summaryrefslogtreecommitdiff
path: root/drivers/iio/potentiometer/ds1803.c
blob: fc183e0790dafb989a1260a6e10526dc458b61db (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
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Maxim Integrated DS1803 and similar digital potentiometer driver
 * Copyright (c) 2016 Slawomir Stepien
 * Copyright (c) 2022 Jagath Jog J
 *
 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS1803.pdf
 * Datasheet: https://datasheets.maximintegrated.com/en/ds/DS3502.pdf
 *
 * DEVID	#Wipers	#Positions	Resistor Opts (kOhm)	i2c address
 * ds1803	2	256		10, 50, 100		0101xxx
 * ds3502	1	128		10			01010xx
 */

#include <linux/err.h>
#include <linux/export.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/property.h>

#define DS1803_WIPER_0         0xA9
#define DS1803_WIPER_1         0xAA
#define DS3502_WR_IVR          0x00

enum ds1803_type {
	DS1803_010,
	DS1803_050,
	DS1803_100,
	DS3502,
};

struct ds1803_cfg {
	int wipers;
	int avail[3];
	int kohms;
	const struct iio_chan_spec *channels;
	u8 num_channels;
	int (*read)(struct iio_dev *indio_dev,
		    struct iio_chan_spec const *chan, int *val);
};

struct ds1803_data {
	struct i2c_client *client;
	const struct ds1803_cfg *cfg;
};

#define DS1803_CHANNEL(ch, addr) {					\
	.type = IIO_RESISTANCE,						\
	.indexed = 1,							\
	.output = 1,							\
	.channel = (ch),						\
	.address = (addr),						\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),			\
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),		\
	.info_mask_shared_by_type_available = BIT(IIO_CHAN_INFO_RAW),   \
}

static const struct iio_chan_spec ds1803_channels[] = {
	DS1803_CHANNEL(0, DS1803_WIPER_0),
	DS1803_CHANNEL(1, DS1803_WIPER_1),
};

static const struct iio_chan_spec ds3502_channels[] = {
	DS1803_CHANNEL(0, DS3502_WR_IVR),
};

static int ds1803_read(struct iio_dev *indio_dev,
		       struct iio_chan_spec const *chan,
		       int *val)
{
	struct ds1803_data *data = iio_priv(indio_dev);
	int ret;
	u8 result[ARRAY_SIZE(ds1803_channels)];

	ret = i2c_master_recv(data->client, result, indio_dev->num_channels);
	if (ret < 0)
		return ret;

	*val = result[chan->channel];
	return ret;
}

static int ds3502_read(struct iio_dev *indio_dev,
		       struct iio_chan_spec const *chan,
		       int *val)
{
	struct ds1803_data *data = iio_priv(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(data->client, chan->address);
	if (ret < 0)
		return ret;

	*val = ret;
	return ret;
}

static const struct ds1803_cfg ds1803_cfg[] = {
	[DS1803_010] = {
		.wipers = 2,
		.avail = { 0, 1, 255 },
		.kohms =  10,
		.channels = ds1803_channels,
		.num_channels = ARRAY_SIZE(ds1803_channels),
		.read = ds1803_read,
	},
	[DS1803_050] = {
		.wipers = 2,
		.avail = { 0, 1, 255 },
		.kohms =  50,
		.channels = ds1803_channels,
		.num_channels = ARRAY_SIZE(ds1803_channels),
		.read = ds1803_read,
	},
	[DS1803_100] = {
		.wipers = 2,
		.avail = { 0, 1, 255 },
		.kohms = 100,
		.channels = ds1803_channels,
		.num_channels = ARRAY_SIZE(ds1803_channels),
		.read = ds1803_read,
	},
	[DS3502] = {
	  .wipers = 1,
	  .avail = { 0, 1, 127 },
	  .kohms =  10,
	  .channels = ds3502_channels,
	  .num_channels = ARRAY_SIZE(ds3502_channels),
	  .read = ds3502_read,
	},
};

static int ds1803_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct ds1803_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = data->cfg->read(indio_dev, chan, val);
		if (ret < 0)
			return ret;

		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:
		*val = 1000 * data->cfg->kohms;
		*val2 = data->cfg->avail[2]; /* Max wiper position */
		return IIO_VAL_FRACTIONAL;
	}

	return -EINVAL;
}

static int ds1803_write_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int val, int val2, long mask)
{
	struct ds1803_data *data = iio_priv(indio_dev);
	u8 addr = chan->address;
	int max_pos = data->cfg->avail[2];

	if (val2 != 0)
		return -EINVAL;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		if (val > max_pos || val < 0)
			return -EINVAL;
		break;
	default:
		return -EINVAL;
	}

	return i2c_smbus_write_byte_data(data->client, addr, val);
}

static int ds1803_read_avail(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     const int **vals, int *type,
			     int *length, long mask)
{
	struct ds1803_data *data = iio_priv(indio_dev);

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		*vals = data->cfg->avail;
		*length = ARRAY_SIZE(data->cfg->avail);
		*type = IIO_VAL_INT;
		return IIO_AVAIL_RANGE;
	}
	return -EINVAL;
}

static const struct iio_info ds1803_info = {
	.read_raw = ds1803_read_raw,
	.write_raw = ds1803_write_raw,
	.read_avail = ds1803_read_avail,
};

static int ds1803_probe(struct i2c_client *client)
{
	const struct i2c_device_id *id = i2c_client_get_device_id(client);
	struct device *dev = &client->dev;
	struct ds1803_data *data;
	struct iio_dev *indio_dev;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
	if (!indio_dev)
		return -ENOMEM;

	i2c_set_clientdata(client, indio_dev);

	data = iio_priv(indio_dev);
	data->client = client;
	data->cfg = device_get_match_data(dev);
	if (!data->cfg)
		data->cfg = &ds1803_cfg[id->driver_data];

	indio_dev->info = &ds1803_info;
	indio_dev->channels = data->cfg->channels;
	indio_dev->num_channels = data->cfg->num_channels;
	indio_dev->name = client->name;

	return devm_iio_device_register(dev, indio_dev);
}

static const struct of_device_id ds1803_dt_ids[] = {
	{ .compatible = "maxim,ds1803-010", .data = &ds1803_cfg[DS1803_010] },
	{ .compatible = "maxim,ds1803-050", .data = &ds1803_cfg[DS1803_050] },
	{ .compatible = "maxim,ds1803-100", .data = &ds1803_cfg[DS1803_100] },
	{ .compatible = "maxim,ds3502", .data = &ds1803_cfg[DS3502] },
	{}
};
MODULE_DEVICE_TABLE(of, ds1803_dt_ids);

static const struct i2c_device_id ds1803_id[] = {
	{ "ds1803-010", DS1803_010 },
	{ "ds1803-050", DS1803_050 },
	{ "ds1803-100", DS1803_100 },
	{ "ds3502", DS3502 },
	{}
};
MODULE_DEVICE_TABLE(i2c, ds1803_id);

static struct i2c_driver ds1803_driver = {
	.driver = {
		.name	= "ds1803",
		.of_match_table = ds1803_dt_ids,
	},
	.probe		= ds1803_probe,
	.id_table	= ds1803_id,
};

module_i2c_driver(ds1803_driver);

MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>");
MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
MODULE_DESCRIPTION("DS1803 digital potentiometer");
MODULE_LICENSE("GPL v2");