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 | |
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(client: data->client, buf: data->buf, count: sizeof(data->buf)); |
72 | mutex_unlock(lock: &data->lock); |
73 | return ret < 0 ? ret : 0; |
74 | } |
75 | |
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(client: data->client, buf: data->buf, count: sizeof(data->buf)); |
85 | if (ret < 0) |
86 | goto error; |
87 | |
88 | ret = i2c_master_recv(client: data->client, buf: data->buf, count: 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(lock: &data->lock); |
96 | return ret; |
97 | } |
98 | |
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 | |
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: 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 | |
141 | static int ad5272_reset(struct ad5272_data *data) |
142 | { |
143 | struct gpio_desc *reset_gpio; |
144 | |
145 | reset_gpio = devm_gpiod_get_optional(dev: &data->client->dev, con_id: "reset" , |
146 | flags: GPIOD_OUT_HIGH); |
147 | if (IS_ERR(ptr: reset_gpio)) |
148 | return PTR_ERR(ptr: reset_gpio); |
149 | |
150 | if (reset_gpio) { |
151 | udelay(1); |
152 | gpiod_set_value(desc: reset_gpio, value: 0); |
153 | } else { |
154 | ad5272_write(data, AD5272_RESET, val: 0); |
155 | } |
156 | usleep_range(min: 1000, max: 2000); |
157 | |
158 | return 0; |
159 | } |
160 | |
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(parent: dev, sizeof_priv: sizeof(*data)); |
170 | if (!indio_dev) |
171 | return -ENOMEM; |
172 | |
173 | i2c_set_clientdata(client, data: 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 | |