openocd/src/jtag/drivers/linuxgpiod.c

/* 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/interface.h>
#include <transport/transport.h>
#include "bitbang.h"

/* gpio numbers for each gpio. Negative values are invalid */
static int tck_gpio = -1;
static int tms_gpio = -1;
static int tdi_gpio = -1;
static int tdo_gpio = -1;
static int trst_gpio = -1;
static int srst_gpio = -1;
static int swclk_gpio = -1;
static int swdio_gpio = -1;
static int swdio_dir_gpio = -1;
static int led_gpio = -1;
static int gpiochip = -1;
static int tck_gpiochip = -1;
static int tms_gpiochip = -1;
static int tdi_gpiochip = -1;
static int tdo_gpiochip = -1;
static int trst_gpiochip = -1;
static int srst_gpiochip = -1;
static int swclk_gpiochip = -1;
static int swdio_gpiochip = -1;
static int swdio_dir_gpiochip = -1;
static int led_gpiochip = -1;

static struct gpiod_chip *gpiod_chip_tck;
static struct gpiod_chip *gpiod_chip_tms;
static struct gpiod_chip *gpiod_chip_tdi;
static struct gpiod_chip *gpiod_chip_tdo;
static struct gpiod_chip *gpiod_chip_trst;
static struct gpiod_chip *gpiod_chip_srst;
static struct gpiod_chip *gpiod_chip_swclk;
static struct gpiod_chip *gpiod_chip_swdio;
static struct gpiod_chip *gpiod_chip_swdio_dir;
static struct gpiod_chip *gpiod_chip_led;

static struct gpiod_line *gpiod_tck;
static struct gpiod_line *gpiod_tms;
static struct gpiod_line *gpiod_tdi;
static struct gpiod_line *gpiod_tdo;
static struct gpiod_line *gpiod_trst;
static struct gpiod_line *gpiod_swclk;
static struct gpiod_line *gpiod_swdio;
static struct gpiod_line *gpiod_swdio_dir;
static struct gpiod_line *gpiod_srst;
static struct gpiod_line *gpiod_led;

static int last_swclk;
static int last_swdio;
static bool last_stored;
static bool swdio_input;
static bool swdio_dir_is_active_high = true;

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

	retval = gpiod_line_get_value(gpiod_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 = gpiod_line_set_value(gpiod_tdi, tdi);
		if (retval < 0)
			LOG_WARNING("writing tdi failed");
	}

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

	/* write clk last */
	if (tck != last_tck) {
		retval = gpiod_line_set_value(gpiod_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 = gpiod_line_get_value(gpiod_swdio);
	if (retval < 0) {
		LOG_WARNING("Fail read swdio");
		return 0;
	}

	return retval;
}

static void linuxgpiod_swdio_drive(bool is_output)
{
	int retval;

	/*
	 * FIXME: change direction requires release and re-require the line
	 * https://stackoverflow.com/questions/58735140/
	 * this would change in future libgpiod
	 */
	gpiod_line_release(gpiod_swdio);

	if (is_output) {
		if (gpiod_swdio_dir) {
			retval = gpiod_line_set_value(gpiod_swdio_dir, swdio_dir_is_active_high ? 1 : 0);
			if (retval < 0)
				LOG_WARNING("Fail set swdio_dir");
		}
		retval = gpiod_line_request_output(gpiod_swdio, "OpenOCD", 1);
		if (retval < 0)
			LOG_WARNING("Fail request_output line swdio");
	} else {
		retval = gpiod_line_request_input(gpiod_swdio, "OpenOCD");
		if (retval < 0)
			LOG_WARNING("Fail request_input line swdio");
		if (gpiod_swdio_dir) {
			retval = gpiod_line_set_value(gpiod_swdio_dir, swdio_dir_is_active_high ? 0 : 1);
			if (retval < 0)
				LOG_WARNING("Fail set swdio_dir");
		}
	}

	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 = gpiod_line_set_value(gpiod_swdio, swdio);
			if (retval < 0)
				LOG_WARNING("Fail set swdio");
		}
	}

