// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Bitbang driver for Linux GPIO descriptors through libgpiod
 * Copyright (C) 2020 Antonio Borneo <borneo.antonio@gmail.com>
 *
 * Largely based on sysfsgpio driver
 * Copyright (C) 2012 by Creative Product Design, marc @ cpdesign.com.au
 * Copyright (C) 2014 by Jean-Christian de Rivaz <jc@eclis.ch>
 * Copyright (C) 2014 by Paul Fertser <fercerpav@gmail.com>
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gpiod.h>
#include <jtag/adapter.h>
#include <jtag/interface.h>
#include <transport/transport.h>
#include "bitbang.h"

/*
 * In case of libgpiod v1, use as much as possible API from v2 plus
 * the dummy wrappers below.
 */
#ifdef HAVE_LIBGPIOD_V1

#define GPIOD_LINE_DIRECTION_INPUT      GPIOD_LINE_REQUEST_DIRECTION_INPUT
#define GPIOD_LINE_DIRECTION_OUTPUT     GPIOD_LINE_REQUEST_DIRECTION_OUTPUT

#define GPIOD_LINE_VALUE_INACTIVE       0
#define GPIOD_LINE_VALUE_ACTIVE         1

#define GPIOD_LINE_DRIVE_PUSH_PULL      0
#define GPIOD_LINE_DRIVE_OPEN_DRAIN     GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN
#define GPIOD_LINE_DRIVE_OPEN_SOURCE    GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE

#define GPIOD_LINE_BIAS_DISABLED        GPIOD_LINE_REQUEST_FLAG_BIAS_DISABLE
#define GPIOD_LINE_BIAS_PULL_UP         GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_UP
#define GPIOD_LINE_BIAS_PULL_DOWN       GPIOD_LINE_REQUEST_FLAG_BIAS_PULL_DOWN

struct gpiod_line_settings {
	int direction;
	int value;
	int drive;
	int bias;
	int active_low;
};

static struct gpiod_line_settings *gpiod_line_settings_new(void)
{
	struct gpiod_line_settings *rv;

	rv = calloc(sizeof(struct gpiod_line_settings), 1);
	if (!rv) {
		LOG_ERROR("No memory for gpiod line settings");
		return NULL;
	}

	return rv;
}

static void gpiod_line_settings_free(struct gpiod_line_settings *settings)
{
	free(settings);
}

static int gpiod_line_settings_set_direction(struct gpiod_line_settings *settings,
	int direction)
{
	settings->direction = direction;

	return 0;
}

static int gpiod_line_settings_set_output_value(struct gpiod_line_settings *settings,
	int value)
{
	settings->value = value;

	return 0;
}

static int gpiod_line_settings_set_drive(struct gpiod_line_settings *settings, int drive)
{
	settings->drive = drive;

	return 0;
}

static void gpiod_line_settings_set_active_low(struct gpiod_line_settings *settings,
	bool active_low)
{
	if (active_low)
		settings->active_low = GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW;
}

#ifdef HAVE_LIBGPIOD1_FLAGS_BIAS

static int gpiod_line_settings_set_bias(struct gpiod_line_settings *settings, int bias)
{
	settings->bias = bias;

	return 0;
}

#else /* HAVE_LIBGPIOD1_FLAGS_BIAS */

static int gpiod_line_settings_set_bias(struct gpiod_line_settings *settings, int bias)
{
	if (bias == GPIOD_LINE_BIAS_DISABLED)
		return 0;

