summaryrefslogtreecommitdiff
path: root/drivers/iio/potentiometer/ad5272.c
blob: 70c45d346df08efd99efa40c721ce2fc7303ec33 (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
// SPDX-License-Identifier: GPL-2.0+
/*
 * Analog Devices AD5272 digital potentiometer driver
 * Copyright (C) 2018 Phil Reid <preid@electromag.com.au>
 *
 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf
 *
 * DEVID	#Wipers	#Positions	Resistor Opts (kOhm)	i2c address
 * ad5272	1	1024		20, 50, 100		01011xx
 * ad5274	1	256		20, 100			01011xx
 */

#include <linux/delay.h>
#include <linux/gpio/consumer.h>
#include <linux/i2c.h>
#include <linux/iio/iio.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>

#define  AD5272_RDAC_WR  1
#define  AD5272_RDAC_RD  2
#define  AD5272_RESET    4
#define  AD5272_CTL      7

#define  AD5272_RDAC_WR_EN  BIT(1)

struct ad5272_cfg {
	int max_pos;
	int kohms;
	int shift;
};

enum ad5272_type {
	AD5272_020,
	AD5272_050,
	AD5272_100,
	AD5274_020,
	AD5274_100,
};

static const struct ad5272_cfg ad5272_cfg[] = {
	[AD5272_020] = { .max_pos = 1024, .kohms = 20 },
	[AD5272_050] = { .max_pos = 1024, .kohms = 50 },
	[AD5272_100] = { .max_pos = 1024, .kohms = 100 },
	[AD5274_020] = { .max_pos = 256,  .kohms = 20,  .shift = 2 },
	[AD5274_100] = { .max_pos = 256,  .kohms = 100, .shift = 2 },
};

struct ad5272_data {
	struct i2c_client       *client;
	struct mutex            lock;
	const struct ad5272_cfg *cfg;
	u8                      buf[2] ____cacheline_aligned;
};

static const struct iio_chan_spec ad5272_channel = {
	.type = IIO_RESISTANCE,
	.output = 1,
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
};

static int ad5272_write(struct ad5272_data *data, int reg, int val)
{
	int ret;

	data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
	data->buf[1] = (u8)val;

	mutex_lock(&data->lock);
	ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
	mutex_unlock(&data->lock);
	return ret < 0 ? ret : 0;
}

static int ad5272_read(struct ad5272_data *data, int reg, int *val)
{
	int ret;

	data->buf[0] = reg << 2;
	data->buf[1] = 0;

	mutex_lock(&data->lock);
	ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
	if (ret < 0)
		goto error;

	ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
	if (ret < 0)
		goto error;

	*val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
	ret = 0;
error:
	mutex_unlock(&data->lock);
	return ret;
}

static int ad5272_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	struct ad5272_data *data = iio_priv(indio_dev);
	int ret;

	switch (mask) {
	case IIO_CHAN_INFO_RAW: {
		ret = ad5272_read(data, AD5272_RDAC_RD, val);
		*val = *val >> data->cfg->shift;
		return ret ? ret : IIO_VAL_INT;
	}
	case IIO_CHAN_INFO_SCALE:
		*val = 1000 * data->cfg->kohms;
		*val2 = data->cfg->max_pos;
		return IIO_VAL_FRACTIONAL;
	}

	return -EINVAL;
}

static int ad5272_write_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int val, int val2, long mask)
{
	struct ad5272_data *data = iio_priv(indio_dev);

	if (mask != IIO_CHAN_INFO_RAW)
		return -EINVAL;

	if (val >= data->cfg->max_pos || val < 0 || val2)
		return -EINVAL;

	return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
}

static const struct iio_info ad5272_info = {
	.read_raw = ad5272_read_raw,
	.write_raw = ad5272_write_raw,
};

static int ad5272_reset(struct ad5272_data *data)
{
	struct gpio_desc *reset_gpio;

	reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
		GPIOD_OUT_LOW);
	if (IS_ERR(reset_gpio))
		return PTR_ERR(reset_gpio);

	if (reset_gpio) {
		udelay(1);
		gpiod_set_value(reset_gpio, 1);
	} else {
		ad5272_write(data, AD5272_RESET, 0);
	}
	usleep_range(1000, 2000);

	return 0;
}

static int ad5272_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct iio_dev *indio_dev;
	struct ad5272_data *data;
	int ret;

	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;
	mutex_init(&data->lock);
	data->cfg = &ad5272_cfg[id->driver_data];

	ret = ad5272_reset(data);
	if (ret)
		return ret;

	ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
	if (ret < 0)
		return -ENODEV;

	indio_dev->info = &ad5272_info;
	indio_dev->channels = &ad5272_channel;
	indio_dev->num_channels = 1;
	indio_dev->name = client->name;

	return devm_iio_device_register(dev, indio_dev);
}

static const struct of_device_id ad5272_dt_ids[] = {
	{ .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
	{ .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
	{ .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
	{ .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
	{ .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
	{}
};
MODULE_DEVICE_TABLE(of, ad5272_dt_ids);

static const struct i2c_device_id ad5272_id[] = {
	{ "ad5272-020", AD5272_020 },
	{ "ad5272-050", AD5272_050 },
	{ "ad5272-100", AD5272_100 },
	{ "ad5274-020", AD5274_020 },
	{ "ad5274-100", AD5274_100 },
	{}
};
MODULE_DEVICE_TABLE(i2c, ad5272_id);

static struct i2c_driver ad5272_driver = {
	.driver = {
		.name	= "ad5272",
		.of_match_table = ad5272_dt_ids,
	},
	.probe		= ad5272_probe,
	.id_table	= ad5272_id,
};

module_i2c_driver(ad5272_driver);

MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
MODULE_DESCRIPTION("AD5272 digital potentiometer");
MODULE_LICENSE("GPL v2");