COMMAND_PD		0x08 /* Power Down */
40
41enum max517_device_ids {
42	ID_MAX517,
43	ID_MAX518,
44	ID_MAX519,
45};
46
47struct max517_data {
48	struct iio_dev		*indio_dev;
49	struct i2c_client	*client;
50	unsigned short		vref_mv[2];
51};
52
53/*
54 * channel: bit 0: channel 1
55 *          bit 1: channel 2
56 * (this way, it's possible to set both channels at once)
57 */
58static ssize_t max517_set_value(struct device *dev,
59				 struct device_attribute *attr,
60				 const char *buf, size_t count, int channel)
61{
62	struct iio_dev *indio_dev = dev_get_drvdata(dev);
63	struct max517_data *data = iio_priv(indio_dev);
64	struct i2c_client *client = data->client;
65	u8 outbuf[4]; /* 1x or 2x command + value */
66	int outbuf_size = 0;
67	int res;
68	long val;
69
70	res = strict_strtol(buf, 10, &val);
71
72	if (res)
73		return res;
74
75	if (val < 0 || val > 255)
76		return -EINVAL;
77
78	if (channel & 1) {
79		outbuf[outbuf_size++] = COMMAND_CHANNEL0;
80		outbuf[outbuf_size++] = val;
81	}
82	if (channel & 2) {
83		outbuf[outbuf_size++] = COMMAND_CHANNEL1;
84		outbuf[outbuf_size++] = val;
85	}
86
87	/*
88	 * At this point, there are always 1 or 2 two-byte commands in
89	 * outbuf. With 2 commands, the device can set two outputs
90	 * simultaneously, latching the values upon the end of the I2C
91	 * transfer.
92	 */
93
94	res = i2c_master_send(client, outbuf, outbuf_size);
95	if (res < 0)
96		return res;
97
98	return count;
99}
100
101static ssize_t max517_set_value_1(struct device *dev,
102				 struct device_attribute *attr,
103				 const char *buf, size_t count)
104{
105	return max517_set_value(dev, attr, buf, count, 1);
106}
107static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
108
109static ssize_t max517_set_value_2(struct device *dev,
110				 struct device_attribute *attr,
111				 const char *buf, size_t count)
112{
113	return max517_set_value(dev, attr, buf, count, 2);
114}
115static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
116
117static ssize_t max517_set_value_both(struct device *dev,
118				 struct device_attribute *attr,
119				 const char *buf, size_t count)
120{
121	return max517_set_value(dev, attr, buf, count, 3);
122}
123static IIO_DEVICE_ATTR_NAMED(out_voltage1and2_raw,
124			     out_voltage1&2_raw, S_IWUSR, NULL,
125			     max517_set_value_both, -1);
126
127static ssize_t max517_show_scale(struct device *dev,
128				struct device_attribute *attr,
129				char *buf, int channel)
130{
131	struct iio_dev *indio_dev = dev_get_drvdata(dev);
132	struct max517_data *data = iio_priv(indio_dev);
133	/* Corresponds to Vref / 2^(bits) */
134	unsigned int scale_uv = (data->vref_mv[channel - 1] * 1000) >> 8;
135
136	return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
137}
138
139static ssize_t max517_show_scale1(struct device *dev,
140				struct device_attribute *attr,
141				char *buf)
142{
143	return max517_show_scale(dev, attr, buf, 1);
144}
145static IIO_DEVICE_ATTR(out_voltage1_scale, S_IRUGO,
146		       max517_show_scale1, NULL, 0);
147
148static ssize_t max517_show_scale2(struct device *dev,
149				struct device_attribute *attr,
150				char *buf)
151{
152	return max517_show_scale(dev, attr, buf, 2);
153}
154static IIO_DEVICE_ATTR(out_voltage2_scale, S_IRUGO,
155		       max517_show_scale2, NULL, 0);
156
157/* On MAX517 variant, we have one output */
158static struct attribute *max517_attributes[] = {
159	&iio_dev_attr_out_voltage1_raw.dev_attr.attr,
