linux_gpio2_spi.c - flashprog - Gitiles

 /*
  * This file is part of the flashrom project.
  *
  * Copyright (C) 2024 Nico Huber <nico.h@gmx.de>
  *
  * based on linux_gpio_spi.c
  * Copyright (C) 2023 Steve Markgraf <steve@steve-m.de>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation; either version 2 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>
 #include <errno.h>
 #include <gpiod.h>
 #include "programmer.h"
 #include "bitbang_spi.h"
 #include "spi.h"
 #include "flash.h"

 #define CONSUMER "flashprog"

 enum {
 	CS	= 0,
 	SCK	= 1,
 	MOSI	= 2,
 	MISO	= 3,
 	IO0	= 2,
 	IO1	= 3,
 	IO2	= 4,
 	IO3	= 5,
 	MAX_LINES
 };

 struct linux_gpio_spi {
 	struct gpiod_chip *chip;
 	struct gpiod_line_request *lines;
 	struct gpiod_line_config *single;
 	struct gpiod_line_config *multi_in;
 	struct gpiod_line_config *multi_out;
 	struct gpiod_line_config *current_config;
 	unsigned int offsets[MAX_LINES];
 	unsigned int io_lines;
 };

 static int ensure_spi_mode(struct linux_gpio_spi *gpio_spi, struct gpiod_line_config *config)
 {
 	if (gpio_spi->current_config == config)
 		return 0;

 	const int ret = gpiod_line_request_reconfigure_lines(gpio_spi->lines, config);
 	if (ret < 0)
 		msg_perr("Switching line config failed: %s\n", strerror(errno));
 	else
 		gpio_spi->current_config = config;

 	return ret;
 }

 static void linux_gpio_spi_bitbang_set_cs(int val, void *data)
 {
 	const struct linux_gpio_spi *const gpio_spi = data;

 	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[CS], val) < 0)
 		msg_perr("Setting cs line failed: %s\n", strerror(errno));
 }

 static void linux_gpio_spi_bitbang_set_sck(int val, void *data)
 {
 	const struct linux_gpio_spi *const gpio_spi = data;

 	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[SCK], val) < 0)
 		msg_perr("Setting sck line failed: %s\n", strerror(errno));
 }

 static void linux_gpio_spi_bitbang_set_mosi(int val, void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
 		return;

 	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[MOSI], val) < 0)
 		msg_perr("Setting mosi line failed: %s\n", strerror(errno));
 }

 static int linux_gpio_spi_bitbang_get_miso(void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
 		return -1;

 	const enum gpiod_line_value ret =
 		gpiod_line_request_get_value(gpio_spi->lines, gpio_spi->offsets[MISO]);
 	if (ret < 0)
 		msg_perr("Getting miso line failed: %s\n", strerror(errno));
 	return ret;
 }

 static void linux_gpio_spi_bitbang_set_sck_set_mosi(int sck, int mosi, void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
 		return;

 	enum gpiod_line_value vals[] = { sck, mosi };
 	if (gpiod_line_request_set_values_subset(gpio_spi->lines, 2, &gpio_spi->offsets[SCK], vals) < 0)
 		msg_perr("Setting sck/mosi lines failed: %s\n", strerror(errno));
 }

 static void linux_gpio_spi_bitbang_set_sck_set_multi_io(int sck, int io, void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	if (ensure_spi_mode(gpio_spi, gpio_spi->multi_out) < 0)
 		return;

 	enum gpiod_line_value vals[] = { sck, io & 1, io >> 1 & 1, io >> 2 & 1, io >> 3 & 1 };
 	if (gpiod_line_request_set_values_subset(gpio_spi->lines,
 				gpio_spi->io_lines + 1, &gpio_spi->offsets[SCK], vals) < 0)
 		msg_perr("Setting sck/io lines failed: %s\n", strerror(errno));
 }

 static int linux_gpio_spi_bitbang_set_sck_get_multi_io(int sck, void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	if (ensure_spi_mode(gpio_spi, gpio_spi->multi_in) < 0)
 		return -1;

 	linux_gpio_spi_bitbang_set_sck(sck, data);

 	enum gpiod_line_value vals[4] = { 0, };
 	const int ret = gpiod_line_request_get_values_subset(gpio_spi->lines,
 				gpio_spi->io_lines, &gpio_spi->offsets[IO0], vals);
 	if (ret < 0) {
 		msg_perr("Getting io lines failed: %s\n", strerror(errno));
 		return -1;
 	}

 	return vals[0] | vals[1] << 1 | vals[2] << 2 | vals[3] << 3;
 }

 static void linux_gpio_spi_bitbang_set_idle_io(void *data)
 {
 	struct linux_gpio_spi *const gpio_spi = data;

