tpl0102.c

  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
 16struct tpl0102_cfg {
 17	int wipers;
 18	int avail[3];
 19	int kohms;
 20};
 21
 22enum tpl0102_type {
 23	CAT5140_503,
 24	CAT5140_104,
 25	TPL0102_104,
 26	TPL0401_103,
 27};
 28
 29static 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
 38struct tpl0102_data {
 39	struct regmap *regmap;
 40	const struct tpl0102_cfg *cfg;
 41};
 42
 43static 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
 58static const struct iio_chan_spec tpl0102_channels[] = {
 59	TPL0102_CHANNEL(0),
 60	TPL0102_CHANNEL(1),
 61};
 62
 63static 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
 84static 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
102static 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
117static 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
123static 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
151static 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};
158MODULE_DEVICE_TABLE(i2c, tpl0102_id);
159
160static struct i2c_driver tpl0102_driver = {
161	.driver = {
162		.name = "tpl0102",
163	},
164	.probe = tpl0102_probe,
165	.id_table = tpl0102_id,
166};
167
168module_i2c_driver(tpl0102_driver);
169
170MODULE_AUTHOR("Matt Ranostay <matt.ranostay@konsulko.com>");
171MODULE_DESCRIPTION("TPL0102 digital potentiometer");
172MODULE_LICENSE("GPL");