160	&iio_dev_attr_out_voltage1_scale.dev_attr.attr,
161	NULL
162};
163
164static struct attribute_group max517_attribute_group = {
165	.attrs = max517_attributes,
166};
167
168/* On MAX518 and MAX519 variant, we have two outputs */
169static struct attribute *max518_attributes[] = {
170	&iio_dev_attr_out_voltage1_raw.dev_attr.attr,
171	&iio_dev_attr_out_voltage1_scale.dev_attr.attr,
172	&iio_dev_attr_out_voltage2_raw.dev_attr.attr,
173	&iio_dev_attr_out_voltage2_scale.dev_attr.attr,
174	&iio_dev_attr_out_voltage1and2_raw.dev_attr.attr,
175	NULL
176};
177
178static struct attribute_group max518_attribute_group = {
179	.attrs = max518_attributes,
180};
181
182static int max517_suspend(struct i2c_client *client, pm_message_t mesg)
183{
184	u8 outbuf = COMMAND_PD;
185
186	return i2c_master_send(client, &outbuf, 1);
187}
188
189static int max517_resume(struct i2c_client *client)
190{
191	u8 outbuf = 0;
192
193	return i2c_master_send(client, &outbuf, 1);
194}
195
196static const struct iio_info max517_info = {
197	.attrs = &max517_attribute_group,
198	.driver_module = THIS_MODULE,
199};
200
201static const struct iio_info max518_info = {
202	.attrs = &max518_attribute_group,
203	.driver_module = THIS_MODULE,
204};
205
206static int max517_probe(struct i2c_client *client,
207			const struct i2c_device_id *id)
208{
209	struct max517_data *data;
210	struct iio_dev *indio_dev;
211	struct max517_platform_data *platform_data = client->dev.platform_data;
212	int err;
213
214	indio_dev = iio_allocate_device(sizeof(*data));
215	if (indio_dev == NULL) {
216		err = -ENOMEM;
217		goto exit;
218	}
219	data = iio_priv(indio_dev);
220	i2c_set_clientdata(client, indio_dev);
221	data->client = client;
222
223	/* establish that the iio_dev is a child of the i2c device */
224	indio_dev->dev.parent = &client->dev;
225
226	/* reduced attribute set for MAX517 */
227	if (id->driver_data == ID_MAX517)
228		indio_dev->info = &max517_info;
229	else
230		indio_dev->info = &max518_info;
231	indio_dev->modes = INDIO_DIRECT_MODE;
232
233	/*
234	 * Reference voltage on MAX518 and default is 5V, else take vref_mv
235	 * from platform_data
236	 */
237	if (id->driver_data == ID_MAX518 || !platform_data) {
238		data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
239	} else {
240		data->vref_mv[0] = platform_data->vref_mv[0];
241		data->vref_mv[1] = platform_data->vref_mv[1];
242	}
243
244	err = iio_device_register(indio_dev);
245	if (err)
246		goto exit_free_device;
247
248	dev_info(&client->dev, "DAC registered\n");
249
250	return 0;
251
252exit_free_device:
253	iio_free_device(indio_dev);
254exit:
255	return err;
256}
257
258static int max517_remove(struct i2c_client *client)
259{
260	iio_free_device(i2c_get_clientdata(client));
261
262	return 0;
263}
264
265static const struct i2c_device_id max517_id[] = {
266	{ "max517", ID_MAX517 },
267	{ "max518", ID_MAX518 },
268	{ "max519", ID_MAX519 },
269	{ }
270};
271MODULE_DEVICE_TABLE(i2c, max517_id);
272
273static struct i2c_driver max517_driver = {
274	.driver = {
275		.name	= MAX517_DRV_NAME,
276	},
277	.probe		= max517_probe,
278	.remove		= max517_remove,
279	.suspend	= max517_suspend,
280	.resume		= max517_resume,
281	.id_table	= max517_id,
282};
283module_i2c_driver(max517_driver);
284
285MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
286MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
287MODULE_LICENSE("GPL");
288