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23#include <linux/module.h>
24#include <linux/i2c.h>
25#include <linux/err.h>
26
27#include <linux/iio/iio.h>
28
29struct mcp4531_cfg {
30 int wipers;
31 int max_pos;
32 int kohms;
33};
34
35enum mcp4531_type {
36 MCP453x_502,
37 MCP453x_103,
38 MCP453x_503,
39 MCP453x_104,
40 MCP455x_502,
41 MCP455x_103,
42 MCP455x_503,
43 MCP455x_104,
44 MCP463x_502,
45 MCP463x_103,
46 MCP463x_503,
47 MCP463x_104,
48 MCP465x_502,
49 MCP465x_103,
50 MCP465x_503,
51 MCP465x_104,
52};
53
54static const struct mcp4531_cfg mcp4531_cfg[] = {
55 [MCP453x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, },
56 [MCP453x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
57 [MCP453x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, },
58 [MCP453x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, },
59 [MCP455x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, },
60 [MCP455x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, },
61 [MCP455x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, },
62 [MCP455x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
63 [MCP463x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, },
64 [MCP463x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, },
65 [MCP463x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, },
66 [MCP463x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, },
67 [MCP465x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, },
68 [MCP465x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, },
69 [MCP465x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, },
70 [MCP465x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, },
71};
72
73#define MCP4531_WRITE (0 << 2)
74#define MCP4531_INCR (1 << 2)
75#define MCP4531_DECR (2 << 2)
76#define MCP4531_READ (3 << 2)
77
78#define MCP4531_WIPER_SHIFT (4)
79
80struct mcp4531_data {
81 struct i2c_client *client;
82 unsigned long devid;
83};
84
85#define MCP4531_CHANNEL(ch) { \
86 .type = IIO_RESISTANCE, \
87 .indexed = 1, \
88 .output = 1, \
89 .channel = (ch), \
90 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
91 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
92}
93
94static const struct iio_chan_spec mcp4531_channels[] = {
95 MCP4531_CHANNEL(0),
96 MCP4531_CHANNEL(1),
97};
98
99static int mcp4531_read_raw(struct iio_dev *indio_dev,
100 struct iio_chan_spec const *chan,
101 int *val, int *val2, long mask)
102{
103 struct mcp4531_data *data = iio_priv(indio_dev);
104 int address = chan->channel << MCP4531_WIPER_SHIFT;
105 s32 ret;
106
107 switch (mask) {
108 case IIO_CHAN_INFO_RAW:
109 ret = i2c_smbus_read_word_swapped(data->client,
110 MCP4531_READ | address);
111 if (ret < 0)
112 return ret;
113 *val = ret;
114 return IIO_VAL_INT;
115 case IIO_CHAN_INFO_SCALE:
116 *val = 1000 * mcp4531_cfg[data->devid].kohms;
117 *val2 = mcp4531_cfg[data->devid].max_pos;
118 return IIO_VAL_FRACTIONAL;
119 }
120
121 return -EINVAL;
122}
123
124static int mcp4531_write_raw(struct iio_dev *indio_dev,
125 struct iio_chan_spec const *chan,
126 int val, int val2, long mask)
127{
128 struct mcp4531_data *data = iio_priv(indio_dev);
129 int address = chan->channel << MCP4531_WIPER_SHIFT;
130
131 switch (mask) {
132 case IIO_CHAN_INFO_RAW:
133 if (val > mcp4531_cfg[data->devid].max_pos || val < 0)
134 return -EINVAL;
135 break;
136 default:
137 return -EINVAL;
138 }
139
140 return i2c_smbus_write_byte_data(data->client,
141 MCP4531_WRITE | address | (val >> 8),
142 val & 0xff);
143}
144
145static const struct iio_info mcp4531_info = {
146 .read_raw = mcp4531_read_raw,
147 .write_raw = mcp4531_write_raw,
148 .driver_module = THIS_MODULE,
149};
150
151static int mcp4531_probe(struct i2c_client *client,
152 const struct i2c_device_id *id)
153{
154 struct device *dev = &client->dev;
155 unsigned long devid = id->driver_data;
156 struct mcp4531_data *data;
157 struct iio_dev *indio_dev;
158
159 if (!i2c_check_functionality(client->adapter,
160 I2C_FUNC_SMBUS_WORD_DATA)) {
161 dev_err(dev, "SMBUS Word Data not supported\n");
162 return -EOPNOTSUPP;
163 }
164
165 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
166 if (!indio_dev)
167 return -ENOMEM;
168 data = iio_priv(indio_dev);
169 i2c_set_clientdata(client, indio_dev);
170 data->client = client;
171 data->devid = devid;
172
173 indio_dev->dev.parent = dev;
174 indio_dev->info = &mcp4531_info;
175 indio_dev->channels = mcp4531_channels;
176 indio_dev->num_channels = mcp4531_cfg[devid].wipers;
177 indio_dev->name = client->name;
178
179 return devm_iio_device_register(dev, indio_dev);
180}
181
182static const struct i2c_device_id mcp4531_id[] = {
183 { "mcp4531-502", MCP453x_502 },
184 { "mcp4531-103", MCP453x_103 },
185 { "mcp4531-503", MCP453x_503 },
186 { "mcp4531-104", MCP453x_104 },
187 { "mcp4532-502", MCP453x_502 },
188 { "mcp4532-103", MCP453x_103 },
189 { "mcp4532-503", MCP453x_503 },
190 { "mcp4532-104", MCP453x_104 },
191 { "mcp4551-502", MCP455x_502 },
192 { "mcp4551-103", MCP455x_103 },
193 { "mcp4551-503", MCP455x_503 },
194 { "mcp4551-104", MCP455x_104 },
195 { "mcp4552-502", MCP455x_502 },
196 { "mcp4552-103", MCP455x_103 },
197 { "mcp4552-503", MCP455x_503 },
198 { "mcp4552-104", MCP455x_104 },
199 { "mcp4631-502", MCP463x_502 },
200 { "mcp4631-103", MCP463x_103 },
201 { "mcp4631-503", MCP463x_503 },
202 { "mcp4631-104", MCP463x_104 },
203 { "mcp4632-502", MCP463x_502 },
204 { "mcp4632-103", MCP463x_103 },
205 { "mcp4632-503", MCP463x_503 },
206 { "mcp4632-104", MCP463x_104 },
207 { "mcp4651-502", MCP465x_502 },
208 { "mcp4651-103", MCP465x_103 },
209 { "mcp4651-503", MCP465x_503 },
210 { "mcp4651-104", MCP465x_104 },
211 { "mcp4652-502", MCP465x_502 },
212 { "mcp4652-103", MCP465x_103 },
213 { "mcp4652-503", MCP465x_503 },
214 { "mcp4652-104", MCP465x_104 },
215 {}
216};
217MODULE_DEVICE_TABLE(i2c, mcp4531_id);
218
219static struct i2c_driver mcp4531_driver = {
220 .driver = {
221 .name = "mcp4531",
222 },
223 .probe = mcp4531_probe,
224 .id_table = mcp4531_id,
225};
226
227module_i2c_driver(mcp4531_driver);
228
229MODULE_AUTHOR("Peter Rosin <peda@axentia.se>");
230MODULE_DESCRIPTION("MCP4531 digital potentiometer");
231MODULE_LICENSE("GPL");
232