	LOG_WARNING("linuxgpiod: ignoring request for pull-%s: not supported by libgpiod v%s",
				(bias == GPIOD_LINE_BIAS_PULL_UP) ? "up" : "down",
				gpiod_version_string());

	return 0;
}

#endif /* HAVE_LIBGPIOD1_FLAGS_BIAS */

struct gpiod_line_config {
	unsigned int gpio_num;
	struct gpiod_line_settings *line_settings;
};

static struct gpiod_line_config *gpiod_line_config_new(void)
{
	struct gpiod_line_config *rv;

	rv = calloc(sizeof(struct gpiod_line_config), 1);
	if (!rv) {
		LOG_ERROR("No memory for gpiod line config");
		return NULL;
	}

	return rv;
}

static void gpiod_line_config_free(struct gpiod_line_config *config)
{
	free(config);
}

static int gpiod_line_config_add_line_settings(struct gpiod_line_config *config,
	const unsigned int *offsets, size_t num_offsets, struct gpiod_line_settings *settings)
{
	assert(num_offsets == 1);

	config->gpio_num = *offsets;
	config->line_settings = settings;

	return 0;
}

struct gpiod_request_config {
	const char *consumer;
};

static struct gpiod_request_config *gpiod_request_config_new(void)
{
	struct gpiod_request_config *rv;

	rv = calloc(sizeof(struct gpiod_request_config), 1);
	if (!rv) {
		LOG_ERROR("No memory for gpiod request config");
		return NULL;
	}

	return rv;
}

static void gpiod_request_config_free(struct gpiod_request_config *config)
{
	free(config);
}

static void gpiod_request_config_set_consumer(struct gpiod_request_config *config,
	const char *consumer)
{
	config->consumer = consumer;
}

struct gpiod_line_request {
	struct gpiod_line *gpio_line;
	struct gpiod_chip *chip;
	struct gpiod_request_config *req_cfg;
	struct gpiod_line_config *line_cfg;
};

static void gpiod_line_request_release(struct gpiod_line_request *request);

static struct gpiod_line_request *gpiod_chip_request_lines(struct gpiod_chip *chip,
	struct gpiod_request_config *req_cfg, struct gpiod_line_config *line_cfg)
{
	struct gpiod_line_request *line_req;
	int rv, flags = 0;

	assert(req_cfg);

	line_req = calloc(sizeof(struct gpiod_line_request), 1);
	if (!line_req) {
		LOG_ERROR("No memory for gpiod line request");
		return NULL;
	}

	line_req->gpio_line = gpiod_chip_get_line(chip, line_cfg->gpio_num);
	if (!line_req->gpio_line) {
		free(line_req);
		return NULL;
	}

	/* remember stuff in case we need to reconfigure later */
	line_req->chip = chip;
	line_req->req_cfg = gpiod_request_config_new();
	*line_req->req_cfg = *req_cfg;
	line_req->line_cfg = line_cfg;

	flags |= line_cfg->line_settings->drive;
	flags |= line_cfg->line_settings->bias;
	flags |= line_cfg->line_settings->active_low;

	struct gpiod_line_request_config config = {
		.consumer = line_req->req_cfg->consumer,
		.request_type = line_cfg->line_settings->direction,
		.flags = flags,
	};

	rv = gpiod_line_request(line_req->gpio_line, &config, line_cfg->line_settings->value);
	if (rv < 0) {
		gpiod_line_request_release(line_req);
		return NULL;
	}

	return line_req;
}

static int gpiod_line_request_get_value(struct gpiod_line_request *request,
					__attribute__((unused)) unsigned int offset)
{
	return gpiod_line_get_value(request->gpio_line);
}

static int gpiod_line_request_set_value(struct gpiod_line_request *request,
					__attribute__((unused)) unsigned int offset, int value)
{
	return gpiod_line_set_value(request->gpio_line, value);
}

static void gpiod_line_request_release(struct gpiod_line_request *request)
{
	gpiod_request_config_free(request->req_cfg);
	gpiod_line_release(request->gpio_line);
	free(request);
}

static int gpiod_line_request_reconfigure_lines(struct gpiod_line_request *request,
												struct gpiod_line_config *line_cfg)
{
	int rv, flags = 0;