	/* write swclk last */
	if (!last_stored || (swclk != last_swclk)) {
		retval = gpiod_line_set_value(gpiod_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(int on)
{
	int retval;

	if (!gpiod_led)
		return ERROR_OK;

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

static 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");

	/* assume active low */
	if (gpiod_srst) {
		retval1 = gpiod_line_set_value(gpiod_srst, srst ? 0 : 1);
		if (retval1 < 0)
			LOG_WARNING("set srst value failed");
	}

	/* assume active low */
	if (gpiod_trst) {
		retval2 = gpiod_line_set_value(gpiod_trst, trst ? 0 : 1);
		if (retval2 < 0)
			LOG_WARNING("set trst value failed");
	}

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

/*
 * Helper function to determine if gpio number is valid
 *
 * Assume here that there will be less than 10000 gpios per gpiochip
 */
static bool is_gpio_valid(int gpio)
{
	return gpio >= 0 && gpio < 10000;
}

static bool linuxgpiod_jtag_mode_possible(void)
{
	if (!is_gpio_valid(tck_gpio))
		return false;
	if (!is_gpio_valid(tms_gpio))
		return false;
	if (!is_gpio_valid(tdi_gpio))
		return false;
	if (!is_gpio_valid(tdo_gpio))
		return false;
	return true;
}

static bool linuxgpiod_swd_mode_possible(void)
{
	if (!is_gpio_valid(swclk_gpio))
		return false;
	if (!is_gpio_valid(swdio_gpio))
		return false;
	return true;
}

static inline void helper_release(struct gpiod_line *line, struct gpiod_chip *chip)
{
	if (line)
		gpiod_line_release(line);
	if (chip)
		gpiod_chip_close(chip);
}

static int linuxgpiod_quit(void)
{
	helper_release(gpiod_led,       gpiod_chip_led);
	helper_release(gpiod_srst,      gpiod_chip_srst);
	helper_release(gpiod_swdio,     gpiod_chip_swdio);
	helper_release(gpiod_swdio_dir, gpiod_chip_swdio_dir);
	helper_release(gpiod_swclk,     gpiod_chip_swclk);
	helper_release(gpiod_trst,      gpiod_chip_trst);
	helper_release(gpiod_tms,       gpiod_chip_tms);
	helper_release(gpiod_tck,       gpiod_chip_tck);
	helper_release(gpiod_tdi,       gpiod_chip_tdi);
	helper_release(gpiod_tdo,       gpiod_chip_tdo);

	return ERROR_OK;
}

static struct gpiod_line *helper_get_line(const char *label,
		struct gpiod_chip *gpiod_chip, unsigned int offset,
		int val, int dir, int flags)
{
	struct gpiod_line *line;
	int retval;

	line = gpiod_chip_get_line(gpiod_chip, offset);
	if (!line) {
		LOG_ERROR("Error get line %s", label);
		return NULL;
	}

	struct gpiod_line_request_config config = {
		.consumer = "OpenOCD",
		.request_type = dir,
		.flags = flags,
	};

	retval = gpiod_line_request(line, &config, val);
	if (retval < 0) {
		LOG_ERROR("Error requesting gpio line %s", label);
		return NULL;
	}

	return line;
}

static struct gpiod_line *helper_get_input_line(const char *label,
		struct gpiod_chip *gpiod_chip, unsigned int offset)
{
	return helper_get_line(label, gpiod_chip, offset, 0,
			GPIOD_LINE_REQUEST_DIRECTION_INPUT, 0);
}

static struct gpiod_line *helper_get_output_line(const char *label,
		struct gpiod_chip *gpiod_chip, unsigned int offset, int val)
{
	return helper_get_line(label, gpiod_chip, offset, val,
			GPIOD_LINE_REQUEST_DIRECTION_OUTPUT, 0);
}

static struct gpiod_line *helper_get_open_drain_output_line(const char *label,
		struct gpiod_chip *gpiod_chip, unsigned int offset, int val)
{
	return helper_get_line(label, gpiod_chip, offset, val,
			GPIOD_LINE_REQUEST_DIRECTION_OUTPUT, GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN);
}

