1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * tpl0102.c - Support for Texas Instruments digital potentiometers
4 *
5 * Copyright (C) 2016, 2018
6 * Author: Matt Ranostay <matt.ranostay@konsulko.com>
7 *
8 * TODO: enable/disable hi-z output control
9 */
10
11 #include <linux/module.h>
12 #include <linux/i2c.h>
13 #include <linux/regmap.h>
14 #include <linux/iio/iio.h>
15
16 struct tpl0102_cfg {
17 int wipers;
18 int avail[3];
19 int kohms;
20 };
21
22 enum tpl0102_type {
23 CAT5140_503,
24 CAT5140_104,
25 TPL0102_104,
26 TPL0401_103,
27 };
28
29 static const struct tpl0102_cfg tpl0102_cfg[] = {
30 /* on-semiconductor parts */
31 [CAT5140_503] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 50, },
32 [CAT5140_104] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 100, },
33 /* ti parts */
34 [TPL0102_104] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 100 },
35 [TPL0401_103] = { .wipers = 1, .avail = { 0, 1, 127 }, .kohms = 10, },
36 };
37
38 struct tpl0102_data {
39 struct regmap *regmap;
40 const struct tpl0102_cfg *cfg;
41 };
42
43 static const struct regmap_config tpl0102_regmap_config = {
44 .reg_bits = 8,
45 .val_bits = 8,
46 };
47
48 #define TPL0102_CHANNEL(ch) { \
49 .type = IIO_RESISTANCE, \
50 .indexed = 1, \
51 .output = 1, \
52 .channel = (ch), \
53 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
54 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
55 .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), \
56 }
57
58 static const struct iio_chan_spec tpl0102_channels[] = {
59 TPL0102_CHANNEL(0),
60 TPL0102_CHANNEL(1),
61 };
62
tpl0102_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)63 static int tpl0102_read_raw(struct iio_dev *indio_dev,
64 struct iio_chan_spec const *chan,
65 int *val, int *val2, long mask)
66 {
67 struct tpl0102_data *data = iio_priv(indio_dev);
68
69 switch (mask) {
70 case IIO_CHAN_INFO_RAW: {
71 int ret = regmap_read(data->regmap, chan->channel, val);
72
73 return ret ? ret : IIO_VAL_INT;
74 }
75 case IIO_CHAN_INFO_SCALE:
76 *val = 1000 * data->cfg->kohms;
77 *val2 = data->cfg->avail[2] + 1;
78 return IIO_VAL_FRACTIONAL;
79 }
80
81 return -EINVAL;
82 }
83
tpl0102_read_avail(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,const int ** vals,int * type,int * length,long mask)84 static int tpl0102_read_avail(struct iio_dev *indio_dev,
85 struct iio_chan_spec const *chan,
86 const int **vals, int *type, int *length,
87 long mask)
88 {
89 struct tpl0102_data *data = iio_priv(indio_dev);
90
91 switch (mask) {
92 case IIO_CHAN_INFO_RAW:
93 *length = ARRAY_SIZE(data->cfg->avail);
94 *vals = data->cfg->avail;
95 *type = IIO_VAL_INT;
96 return IIO_AVAIL_RANGE;
97 }
98
99 return -EINVAL;
100 }
101
tpl0102_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)102 static int tpl0102_write_raw(struct iio_dev *indio_dev,
103 struct iio_chan_spec const *chan,
104 int val, int val2, long mask)
105 {
106 struct tpl0102_data *data = iio_priv(indio_dev);
107
108 if (mask != IIO_CHAN_INFO_RAW)
109 return -EINVAL;
110
111 if (val > data->cfg->avail[2] || val < 0)
112 return -EINVAL;
113
114 return regmap_write(data->regmap, chan->channel, val);
115 }
116
117 static const struct iio_info tpl0102_info = {
118 .read_raw = tpl0102_read_raw,
119 .read_avail = tpl0102_read_avail,
120 .write_raw = tpl0102_write_raw,
121 };
122
tpl0102_probe(struct i2c_client * client)123 static int tpl0102_probe(struct i2c_client *client)
124 {
125 const struct i2c_device_id *id = i2c_client_get_device_id(client);
126 struct device *dev = &client->dev;
127 struct tpl0102_data *data;
128 struct iio_dev *indio_dev;
129
130 indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
131 if (!indio_dev)
132 return -ENOMEM;
133 data = iio_priv(indio_dev);
134 i2c_set_clientdata(client, indio_dev);
135
136 data->cfg = &tpl0102_cfg[id->driver_data];
137 data->regmap = devm_regmap_init_i2c(client, &tpl0102_regmap_config);
138 if (IS_ERR(data->regmap)) {
139 dev_err(dev, "regmap initialization failed\n");
140 return PTR_ERR(data->regmap);
141 }
142
143 indio_dev->info = &tpl0102_info;
144 indio_dev->channels = tpl0102_channels;
145 indio_dev->num_channels = data->cfg->wipers;
146 indio_dev->name = client->name;
147
148 return devm_iio_device_register(dev, indio_dev);
149 }
150
151 static const struct i2c_device_id tpl0102_id[] = {
152 { "cat5140-503", CAT5140_503 },
153 { "cat5140-104", CAT5140_104 },
154 { "tpl0102-104", TPL0102_104 },
155 { "tpl0401-103", TPL0401_103 },
156 {}
157 };
158 MODULE_DEVICE_TABLE(i2c, tpl0102_id);
159
160 static struct i2c_driver tpl0102_driver = {
161 .driver = {
162 .name = "tpl0102",
163 },
164 .probe = tpl0102_probe,
165 .id_table = tpl0102_id,
166 };
167
168 module_i2c_driver(tpl0102_driver);
169
170 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
171 MODULE_DESCRIPTION("TPL0102 digital potentiometer");
172 MODULE_LICENSE("GPL");
173