	/* in libgpiod v1 we have to release the line and re-aquire it */
	gpiod_line_release(request->gpio_line);
	request->gpio_line = gpiod_chip_get_line(request->chip, request->line_cfg->gpio_num);
	if (!request->gpio_line)
		return -1;

	flags |= line_cfg->line_settings->drive;
	flags |= line_cfg->line_settings->bias;
	flags |= line_cfg->line_settings->active_low;

	struct gpiod_line_request_config config = {
		.consumer = request->req_cfg->consumer,
		.request_type = line_cfg->line_settings->direction,
		.flags = flags,
	};

	rv = gpiod_line_request(request->gpio_line, &config, line_cfg->line_settings->value);
	if (rv < 0)
		return -1;

	/* remember updated line_cfg */
	request->line_cfg = line_cfg;
	return 0;
}

#endif /* HAVE_LIBGPIOD_V1 */

static struct gpiod_chip *gpiod_chip[ADAPTER_GPIO_IDX_NUM] = {};
static struct gpiod_line_settings *gpiod_line_settings[ADAPTER_GPIO_IDX_NUM] = {};
static struct gpiod_line_config *gpiod_line_config[ADAPTER_GPIO_IDX_NUM] = {};
static struct gpiod_line_request *gpiod_line_req[ADAPTER_GPIO_IDX_NUM] = {};

static int last_swclk;
static int last_swdio;
static bool last_stored;
static bool swdio_input;

static const struct adapter_gpio_config *adapter_gpio_config;

/* Helper to get/set a single line */
static int linuxgpiod_line_get_value(enum adapter_gpio_config_index idx)
{
	return gpiod_line_request_get_value(gpiod_line_req[idx],
				adapter_gpio_config[idx].gpio_num);
}

static int linuxgpiod_line_set_value(enum adapter_gpio_config_index idx, int value)
{
	return gpiod_line_request_set_value(gpiod_line_req[idx],
				adapter_gpio_config[idx].gpio_num,
				value);
}

/*
 * Helper function to determine if gpio config is valid
 *
 * Assume here that there will be less than 10000 gpios per gpiochip, and less
 * than 1000 gpiochips.
 */
static bool is_gpio_config_valid(enum adapter_gpio_config_index idx)
{
	return adapter_gpio_config[idx].chip_num < 1000
		&& adapter_gpio_config[idx].gpio_num < 10000;
}

/* Bitbang interface read of TDO */
static enum bb_value linuxgpiod_read(void)
{
	int retval;

	retval = linuxgpiod_line_get_value(ADAPTER_GPIO_IDX_TDO);
	if (retval < 0) {
		LOG_WARNING("reading tdo failed");
		return 0;
	}

	return retval ? BB_HIGH : BB_LOW;
}

/*
 * Bitbang interface write of TCK, TMS, TDI
 *
 * Seeing as this is the only function where the outputs are changed,
 * we can cache the old value to avoid needlessly writing it.
 */
static int linuxgpiod_write(int tck, int tms, int tdi)
{
	static int last_tck;
	static int last_tms;
	static int last_tdi;

	static int first_time;

	int retval;

	if (!first_time) {
		last_tck = !tck;
		last_tms = !tms;
		last_tdi = !tdi;
		first_time = 1;
	}

	if (tdi != last_tdi) {
		retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_TDI, tdi);
		if (retval < 0)
			LOG_WARNING("writing tdi failed");
	}

	if (tms != last_tms) {
		retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_TMS, tms);
		if (retval < 0)
			LOG_WARNING("writing tms failed");
	}