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

	bitbang_interface = &linuxgpiod_bitbang;

	/*
	 * Configure TDO as an input, and TDI, TCK, TMS, TRST, SRST
	 * as outputs.  Drive TDI and TCK low, and TMS/TRST/SRST high.
	 * For SWD, SWCLK and SWDIO are configures as output high.
	 */

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

		gpiod_chip_tdo = gpiod_chip_open_by_number(tdo_gpiochip);
		if (!gpiod_chip_tdo) {
			LOG_ERROR("Cannot open LinuxGPIOD tdo_gpiochip %d", tdo_gpiochip);
			goto out_error;
		}
		gpiod_chip_tdi = gpiod_chip_open_by_number(tdi_gpiochip);
		if (!gpiod_chip_tdi) {
			LOG_ERROR("Cannot open LinuxGPIOD tdi_gpiochip %d", tdi_gpiochip);
			goto out_error;
		}
		gpiod_chip_tck = gpiod_chip_open_by_number(tck_gpiochip);
		if (!gpiod_chip_tck) {
			LOG_ERROR("Cannot open LinuxGPIOD tck_gpiochip %d", tck_gpiochip);
			goto out_error;
		}
		gpiod_chip_tms = gpiod_chip_open_by_number(tms_gpiochip);
		if (!gpiod_chip_tms) {
			LOG_ERROR("Cannot open LinuxGPIOD tms_gpiochip %d", tms_gpiochip);
			goto out_error;
		}

		gpiod_tdo = helper_get_input_line("tdo", gpiod_chip_tdo, tdo_gpio);
		if (!gpiod_tdo)
			goto out_error;

		gpiod_tdi = helper_get_output_line("tdi", gpiod_chip_tdi, tdi_gpio, 0);
		if (!gpiod_tdi)
			goto out_error;

		gpiod_tck = helper_get_output_line("tck", gpiod_chip_tck, tck_gpio, 0);
		if (!gpiod_tck)
			goto out_error;

		gpiod_tms = helper_get_output_line("tms", gpiod_chip_tms, tms_gpio, 1);
		if (!gpiod_tms)
			goto out_error;

		if (is_gpio_valid(trst_gpio)) {
			gpiod_chip_trst = gpiod_chip_open_by_number(trst_gpiochip);
			if (!gpiod_chip_trst) {
				LOG_ERROR("Cannot open LinuxGPIOD trst_gpiochip %d", trst_gpiochip);
				goto out_error;
			}

			if (jtag_get_reset_config() & RESET_TRST_OPEN_DRAIN)
				gpiod_trst = helper_get_open_drain_output_line("trst", gpiod_chip_trst, trst_gpio, 1);
			else
				gpiod_trst = helper_get_output_line("trst", gpiod_chip_trst, trst_gpio, 1);

			if (!gpiod_trst)
				goto out_error;
		}
	}

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

		gpiod_chip_swclk = gpiod_chip_open_by_number(swclk_gpiochip);
		if (!gpiod_chip_swclk) {
			LOG_ERROR("Cannot open LinuxGPIOD swclk_gpiochip %d", swclk_gpiochip);
			goto out_error;
		}
		gpiod_chip_swdio = gpiod_chip_open_by_number(swdio_gpiochip);
		if (!gpiod_chip_swdio) {
			LOG_ERROR("Cannot open LinuxGPIOD swdio_gpiochip %d", swdio_gpiochip);
			goto out_error;
		}

		if (is_gpio_valid(swdio_dir_gpio)) {
			gpiod_chip_swdio_dir = gpiod_chip_open_by_number(swdio_dir_gpiochip);
			if (!gpiod_chip_swdio_dir) {
				LOG_ERROR("Cannot open LinuxGPIOD swdio_dir_gpiochip %d", swdio_dir_gpiochip);
				goto out_error;
			}
		}

		gpiod_swclk = helper_get_output_line("swclk", gpiod_chip_swclk, swclk_gpio, 1);
		if (!gpiod_swclk)
			goto out_error;