 	(void)ensure_spi_mode(gpio_spi, gpio_spi->multi_in);
 }

 static struct bitbang_spi_master bitbang_spi_master_gpiod = {
 	.set_cs			= linux_gpio_spi_bitbang_set_cs,
 	.set_sck		= linux_gpio_spi_bitbang_set_sck,
 	.set_mosi		= linux_gpio_spi_bitbang_set_mosi,
 	.get_miso		= linux_gpio_spi_bitbang_get_miso,
 	.set_sck_set_mosi	= linux_gpio_spi_bitbang_set_sck_set_mosi,
 	.set_sck_set_dual_io	= linux_gpio_spi_bitbang_set_sck_set_multi_io,
 	.set_sck_get_dual_io	= linux_gpio_spi_bitbang_set_sck_get_multi_io,
 	.set_idle_io		= linux_gpio_spi_bitbang_set_idle_io,
 };

 static int linux_gpio_spi_shutdown(void *data)
 {
 	struct linux_gpio_spi *gpio_spi = data;

 	if (gpio_spi->multi_out)
 		gpiod_line_config_free(gpio_spi->multi_out);
 	if (gpio_spi->multi_in)
 		gpiod_line_config_free(gpio_spi->multi_in);
 	if (gpio_spi->single)
 		gpiod_line_config_free(gpio_spi->single);
 	if (gpio_spi->lines)
 		gpiod_line_request_release(gpio_spi->lines);
 	if (gpio_spi->chip)
 		gpiod_chip_close(gpio_spi->chip);

 	free(data);

 	return 0;
 }

 static int linux_gpio_spi_init(struct flashprog_programmer *const prog)
 {
 	struct param {
 		const char *names[2];
 		bool required;
 	};
 	static const struct param int_params[] = {
 		{ .names = { "cs", },		.required = true, },
 		{ .names = { "sck", },		.required = true, },
 		{ .names = { "mosi", "io0", }, 	.required = true, },
 		{ .names = { "miso", "io1", }, 	.required = true, },
 		{ .names = { "io2", }, 		.required = false, },
 		{ .names = { "io3", }, 		.required = false, },
 		{ .names = { "gpiochip", },	.required = false, },
 	};

 	struct linux_gpio_spi *gpio_spi = NULL;
 	unsigned int param_int[ARRAY_SIZE(int_params)];
 	unsigned int i, j;
 	int r;

 	gpio_spi = calloc(1, sizeof(*gpio_spi));
 	if (!gpio_spi) {
 		msg_perr("Unable to allocate space for SPI master data\n");
 		return SPI_GENERIC_ERROR;
 	}

 	for (i = 0; i < ARRAY_SIZE(int_params); i++) {
 		const char *param_name = int_params[i].names[0];
 		char *param = NULL, *endptr;

 		for (j = 0; j < 2 && int_params[i].names[j]; ++j) {
 			char *const p = extract_programmer_param(int_params[i].names[j]);
 			if (param && p) {
 				msg_perr("Parameters `%s' and `%s' are mutually exclusive.\n",
 					 int_params[i].names[0], int_params[i].names[1]);
 				free(param);
 				free(p);
 				goto err_exit;
 			}
 			if (p) {
 				param_name = int_params[i].names[j];
 				param = p;
 			}
 		}

 		r = 1;

 		if (param) {
 			errno = 0;
 			param_int[i] = strtoul(param, &endptr, 10);
 			r = (*endptr != '\0') || (errno != 0);
 			free(param);
 		} else {
 			param_int[i] = UINT_MAX;
 		}

 		if ((int_params[i].required || param) && r) {
 			msg_perr("Invalid or missing required programmer parameter "
 				 "%s=<n>\n", param_name);
 			goto err_exit;
 		}
 	}

