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 = spi_get_device_match_data(spi);
120
121	indio_dev->name = st->chip_info->name;
122	indio_dev->modes = INDIO_DIRECT_MODE;
123	indio_dev->channels = max11205_channels;
124	indio_dev->num_channels = 1;
125	indio_dev->info = &max11205_iio_info;
126
127	st->vref = devm_regulator_get(&spi->dev, "vref");
128	if (IS_ERR(st->vref))
129		return dev_err_probe(&spi->dev, PTR_ERR(st->vref),
130				     "Failed to get vref regulator\n");
131
132	ret = regulator_enable(st->vref);
133	if (ret)
134		return ret;
135
136	ret = devm_add_action_or_reset(&spi->dev, max11205_reg_disable, st->vref);
137	if (ret)
138		return ret;
139
140	ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
141	if (ret)
142		return ret;
143
144	return devm_iio_device_register(&spi->dev, indio_dev);
145}
146
147static const struct spi_device_id max11205_spi_ids[] = {
148	{ "max11205a", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205A] },
149	{ "max11205b", (kernel_ulong_t)&max11205_chip_info[TYPE_MAX11205B] },
150	{ }
151};
152MODULE_DEVICE_TABLE(spi, max11205_spi_ids);
153
154static const struct of_device_id max11205_dt_ids[] = {
155	{
156		.compatible = "maxim,max11205a",
157		.data = &max11205_chip_info[TYPE_MAX11205A],
158	},
159	{
160		.compatible = "maxim,max11205b",
161		.data = &max11205_chip_info[TYPE_MAX11205B],
162	},
163	{ }
164};
165MODULE_DEVICE_TABLE(of, max11205_dt_ids);
166
167static struct spi_driver max11205_spi_driver = {
168	.driver = {
169		.name = "max11205",
170		.of_match_table = max11205_dt_ids,
171	},
172	.probe = max11205_probe,
173	.id_table = max11205_spi_ids,
174};
175module_spi_driver(max11205_spi_driver);
176
177MODULE_AUTHOR("Ramona Bolboaca <ramona.bolboaca@analog.com>");
178MODULE_DESCRIPTION("MAX11205 ADC driver");
179MODULE_LICENSE("GPL v2");
180MODULE_IMPORT_NS("IIO_AD_SIGMA_DELTA");