ftrace: Synchronize the initialization of ftrace_opsgrafted

There's some internal state that ftrace_ops needs to have set, but since
it can be declared outside of the ftrace.c code, it calls
ftrace_ops_init() on the ops in every global function. The issue is that
if two tasks call it on the same ops at the same time it is possible to
have the initialization of one corrupt the initialization of the other
call.

Create a ops_mutex to use to synchronize every initialization of the
ftrace_ops. The mutex is taken within checking the ftrace_ops flag that
states it was initializied but the flag is checked again after the mutex
has been taken. Checking first outside the mutex allows it to shortcut
having to take the mutex. But then the check needs to be done again after
the mute is taken in case of races.

Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home
Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock")
Reported-by: sashiko-bot@kernel.org
Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

10 files changed, 1447 insertions, 0 deletions

diff --git a/tools/gpio/.gitignore b/tools/gpio/.gitignore
new file mode 100644
index 000000000..a00d60402
--- /dev/null
+++ b/tools/gpio/.gitignore
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+gpio-event-mon
+gpio-hammer
+gpio-watch
+lsgpio
+include/linux/gpio.h
diff --git a/tools/gpio/Build b/tools/gpio/Build
new file mode 100644
index 000000000..67c7b7f6a
--- /dev/null
+++ b/tools/gpio/Build
@@ -0,0 +1,5 @@
+gpio-utils-y += gpio-utils.o
+lsgpio-y += lsgpio.o gpio-utils.o
+gpio-hammer-y += gpio-hammer.o gpio-utils.o
+gpio-event-mon-y += gpio-event-mon.o gpio-utils.o
+gpio-watch-y += gpio-watch.o
diff --git a/tools/gpio/Makefile b/tools/gpio/Makefile
new file mode 100644
index 000000000..342e056c8
--- /dev/null
+++ b/tools/gpio/Makefile
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: GPL-2.0
+include ../scripts/Makefile.include
+
+bindir ?= /usr/bin
+
+# This will work when gpio is built in tools env. where srctree
+# isn't set and when invoked from selftests build, where srctree
+# is set to ".". building_out_of_srctree is undefined for in srctree
+# builds
+ifndef building_out_of_srctree
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+# Do not use make's built-in rules
+# (this improves performance and avoids hard-to-debug behaviour);
+MAKEFLAGS += -r
+
+override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+
+ALL_TARGETS := lsgpio gpio-hammer gpio-event-mon gpio-watch
+ALL_PROGRAMS := $(patsubst %,$(OUTPUT)%,$(ALL_TARGETS))
+
+all: $(ALL_PROGRAMS)
+
+export srctree OUTPUT CC LD CFLAGS
+include $(srctree)/tools/build/Makefile.include
+
+#
+# We need the following to be outside of kernel tree
+#
+$(OUTPUT)include/linux/gpio.h: ../../include/uapi/linux/gpio.h
+	mkdir -p $(OUTPUT)include/linux 2>&1 || true
+	ln -sf $(CURDIR)/../../include/uapi/linux/gpio.h $@
+
+prepare: $(OUTPUT)include/linux/gpio.h
+
+GPIO_UTILS_IN := $(OUTPUT)gpio-utils-in.o
+$(GPIO_UTILS_IN): prepare FORCE
+	$(Q)$(MAKE) $(build)=gpio-utils
+
+#
+# lsgpio
+#
+LSGPIO_IN := $(OUTPUT)lsgpio-in.o
+$(LSGPIO_IN): prepare FORCE $(OUTPUT)gpio-utils-in.o
+	$(Q)$(MAKE) $(build)=lsgpio
+$(OUTPUT)lsgpio: $(LSGPIO_IN)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+#
+# gpio-hammer
+#
+GPIO_HAMMER_IN := $(OUTPUT)gpio-hammer-in.o