 	char *const dev = extract_programmer_param("dev");
 	const unsigned int gpiochip = param_int[MAX_LINES];
 	if (!dev && gpiochip == UINT_MAX) {
 		msg_perr("Either a `dev' or `gpiochip' parameter must be specified.\n"
 			 "e.g. `-p linux_gpio2_spi:dev=/dev/gpiochip0'.\n");
 		goto err_exit;
 	}
 	if (dev && gpiochip != UINT_MAX) {
 		msg_perr("Only one of `dev' or `gpiochip' parameters can be specified.\n");
 		goto free_dev_exit;
 	}

 	if ((param_int[IO2] == UINT_MAX) ^ (param_int[IO3] == UINT_MAX)) {
 		msg_perr("Both `io2' and `io3' are required for quad i/o.\n");
 		goto free_dev_exit;
 	}

 	const char *devpath;
 	char devpath_template[] = "/dev/gpiochipX";
 	if (dev) {
 		devpath = dev;
 	} else if (gpiochip > 9) {
 		msg_perr("Maximum `gpiochip' number supported is 9.\n");
 		goto err_exit;
 	} else {
 		devpath_template[13] = '0' + gpiochip;
 		devpath = devpath_template;
 	}

 	gpio_spi->chip = gpiod_chip_open(devpath);
 	if (!gpio_spi->chip) {
 		msg_perr("Failed to open gpiochip `%s': %s\n", devpath, strerror(errno));
 		goto free_dev_exit;
 	}
 	free(dev);

 	if (param_int[IO2] != UINT_MAX) {
 		bitbang_spi_master_gpiod.set_sck_set_quad_io = linux_gpio_spi_bitbang_set_sck_set_multi_io;
 		bitbang_spi_master_gpiod.set_sck_get_quad_io = linux_gpio_spi_bitbang_set_sck_get_multi_io;
 		gpio_spi->io_lines = 4;
 	} else {
 		gpio_spi->io_lines = 2;
 	}

 	struct gpiod_line_settings *const in = gpiod_line_settings_new();
 	struct gpiod_line_settings *const out = gpiod_line_settings_new();
 	gpio_spi->multi_out = gpiod_line_config_new();
 	gpio_spi->multi_in = gpiod_line_config_new();
 	gpio_spi->single = gpiod_line_config_new();
 	if (!in || !out || !gpio_spi->multi_out || !gpio_spi->multi_in || !gpio_spi->single) {
 		msg_perr("Unable to allocate space for GPIO line config\n");
 		if (out)
 			gpiod_line_settings_free(out);
 		if (in)
 			gpiod_line_settings_free(in);
 		goto err_exit;
 	}

 	gpiod_line_settings_set_direction(in, GPIOD_LINE_DIRECTION_INPUT);
 	gpiod_line_settings_set_direction(out, GPIOD_LINE_DIRECTION_OUTPUT);

 	gpiod_line_config_add_line_settings(gpio_spi->single, &param_int[CS], 3, out);
 	gpiod_line_config_add_line_settings(gpio_spi->single, &param_int[MISO], gpio_spi->io_lines - 1, in);

 	gpiod_line_config_add_line_settings(gpio_spi->multi_in, &param_int[CS], 2, out);
 	gpiod_line_config_add_line_settings(gpio_spi->multi_in, &param_int[IO0], gpio_spi->io_lines, in);

 	gpiod_line_config_add_line_settings(gpio_spi->multi_out, &param_int[CS], 2 + gpio_spi->io_lines, out);

 	gpiod_line_settings_free(out);
 	gpiod_line_settings_free(in);

 	gpio_spi->lines = gpiod_chip_request_lines(gpio_spi->chip, NULL, gpio_spi->single);
 	if (!gpio_spi->lines) {
 		msg_perr("Failed to acquire GPIO lines\n");
 		goto err_exit;
 	}
 	gpio_spi->current_config = gpio_spi->single;

 	memcpy(gpio_spi->offsets, param_int, sizeof(gpio_spi->offsets));

 	if (register_shutdown(linux_gpio_spi_shutdown, gpio_spi))
 		goto err_exit;

