aboutsummaryrefslogtreecommitdiff
path: root/drivers/iio/dac/mcp4725.c
blob: b4dde8315210c6519c7e2a7db4bd8bf3b6607988 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
/*
 * mcp4725.c - Support for Microchip MCP4725
 *
 * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
 *
 * Based on max517 by Roland Stigge <stigge@antcom.de>
 *
 * This file is subject to the terms and conditions of version 2 of
 * the GNU General Public License.  See the file COPYING in the main
 * directory of this archive for more details.
 *
 * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
 * (7-bit I2C slave address 0x60, the three LSBs can be configured in
 * hardware)
 */

#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/delay.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>

#include <linux/iio/dac/mcp4725.h>

#define MCP4725_DRV_NAME "mcp4725"

struct mcp4725_data {
	struct i2c_client *client;
	u16 vref_mv;
	u16 dac_value;
	bool powerdown;
	unsigned powerdown_mode;
};

static int mcp4725_suspend(struct device *dev)
{
	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
		to_i2c_client(dev)));
	u8 outbuf[2];

	outbuf[0] = (data->powerdown_mode + 1) << 4;
	outbuf[1] = 0;
	data->powerdown = true;

	return i2c_master_send(data->client, outbuf, 2);
}

static int mcp4725_resume(struct device *dev)
{
	struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
		to_i2c_client(dev)));
	u8 outbuf[2];

	/* restore previous DAC value */
	outbuf[0] = (data->dac_value >> 8) & 0xf;
	outbuf[1] = data->dac_value & 0xff;
	data->powerdown = false;

	return i2c_master_send(data->client, outbuf, 2);
}

#ifdef CONFIG_PM_SLEEP
static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
#define MCP4725_PM_OPS (&mcp4725_pm_ops)
#else
#define MCP4725_PM_OPS NULL
#endif

static ssize_t mcp4725_store_eeprom(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t len)
{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct mcp4725_data *data = iio_priv(indio_dev);
	int tries = 20;
	u8 inoutbuf[3];
	bool state;
	int ret;

	ret = strtobool(buf, &state);
	if (ret < 0)
		return ret;

	if (!state)
		return 0;

	inoutbuf[0] = 0x60; /* write EEPROM */
	inoutbuf[1] = data->dac_value >> 4;
	inoutbuf[2] = (data->dac_value & 0xf) << 4;

	ret = i2c_master_send(data->client, inoutbuf, 3);
	if (ret < 0)
		return ret;
	else if (ret != 3)
		return -EIO;

	/* wait for write complete, takes up to 50ms */
	while (tries--) {
		msleep(20);
		ret = i2c_master_recv(data->client, inoutbuf, 3);
		if (ret < 0)
			return ret;
		else if (ret != 3)
			return -EIO;

		if (inoutbuf[0] & 0x80)
			break;
	}

	if (tries < 0) {
		dev_err(&data->client->dev,
			"mcp4725_store_eeprom() failed, incomplete\n");
		return -EIO;
	}

	return len;
}

static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);

static struct attribute *mcp4725_attributes[] = {
	&iio_dev_attr_store_eeprom.dev_attr.attr,
	NULL,
};

static const struct attribute_group mcp4725_attribute_group = {
	.attrs = mcp4725_attributes,
};

static const char * const mcp4725_powerdown_modes[] = {
	"1kohm_to_gnd",
	"100kohm_to_gnd",
	"500kohm_to_gnd"
};

static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	return data->powerdown_mode;
}

static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
	const struct iio_chan_spec *chan, unsigned mode)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	data->powerdown_mode = mode;

	return 0;
}

static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
	uintptr_t private, const struct iio_chan_spec *chan, char *buf)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	return sprintf(buf, "%d\n", data->powerdown);
}

static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
	 uintptr_t private, const struct iio_chan_spec *chan,
	 const char *buf, size_t len)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	bool state;
	int ret;

	ret = strtobool(buf, &state);
	if (ret)
		return ret;