+$(GPIO_HAMMER_IN): prepare FORCE $(OUTPUT)gpio-utils-in.o
+	$(Q)$(MAKE) $(build)=gpio-hammer
+$(OUTPUT)gpio-hammer: $(GPIO_HAMMER_IN)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+#
+# gpio-event-mon
+#
+GPIO_EVENT_MON_IN := $(OUTPUT)gpio-event-mon-in.o
+$(GPIO_EVENT_MON_IN): prepare FORCE $(OUTPUT)gpio-utils-in.o
+	$(Q)$(MAKE) $(build)=gpio-event-mon
+$(OUTPUT)gpio-event-mon: $(GPIO_EVENT_MON_IN)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+#
+# gpio-watch
+#
+GPIO_WATCH_IN := $(OUTPUT)gpio-watch-in.o
+$(GPIO_WATCH_IN): prepare FORCE
+	$(Q)$(MAKE) $(build)=gpio-watch
+$(OUTPUT)gpio-watch: $(GPIO_WATCH_IN)
+	$(QUIET_LINK)$(CC) $(CFLAGS) $(LDFLAGS) $< -o $@
+
+clean:
+	rm -f $(ALL_PROGRAMS)
+	rm -rf $(OUTPUT)include
+	find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '\.*.d' -delete -o -name '\.*.cmd' -delete
+
+install: $(ALL_PROGRAMS)
+	install -d -m 755 $(DESTDIR)$(bindir);		\
+	for program in $(ALL_PROGRAMS); do		\
+		install $$program $(DESTDIR)$(bindir);	\
+	done
+
+FORCE:
+
+.PHONY: all install clean FORCE prepare
diff --git a/tools/gpio/gpio-event-mon.c b/tools/gpio/gpio-event-mon.c
new file mode 100644
index 000000000..b70813b0b
--- /dev/null
+++ b/tools/gpio/gpio-event-mon.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * gpio-event-mon - monitor GPIO line events from userspace
+ *
+ * Copyright (C) 2016 Linus Walleij
+ *
+ * Usage:
+ *	gpio-event-mon -n <device-name> -o <offset>
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <errno.h>
+#include <string.h>
+#include <poll.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <linux/gpio.h>
+#include "gpio-utils.h"
+
+int monitor_device(const char *device_name,
+		   unsigned int *lines,
+		   unsigned int num_lines,
+		   struct gpio_v2_line_config *config,
+		   unsigned int loops)
+{
+	struct gpio_v2_line_values values;
+	char *chrdev_name;
+	int cfd, lfd;
+	int ret;
+	int i = 0;
+
+	ret = asprintf(&chrdev_name, "/dev/%s", device_name);
+	if (ret < 0)
+		return -ENOMEM;
+
+	cfd = open(chrdev_name, 0);
+	if (cfd == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to open %s\n", chrdev_name);
+		goto exit_free_name;
+	}
+
+	ret = gpiotools_request_line(device_name, lines, num_lines, config,
+				     "gpio-event-mon");
+	if (ret < 0)
+		goto exit_device_close;
+	else
+		lfd = ret;
+
+	/* Read initial states */
+	values.mask = 0;
+	values.bits = 0;
+	for (i = 0; i < num_lines; i++)
+		gpiotools_set_bit(&values.mask, i);
+	ret = gpiotools_get_values(lfd, &values);
+	if (ret < 0) {
+		fprintf(stderr,
+			"Failed to issue GPIO LINE GET VALUES IOCTL (%d)\n",
+			ret);
+		goto exit_line_close;
+	}
+
+	if (num_lines == 1) {
+		fprintf(stdout, "Monitoring line %u on %s\n", lines[0], device_name);
+		fprintf(stdout, "Initial line value: %d\n",
+			gpiotools_test_bit(values.bits, 0));
+	} else {
+		fprintf(stdout, "Monitoring lines %u", lines[0]);
+		for (i = 1; i < num_lines - 1; i++)
+			fprintf(stdout, ", %u", lines[i]);
+		fprintf(stdout, " and %u on %s\n", lines[i], device_name);
+		fprintf(stdout, "Initial line values: %d",
+			gpiotools_test_bit(values.bits, 0));
+		for (i = 1; i < num_lines - 1; i++)
+			fprintf(stdout, ", %d",
+				gpiotools_test_bit(values.bits, i));
+		fprintf(stdout, " and %d\n",
+			gpiotools_test_bit(values.bits, i));
+	}
+
+	i = 0;
+	while (1) {
+		struct gpio_v2_line_event event;
+