 	/* shutdown function does the cleanup */
 	return register_spi_bitbang_master(&bitbang_spi_master_gpiod, gpio_spi);

 free_dev_exit:
 	free(dev);
 err_exit:
 	linux_gpio_spi_shutdown(gpio_spi);
 	return SPI_GENERIC_ERROR;
 }

 const struct programmer_entry programmer_linux_gpio_spi = {
 	.name		= "linux_gpio_spi",
 	.type		= OTHER,
 	.devs.note	= "Device file /dev/gpiochip<n>\n",
 	.init		= linux_gpio_spi_init,
 };
	/*
	* This file is part of the flashrom project.
	*
	* Copyright (C) 2024 Nico Huber <nico.h@gmx.de>
	*
	* based on linux_gpio_spi.c
	* Copyright (C) 2023 Steve Markgraf <steve@steve-m.de>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License as published by
	* the Free Software Foundation; either version 2 of the License, or
	* (at your option) any later version.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#include <stdlib.h>
	#include <string.h>
	#include <limits.h>
	#include <errno.h>
	#include <gpiod.h>
	#include "programmer.h"
	#include "bitbang_spi.h"
	#include "spi.h"
	#include "flash.h"

	#define CONSUMER "flashprog"

	enum {
	CS = 0,
	SCK = 1,
	MOSI = 2,
	MISO = 3,
	IO0 = 2,
	IO1 = 3,
	IO2 = 4,
	IO3 = 5,
	MAX_LINES
	};

	struct linux_gpio_spi {
	struct gpiod_chip *chip;
	struct gpiod_line_request *lines;
	struct gpiod_line_config *single;
	struct gpiod_line_config *multi_in;
	struct gpiod_line_config *multi_out;
	struct gpiod_line_config *current_config;
	unsigned int offsets[MAX_LINES];
	unsigned int io_lines;
	};

	static int ensure_spi_mode(struct linux_gpio_spi gpio_spi, struct gpiod_line_config config)
	{
	if (gpio_spi->current_config == config)
	return 0;

	const int ret = gpiod_line_request_reconfigure_lines(gpio_spi->lines, config);
	if (ret < 0)
	msg_perr("Switching line config failed: %s\n", strerror(errno));
	else
	gpio_spi->current_config = config;

	return ret;
	}

	static void linux_gpio_spi_bitbang_set_cs(int val, void *data)
	{
	const struct linux_gpio_spi *const gpio_spi = data;

	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[CS], val) < 0)
	msg_perr("Setting cs line failed: %s\n", strerror(errno));
	}

	static void linux_gpio_spi_bitbang_set_sck(int val, void *data)
	{
	const struct linux_gpio_spi *const gpio_spi = data;

	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[SCK], val) < 0)
	msg_perr("Setting sck line failed: %s\n", strerror(errno));
	}

	static void linux_gpio_spi_bitbang_set_mosi(int val, void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
	return;

	if (gpiod_line_request_set_value(gpio_spi->lines, gpio_spi->offsets[MOSI], val) < 0)
	msg_perr("Setting mosi line failed: %s\n", strerror(errno));
	}

	static int linux_gpio_spi_bitbang_get_miso(void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
	return -1;

	const enum gpiod_line_value ret =
	gpiod_line_request_get_value(gpio_spi->lines, gpio_spi->offsets[MISO]);
	if (ret < 0)
	msg_perr("Getting miso line failed: %s\n", strerror(errno));
	return ret;
	}

	static void linux_gpio_spi_bitbang_set_sck_set_mosi(int sck, int mosi, void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	if (ensure_spi_mode(gpio_spi, gpio_spi->single) < 0)
	return;

	enum gpiod_line_value vals[] = { sck, mosi };
	if (gpiod_line_request_set_values_subset(gpio_spi->lines, 2, &gpio_spi->offsets[SCK], vals) < 0)
	msg_perr("Setting sck/mosi lines failed: %s\n", strerror(errno));
	}

	static void linux_gpio_spi_bitbang_set_sck_set_multi_io(int sck, int io, void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	if (ensure_spi_mode(gpio_spi, gpio_spi->multi_out) < 0)
	return;

	enum gpiod_line_value vals[] = { sck, io & 1, io >> 1 & 1, io >> 2 & 1, io >> 3 & 1 };
	if (gpiod_line_request_set_values_subset(gpio_spi->lines,
	gpio_spi->io_lines + 1, &gpio_spi->offsets[SCK], vals) < 0)
	msg_perr("Setting sck/io lines failed: %s\n", strerror(errno));
	}

	static int linux_gpio_spi_bitbang_set_sck_get_multi_io(int sck, void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	if (ensure_spi_mode(gpio_spi, gpio_spi->multi_in) < 0)
	return -1;

	linux_gpio_spi_bitbang_set_sck(sck, data);

	enum gpiod_line_value vals[4] = { 0, };
	const int ret = gpiod_line_request_get_values_subset(gpio_spi->lines,
	gpio_spi->io_lines, &gpio_spi->offsets[IO0], vals);
	if (ret < 0) {
	msg_perr("Getting io lines failed: %s\n", strerror(errno));
	return -1;
	}

	return vals[0] \| vals[1] << 1 \| vals[2] << 2 \| vals[3] << 3;
	}

	static void linux_gpio_spi_bitbang_set_idle_io(void *data)
	{
	struct linux_gpio_spi *const gpio_spi = data;

