1092cb71aSChris Coffey // SPDX-License-Identifier: GPL-2.0
2092cb71aSChris Coffey /*
3092cb71aSChris Coffey * Industrial I/O driver for Microchip digital potentiometers
4092cb71aSChris Coffey *
5092cb71aSChris Coffey * Copyright (c) 2018 Chris Coffey <cmc@babblebit.net>
6092cb71aSChris Coffey * Based on: Slawomir Stepien's code from mcp4131.c
7092cb71aSChris Coffey *
83593cd53SAlexander A. Klimov * Datasheet: https://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf
9092cb71aSChris Coffey *
10092cb71aSChris Coffey * DEVID #Wipers #Positions Resistance (kOhm)
11092cb71aSChris Coffey * mcp41010 1 256 10
12092cb71aSChris Coffey * mcp41050 1 256 50
13092cb71aSChris Coffey * mcp41100 1 256 100
14092cb71aSChris Coffey * mcp42010 2 256 10
15092cb71aSChris Coffey * mcp42050 2 256 50
16092cb71aSChris Coffey * mcp42100 2 256 100
17092cb71aSChris Coffey */
18092cb71aSChris Coffey
19092cb71aSChris Coffey #include <linux/cache.h>
20092cb71aSChris Coffey #include <linux/err.h>
21092cb71aSChris Coffey #include <linux/iio/iio.h>
22092cb71aSChris Coffey #include <linux/iio/types.h>
23092cb71aSChris Coffey #include <linux/module.h>
2492311717SJonathan Cameron #include <linux/mod_devicetable.h>
25092cb71aSChris Coffey #include <linux/mutex.h>
2692311717SJonathan Cameron #include <linux/property.h>
27092cb71aSChris Coffey #include <linux/spi/spi.h>
28092cb71aSChris Coffey
29092cb71aSChris Coffey #define MCP41010_MAX_WIPERS 2
30092cb71aSChris Coffey #define MCP41010_WRITE BIT(4)
31092cb71aSChris Coffey #define MCP41010_WIPER_MAX 255
32092cb71aSChris Coffey #define MCP41010_WIPER_CHANNEL BIT(0)
33092cb71aSChris Coffey
34092cb71aSChris Coffey struct mcp41010_cfg {
35092cb71aSChris Coffey char name[16];
36092cb71aSChris Coffey int wipers;
37092cb71aSChris Coffey int kohms;
38092cb71aSChris Coffey };
39092cb71aSChris Coffey
40092cb71aSChris Coffey enum mcp41010_type {
41092cb71aSChris Coffey MCP41010,
42092cb71aSChris Coffey MCP41050,
43092cb71aSChris Coffey MCP41100,
44092cb71aSChris Coffey MCP42010,
45092cb71aSChris Coffey MCP42050,
46092cb71aSChris Coffey MCP42100,
47092cb71aSChris Coffey };
48092cb71aSChris Coffey
49092cb71aSChris Coffey static const struct mcp41010_cfg mcp41010_cfg[] = {
50092cb71aSChris Coffey [MCP41010] = { .name = "mcp41010", .wipers = 1, .kohms = 10, },
51092cb71aSChris Coffey [MCP41050] = { .name = "mcp41050", .wipers = 1, .kohms = 50, },
52092cb71aSChris Coffey [MCP41100] = { .name = "mcp41100", .wipers = 1, .kohms = 100, },
53092cb71aSChris Coffey [MCP42010] = { .name = "mcp42010", .wipers = 2, .kohms = 10, },
54092cb71aSChris Coffey [MCP42050] = { .name = "mcp42050", .wipers = 2, .kohms = 50, },
55092cb71aSChris Coffey [MCP42100] = { .name = "mcp42100", .wipers = 2, .kohms = 100, },
56092cb71aSChris Coffey };
57092cb71aSChris Coffey
58092cb71aSChris Coffey struct mcp41010_data {
59092cb71aSChris Coffey struct spi_device *spi;
60092cb71aSChris Coffey const struct mcp41010_cfg *cfg;
61092cb71aSChris Coffey struct mutex lock; /* Protect write sequences */
62092cb71aSChris Coffey unsigned int value[MCP41010_MAX_WIPERS]; /* Cache wiper values */
63*c5f78f4dSJonathan Cameron u8 buf[2] __aligned(IIO_DMA_MINALIGN);
64092cb71aSChris Coffey };
65092cb71aSChris Coffey
66092cb71aSChris Coffey #define MCP41010_CHANNEL(ch) { \
67092cb71aSChris Coffey .type = IIO_RESISTANCE, \
68092cb71aSChris Coffey .indexed = 1, \
69092cb71aSChris Coffey .output = 1, \
