2 * mcp4725.c - Support for Microchip MCP4725
4 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
6 * Based on max517 by Roland Stigge <stigge@antcom.de>
8 * This file is subject to the terms and conditions of version 2 of
9 * the GNU General Public License. See the file COPYING in the main
10 * directory of this archive for more details.
12 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
13 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
17 #include <linux/module.h>
18 #include <linux/i2c.h>
19 #include <linux/err.h>
20 #include <linux/delay.h>
22 #include <linux/iio/iio.h>
23 #include <linux/iio/sysfs.h>
25 #include <linux/iio/dac/mcp4725.h>
27 #define MCP4725_DRV_NAME "mcp4725"
30 struct i2c_client *client;
34 unsigned powerdown_mode;
37 static int mcp4725_suspend(struct device *dev)
39 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
43 outbuf[0] = (data->powerdown_mode + 1) << 4;
45 data->powerdown = true;
47 return i2c_master_send(data->client, outbuf, 2);
50 static int mcp4725_resume(struct device *dev)
52 struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
56 /* restore previous DAC value */
57 outbuf[0] = (data->dac_value >> 8) & 0xf;
58 outbuf[1] = data->dac_value & 0xff;
59 data->powerdown = false;
61 return i2c_master_send(data->client, outbuf, 2);
64 #ifdef CONFIG_PM_SLEEP
65 static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
66 #define MCP4725_PM_OPS (&mcp4725_pm_ops)
68 #define MCP4725_PM_OPS NULL
71 static ssize_t mcp4725_store_eeprom(struct device *dev,
72 struct device_attribute *attr, const char *buf, size_t len)
74 struct iio_dev *indio_dev = dev_to_iio_dev(dev);
75 struct mcp4725_data *data = iio_priv(indio_dev);
81 ret = strtobool(buf, &state);
88 inoutbuf[0] = 0x60; /* write EEPROM */
89 inoutbuf[1] = data->dac_value >> 4;
90 inoutbuf[2] = (data->dac_value & 0xf) << 4;
92 ret = i2c_master_send(data->client, inoutbuf, 3);
98 /* wait for write complete, takes up to 50ms */
101 ret = i2c_master_recv(data->client, inoutbuf, 3);
107 if (inoutbuf[0] & 0x80)
112 dev_err(&data->client->dev,
113 "mcp4725_store_eeprom() failed, incomplete\n");
120 static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
122 static struct attribute *mcp4725_attributes[] = {
123 &iio_dev_attr_store_eeprom.dev_attr.attr,
127 static const struct attribute_group mcp4725_attribute_group = {
128 .attrs = mcp4725_attributes,
131 static const char * const mcp4725_powerdown_modes[] = {
137 static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
138 const struct iio_chan_spec *chan)
140 struct mcp4725_data *data = iio_priv(indio_dev);
142 return data->powerdown_mode;
145 static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
146 const struct iio_chan_spec *chan, unsigned mode)
148 struct mcp4725_data *data = iio_priv(indio_dev);
150 data->powerdown_mode = mode;
155 static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
156 uintptr_t private, const struct iio_chan_spec *chan, char *buf)
158 struct mcp4725_data *data = iio_priv(indio_dev);
160 return sprintf(buf, "%d\n", data->powerdown);
163 static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
164 uintptr_t private, const struct iio_chan_spec *chan,
165 const char *buf, size_t len)
167 struct mcp4725_data *data = iio_priv(indio_dev);
171 ret = strtobool(buf, &state);
176 ret = mcp4725_suspend(&data->client->dev);
178 ret = mcp4725_resume(&data->client->dev);
185 static const struct iio_enum mcp4725_powerdown_mode_enum = {
186 .items = mcp4725_powerdown_modes,
187 .num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
188 .get = mcp4725_get_powerdown_mode,
189 .set = mcp4725_set_powerdown_mode,
192 static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
195 .read = mcp4725_read_powerdown,
196 .write = mcp4725_write_powerdown,
197 .shared = IIO_SEPARATE,
199 IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
200 IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
204 static const struct iio_chan_spec mcp4725_channel = {
209 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
210 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
211 .ext_info = mcp4725_ext_info,
214 static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
216 struct mcp4725_data *data = iio_priv(indio_dev);
220 if (val >= (1 << 12) || val < 0)
223 outbuf[0] = (val >> 8) & 0xf;
224 outbuf[1] = val & 0xff;
226 ret = i2c_master_send(data->client, outbuf, 2);
235 static int mcp4725_read_raw(struct iio_dev *indio_dev,
236 struct iio_chan_spec const *chan,
237 int *val, int *val2, long mask)
239 struct mcp4725_data *data = iio_priv(indio_dev);
242 case IIO_CHAN_INFO_RAW:
243 *val = data->dac_value;
245 case IIO_CHAN_INFO_SCALE:
246 *val = data->vref_mv;
248 return IIO_VAL_FRACTIONAL_LOG2;
253 static int mcp4725_write_raw(struct iio_dev *indio_dev,
254 struct iio_chan_spec const *chan,
255 int val, int val2, long mask)
257 struct mcp4725_data *data = iio_priv(indio_dev);
261 case IIO_CHAN_INFO_RAW:
262 ret = mcp4725_set_value(indio_dev, val);
263 data->dac_value = val;
273 static const struct iio_info mcp4725_info = {
274 .read_raw = mcp4725_read_raw,
275 .write_raw = mcp4725_write_raw,
276 .attrs = &mcp4725_attribute_group,
277 .driver_module = THIS_MODULE,
280 static int mcp4725_probe(struct i2c_client *client,
281 const struct i2c_device_id *id)
283 struct mcp4725_data *data;
284 struct iio_dev *indio_dev;
285 struct mcp4725_platform_data *platform_data = client->dev.platform_data;
290 if (!platform_data || !platform_data->vref_mv) {
291 dev_err(&client->dev, "invalid platform data");
295 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
296 if (indio_dev == NULL)
298 data = iio_priv(indio_dev);
299 i2c_set_clientdata(client, indio_dev);
300 data->client = client;
302 indio_dev->dev.parent = &client->dev;
303 indio_dev->info = &mcp4725_info;
304 indio_dev->channels = &mcp4725_channel;
305 indio_dev->num_channels = 1;
306 indio_dev->modes = INDIO_DIRECT_MODE;
308 data->vref_mv = platform_data->vref_mv;
310 /* read current DAC value */
311 err = i2c_master_recv(client, inbuf, 3);
313 dev_err(&client->dev, "failed to read DAC value");
316 pd = (inbuf[0] >> 1) & 0x3;
317 data->powerdown = pd > 0 ? true : false;
318 data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
319 data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
321 return iio_device_register(indio_dev);
324 static int mcp4725_remove(struct i2c_client *client)
326 iio_device_unregister(i2c_get_clientdata(client));
330 static const struct i2c_device_id mcp4725_id[] = {
334 MODULE_DEVICE_TABLE(i2c, mcp4725_id);
336 static struct i2c_driver mcp4725_driver = {
338 .name = MCP4725_DRV_NAME,
339 .pm = MCP4725_PM_OPS,
341 .probe = mcp4725_probe,
342 .remove = mcp4725_remove,
343 .id_table = mcp4725_id,
345 module_i2c_driver(mcp4725_driver);
347 MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
348 MODULE_DESCRIPTION("MCP4725 12-bit DAC");
349 MODULE_LICENSE("GPL");