1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Maxim MAX11205 16-Bit Delta-Sigma ADC
4 *
5 * Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-max11205.pdf
6 * Copyright (C) 2022 Analog Devices, Inc.
7 * Author: Ramona Bolboaca <ramona.bolboaca@analog.com>
8 */
9
10#include <linux/device.h>
11#include <linux/module.h>
12#include <linux/regulator/consumer.h>
13#include <linux/spi/spi.h>
14
15#include <linux/iio/iio.h>
16#include <linux/iio/adc/ad_sigma_delta.h>
17
18#define MAX11205_BIT_SCALE	15
19#define MAX11205A_OUT_DATA_RATE	116
20#define MAX11205B_OUT_DATA_RATE	13
21
22enum max11205_chip_type {
23	TYPE_MAX11205A,
24	TYPE_MAX11205B,
25};
26
27struct max11205_chip_info {
28	unsigned int	out_data_rate;
29	const char	*name;
30};
31
32struct max11205_state {
33	const struct max11205_chip_info	*chip_info;
34	struct regulator		*vref;
35	struct ad_sigma_delta		sd;
36};
37
38static const struct ad_sigma_delta_info max11205_sigma_delta_info = {
39	.has_registers = false,
40};
41
42static int max11205_read_raw(struct iio_dev *indio_dev,
43			     struct iio_chan_spec const *chan,
44			     int *val, int *val2, long mask)
45{
46	struct max11205_state *st = iio_priv(indio_dev);
47	int reg_mv;
48
49	switch (mask) {
50	case IIO_CHAN_INFO_RAW:
51		return ad_sigma_delta_single_conversion(indio_dev, chan, val);
52	case IIO_CHAN_INFO_SCALE:
53		reg_mv = regulator_get_voltage(st->vref);
54		if (reg_mv < 0)
55			return reg_mv;
56		reg_mv /= 1000;
57		*val = reg_mv;
58		*val2 = MAX11205_BIT_SCALE;
59		return IIO_VAL_FRACTIONAL_LOG2;
60	case IIO_CHAN_INFO_SAMP_FREQ:
61		*val = st->chip_info->out_data_rate;
62		return IIO_VAL_INT;
63	default:
64		return -EINVAL;
65	}
66}
67
68static const struct iio_info max11205_iio_info = {
69	.read_raw = max11205_read_raw,
70	.validate_trigger = ad_sd_validate_trigger,
71};
72
73static const struct iio_chan_spec max11205_channels[] = {
74	{
75		.type = IIO_VOLTAGE,
76		.indexed = 1,
77		.scan_type = {
78			.sign = 's',
79			.realbits = 16,
80			.storagebits = 16,
81			.endianness = IIO_BE,
82		},
83		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
84				      BIT(IIO_CHAN_INFO_SAMP_FREQ) |
85				      BIT(IIO_CHAN_INFO_SCALE),
86	},
87};
88
89static const struct max11205_chip_info max11205_chip_info[] = {
90	[TYPE_MAX11205A] = {
91		.out_data_rate = MAX11205A_OUT_DATA_RATE,
92		.name = "max11205a",
93	},
94	[TYPE_MAX11205B] = {
95		.out_data_rate = MAX11205B_OUT_DATA_RATE,
96		.name = "max11205b",
97	},
98};
99
100static void max11205_reg_disable(void *reg)
101{
102	regulator_disable(reg);
103}
104
105static int max11205_probe(struct spi_device *spi)
106{
107	struct max11205_state *st;
108	struct iio_dev *indio_dev;
109	int ret;
110
111	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
112	if (!indio_dev)
113		return -ENOMEM;
114
115	st = iio_priv(indio_dev);
116
117	ad_sd_init(&st->sd, indio_dev, spi, &max11205_sigma_delta_info);
118
119	st->chip_info = device_get_match_data(&spi->dev);
120	if (!st->chip_info)
121		st->chip_info =
122			(const struct max11205_chip_info *)spi_get_device_id(spi)->driver_data;
123
124	indio_dev->name = st->chip_info->name;
125	indio_dev->modes = INDIO_DIRECT_MODE;
126	indio_dev->channels = max11205_channels;
127	indio_dev->num_channels = 1;
128	indio_dev->info = &max11205_iio_info;
129
130	st->vref = devm_regulator_get(&spi->dev, "vref");
131	if (IS_ERR(st->vref))
132		return dev_err_probe(&spi->dev, PTR_ERR(st->vref),
133				     "Failed to get vref regulator\n");
134
135	ret = regulator_enable(st->vref);
136	if (ret)
137		return ret;
138
139	ret = devm_add_action_or_reset(&spi->dev, max11205_reg_disable, st->vref);
140	if (ret)
141		return ret;
142
143	ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
144	if (ret)
145		return ret;
146
147	return devm_iio_device_register(&spi->dev, indio_dev);
148}
149
150static const struct spi_device_id max11205_spi_ids[] = {
151	{ "max11205a", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205A] },
152	{ "max11205b", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205B] },
153	{ }
154};
155MODULE_DEVICE_TABLE(spi, max11205_spi_ids);
156
157static const struct of_device_id max11205_dt_ids[] = {
158	{
159		.compatible = "maxim,max11205a",
160		.data = &max11205_chip_info[TYPE_MAX11205A],
161	},
162	{
163		.compatible = "maxim,max11205b",
164		.data = &max11205_chip_info[TYPE_MAX11205B],
165	},
166	{ }
167};
168MODULE_DEVICE_TABLE(of, max11205_dt_ids);
169
170static struct spi_driver max11205_spi_driver = {
171	.driver = {
172		.name = "max11205",
173		.of_match_table = max11205_dt_ids,
174	},
175	.probe = max11205_probe,
176	.id_table = max11205_spi_ids,
177};
178module_spi_driver(max11205_spi_driver);
179
180MODULE_AUTHOR("Ramona Bolboaca <ramona.bolboaca@analog.com>");
181MODULE_DESCRIPTION("MAX11205 ADC driver");
182MODULE_LICENSE("GPL v2");
183MODULE_IMPORT_NS(IIO_AD_SIGMA_DELTA);
184