	(void)ensure_spi_mode(gpio_spi, gpio_spi->multi_in);
	}

	static struct bitbang_spi_master bitbang_spi_master_gpiod = {
	.set_cs = linux_gpio_spi_bitbang_set_cs,
	.set_sck = linux_gpio_spi_bitbang_set_sck,
	.set_mosi = linux_gpio_spi_bitbang_set_mosi,
	.get_miso = linux_gpio_spi_bitbang_get_miso,
	.set_sck_set_mosi = linux_gpio_spi_bitbang_set_sck_set_mosi,
	.set_sck_set_dual_io = linux_gpio_spi_bitbang_set_sck_set_multi_io,
	.set_sck_get_dual_io = linux_gpio_spi_bitbang_set_sck_get_multi_io,
	.set_idle_io = linux_gpio_spi_bitbang_set_idle_io,
	};

	static int linux_gpio_spi_shutdown(void *data)
	{
	struct linux_gpio_spi *gpio_spi = data;

	if (gpio_spi->multi_out)
	gpiod_line_config_free(gpio_spi->multi_out);
	if (gpio_spi->multi_in)
	gpiod_line_config_free(gpio_spi->multi_in);
	if (gpio_spi->single)
	gpiod_line_config_free(gpio_spi->single);
	if (gpio_spi->lines)
	gpiod_line_request_release(gpio_spi->lines);
	if (gpio_spi->chip)
	gpiod_chip_close(gpio_spi->chip);

	free(data);

	return 0;
	}

	static int linux_gpio_spi_init(struct flashprog_programmer *const prog)
	{
	struct param {
	const char *names[2];
	bool required;
	};
	static const struct param int_params[] = {
	{ .names = { "cs", }, .required = true, },
	{ .names = { "sck", }, .required = true, },
	{ .names = { "mosi", "io0", }, .required = true, },
	{ .names = { "miso", "io1", }, .required = true, },
	{ .names = { "io2", }, .required = false, },
	{ .names = { "io3", }, .required = false, },
	{ .names = { "gpiochip", }, .required = false, },
	};

	struct linux_gpio_spi *gpio_spi = NULL;
	unsigned int param_int[ARRAY_SIZE(int_params)];
	unsigned int i, j;
	int r;

	gpio_spi = calloc(1, sizeof(*gpio_spi));
	if (!gpio_spi) {
	msg_perr("Unable to allocate space for SPI master data\n");
	return SPI_GENERIC_ERROR;
	}

	for (i = 0; i < ARRAY_SIZE(int_params); i++) {
	const char *param_name = int_params[i].names[0];
	char param = NULL, endptr;

	for (j = 0; j < 2 && int_params[i].names[j]; ++j) {
	char *const p = extract_programmer_param(int_params[i].names[j]);
	if (param && p) {
	msg_perr("Parameters `%s' and `%s' are mutually exclusive.\n",
	int_params[i].names[0], int_params[i].names[1]);
	free(param);
	free(p);
	goto err_exit;
	}
	if (p) {
	param_name = int_params[i].names[j];
	param = p;
	}
	}

	r = 1;

	if (param) {
	errno = 0;
	param_int[i] = strtoul(param, &endptr, 10);
	r = (*endptr != '\0') \|\| (errno != 0);
	free(param);
	} else {
	param_int[i] = UINT_MAX;
	}

	if ((int_params[i].required \|\| param) && r) {
	msg_perr("Invalid or missing required programmer parameter "
	"%s=<n>\n", param_name);
	goto err_exit;
	}
	}