	/* write clk last */
	if (tck != last_tck) {
		retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_TCK, tck);
		if (retval < 0)
			LOG_WARNING("writing tck failed");
	}

	last_tdi = tdi;
	last_tms = tms;
	last_tck = tck;

	return ERROR_OK;
}

static int linuxgpiod_swdio_read(void)
{
	int retval;

	retval = linuxgpiod_line_get_value(ADAPTER_GPIO_IDX_SWDIO);
	if (retval < 0) {
		LOG_WARNING("Fail read swdio");
		return 0;
	}

	return retval;
}

static void linuxgpiod_swdio_drive(bool is_output)
{
	int retval;

	if (is_output) {
		if (gpiod_line_req[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
			retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_SWDIO_DIR, 1);
			if (retval < 0)
				LOG_WARNING("Failed to set swdio_dir=1");
		}

		retval = gpiod_line_settings_set_direction(gpiod_line_settings[ADAPTER_GPIO_IDX_SWDIO],
													GPIOD_LINE_DIRECTION_OUTPUT);
		if (retval < 0)
			LOG_WARNING("Failed to set new direction of swdio");

		retval = gpiod_line_settings_set_output_value(gpiod_line_settings[ADAPTER_GPIO_IDX_SWDIO],
														GPIOD_LINE_VALUE_ACTIVE);
		if (retval < 0)
			LOG_WARNING("Failed to set output value of swdio");

		retval = gpiod_line_config_add_line_settings(gpiod_line_config[ADAPTER_GPIO_IDX_SWDIO],
														&adapter_gpio_config[ADAPTER_GPIO_IDX_SWDIO].gpio_num, 1,
														gpiod_line_settings[ADAPTER_GPIO_IDX_SWDIO]);
		if (retval < 0)
			LOG_WARNING("Failed to apply output configuration to swdio");

		retval = gpiod_line_request_reconfigure_lines(gpiod_line_req[ADAPTER_GPIO_IDX_SWDIO],
														gpiod_line_config[ADAPTER_GPIO_IDX_SWDIO]);
		if (retval < 0)
			LOG_WARNING("Failed to switch swdio to output");
	} else {
		retval = gpiod_line_settings_set_direction(gpiod_line_settings[ADAPTER_GPIO_IDX_SWDIO],
														GPIOD_LINE_DIRECTION_INPUT);
		if (retval < 0)
			LOG_WARNING("Failed to switch swdio to output");

		retval = gpiod_line_config_add_line_settings(gpiod_line_config[ADAPTER_GPIO_IDX_SWDIO],
														&adapter_gpio_config[ADAPTER_GPIO_IDX_SWDIO].gpio_num, 1,
														gpiod_line_settings[ADAPTER_GPIO_IDX_SWDIO]);
		if (retval < 0)
			LOG_WARNING("Failed to apply input configuration to swdio");

		retval = gpiod_line_request_reconfigure_lines(gpiod_line_req[ADAPTER_GPIO_IDX_SWDIO],
														gpiod_line_config[ADAPTER_GPIO_IDX_SWDIO]);
		if (retval < 0)
			LOG_WARNING("Failed to switch swdio to input");

		if (gpiod_line_req[ADAPTER_GPIO_IDX_SWDIO_DIR]) {
			retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_SWDIO_DIR, 0);
			if (retval < 0)
				LOG_WARNING("Failed to set swdio_dir=0");
		}
	}

	last_stored = false;
	swdio_input = !is_output;
}

static int linuxgpiod_swd_write(int swclk, int swdio)
{
	int retval;

	if (!swdio_input) {
		if (!last_stored || swdio != last_swdio) {
			retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_SWDIO, swdio);
			if (retval < 0)
				LOG_WARNING("Fail set swdio");
		}
	}

	/* write swclk last */
	if (!last_stored || swclk != last_swclk) {
		retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_SWCLK, swclk);
		if (retval < 0)
			LOG_WARNING("Fail set swclk");
	}

	last_swdio = swdio;
	last_swclk = swclk;
	last_stored = true;

	return ERROR_OK;
}

static int linuxgpiod_blink(bool on)
{
	int retval;