70092cb71aSChris Coffey .channel = (ch), \
71092cb71aSChris Coffey .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
72092cb71aSChris Coffey .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
73092cb71aSChris Coffey }
74092cb71aSChris Coffey
75092cb71aSChris Coffey static const struct iio_chan_spec mcp41010_channels[] = {
76092cb71aSChris Coffey MCP41010_CHANNEL(0),
77092cb71aSChris Coffey MCP41010_CHANNEL(1),
78092cb71aSChris Coffey };
79092cb71aSChris Coffey
mcp41010_read_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int * val,int * val2,long mask)80092cb71aSChris Coffey static int mcp41010_read_raw(struct iio_dev *indio_dev,
81092cb71aSChris Coffey struct iio_chan_spec const *chan,
82092cb71aSChris Coffey int *val, int *val2, long mask)
83092cb71aSChris Coffey {
84092cb71aSChris Coffey struct mcp41010_data *data = iio_priv(indio_dev);
85092cb71aSChris Coffey int channel = chan->channel;
86092cb71aSChris Coffey
87092cb71aSChris Coffey switch (mask) {
88092cb71aSChris Coffey case IIO_CHAN_INFO_RAW:
89092cb71aSChris Coffey *val = data->value[channel];
90092cb71aSChris Coffey return IIO_VAL_INT;
91092cb71aSChris Coffey
92092cb71aSChris Coffey case IIO_CHAN_INFO_SCALE:
93092cb71aSChris Coffey *val = 1000 * data->cfg->kohms;
94092cb71aSChris Coffey *val2 = MCP41010_WIPER_MAX;
95092cb71aSChris Coffey return IIO_VAL_FRACTIONAL;
96092cb71aSChris Coffey }
97092cb71aSChris Coffey
98092cb71aSChris Coffey return -EINVAL;
99092cb71aSChris Coffey }
100092cb71aSChris Coffey
mcp41010_write_raw(struct iio_dev * indio_dev,struct iio_chan_spec const * chan,int val,int val2,long mask)101092cb71aSChris Coffey static int mcp41010_write_raw(struct iio_dev *indio_dev,
102092cb71aSChris Coffey struct iio_chan_spec const *chan,
103092cb71aSChris Coffey int val, int val2, long mask)
104092cb71aSChris Coffey {
105092cb71aSChris Coffey int err;
106092cb71aSChris Coffey struct mcp41010_data *data = iio_priv(indio_dev);
107092cb71aSChris Coffey int channel = chan->channel;
108092cb71aSChris Coffey
109092cb71aSChris Coffey if (mask != IIO_CHAN_INFO_RAW)
110092cb71aSChris Coffey return -EINVAL;
111092cb71aSChris Coffey
112092cb71aSChris Coffey if (val > MCP41010_WIPER_MAX || val < 0)
113092cb71aSChris Coffey return -EINVAL;
114092cb71aSChris Coffey
115092cb71aSChris Coffey mutex_lock(&data->lock);
116092cb71aSChris Coffey
117092cb71aSChris Coffey data->buf[0] = MCP41010_WIPER_CHANNEL << channel;
118092cb71aSChris Coffey data->buf[0] |= MCP41010_WRITE;
119092cb71aSChris Coffey data->buf[1] = val & 0xff;
120092cb71aSChris Coffey
121092cb71aSChris Coffey err = spi_write(data->spi, data->buf, sizeof(data->buf));
122092cb71aSChris Coffey if (!err)
123092cb71aSChris Coffey data->value[channel] = val;
124092cb71aSChris Coffey
125092cb71aSChris Coffey mutex_unlock(&data->lock);
126092cb71aSChris Coffey
127092cb71aSChris Coffey return err;
128092cb71aSChris Coffey }
129092cb71aSChris Coffey
130092cb71aSChris Coffey static const struct iio_info mcp41010_info = {
131092cb71aSChris Coffey .read_raw = mcp41010_read_raw,
132092cb71aSChris Coffey .write_raw = mcp41010_write_raw,
133092cb71aSChris Coffey };
134092cb71aSChris Coffey
mcp41010_probe(struct spi_device * spi)135092cb71aSChris Coffey static int mcp41010_probe(struct spi_device *spi)
136092cb71aSChris Coffey {
137092cb71aSChris Coffey int err;
138092cb71aSChris Coffey struct device *dev = &spi->dev;