	char *const dev = extract_programmer_param("dev");
	const unsigned int gpiochip = param_int[MAX_LINES];
	if (!dev && gpiochip == UINT_MAX) {
	msg_perr("Either a `dev' or `gpiochip' parameter must be specified.\n"
	"e.g. `-p linux_gpio2_spi:dev=/dev/gpiochip0'.\n");
	goto err_exit;
	}
	if (dev && gpiochip != UINT_MAX) {
	msg_perr("Only one of `dev' or `gpiochip' parameters can be specified.\n");
	goto free_dev_exit;
	}

	if ((param_int[IO2] == UINT_MAX) ^ (param_int[IO3] == UINT_MAX)) {
	msg_perr("Both `io2' and `io3' are required for quad i/o.\n");
	goto free_dev_exit;
	}

	const char *devpath;
	char devpath_template[] = "/dev/gpiochipX";
	if (dev) {
	devpath = dev;
	} else if (gpiochip > 9) {
	msg_perr("Maximum `gpiochip' number supported is 9.\n");
	goto err_exit;
	} else {
	devpath_template[13] = '0' + gpiochip;
	devpath = devpath_template;
	}

	gpio_spi->chip = gpiod_chip_open(devpath);
	if (!gpio_spi->chip) {
	msg_perr("Failed to open gpiochip `%s': %s\n", devpath, strerror(errno));
	goto free_dev_exit;
	}
	free(dev);

	if (param_int[IO2] != UINT_MAX) {
	bitbang_spi_master_gpiod.set_sck_set_quad_io = linux_gpio_spi_bitbang_set_sck_set_multi_io;
	bitbang_spi_master_gpiod.set_sck_get_quad_io = linux_gpio_spi_bitbang_set_sck_get_multi_io;
	gpio_spi->io_lines = 4;
	} else {
	gpio_spi->io_lines = 2;
	}

	struct gpiod_line_settings *const in = gpiod_line_settings_new();
	struct gpiod_line_settings *const out = gpiod_line_settings_new();
	gpio_spi->multi_out = gpiod_line_config_new();
	gpio_spi->multi_in = gpiod_line_config_new();
	gpio_spi->single = gpiod_line_config_new();
	if (!in \|\| !out \|\| !gpio_spi->multi_out \|\| !gpio_spi->multi_in \|\| !gpio_spi->single) {
	msg_perr("Unable to allocate space for GPIO line config\n");
	if (out)
	gpiod_line_settings_free(out);
	if (in)
	gpiod_line_settings_free(in);
	goto err_exit;
	}

	gpiod_line_settings_set_direction(in, GPIOD_LINE_DIRECTION_INPUT);
	gpiod_line_settings_set_direction(out, GPIOD_LINE_DIRECTION_OUTPUT);

	gpiod_line_config_add_line_settings(gpio_spi->single, &param_int[CS], 3, out);
	gpiod_line_config_add_line_settings(gpio_spi->single, &param_int[MISO], gpio_spi->io_lines - 1, in);

	gpiod_line_config_add_line_settings(gpio_spi->multi_in, &param_int[CS], 2, out);
	gpiod_line_config_add_line_settings(gpio_spi->multi_in, &param_int[IO0], gpio_spi->io_lines, in);

	gpiod_line_config_add_line_settings(gpio_spi->multi_out, &param_int[CS], 2 + gpio_spi->io_lines, out);

	gpiod_line_settings_free(out);
	gpiod_line_settings_free(in);

	gpio_spi->lines = gpiod_chip_request_lines(gpio_spi->chip, NULL, gpio_spi->single);
	if (!gpio_spi->lines) {
	msg_perr("Failed to acquire GPIO lines\n");
	goto err_exit;
	}
	gpio_spi->current_config = gpio_spi->single;

	memcpy(gpio_spi->offsets, param_int, sizeof(gpio_spi->offsets));

	if (register_shutdown(linux_gpio_spi_shutdown, gpio_spi))
	goto err_exit;

	/* shutdown function does the cleanup */
	return register_spi_bitbang_master(&bitbang_spi_master_gpiod, gpio_spi);

	free_dev_exit:
	free(dev);
	err_exit:
	linux_gpio_spi_shutdown(gpio_spi);
	return SPI_GENERIC_ERROR;
	}

	const struct programmer_entry programmer_linux_gpio_spi = {
	.name = "linux_gpio_spi",
	.type = OTHER,
	.devs.note = "Device file /dev/gpiochip<n>\n",
	.init = linux_gpio_spi_init,
	};