1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Analog Devices AD5272 digital potentiometer driver
4 * Copyright (C) 2018 Phil Reid <preid@electromag.com.au>
5 *
6 * Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/AD5272_5274.pdf
7 *
8 * DEVID #Wipers #Positions Resistor Opts (kOhm) i2c address
9 * ad5272 1 1024 20, 50, 100 01011xx
10 * ad5274 1 256 20, 100 01011xx
11 */
12
13 #include <linux/delay.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/i2c.h>
16 #include <linux/iio/iio.h>
17 #include <linux/module.h>
18 #include <linux/mod_devicetable.h>
19
20 #define AD5272_RDAC_WR 1
21 #define AD5272_RDAC_RD 2
22 #define AD5272_RESET 4
23 #define AD5272_CTL 7
24
25 #define AD5272_RDAC_WR_EN BIT(1)
26
27 struct ad5272_cfg {
28 int max_pos;
29 int kohms;
30 int shift;
31 };
32
33 enum ad5272_type {
34 AD5272_020,
35 AD5272_050,
36 AD5272_100,
37 AD5274_020,
38 AD5274_100,
39 };
40
41 static const struct ad5272_cfg ad5272_cfg[] = {
42 [AD5272_020] = { .max_pos = 1024, .kohms = 20 },
43 [AD5272_050] = { .max_pos = 1024, .kohms = 50 },
44 [AD5272_100] = { .max_pos = 1024, .kohms = 100 },
45 [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },
46 [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },
47 };
48
49 struct ad5272_data {
50 struct i2c_client *client;
51 struct mutex lock;
52 const struct ad5272_cfg *cfg;
53 u8 buf[2] __aligned(IIO_DMA_MINALIGN);
54 };
55
56 static const struct iio_chan_spec ad5272_channel = {
57 .type = IIO_RESISTANCE,
58 .output = 1,
59 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
60 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
61 };
62
ad5272_write(struct ad5272_data * data,int reg,int val)63 static int ad5272_write(struct ad5272_data *data, int reg, int val)
64 {
65 int ret;
66
67 data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
68 data->buf[1] = (u8)val;
69
70 mutex_lock(&data->lock);
71 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
72 mutex_unlock(&data->lock);
73 return ret < 0 ? ret : 0;
74 }
75
ad5272_read(struct ad5272_data * data,int reg,int * val)76 static int ad5272_read(struct ad5272_data *data, int reg, int *val)
77 {
78 int ret;
79
80 data->buf[0] = reg << 2;
81 data->buf[1] = 0;
82
83 mutex_lock(&data->lock);
84 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
85 if (ret < 0)
86 goto error;
87
88 ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
89 if (ret < 0)
90 goto error;
91
92 *val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
93 ret = 0;
94 error:
95 mutex_unlock(&data->lock);
96 return ret;
97 }
98
ad5272_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)99 static int ad5272_read_raw(struct iio_dev *indio_dev,
100 struct iio_chan_spec const *chan,
101 int *val, int *val2, long mask)
102 {
103 struct ad5272_data *data = iio_priv(indio_dev);
104 int ret;
105
106 switch (mask) {
107 case IIO_CHAN_INFO_RAW: {
108 ret = ad5272_read(data, AD5272_RDAC_RD, val);
109 *val = *val >> data->cfg->shift;
110 return ret ? ret : IIO_VAL_INT;
111 }
112 case IIO_CHAN_INFO_SCALE:
113 *val = 1000 * data->cfg->kohms;
114 *val2 = data->cfg->max_pos;
115 return IIO_VAL_FRACTIONAL;
116 }
117
118 return -EINVAL;
119 }
120
ad5272_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)121 static int ad5272_write_raw(struct iio_dev *indio_dev,
122 struct iio_chan_spec const *chan,
123 int val, int val2, long mask)
124 {
125 struct ad5272_data *data = iio_priv(indio_dev);
126
127 if (mask != IIO_CHAN_INFO_RAW)
128 return -EINVAL;
129
130 if (val >= data->cfg->max_pos || val < 0 || val2)
131 return -EINVAL;
132
133 return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
134 }
135
136 static const struct iio_info ad5272_info = {
137 .read_raw = ad5272_read_raw,
138 .write_raw = ad5272_write_raw,
139 };
140
ad5272_reset(struct ad5272_data * data)141 static int ad5272_reset(struct ad5272_data *data)
142 {
143 struct gpio_desc *reset_gpio;
144
145 reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
146 GPIOD_OUT_HIGH);
147 if (IS_ERR(reset_gpio))
148 return PTR_ERR(reset_gpio);
149
150 if (reset_gpio) {
151 udelay(1);
152 gpiod_set_value(reset_gpio, 0);
153 } else {
154 ad5272_write(data, AD5272_RESET, 0);
155 }
156 usleep_range(1000, 2000);
157
158 return 0;
159 }
160
ad5272_probe(struct i2c_client * client)161 static int ad5272_probe(struct i2c_client *client)
162 {
163 const struct i2c_device_id *id = i2c_client_get_device_id(client);
164 struct device *dev = &client->dev;
165 struct iio_dev *indio_dev;
166 struct ad5272_data *data;
167 int ret;
168
169 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
170 if (!indio_dev)
171 return -ENOMEM;
172
173 i2c_set_clientdata(client, indio_dev);
174
175 data = iio_priv(indio_dev);
176 data->client = client;
177 mutex_init(&data->lock);
178 data->cfg = &ad5272_cfg[id->driver_data];
179
180 ret = ad5272_reset(data);
181 if (ret)
182 return ret;
183
184 ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
185 if (ret < 0)
186 return -ENODEV;
187
188 indio_dev->info = &ad5272_info;
189 indio_dev->channels = &ad5272_channel;
190 indio_dev->num_channels = 1;
191 indio_dev->name = client->name;
192
193 return devm_iio_device_register(dev, indio_dev);
194 }
195
196 static const struct of_device_id ad5272_dt_ids[] = {
197 { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
198 { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
199 { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
200 { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
201 { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
202 {}
203 };
204 MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
205
206 static const struct i2c_device_id ad5272_id[] = {
207 { "ad5272-020", AD5272_020 },
208 { "ad5272-050", AD5272_050 },
209 { "ad5272-100", AD5272_100 },
210 { "ad5274-020", AD5274_020 },
211 { "ad5274-100", AD5274_100 },
212 {}
213 };
214 MODULE_DEVICE_TABLE(i2c, ad5272_id);
215
216 static struct i2c_driver ad5272_driver = {
217 .driver = {
218 .name = "ad5272",
219 .of_match_table = ad5272_dt_ids,
220 },
221 .probe = ad5272_probe,
222 .id_table = ad5272_id,
223 };
224
225 module_i2c_driver(ad5272_driver);
226
227 MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
228 MODULE_DESCRIPTION("AD5272 digital potentiometer");
229 MODULE_LICENSE("GPL v2");
230