2 * max517.c - Support for Maxim MAX517, MAX518 and MAX519
4 * Copyright (C) 2010, 2011 Roland Stigge <stigge@antcom.de>
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.
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.
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.
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>
34 #define MAX517_DRV_NAME "max517"
37 #define COMMAND_CHANNEL0 0x00
38 #define COMMAND_CHANNEL1 0x01 /* for MAX518 and MAX519 */
39 #define COMMAND_PD 0x08 /* Power Down */
41 enum max517_device_ids {
48 struct iio_dev *indio_dev;
49 struct i2c_client *client;
50 unsigned short vref_mv[2];
54 * channel: bit 0: channel 1
56 * (this way, it's possible to set both channels at once)
58 static ssize_t max517_set_value(struct device *dev,
59 struct device_attribute *attr,
60 const char *buf, size_t count, int channel)
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 */
70 res = strict_strtol(buf, 10, &val);
75 if (val < 0 || val > 255)
79 outbuf[outbuf_size++] = COMMAND_CHANNEL0;
80 outbuf[outbuf_size++] = val;
83 outbuf[outbuf_size++] = COMMAND_CHANNEL1;
84 outbuf[outbuf_size++] = val;
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
94 res = i2c_master_send(client, outbuf, outbuf_size);
101 static ssize_t max517_set_value_1(struct device *dev,
102 struct device_attribute *attr,
103 const char *buf, size_t count)
105 return max517_set_value(dev, attr, buf, count, 1);
107 static IIO_DEV_ATTR_OUT_RAW(1, max517_set_value_1, 0);
109 static ssize_t max517_set_value_2(struct device *dev,
110 struct device_attribute *attr,
111 const char *buf, size_t count)
113 return max517_set_value(dev, attr, buf, count, 2);
115 static IIO_DEV_ATTR_OUT_RAW(2, max517_set_value_2, 1);
117 static ssize_t max517_set_value_both(struct device *dev,
118 struct device_attribute *attr,
119 const char *buf, size_t count)
121 return max517_set_value(dev, attr, buf, count, 3);
123 static IIO_DEVICE_ATTR_NAMED(out_voltage1and2_raw,
124 out_voltage1&2_raw, S_IWUSR, NULL,
125 max517_set_value_both, -1);
127 static ssize_t max517_show_scale(struct device *dev,
128 struct device_attribute *attr,
129 char *buf, int channel)
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;
136 return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
139 static ssize_t max517_show_scale1(struct device *dev,
140 struct device_attribute *attr,
143 return max517_show_scale(dev, attr, buf, 1);
145 static IIO_DEVICE_ATTR(out_voltage1_scale, S_IRUGO,
146 max517_show_scale1, NULL, 0);
148 static ssize_t max517_show_scale2(struct device *dev,
149 struct device_attribute *attr,
152 return max517_show_scale(dev, attr, buf, 2);
154 static IIO_DEVICE_ATTR(out_voltage2_scale, S_IRUGO,
155 max517_show_scale2, NULL, 0);
157 /* On MAX517 variant, we have one output */
158 static struct attribute *max517_attributes[] = {
159 &iio_dev_attr_out_voltage1_raw.dev_attr.attr,
160 &iio_dev_attr_out_voltage1_scale.dev_attr.attr,
164 static struct attribute_group max517_attribute_group = {
165 .attrs = max517_attributes,
168 /* On MAX518 and MAX519 variant, we have two outputs */
169 static 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,
178 static struct attribute_group max518_attribute_group = {
179 .attrs = max518_attributes,
182 #ifdef CONFIG_PM_SLEEP
183 static int max517_suspend(struct device *dev)
185 u8 outbuf = COMMAND_PD;
187 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
190 static int max517_resume(struct device *dev)
194 return i2c_master_send(to_i2c_client(dev), &outbuf, 1);
197 static SIMPLE_DEV_PM_OPS(max517_pm_ops, max517_suspend, max517_resume);
198 #define MAX517_PM_OPS (&max517_pm_ops)
200 #define MAX517_PM_OPS NULL
203 static const struct iio_info max517_info = {
204 .attrs = &max517_attribute_group,
205 .driver_module = THIS_MODULE,
208 static const struct iio_info max518_info = {
209 .attrs = &max518_attribute_group,
210 .driver_module = THIS_MODULE,
213 static int max517_probe(struct i2c_client *client,
214 const struct i2c_device_id *id)
216 struct max517_data *data;
217 struct iio_dev *indio_dev;
218 struct max517_platform_data *platform_data = client->dev.platform_data;
221 indio_dev = iio_allocate_device(sizeof(*data));
222 if (indio_dev == NULL) {
226 data = iio_priv(indio_dev);
227 i2c_set_clientdata(client, indio_dev);
228 data->client = client;
230 /* establish that the iio_dev is a child of the i2c device */
231 indio_dev->dev.parent = &client->dev;
233 /* reduced attribute set for MAX517 */
234 if (id->driver_data == ID_MAX517)
235 indio_dev->info = &max517_info;
237 indio_dev->info = &max518_info;
238 indio_dev->modes = INDIO_DIRECT_MODE;
241 * Reference voltage on MAX518 and default is 5V, else take vref_mv
244 if (id->driver_data == ID_MAX518 || !platform_data) {
245 data->vref_mv[0] = data->vref_mv[1] = 5000; /* mV */
247 data->vref_mv[0] = platform_data->vref_mv[0];
248 data->vref_mv[1] = platform_data->vref_mv[1];
251 err = iio_device_register(indio_dev);
253 goto exit_free_device;
255 dev_info(&client->dev, "DAC registered\n");
260 iio_free_device(indio_dev);
265 static int max517_remove(struct i2c_client *client)
267 iio_free_device(i2c_get_clientdata(client));
272 static const struct i2c_device_id max517_id[] = {
273 { "max517", ID_MAX517 },
274 { "max518", ID_MAX518 },
275 { "max519", ID_MAX519 },
278 MODULE_DEVICE_TABLE(i2c, max517_id);
280 static struct i2c_driver max517_driver = {
282 .name = MAX517_DRV_NAME,
285 .probe = max517_probe,
286 .remove = max517_remove,
287 .id_table = max517_id,
289 module_i2c_driver(max517_driver);
291 MODULE_AUTHOR("Roland Stigge <stigge@antcom.de>");
292 MODULE_DESCRIPTION("MAX517/MAX518/MAX519 8-bit DAC");
293 MODULE_LICENSE("GPL");