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 max_pos;
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, .max_pos = 256, .kohms = 50, },
32 	[CAT5140_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
33 	/* ti parts */
34 	[TPL0102_104] = { .wipers = 2, .max_pos = 256, .kohms = 100 },
35 	[TPL0401_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
36 };
37 
38 struct tpl0102_data {
39 	struct regmap *regmap;
40 	unsigned long devid;
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 }
56 
57 static const struct iio_chan_spec tpl0102_channels[] = {
58 	TPL0102_CHANNEL(0),
59 	TPL0102_CHANNEL(1),
60 };
61 
62 static int tpl0102_read_raw(struct iio_dev *indio_dev,
63 			    struct iio_chan_spec const *chan,
64 			    int *val, int *val2, long mask)
65 {
66 	struct tpl0102_data *data = iio_priv(indio_dev);
67 
68 	switch (mask) {
69 	case IIO_CHAN_INFO_RAW: {
70 		int ret = regmap_read(data->regmap, chan->channel, val);
71 
72 		return ret ? ret : IIO_VAL_INT;
73 	}
74 	case IIO_CHAN_INFO_SCALE:
75 		*val = 1000 * tpl0102_cfg[data->devid].kohms;
76 		*val2 = tpl0102_cfg[data->devid].max_pos;
77 		return IIO_VAL_FRACTIONAL;
78 	}
79 
80 	return -EINVAL;
81 }
82 
83 static int tpl0102_write_raw(struct iio_dev *indio_dev,
84 			     struct iio_chan_spec const *chan,
85 			     int val, int val2, long mask)
86 {
87 	struct tpl0102_data *data = iio_priv(indio_dev);
88 
89 	if (mask != IIO_CHAN_INFO_RAW)
90 		return -EINVAL;
91 
92 	if (val >= tpl0102_cfg[data->devid].max_pos || val < 0)
93 		return -EINVAL;
94 
95 	return regmap_write(data->regmap, chan->channel, val);
96 }
97 
98 static const struct iio_info tpl0102_info = {
99 	.read_raw = tpl0102_read_raw,
100 	.write_raw = tpl0102_write_raw,
101 };
102 
103 static int tpl0102_probe(struct i2c_client *client,
104 			 const struct i2c_device_id *id)
105 {
106 	struct device *dev = &client->dev;
107 	struct tpl0102_data *data;
108 	struct iio_dev *indio_dev;
109 
110 	indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
111 	if (!indio_dev)
112 		return -ENOMEM;
113 	data = iio_priv(indio_dev);
114 	i2c_set_clientdata(client, indio_dev);
115 
116 	data->devid = id->driver_data;
117 	data->regmap = devm_regmap_init_i2c(client, &tpl0102_regmap_config);
118 	if (IS_ERR(data->regmap)) {
119 		dev_err(dev, "regmap initialization failed\n");
120 		return PTR_ERR(data->regmap);
121 	}
122 
123 	indio_dev->dev.parent = dev;
124 	indio_dev->info = &tpl0102_info;
125 	indio_dev->channels = tpl0102_channels;
126 	indio_dev->num_channels = tpl0102_cfg[data->devid].wipers;
127 	indio_dev->name = client->name;
128 
129 	return devm_iio_device_register(dev, indio_dev);
130 }
131 
132 static const struct i2c_device_id tpl0102_id[] = {
133 	{ "cat5140-503", CAT5140_503 },
134 	{ "cat5140-104", CAT5140_104 },
135 	{ "tpl0102-104", TPL0102_104 },
136 	{ "tpl0401-103", TPL0401_103 },
137 	{}
138 };
139 MODULE_DEVICE_TABLE(i2c, tpl0102_id);
140 
141 static struct i2c_driver tpl0102_driver = {
142 	.driver = {
143 		.name = "tpl0102",
144 	},
145 	.probe = tpl0102_probe,
146 	.id_table = tpl0102_id,
147 };
148 
149 module_i2c_driver(tpl0102_driver);
150 
151 MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
152 MODULE_DESCRIPTION("TPL0102 digital potentiometer");
153 MODULE_LICENSE("GPL");
154