	if (state)
		ret = mcp4725_suspend(&data->client->dev);
	else
		ret = mcp4725_resume(&data->client->dev);
	if (ret < 0)
		return ret;

	return len;
}

static const struct iio_enum mcp4725_powerdown_mode_enum = {
	.items = mcp4725_powerdown_modes,
	.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
	.get = mcp4725_get_powerdown_mode,
	.set = mcp4725_set_powerdown_mode,
};

static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
	{
		.name = "powerdown",
		.read = mcp4725_read_powerdown,
		.write = mcp4725_write_powerdown,
		.shared = IIO_SEPARATE,
	},
	IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum),
	IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum),
	{ },
};

static const struct iio_chan_spec mcp4725_channel = {
	.type		= IIO_VOLTAGE,
	.indexed	= 1,
	.output		= 1,
	.channel	= 0,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
	.ext_info	= mcp4725_ext_info,
};

static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	u8 outbuf[2];
	int ret;

	if (val >= (1 << 12) || val < 0)
		return -EINVAL;

	outbuf[0] = (val >> 8) & 0xf;
	outbuf[1] = val & 0xff;

	ret = i2c_master_send(data->client, outbuf, 2);
	if (ret < 0)
		return ret;
	else if (ret != 2)
		return -EIO;
	else
		return 0;
}

static int mcp4725_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct mcp4725_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		*val = data->dac_value;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = data->vref_mv;
		*val2 = 12;
		return IIO_VAL_FRACTIONAL_LOG2;
	}
	return -EINVAL;
}

static int mcp4725_write_raw(struct iio_dev *indio_dev,
			       struct iio_chan_spec const *chan,
			       int val, int val2, long mask)
{
	struct mcp4725_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = mcp4725_set_value(indio_dev, val);
		data->dac_value = val;
		break;
	default:
		ret = -EINVAL;
		break;
	}

	return ret;
}

static const struct iio_info mcp4725_info = {
	.read_raw = mcp4725_read_raw,
	.write_raw = mcp4725_write_raw,
	.attrs = &mcp4725_attribute_group,
	.driver_module = THIS_MODULE,
};

static int mcp4725_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct mcp4725_data *data;
	struct iio_dev *indio_dev;
	struct mcp4725_platform_data *platform_data = client->dev.platform_data;
	u8 inbuf[3];
	u8 pd;
	int err;

	if (!platform_data || !platform_data->vref_mv) {
		dev_err(&client->dev, "invalid platform data");
		return -EINVAL;
	}

	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
	if (indio_dev == NULL)
		return -ENOMEM;
	data = iio_priv(indio_dev);
	i2c_set_clientdata(client, indio_dev);
	data->client = client;

	indio_dev->dev.parent = &client->dev;
	indio_dev->name = id->name;
	indio_dev->info = &mcp4725_info;
	indio_dev->channels = &mcp4725_channel;
	indio_dev->num_channels = 1;
	indio_dev->modes = INDIO_DIRECT_MODE;

	data->vref_mv = platform_data->vref_mv;

	/* read current DAC value */
	err = i2c_master_recv(client, inbuf, 3);
	if (err < 0) {
		dev_err(&client->dev, "failed to read DAC value");
		return err;
	}
	pd = (inbuf[0] >> 1) & 0x3;
	data->powerdown = pd > 0 ? true : false;
	data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */
	data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);

	return iio_device_register(indio_dev);
}

static int mcp4725_remove(struct i2c_client *client)
{
	iio_device_unregister(i2c_get_clientdata(client));
	return 0;
}

static const struct i2c_device_id mcp4725_id[] = {
	{ "mcp4725", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mcp4725_id);

static struct i2c_driver mcp4725_driver = {
	.driver = {
		.name	= MCP4725_DRV_NAME,
		.pm	= MCP4725_PM_OPS,
	},
	.probe		= mcp4725_probe,
	.remove		= mcp4725_remove,
	.id_table	= mcp4725_id,
};
module_i2c_driver(mcp4725_driver);

MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>");
MODULE_DESCRIPTION("MCP4725 12-bit DAC");
MODULE_LICENSE("GPL");