1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Maxim MAX5522
4 * Dual, Ultra-Low-Power 10-Bit, Voltage-Output DACs
5 *
6 * Copyright 2022 Timesys Corp.
7 */
8
9#include <linux/device.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/mod_devicetable.h>
13#include <linux/regmap.h>
14#include <linux/regulator/consumer.h>
15#include <linux/slab.h>
16#include <linux/spi/spi.h>
17
18#include <linux/iio/iio.h>
19
20#define MAX5522_MAX_ADDR 15
21#define MAX5522_CTRL_NONE 0
22#define MAX5522_CTRL_LOAD_IN_A 9
23#define MAX5522_CTRL_LOAD_IN_B 10
24
25#define MAX5522_REG_DATA(x) ((x) + MAX5522_CTRL_LOAD_IN_A)
26
27struct max5522_chip_info {
28 const char *name;
29 const struct iio_chan_spec *channels;
30 unsigned int num_channels;
31};
32
33struct max5522_state {
34 struct regmap *regmap;
35 const struct max5522_chip_info *chip_info;
36 unsigned short dac_cache[2];
37 struct regulator *vrefin_reg;
38};
39
40#define MAX5522_CHANNEL(chan) { \
41 .type = IIO_VOLTAGE, \
42 .indexed = 1, \
43 .output = 1, \
44 .channel = chan, \
45 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
46 BIT(IIO_CHAN_INFO_SCALE), \
47 .scan_type = { \
48 .sign = 'u', \
49 .realbits = 10, \
50 .storagebits = 16, \
51 .shift = 2, \
52 } \
53}
54
55static const struct iio_chan_spec max5522_channels[] = {
56 MAX5522_CHANNEL(0),
57 MAX5522_CHANNEL(1),
58};
59
60enum max5522_type {
61 ID_MAX5522,
62};
63
64static const struct max5522_chip_info max5522_chip_info_tbl[] = {
65 [ID_MAX5522] = {
66 .name = "max5522",
67 .channels = max5522_channels,
68 .num_channels = 2,
69 },
70};
71
72static inline int max5522_info_to_reg(struct iio_chan_spec const *chan)
73{
74 return MAX5522_REG_DATA(chan->channel);
75}
76
77static int max5522_read_raw(struct iio_dev *indio_dev,
78 struct iio_chan_spec const *chan,
79 int *val, int *val2, long info)
80{
81 struct max5522_state *state = iio_priv(indio_dev);
82 int ret;
83
84 switch (info) {
85 case IIO_CHAN_INFO_RAW:
86 *val = state->dac_cache[chan->channel];
87 return IIO_VAL_INT;
88 case IIO_CHAN_INFO_SCALE:
89 ret = regulator_get_voltage(regulator: state->vrefin_reg);
90 if (ret < 0)
91 return -EINVAL;
92 *val = ret / 1000;
93 *val2 = 10;
94 return IIO_VAL_FRACTIONAL_LOG2;
95 default:
96 return -EINVAL;
97 }
98
99 return -EINVAL;
100}
101
102static int max5522_write_raw(struct iio_dev *indio_dev,
103 struct iio_chan_spec const *chan,
104 int val, int val2, long info)
105{
106 struct max5522_state *state = iio_priv(indio_dev);
107 int rval;
108
109 if (val > 1023 || val < 0)
110 return -EINVAL;
111
112 rval = regmap_write(map: state->regmap, reg: max5522_info_to_reg(chan),
113 val: val << chan->scan_type.shift);
114 if (rval < 0)
115 return rval;
116
117 state->dac_cache[chan->channel] = val;
118
119 return 0;
120}
121
122static const struct iio_info max5522_info = {
123 .read_raw = max5522_read_raw,
124 .write_raw = max5522_write_raw,
125};
126
127static const struct regmap_config max5522_regmap_config = {
128 .reg_bits = 4,
129 .val_bits = 12,
130 .max_register = MAX5522_MAX_ADDR,
131};
132
133static int max5522_spi_probe(struct spi_device *spi)
134{
135 const struct spi_device_id *id = spi_get_device_id(sdev: spi);
136 struct iio_dev *indio_dev;
137 struct max5522_state *state;
138 int ret;
139
140 indio_dev = devm_iio_device_alloc(parent: &spi->dev, sizeof_priv: sizeof(*state));
141 if (indio_dev == NULL) {
142 dev_err(&spi->dev, "failed to allocate iio device\n");
143 return -ENOMEM;
144 }
145
146 state = iio_priv(indio_dev);
147 state->chip_info = device_get_match_data(dev: &spi->dev);
148 if (!state->chip_info) {
149 state->chip_info =
150 (struct max5522_chip_info *)(id->driver_data);
151 if (!state->chip_info)
152 return -EINVAL;
153 }
154
155 state->vrefin_reg = devm_regulator_get(dev: &spi->dev, id: "vrefin");
156 if (IS_ERR(ptr: state->vrefin_reg))
157 return dev_err_probe(dev: &spi->dev, err: PTR_ERR(ptr: state->vrefin_reg),
158 fmt: "Vrefin regulator not specified\n");
159
160 ret = regulator_enable(regulator: state->vrefin_reg);
161 if (ret) {
162 return dev_err_probe(dev: &spi->dev, err: ret,
163 fmt: "Failed to enable vref regulators\n");
164 }
165
166 state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);
167
168 if (IS_ERR(ptr: state->regmap))
169 return PTR_ERR(ptr: state->regmap);
170
171 indio_dev->info = &max5522_info;
172 indio_dev->modes = INDIO_DIRECT_MODE;
173 indio_dev->channels = max5522_channels;
174 indio_dev->num_channels = ARRAY_SIZE(max5522_channels);
175 indio_dev->name = max5522_chip_info_tbl[ID_MAX5522].name;
176
177 return devm_iio_device_register(&spi->dev, indio_dev);
178}
179
180static const struct spi_device_id max5522_ids[] = {
181 { "max5522", (kernel_ulong_t)&max5522_chip_info_tbl[ID_MAX5522] },
182 {}
183};
184MODULE_DEVICE_TABLE(spi, max5522_ids);
185
186static const struct of_device_id max5522_of_match[] = {
187 {
188 .compatible = "maxim,max5522",
189 .data = &max5522_chip_info_tbl[ID_MAX5522],
190 },
191 {}
192};
193MODULE_DEVICE_TABLE(of, max5522_of_match);
194
195static struct spi_driver max5522_spi_driver = {
196 .driver = {
197 .name = "max5522",
198 .of_match_table = max5522_of_match,
199 },
200 .probe = max5522_spi_probe,
201 .id_table = max5522_ids,
202};
203module_spi_driver(max5522_spi_driver);
204
205MODULE_AUTHOR("Angelo Dureghello <angelo.dureghello@timesys.com");
206MODULE_DESCRIPTION("MAX5522 DAC driver");
207MODULE_LICENSE("GPL");
208

source code of linux/drivers/iio/dac/max5522.c