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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
19#define AD5272_RDAC_WR 1
20#define AD5272_RDAC_RD 2
21#define AD5272_RESET 4
22#define AD5272_CTL 7
23
24#define AD5272_RDAC_WR_EN BIT(1)
25
26struct ad5272_cfg {
27 int max_pos;
28 int kohms;
29 int shift;
30};
31
32enum ad5272_type {
33 AD5272_020,
34 AD5272_050,
35 AD5272_100,
36 AD5274_020,
37 AD5274_100,
38};
39
40static const struct ad5272_cfg ad5272_cfg[] = {
41 [AD5272_020] = { .max_pos = 1024, .kohms = 20 },
42 [AD5272_050] = { .max_pos = 1024, .kohms = 50 },
43 [AD5272_100] = { .max_pos = 1024, .kohms = 100 },
44 [AD5274_020] = { .max_pos = 256, .kohms = 20, .shift = 2 },
45 [AD5274_100] = { .max_pos = 256, .kohms = 100, .shift = 2 },
46};
47
48struct ad5272_data {
49 struct i2c_client *client;
50 struct mutex lock;
51 const struct ad5272_cfg *cfg;
52 u8 buf[2] ____cacheline_aligned;
53};
54
55static const struct iio_chan_spec ad5272_channel = {
56 .type = IIO_RESISTANCE,
57 .output = 1,
58 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
59 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
60};
61
62static int ad5272_write(struct ad5272_data *data, int reg, int val)
63{
64 int ret;
65
66 data->buf[0] = (reg << 2) | ((val >> 8) & 0x3);
67 data->buf[1] = (u8)val;
68
69 mutex_lock(&data->lock);
70 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
71 mutex_unlock(&data->lock);
72 return ret < 0 ? ret : 0;
73}
74
75static int ad5272_read(struct ad5272_data *data, int reg, int *val)
76{
77 int ret;
78
79 data->buf[0] = reg << 2;
80 data->buf[1] = 0;
81
82 mutex_lock(&data->lock);
83 ret = i2c_master_send(data->client, data->buf, sizeof(data->buf));
84 if (ret < 0)
85 goto error;
86
87 ret = i2c_master_recv(data->client, data->buf, sizeof(data->buf));
88 if (ret < 0)
89 goto error;
90
91 *val = ((data->buf[0] & 0x3) << 8) | data->buf[1];
92 ret = 0;
93error:
94 mutex_unlock(&data->lock);
95 return ret;
96}
97
98static int ad5272_read_raw(struct iio_dev *indio_dev,
99 struct iio_chan_spec const *chan,
100 int *val, int *val2, long mask)
101{
102 struct ad5272_data *data = iio_priv(indio_dev);
103 int ret;
104
105 switch (mask) {
106 case IIO_CHAN_INFO_RAW: {
107 ret = ad5272_read(data, AD5272_RDAC_RD, val);
108 *val = *val >> data->cfg->shift;
109 return ret ? ret : IIO_VAL_INT;
110 }
111 case IIO_CHAN_INFO_SCALE:
112 *val = 1000 * data->cfg->kohms;
113 *val2 = data->cfg->max_pos;
114 return IIO_VAL_FRACTIONAL;
115 }
116
117 return -EINVAL;
118}
119
120static int ad5272_write_raw(struct iio_dev *indio_dev,
121 struct iio_chan_spec const *chan,
122 int val, int val2, long mask)
123{
124 struct ad5272_data *data = iio_priv(indio_dev);
125
126 if (mask != IIO_CHAN_INFO_RAW)
127 return -EINVAL;
128
129 if (val >= data->cfg->max_pos || val < 0 || val2)
130 return -EINVAL;
131
132 return ad5272_write(data, AD5272_RDAC_WR, val << data->cfg->shift);
133}
134
135static const struct iio_info ad5272_info = {
136 .read_raw = ad5272_read_raw,
137 .write_raw = ad5272_write_raw,
138};
139
140static int ad5272_reset(struct ad5272_data *data)
141{
142 struct gpio_desc *reset_gpio;
143
144 reset_gpio = devm_gpiod_get_optional(&data->client->dev, "reset",
145 GPIOD_OUT_LOW);
146 if (IS_ERR(reset_gpio))
147 return PTR_ERR(reset_gpio);
148
149 if (reset_gpio) {
150 udelay(1);
151 gpiod_set_value(reset_gpio, 1);
152 } else {
153 ad5272_write(data, AD5272_RESET, 0);
154 }
155 usleep_range(1000, 2000);
156
157 return 0;
158}
159
160static int ad5272_probe(struct i2c_client *client,
161 const struct i2c_device_id *id)
162{
163 struct device *dev = &client->dev;
164 struct iio_dev *indio_dev;
165 struct ad5272_data *data;
166 int ret;
167
168 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
169 if (!indio_dev)
170 return -ENOMEM;
171
172 i2c_set_clientdata(client, indio_dev);
173
174 data = iio_priv(indio_dev);
175 data->client = client;
176 mutex_init(&data->lock);
177 data->cfg = &ad5272_cfg[id->driver_data];
178
179 ret = ad5272_reset(data);
180 if (ret)
181 return ret;
182
183 ret = ad5272_write(data, AD5272_CTL, AD5272_RDAC_WR_EN);
184 if (ret < 0)
185 return -ENODEV;
186
187 indio_dev->dev.parent = dev;
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#if defined(CONFIG_OF)
197static const struct of_device_id ad5272_dt_ids[] = {
198 { .compatible = "adi,ad5272-020", .data = (void *)AD5272_020 },
199 { .compatible = "adi,ad5272-050", .data = (void *)AD5272_050 },
200 { .compatible = "adi,ad5272-100", .data = (void *)AD5272_100 },
201 { .compatible = "adi,ad5274-020", .data = (void *)AD5274_020 },
202 { .compatible = "adi,ad5274-100", .data = (void *)AD5274_100 },
203 {}
204};
205MODULE_DEVICE_TABLE(of, ad5272_dt_ids);
206#endif
207
208static const struct i2c_device_id ad5272_id[] = {
209 { "ad5272-020", AD5272_020 },
210 { "ad5272-050", AD5272_050 },
211 { "ad5272-100", AD5272_100 },
212 { "ad5274-020", AD5274_020 },
213 { "ad5274-100", AD5274_100 },
214 {}
215};
216MODULE_DEVICE_TABLE(i2c, ad5272_id);
217
218static struct i2c_driver ad5272_driver = {
219 .driver = {
220 .name = "ad5272",
221 .of_match_table = of_match_ptr(ad5272_dt_ids),
222 },
223 .probe = ad5272_probe,
224 .id_table = ad5272_id,
225};
226
227module_i2c_driver(ad5272_driver);
228
229MODULE_AUTHOR("Phil Reid <preid@eletromag.com.au>");
230MODULE_DESCRIPTION("AD5272 digital potentiometer");
231MODULE_LICENSE("GPL v2");
232
