path: root/drivers/iio/accel/kionix-kx022a.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2022 ROHM Semiconductors
 *
 * ROHM/KIONIX KX022A accelerometer driver
 */

#include <linux/delay.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/mutex.h>
#include <linux/property.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/string_helpers.h>
#include <linux/units.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#include "kionix-kx022a.h"

/*
 * The KX022A has FIFO which can store 43 samples of HiRes data from 2
 * channels. This equals to 43 (samples) * 3 (channels) * 2 (bytes/sample) to
 * 258 bytes of sample data. The quirk to know is that the amount of bytes in
 * the FIFO is advertised via 8 bit register (max value 255). The thing to note
 * is that full 258 bytes of data is indicated using the max value 255.
 */
#define KX022A_FIFO_LENGTH			43
#define KX022A_FIFO_FULL_VALUE			255
#define KX022A_SOFT_RESET_WAIT_TIME_US		(5 * USEC_PER_MSEC)
#define KX022A_SOFT_RESET_TOTAL_WAIT_TIME_US	(500 * USEC_PER_MSEC)

/* 3 axis, 2 bytes of data for each of the axis */
#define KX022A_FIFO_SAMPLES_SIZE_BYTES		6
#define KX022A_FIFO_MAX_BYTES					\
	(KX022A_FIFO_LENGTH * KX022A_FIFO_SAMPLES_SIZE_BYTES)

enum {
	KX022A_STATE_SAMPLE,
	KX022A_STATE_FIFO,
};

/* Regmap configs */
static const struct regmap_range kx022a_volatile_ranges[] = {
	{
		.range_min = KX022A_REG_XHP_L,
		.range_max = KX022A_REG_COTR,
	}, {
		.range_min = KX022A_REG_TSCP,
		.range_max = KX022A_REG_INT_REL,
	}, {
		/* The reset bit will be cleared by sensor */
		.range_min = KX022A_REG_CNTL2,
		.range_max = KX022A_REG_CNTL2,
	}, {
		.range_min = KX022A_REG_BUF_STATUS_1,
		.range_max = KX022A_REG_BUF_READ,
	},
};

static const struct regmap_access_table kx022a_volatile_regs = {
	.yes_ranges = &kx022a_volatile_ranges[0],
	.n_yes_ranges = ARRAY_SIZE(kx022a_volatile_ranges),
};

static const struct regmap_range kx022a_precious_ranges[] = {
	{
		.range_min = KX022A_REG_INT_REL,
		.range_max = KX022A_REG_INT_REL,
	},
};

static const struct regmap_access_table kx022a_precious_regs = {
	.yes_ranges = &kx022a_precious_ranges[0],
	.n_yes_ranges = ARRAY_SIZE(kx022a_precious_ranges),
};

/*
 * The HW does not set WHO_AM_I reg as read-only but we don't want to write it
 * so we still include it in the read-only ranges.
 */
static const struct regmap_range kx022a_read_only_ranges[] = {
	{
		.range_min = KX022A_REG_XHP_L,
		.range_max = KX022A_REG_INT_REL,
	}, {
		.range_min = KX022A_REG_BUF_STATUS_1,
		.range_max = KX022A_REG_BUF_STATUS_2,
	}, {
		.range_min = KX022A_REG_BUF_READ,
		.range_max = KX022A_REG_BUF_READ,
	},
};

static const struct regmap_access_table kx022a_ro_regs = {
	.no_ranges = &kx022a_read_only_ranges[0],
	.n_no_ranges = ARRAY_SIZE(kx022a_read_only_ranges),
};

static const struct regmap_range kx022a_write_only_ranges[] = {
	{
		.range_min = KX022A_REG_BTS_WUF_TH,
		.range_max = KX022A_REG_BTS_WUF_TH,
	}, {
		.range_min = KX022A_REG_MAN_WAKE,
		.range_max = KX022A_REG_MAN_WAKE,
	}, {
		.range_min = KX022A_REG_SELF_TEST,
		.range_max = KX022A_REG_SELF_TEST,
	}, {
		.range_min = KX022A_REG_BUF_CLEAR,
		.range_max = KX022A_REG_BUF_CLEAR,
	},
};

static const struct regmap_access_table kx022a_wo_regs = {
	.no_ranges = &kx022a_write_only_ranges[0],
	.n_no_ranges = ARRAY_SIZE(kx022a_write_only_ranges),
};

static const struct regmap_range kx022a_noinc_read_ranges[] = {
	{
		.range_min = KX022A_REG_BUF_READ,
		.range_max = KX022A_REG_BUF_READ,
	},
};

static const struct regmap_access_table kx022a_nir_regs = {
	.yes_ranges = &kx022a_noinc_read_ranges[0],
	.n_yes_ranges = ARRAY_SIZE(kx022a_noinc_read_ranges),
};

const struct regmap_config kx022a_regmap = {
	.reg_bits = 8,
	.val_bits = 8,
	.volatile_table = &kx022a_volatile_regs,
	.rd_table = &kx022a_wo_regs,
	.wr_table = &kx022a_ro_regs,
	.rd_noinc_table = &kx022a_nir_regs,
	.precious_table = &kx022a_precious_regs,
	.max_register = KX022A_MAX_REGISTER,
	.cache_type = REGCACHE_RBTREE,
};
EXPORT_SYMBOL_NS_GPL(kx022a_regmap, IIO_KX022A);

struct kx022a_data {
	struct regmap *regmap;
	struct iio_trigger *trig;
	struct device *dev;
	struct iio_mount_matrix orientation;
	int64_t timestamp, old_timestamp;

	int irq;
	int inc_reg;
	int ien_reg;

	unsigned int state;
	unsigned int odr_ns;

	bool trigger_enabled;
	/*
	 * Prevent toggling the sensor stby/active state (PC1 bit) in the
	 * middle of a configuration, or when the fifo is enabled. Also,
	 * protect the data stored/retrieved from this structure from
	 * concurrent accesses.
	 */
	struct mutex mutex;
	u8 watermark;

	/* 3 x 16bit accel data + timestamp */
	__le16 buffer[8] __aligned(IIO_DMA_MINALIGN);
	struct {