139092cb71aSChris Coffey struct mcp41010_data *data;
140092cb71aSChris Coffey struct iio_dev *indio_dev;
141092cb71aSChris Coffey
142092cb71aSChris Coffey indio_dev = devm_iio_device_alloc(dev, sizeof(*data));
143092cb71aSChris Coffey if (!indio_dev)
144092cb71aSChris Coffey return -ENOMEM;
145092cb71aSChris Coffey
146092cb71aSChris Coffey data = iio_priv(indio_dev);
147092cb71aSChris Coffey spi_set_drvdata(spi, indio_dev);
148092cb71aSChris Coffey data->spi = spi;
14992311717SJonathan Cameron data->cfg = device_get_match_data(&spi->dev);
150092cb71aSChris Coffey if (!data->cfg)
151092cb71aSChris Coffey data->cfg = &mcp41010_cfg[spi_get_device_id(spi)->driver_data];
152092cb71aSChris Coffey
153092cb71aSChris Coffey mutex_init(&data->lock);
154092cb71aSChris Coffey
155092cb71aSChris Coffey indio_dev->info = &mcp41010_info;
156092cb71aSChris Coffey indio_dev->channels = mcp41010_channels;
157092cb71aSChris Coffey indio_dev->num_channels = data->cfg->wipers;
158092cb71aSChris Coffey indio_dev->name = data->cfg->name;
159092cb71aSChris Coffey
160092cb71aSChris Coffey err = devm_iio_device_register(dev, indio_dev);
161092cb71aSChris Coffey if (err)
162092cb71aSChris Coffey dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name);
163092cb71aSChris Coffey
164092cb71aSChris Coffey return err;
165092cb71aSChris Coffey }
166092cb71aSChris Coffey
167092cb71aSChris Coffey static const struct of_device_id mcp41010_match[] = {
168092cb71aSChris Coffey { .compatible = "microchip,mcp41010", .data = &mcp41010_cfg[MCP41010] },
169092cb71aSChris Coffey { .compatible = "microchip,mcp41050", .data = &mcp41010_cfg[MCP41050] },
170092cb71aSChris Coffey { .compatible = "microchip,mcp41100", .data = &mcp41010_cfg[MCP41100] },
171092cb71aSChris Coffey { .compatible = "microchip,mcp42010", .data = &mcp41010_cfg[MCP42010] },
172092cb71aSChris Coffey { .compatible = "microchip,mcp42050", .data = &mcp41010_cfg[MCP42050] },
173092cb71aSChris Coffey { .compatible = "microchip,mcp42100", .data = &mcp41010_cfg[MCP42100] },
174092cb71aSChris Coffey {}
175092cb71aSChris Coffey };
176092cb71aSChris Coffey MODULE_DEVICE_TABLE(of, mcp41010_match);
177092cb71aSChris Coffey
178092cb71aSChris Coffey static const struct spi_device_id mcp41010_id[] = {
179092cb71aSChris Coffey { "mcp41010", MCP41010 },
180092cb71aSChris Coffey { "mcp41050", MCP41050 },
181092cb71aSChris Coffey { "mcp41100", MCP41100 },
182092cb71aSChris Coffey { "mcp42010", MCP42010 },
183092cb71aSChris Coffey { "mcp42050", MCP42050 },
184092cb71aSChris Coffey { "mcp42100", MCP42100 },
185092cb71aSChris Coffey {}
186092cb71aSChris Coffey };
187092cb71aSChris Coffey MODULE_DEVICE_TABLE(spi, mcp41010_id);
188092cb71aSChris Coffey
189092cb71aSChris Coffey static struct spi_driver mcp41010_driver = {
190092cb71aSChris Coffey .driver = {
191092cb71aSChris Coffey .name = "mcp41010",
192092cb71aSChris Coffey .of_match_table = mcp41010_match,
193092cb71aSChris Coffey },
194092cb71aSChris Coffey .probe = mcp41010_probe,
195092cb71aSChris Coffey .id_table = mcp41010_id,
196092cb71aSChris Coffey };
197092cb71aSChris Coffey
198092cb71aSChris Coffey module_spi_driver(mcp41010_driver);
199092cb71aSChris Coffey
200092cb71aSChris Coffey MODULE_AUTHOR("Chris Coffey <cmc@babblebit.net>");
201092cb71aSChris Coffey MODULE_DESCRIPTION("MCP41010 digital potentiometer");
202092cb71aSChris Coffey MODULE_LICENSE("GPL v2");
203