		/* Set buffer direction before making SWDIO an output */
		if (is_gpio_valid(swdio_dir_gpio)) {
			gpiod_swdio_dir = helper_get_output_line("swdio_dir", gpiod_chip_swdio_dir, swdio_dir_gpio,
					swdio_dir_is_active_high ? 1 : 0);
			if (!gpiod_swdio_dir)
				goto out_error;
		}

		gpiod_swdio = helper_get_output_line("swdio", gpiod_chip_swdio, swdio_gpio, 1);
		if (!gpiod_swdio)
			goto out_error;
	}

	if (is_gpio_valid(srst_gpio)) {
		gpiod_chip_srst = gpiod_chip_open_by_number(srst_gpiochip);
		if (!gpiod_chip_srst) {
			LOG_ERROR("Cannot open LinuxGPIOD srst_gpiochip %d", srst_gpiochip);
			goto out_error;
		}

		if (jtag_get_reset_config() & RESET_SRST_PUSH_PULL)
			gpiod_srst = helper_get_output_line("srst", gpiod_chip_srst, srst_gpio, 1);
		else
			gpiod_srst = helper_get_open_drain_output_line("srst", gpiod_chip_srst, srst_gpio, 1);

		if (!gpiod_srst)
			goto out_error;
	}

	if (is_gpio_valid(led_gpio)) {
		gpiod_chip_led = gpiod_chip_open_by_number(led_gpiochip);
		if (!gpiod_chip_led) {
			LOG_ERROR("Cannot open LinuxGPIOD led_gpiochip %d", led_gpiochip);
			goto out_error;
		}

		gpiod_led = helper_get_output_line("led", gpiod_chip_led, led_gpio, 0);
		if (!gpiod_led)
			goto out_error;
	}

	return ERROR_OK;

out_error:
	linuxgpiod_quit();

	return ERROR_JTAG_INIT_FAILED;
}

COMMAND_HELPER(linuxgpiod_helper_gpionum, const char *name, int *chip, int *line)
{
	int i = 0;
	if (CMD_ARGC > 2)
		return ERROR_COMMAND_SYNTAX_ERROR;
	if (CMD_ARGC == 2) {
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], *chip);
		i = 1;
	}
	if (CMD_ARGC > 0)
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[i], *line);
	command_print(CMD, "LinuxGPIOD %s: chip = %d, num = %d", name, *chip, *line);
	return ERROR_OK;
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionums)
{
	if (CMD_ARGC == 4) {
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], tck_gpio);
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], tms_gpio);
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[2], tdi_gpio);
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[3], tdo_gpio);
	} else if (CMD_ARGC != 0) {
		return ERROR_COMMAND_SYNTAX_ERROR;
	}

	command_print(CMD,
			"LinuxGPIOD nums: tck = %d, tms = %d, tdi = %d, tdo = %d",
			tck_gpio, tms_gpio, tdi_gpio, tdo_gpio);

	return ERROR_OK;
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tck)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tck", &tck_gpiochip,
			&tck_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tms)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tms", &tms_gpiochip,
			&tms_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdo)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tdo", &tdo_gpiochip,
			&tdo_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_tdi)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "tdi", &tdi_gpiochip,
			&tdi_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_srst)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "srst", &srst_gpiochip,
			&srst_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_jtag_gpionum_trst)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "trst", &trst_gpiochip,
			&trst_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_swd_gpionums)
{
	if (CMD_ARGC == 2) {
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], swclk_gpio);
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[1], swdio_gpio);
	} else if (CMD_ARGC != 0) {
		return ERROR_COMMAND_SYNTAX_ERROR;
	}

	command_print(CMD,
			"LinuxGPIOD nums: swclk = %d, swdio = %d",
			swclk_gpio, swdio_gpio);

	return ERROR_OK;
}

COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swclk)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swclk", &swclk_gpiochip,
			&swclk_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swdio", &swdio_gpiochip,
			&swdio_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_swd_gpionum_swdio_dir)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "swdio_dir", &swdio_dir_gpiochip,
			&swdio_dir_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_gpionum_led)
{
	return CALL_COMMAND_HANDLER(linuxgpiod_helper_gpionum, "led", &led_gpiochip,
			&led_gpio);
}