	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_LED))
		return ERROR_OK;

	retval = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_LED, on);
	if (retval < 0)
		LOG_WARNING("Fail set led");
	return retval;
}

static const struct bitbang_interface linuxgpiod_bitbang = {
	.read = linuxgpiod_read,
	.write = linuxgpiod_write,
	.swdio_read = linuxgpiod_swdio_read,
	.swdio_drive = linuxgpiod_swdio_drive,
	.swd_write = linuxgpiod_swd_write,
	.blink = linuxgpiod_blink,
};

/*
 * Bitbang interface to manipulate reset lines SRST and TRST
 *
 * (1) assert or (0) deassert reset lines
 */
static int linuxgpiod_reset(int trst, int srst)
{
	int retval1 = 0, retval2 = 0;

	LOG_DEBUG("linuxgpiod_reset");

	/*
	 * active low behavior handled by "adaptor gpio" command and
	 * GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW flag when requesting the line.
	 */
	if (gpiod_line_req[ADAPTER_GPIO_IDX_SRST]) {
		retval1 = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_SRST, srst);
		if (retval1 < 0)
			LOG_WARNING("set srst value failed");
	}

	if (gpiod_line_req[ADAPTER_GPIO_IDX_TRST]) {
		retval2 = linuxgpiod_line_set_value(ADAPTER_GPIO_IDX_TRST, trst);
		if (retval2 < 0)
			LOG_WARNING("set trst value failed");
	}

	return ((retval1 < 0) || (retval2 < 0)) ? ERROR_FAIL : ERROR_OK;
}

static bool linuxgpiod_jtag_mode_possible(void)
{
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TCK))
		return false;
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TMS))
		return false;
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDI))
		return false;
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_TDO))
		return false;
	return true;
}

static bool linuxgpiod_swd_mode_possible(void)
{
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWCLK))
		return false;
	if (!is_gpio_config_valid(ADAPTER_GPIO_IDX_SWDIO))
		return false;
	return true;
}

static inline void helper_release(enum adapter_gpio_config_index idx)
{
	if (gpiod_line_req[idx]) {
		gpiod_line_request_release(gpiod_line_req[idx]);
		gpiod_line_req[idx] = NULL;
	}
	if (gpiod_line_config[idx]) {
		gpiod_line_config_free(gpiod_line_config[idx]);
		gpiod_line_config[idx] = NULL;
	}
	if (gpiod_line_settings[idx]) {
		gpiod_line_settings_free(gpiod_line_settings[idx]);
		gpiod_line_settings[idx] = NULL;
	}
	if (gpiod_chip[idx]) {
		gpiod_chip_close(gpiod_chip[idx]);
		gpiod_chip[idx] = NULL;
	}
}

static int linuxgpiod_quit(void)
{
	LOG_DEBUG("linuxgpiod_quit");
	for (int i = 0; i < ADAPTER_GPIO_IDX_NUM; ++i)
		helper_release(i);

	return ERROR_OK;
}

static int helper_get_line(enum adapter_gpio_config_index idx)
{
	struct gpiod_request_config *req_cfg = NULL;
	char chip_path[24];
	int rv = 0;

	if (!is_gpio_config_valid(idx))
		return ERROR_OK;

	snprintf(chip_path, sizeof(chip_path), "/dev/gpiochip%u", adapter_gpio_config[idx].chip_num);
	gpiod_chip[idx] = gpiod_chip_open(chip_path);

	if (!gpiod_chip[idx]) {
		LOG_ERROR("Cannot open LinuxGPIOD chip %d for %s", adapter_gpio_config[idx].chip_num,
			adapter_gpio_get_name(idx));
		return ERROR_JTAG_INIT_FAILED;
	}

	gpiod_line_settings[idx] = gpiod_line_settings_new();
	gpiod_line_config[idx] = gpiod_line_config_new();
	req_cfg = gpiod_request_config_new();

