path: root/drivers/iio/adc/ti-ads1015.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * ADS1015 - Texas Instruments Analog-to-Digital Converter
 *
 * Copyright (c) 2016, Intel Corporation.
 *
 * IIO driver for ADS1015 ADC 7-bit I2C slave address:
 *	* 0x48 - ADDR connected to Ground
 *	* 0x49 - ADDR connected to Vdd
 *	* 0x4A - ADDR connected to SDA
 *	* 0x4B - ADDR connected to SCL
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/i2c.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/pm_runtime.h>
#include <linux/mutex.h>
#include <linux/delay.h>

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

#define ADS1015_DRV_NAME "ads1015"

#define ADS1015_CHANNELS 8

#define ADS1015_CONV_REG	0x00
#define ADS1015_CFG_REG		0x01
#define ADS1015_LO_THRESH_REG	0x02
#define ADS1015_HI_THRESH_REG	0x03

#define ADS1015_CFG_COMP_QUE_SHIFT	0
#define ADS1015_CFG_COMP_LAT_SHIFT	2
#define ADS1015_CFG_COMP_POL_SHIFT	3
#define ADS1015_CFG_COMP_MODE_SHIFT	4
#define ADS1015_CFG_DR_SHIFT	5
#define ADS1015_CFG_MOD_SHIFT	8
#define ADS1015_CFG_PGA_SHIFT	9
#define ADS1015_CFG_MUX_SHIFT	12

#define ADS1015_CFG_COMP_QUE_MASK	GENMASK(1, 0)
#define ADS1015_CFG_COMP_LAT_MASK	BIT(2)
#define ADS1015_CFG_COMP_POL_MASK	BIT(3)
#define ADS1015_CFG_COMP_MODE_MASK	BIT(4)
#define ADS1015_CFG_DR_MASK	GENMASK(7, 5)
#define ADS1015_CFG_MOD_MASK	BIT(8)
#define ADS1015_CFG_PGA_MASK	GENMASK(11, 9)
#define ADS1015_CFG_MUX_MASK	GENMASK(14, 12)

/* Comparator queue and disable field */
#define ADS1015_CFG_COMP_DISABLE	3

/* Comparator polarity field */
#define ADS1015_CFG_COMP_POL_LOW	0
#define ADS1015_CFG_COMP_POL_HIGH	1

/* Comparator mode field */
#define ADS1015_CFG_COMP_MODE_TRAD	0
#define ADS1015_CFG_COMP_MODE_WINDOW	1

/* device operating modes */
#define ADS1015_CONTINUOUS	0
#define ADS1015_SINGLESHOT	1

#define ADS1015_SLEEP_DELAY_MS		2000
#define ADS1015_DEFAULT_PGA		2
#define ADS1015_DEFAULT_DATA_RATE	4
#define ADS1015_DEFAULT_CHAN		0

struct ads1015_chip_data {
	struct iio_chan_spec const	*channels;
	int				num_channels;
	const struct iio_info		*info;
	const int			*data_rate;
	const int			data_rate_len;
	const int			*scale;
	const int			scale_len;
	bool				has_comparator;
};

enum ads1015_channels {
	ADS1015_AIN0_AIN1 = 0,
	ADS1015_AIN0_AIN3,
	ADS1015_AIN1_AIN3,
	ADS1015_AIN2_AIN3,
	ADS1015_AIN0,
	ADS1015_AIN1,
	ADS1015_AIN2,
	ADS1015_AIN3,
	ADS1015_TIMESTAMP,
};

static const int ads1015_data_rate[] = {
	128, 250, 490, 920, 1600, 2400, 3300, 3300
};

static const int ads1115_data_rate[] = {
	8, 16, 32, 64, 128, 250, 475, 860
};

/*
 * Translation from PGA bits to full-scale positive and negative input voltage
 * range in mV
 */
static const int ads1015_fullscale_range[] = {
	6144, 4096, 2048, 1024, 512, 256, 256, 256
};

static const int ads1015_scale[] = {	/* 12bit ADC */
	256, 11,
	512, 11,
	1024, 11,
	2048, 11,
	4096, 11,
	6144, 11
};

static const int ads1115_scale[] = {	/* 16bit ADC */
	256, 15,
	512, 15,
	1024, 15,
	2048, 15,
	4096, 15,
	6144, 15
};

/*
 * Translation from COMP_QUE field value to the number of successive readings
 * exceed the threshold values before an interrupt is generated
 */
static const int ads1015_comp_queue[] = { 1, 2, 4 };

static const struct iio_event_spec ads1015_events[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE) |
				BIT(IIO_EV_INFO_ENABLE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_FALLING,
		.mask_separate = BIT(IIO_EV_INFO_VALUE),
	}, {
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_EITHER,
		.mask_separate = BIT(IIO_EV_INFO_ENABLE) |
				BIT(IIO_EV_INFO_PERIOD),
	},
};

/*
 * Compile-time check whether _fitbits can accommodate up to _testbits
 * bits. Returns _fitbits on success, fails to compile otherwise.
 *
 * The test works such that it multiplies constant _fitbits by constant
 * double-negation of size of a non-empty structure, i.e. it multiplies
 * constant _fitbits by constant 1 in each successful compilation case.
 * The non-empty structure may contain C11 _Static_assert(), make use of
 * this and place the kernel variant of static assert in there, so that
 * it performs the compile-time check for _testbits <= _fitbits. Note
 * that it is not possible to directly use static_assert in compound
 * statements, hence this convoluted construct.
 */
#define FIT_CHECK(_testbits, _fitbits)					\
	(								\
		(_fitbits) *						\
		!!sizeof(struct {					\
			static_assert((_testbits) <= (_fitbits));	\
			int pad;					\
		})							\
	)

#define ADS1015_V_CHAN(_chan, _addr, _realbits, _shift, _event_spec, _num_event_specs) { \
	.type = IIO_VOLTAGE,					\
	.indexed = 1,						\
	.address = _addr,					\
	.channel = _chan,					\