COMMAND_HANDLER(linuxgpiod_handle_gpiochip)
{
	if (CMD_ARGC == 1) {
		COMMAND_PARSE_NUMBER(int, CMD_ARGV[0], gpiochip);
		tck_gpiochip = gpiochip;
		tms_gpiochip = gpiochip;
		tdi_gpiochip = gpiochip;
		tdo_gpiochip = gpiochip;
		trst_gpiochip = gpiochip;
		srst_gpiochip = gpiochip;
		swclk_gpiochip = gpiochip;
		swdio_gpiochip = gpiochip;
		swdio_dir_gpiochip = gpiochip;
		led_gpiochip = gpiochip;
	}

	command_print(CMD, "LinuxGPIOD gpiochip = %d", gpiochip);
	return ERROR_OK;
}

static const struct command_registration linuxgpiod_subcommand_handlers[] = {
	{
		.name = "jtag_nums",
		.handler = linuxgpiod_handle_jtag_gpionums,
		.mode = COMMAND_CONFIG,
		.help = "gpio numbers for tck, tms, tdi, tdo. (in that order)",
		.usage = "tck tms tdi tdo",
	},
	{
		.name = "tck_num",
		.handler = linuxgpiod_handle_jtag_gpionum_tck,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for tck.",
		.usage = "[chip] tck",
	},
	{
		.name = "tms_num",
		.handler = linuxgpiod_handle_jtag_gpionum_tms,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for tms.",
		.usage = "[chip] tms",
	},
	{
		.name = "tdo_num",
		.handler = linuxgpiod_handle_jtag_gpionum_tdo,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for tdo.",
		.usage = "[chip] tdo",
	},
	{
		.name = "tdi_num",
		.handler = linuxgpiod_handle_jtag_gpionum_tdi,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for tdi.",
		.usage = "[chip] tdi",
	},
	{
		.name = "srst_num",
		.handler = linuxgpiod_handle_jtag_gpionum_srst,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for srst.",
		.usage = "[chip] srst",
	},
	{
		.name = "trst_num",
		.handler = linuxgpiod_handle_jtag_gpionum_trst,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for trst.",
		.usage = "[chip] trst",
	},
	{
		.name = "swd_nums",
		.handler = linuxgpiod_handle_swd_gpionums,
		.mode = COMMAND_CONFIG,
		.help = "gpio numbers for swclk, swdio. (in that order)",
		.usage = "swclk swdio",
	},
	{
		.name = "swclk_num",
		.handler = linuxgpiod_handle_swd_gpionum_swclk,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for swclk.",
		.usage = "[chip] swclk",
	},
	{
		.name = "swdio_num",
		.handler = linuxgpiod_handle_swd_gpionum_swdio,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for swdio.",
		.usage = "[chip] swdio",
	},
	{
		.name = "swdio_dir_num",
		.handler = linuxgpiod_handle_swd_gpionum_swdio_dir,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for swdio_dir.",
		.usage = "[chip] swdio_dir",
	},
	{
		.name = "led_num",
		.handler = linuxgpiod_handle_gpionum_led,
		.mode = COMMAND_CONFIG,
		.help = "gpio chip number (optional) and gpio number for LED.",
		.usage = "[chip] led",
	},
	{
		.name = "gpiochip",
		.handler = linuxgpiod_handle_gpiochip,
		.mode = COMMAND_CONFIG,
		.help = "number of the gpiochip.",
		.usage = "gpiochip",
	},
	COMMAND_REGISTRATION_DONE
};

static const struct command_registration linuxgpiod_command_handlers[] = {
	{
		.name = "linuxgpiod",
		.mode = COMMAND_ANY,
		.help = "perform linuxgpiod management",
		.chain = linuxgpiod_subcommand_handlers,
		.usage = "",
	},
	COMMAND_REGISTRATION_DONE
};

static const char *const linuxgpiod_transport[] = { "swd", "jtag", NULL };

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

struct adapter_driver linuxgpiod_adapter_driver = {
	.name = "linuxgpiod",
	.transports = linuxgpiod_transport,
	.commands = linuxgpiod_command_handlers,

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

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