	if (!gpiod_line_settings[idx] || !gpiod_line_config[idx] || !req_cfg) {
		LOG_ERROR("Cannot configure LinuxGPIOD line for %s", adapter_gpio_get_name(idx));
		gpiod_request_config_free(req_cfg);
		return ERROR_JTAG_INIT_FAILED;
	}

	gpiod_request_config_set_consumer(req_cfg, "OpenOCD");

	switch (adapter_gpio_config[idx].init_state) {
	case ADAPTER_GPIO_INIT_STATE_INPUT:
		rv = gpiod_line_settings_set_direction(gpiod_line_settings[idx], GPIOD_LINE_DIRECTION_INPUT);
		break;
	case ADAPTER_GPIO_INIT_STATE_INACTIVE:
		rv = gpiod_line_settings_set_direction(gpiod_line_settings[idx], GPIOD_LINE_DIRECTION_OUTPUT);
		rv |= gpiod_line_settings_set_output_value(gpiod_line_settings[idx], GPIOD_LINE_VALUE_INACTIVE);
		break;
	case ADAPTER_GPIO_INIT_STATE_ACTIVE:
		rv = gpiod_line_settings_set_direction(gpiod_line_settings[idx], GPIOD_LINE_DIRECTION_OUTPUT);
		rv |= gpiod_line_settings_set_output_value(gpiod_line_settings[idx], GPIOD_LINE_VALUE_ACTIVE);
		break;
	}
	if (rv < 0) {
		LOG_ERROR("Error while configuring LinuxGPIOD line init state for %s", adapter_gpio_get_name(idx));
		gpiod_request_config_free(req_cfg);
		return ERROR_JTAG_INIT_FAILED;
	}

	switch (adapter_gpio_config[idx].drive) {
	case ADAPTER_GPIO_DRIVE_MODE_PUSH_PULL:
		rv = gpiod_line_settings_set_drive(gpiod_line_settings[idx], GPIOD_LINE_DRIVE_PUSH_PULL);
		break;
	case ADAPTER_GPIO_DRIVE_MODE_OPEN_DRAIN:
		rv = gpiod_line_settings_set_drive(gpiod_line_settings[idx], GPIOD_LINE_DRIVE_OPEN_DRAIN);
		break;
	case ADAPTER_GPIO_DRIVE_MODE_OPEN_SOURCE:
		rv = gpiod_line_settings_set_drive(gpiod_line_settings[idx], GPIOD_LINE_DRIVE_OPEN_SOURCE);
		break;
	}
	if (rv < 0) {
		LOG_ERROR("Error while configuring LinuxGPIOD line driving for %s", adapter_gpio_get_name(idx));
		gpiod_request_config_free(req_cfg);
		return ERROR_JTAG_INIT_FAILED;
	}

	switch (adapter_gpio_config[idx].pull) {
	case ADAPTER_GPIO_PULL_NONE:
		rv = gpiod_line_settings_set_bias(gpiod_line_settings[idx], GPIOD_LINE_BIAS_DISABLED);
		break;
	case ADAPTER_GPIO_PULL_UP:
		rv = gpiod_line_settings_set_bias(gpiod_line_settings[idx], GPIOD_LINE_BIAS_PULL_UP);
		break;
	case ADAPTER_GPIO_PULL_DOWN:
		rv = gpiod_line_settings_set_bias(gpiod_line_settings[idx], GPIOD_LINE_BIAS_PULL_DOWN);
		break;
	}
	if (rv < 0) {
		LOG_ERROR("Error while configuring LinuxGPIOD line biasing for %s", adapter_gpio_get_name(idx));
		gpiod_request_config_free(req_cfg);
		return ERROR_JTAG_INIT_FAILED;
	}

	gpiod_line_settings_set_active_low(gpiod_line_settings[idx], adapter_gpio_config[idx].active_low);

