path: root/drivers/iio/adc/ad7380.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Analog Devices AD738x Simultaneous Sampling SAR ADCs
 *
 * Copyright 2017 Analog Devices Inc.
 * Copyright 2024 BayLibre, SAS
 *
 * Datasheets of supported parts:
 * ad7380/1 : https://www.analog.com/media/en/technical-documentation/data-sheets/AD7380-7381.pdf
 * ad7383/4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7383-7384.pdf
 * ad7386/7/8 : https://www.analog.com/media/en/technical-documentation/data-sheets/AD7386-7387-7388.pdf
 * ad7380-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7380-4.pdf
 * ad7381-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7381-4.pdf
 * ad7383/4-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7383-4-ad7384-4.pdf
 * ad7386/7/8-4 : https://www.analog.com/media/en/technical-documentation/data-sheets/ad7386-4-7387-4-7388-4.pdf
 */

#include <linux/align.h>
#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/cleanup.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>

#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#define MAX_NUM_CHANNELS		8
/* 2.5V internal reference voltage */
#define AD7380_INTERNAL_REF_MV		2500

/* reading and writing registers is more reliable at lower than max speed */
#define AD7380_REG_WR_SPEED_HZ		10000000

#define AD7380_REG_WR			BIT(15)
#define AD7380_REG_REGADDR		GENMASK(14, 12)
#define AD7380_REG_DATA			GENMASK(11, 0)

#define AD7380_REG_ADDR_NOP		0x0
#define AD7380_REG_ADDR_CONFIG1		0x1
#define AD7380_REG_ADDR_CONFIG2		0x2
#define AD7380_REG_ADDR_ALERT		0x3
#define AD7380_REG_ADDR_ALERT_LOW_TH	0x4
#define AD7380_REG_ADDR_ALERT_HIGH_TH	0x5

#define AD7380_CONFIG1_CH		BIT(11)
#define AD7380_CONFIG1_SEQ		BIT(10)
#define AD7380_CONFIG1_OS_MODE		BIT(9)
#define AD7380_CONFIG1_OSR		GENMASK(8, 6)
#define AD7380_CONFIG1_CRC_W		BIT(5)
#define AD7380_CONFIG1_CRC_R		BIT(4)
#define AD7380_CONFIG1_ALERTEN		BIT(3)
#define AD7380_CONFIG1_RES		BIT(2)
#define AD7380_CONFIG1_REFSEL		BIT(1)
#define AD7380_CONFIG1_PMODE		BIT(0)

#define AD7380_CONFIG2_SDO2		GENMASK(9, 8)
#define AD7380_CONFIG2_SDO		BIT(8)
#define AD7380_CONFIG2_RESET		GENMASK(7, 0)

#define AD7380_CONFIG2_RESET_SOFT	0x3C
#define AD7380_CONFIG2_RESET_HARD	0xFF

#define AD7380_ALERT_LOW_TH		GENMASK(11, 0)
#define AD7380_ALERT_HIGH_TH		GENMASK(11, 0)

#define T_CONVERT_NS 190		/* conversion time */
#define T_CONVERT_0_NS 10		/* 1st conversion start time (oversampling) */
#define T_CONVERT_X_NS 500		/* xth conversion start time (oversampling) */
#define T_POWERUP_US 5000		/* Power up */

struct ad7380_timing_specs {
	const unsigned int t_csh_ns;	/* CS minimum high time */
};

struct ad7380_chip_info {
	const char *name;
	const struct iio_chan_spec *channels;
	unsigned int num_channels;
	unsigned int num_simult_channels;
	bool has_mux;
	const char * const *supplies;
	unsigned int num_supplies;
	bool external_ref_only;
	const char * const *vcm_supplies;
	unsigned int num_vcm_supplies;
	const unsigned long *available_scan_masks;
	const struct ad7380_timing_specs *timing_specs;
};

enum {
	AD7380_SCAN_TYPE_NORMAL,
	AD7380_SCAN_TYPE_RESOLUTION_BOOST,
};

/* Extended scan types for 12-bit unsigned chips. */
static const struct iio_scan_type ad7380_scan_type_12_u[] = {
	[AD7380_SCAN_TYPE_NORMAL] = {
		.sign = 'u',
		.realbits = 12,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
	[AD7380_SCAN_TYPE_RESOLUTION_BOOST] = {
		.sign = 'u',
		.realbits = 14,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
};

/* Extended scan types for 14-bit signed chips. */
static const struct iio_scan_type ad7380_scan_type_14_s[] = {
	[AD7380_SCAN_TYPE_NORMAL] = {
		.sign = 's',
		.realbits = 14,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
	[AD7380_SCAN_TYPE_RESOLUTION_BOOST] = {
		.sign = 's',
		.realbits = 16,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
};

/* Extended scan types for 14-bit unsigned chips. */
static const struct iio_scan_type ad7380_scan_type_14_u[] = {
	[AD7380_SCAN_TYPE_NORMAL] = {
		.sign = 'u',
		.realbits = 14,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
	[AD7380_SCAN_TYPE_RESOLUTION_BOOST] = {
		.sign = 'u',
		.realbits = 16,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
};

/* Extended scan types for 16-bit signed_chips. */
static const struct iio_scan_type ad7380_scan_type_16_s[] = {
	[AD7380_SCAN_TYPE_NORMAL] = {
		.sign = 's',
		.realbits = 16,
		.storagebits = 16,
		.endianness = IIO_CPU,
	},
	[AD7380_SCAN_TYPE_RESOLUTION_BOOST] = {
		.sign = 's',
		.realbits = 18,
		.storagebits = 32,
		.endianness = IIO_CPU,
	},
};

/* Extended scan