	rv = gpiod_line_config_add_line_settings(gpiod_line_config[idx],
												&adapter_gpio_config[idx].gpio_num, 1,
												gpiod_line_settings[idx]);
	if (rv < 0) {
		LOG_ERROR("Error configuring gpio line %s", adapter_gpio_get_name(idx));
		gpiod_request_config_free(req_cfg);
		return ERROR_JTAG_INIT_FAILED;
	}

	gpiod_line_req[idx] = gpiod_chip_request_lines(gpiod_chip[idx], req_cfg, gpiod_line_config[idx]);

	gpiod_request_config_free(req_cfg);

	if (!gpiod_line_req[idx]) {
		LOG_ERROR("Error requesting gpio line %s", adapter_gpio_get_name(idx));
		return ERROR_JTAG_INIT_FAILED;
	}

	return ERROR_OK;
}

static int linuxgpiod_init(void)
{
	LOG_INFO("Linux GPIOD JTAG/SWD bitbang driver");

	bitbang_interface = &linuxgpiod_bitbang;
	adapter_gpio_config = adapter_gpio_get_config();

	/*
	 * Configure JTAG/SWD signals. Default directions and initial states are handled
	 * by adapter.c and "adapter gpio" command.
	 */

	if (transport_is_jtag()) {
		if (!linuxgpiod_jtag_mode_possible()) {
			LOG_ERROR("Require tck, tms, tdi and tdo gpios for JTAG mode");
			goto out_error;
		}

		if (helper_get_line(ADAPTER_GPIO_IDX_TDO) != ERROR_OK
				|| helper_get_line(ADAPTER_GPIO_IDX_TDI) != ERROR_OK
				|| helper_get_line(ADAPTER_GPIO_IDX_TCK) != ERROR_OK
				|| helper_get_line(ADAPTER_GPIO_IDX_TMS) != ERROR_OK
				|| helper_get_line(ADAPTER_GPIO_IDX_TRST) != ERROR_OK)
			goto out_error;
	}

	if (transport_is_swd()) {
		int retval1, retval2;
		if (!linuxgpiod_swd_mode_possible()) {
			LOG_ERROR("Require swclk and swdio gpio for SWD mode");
			goto out_error;
		}

		/*
		 * swdio and its buffer should be initialized in the order that prevents
		 * two outputs from being connected together. This will occur if the
		 * swdio GPIO is configured as an output while the external buffer is
		 * configured to send the swdio signal from the target to the GPIO.
		 */
		if (adapter_gpio_config[ADAPTER_GPIO_IDX_SWDIO].init_state == ADAPTER_GPIO_INIT_STATE_INPUT) {
			retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
			retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
		} else {
			retval1 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO_DIR);
			retval2 = helper_get_line(ADAPTER_GPIO_IDX_SWDIO);
		}
		if (retval1 != ERROR_OK || retval2 != ERROR_OK)
			goto out_error;

		if (helper_get_line(ADAPTER_GPIO_IDX_SWCLK) != ERROR_OK)
			goto out_error;
	}

	if (helper_get_line(ADAPTER_GPIO_IDX_SRST) != ERROR_OK
			|| helper_get_line(ADAPTER_GPIO_IDX_LED) != ERROR_OK)
		goto out_error;

	return ERROR_OK;

out_error:
	linuxgpiod_quit();

	return ERROR_JTAG_INIT_FAILED;
}

static struct jtag_interface linuxgpiod_interface = {
	.supported = DEBUG_CAP_TMS_SEQ,
	.execute_queue = bitbang_execute_queue,
};

struct adapter_driver linuxgpiod_adapter_driver = {
	.name = "linuxgpiod",
	.transport_ids = TRANSPORT_SWD | TRANSPORT_JTAG,
	.transport_preferred_id = TRANSPORT_SWD,

	.init = linuxgpiod_init,
	.quit = linuxgpiod_quit,
	.reset = linuxgpiod_reset,

	.jtag_ops = &linuxgpiod_interface,
	.swd_ops = &bitbang_swd,
};