+		ret = read(lfd, &event, sizeof(event));
+		if (ret == -1) {
+			if (errno == -EAGAIN) {
+				fprintf(stderr, "nothing available\n");
+				continue;
+			} else {
+				ret = -errno;
+				fprintf(stderr, "Failed to read event (%d)\n",
+					ret);
+				break;
+			}
+		}
+
+		if (ret != sizeof(event)) {
+			fprintf(stderr, "Reading event failed\n");
+			ret = -EIO;
+			break;
+		}
+		fprintf(stdout, "GPIO EVENT at %" PRIu64 " on line %d (%d|%d) ",
+			(uint64_t)event.timestamp_ns, event.offset, event.line_seqno,
+			event.seqno);
+		switch (event.id) {
+		case GPIO_V2_LINE_EVENT_RISING_EDGE:
+			fprintf(stdout, "rising edge");
+			break;
+		case GPIO_V2_LINE_EVENT_FALLING_EDGE:
+			fprintf(stdout, "falling edge");
+			break;
+		default:
+			fprintf(stdout, "unknown event");
+		}
+		fprintf(stdout, "\n");
+
+		i++;
+		if (i == loops)
+			break;
+	}
+
+exit_line_close:
+	if (close(lfd) == -1)
+		perror("Failed to close line file");
+exit_device_close:
+	if (close(cfd) == -1)
+		perror("Failed to close GPIO character device file");
+exit_free_name:
+	free(chrdev_name);
+	return ret;
+}
+
+void print_usage(void)
+{
+	fprintf(stderr, "Usage: gpio-event-mon [options]...\n"
+		"Listen to events on GPIO lines, 0->1 1->0\n"
+		"  -n <name>  Listen on GPIOs on a named device (must be stated)\n"
+		"  -o <n>     Offset of line to monitor (may be repeated)\n"
+		"  -d         Set line as open drain\n"
+		"  -s         Set line as open source\n"
+		"  -r         Listen for rising edges\n"
+		"  -f         Listen for falling edges\n"
+		"  -w         Report the wall-clock time for events\n"
+		"  -t         Report the hardware timestamp for events\n"
+		"  -b <n>     Debounce the line with period n microseconds\n"
+		" [-c <n>]    Do <n> loops (optional, infinite loop if not stated)\n"
+		"  -?         This helptext\n"
+		"\n"
+		"Example:\n"
+		"gpio-event-mon -n gpiochip0 -o 4 -r -f -b 10000\n"
+	);
+}
+
+#define EDGE_FLAGS \
+	(GPIO_V2_LINE_FLAG_EDGE_RISING | \
+	 GPIO_V2_LINE_FLAG_EDGE_FALLING)
+
+int main(int argc, char **argv)
+{
+	const char *device_name = NULL;
+	unsigned int lines[GPIO_V2_LINES_MAX];
+	unsigned int num_lines = 0;
+	unsigned int loops = 0;
+	struct gpio_v2_line_config config;
+	int c, attr, i;
+	unsigned long debounce_period_us = 0;
+
+	memset(&config, 0, sizeof(config));
+	config.flags = GPIO_V2_LINE_FLAG_INPUT;
+	while ((c = getopt(argc, argv, "c:n:o:b:dsrfwt?")) != -1) {
+		switch (c) {
+		case 'c':
+			loops = strtoul(optarg, NULL, 10);
+			break;
+		case 'n':
+			device_name = optarg;
+			break;
+		case 'o':
+			if (num_lines >= GPIO_V2_LINES_MAX) {
+				print_usage();
+				return -1;
+			}
+			lines[num_lines] = strtoul(optarg, NULL, 10);
+			num_lines++;
+			break;
+		case 'b':
+			debounce_period_us = strtoul(optarg, NULL, 10);
+			break;
+		case 'd':
+			config.flags |= GPIO_V2_LINE_FLAG_OPEN_DRAIN;
+			break;
+		case 's':
+			config.flags |= GPIO_V2_LINE_FLAG_OPEN_SOURCE;
+			break;
+		case 'r':
+			config.flags |= GPIO_V2_LINE_FLAG_EDGE_RISING;
+			break;
+		case 'f':
+			config.flags |= GPIO_V2_LINE_FLAG_EDGE_FALLING;
+			break;
+		case 'w':
+			config.flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME;
+			break;
+		case 't':
+			config.flags |= GPIO_V2_LINE_FLAG_EVENT_CLOCK_HTE;
+			break;
+		case '?':
+			print_usage();
+			return -1;
+		}
+	}
+
+	if (debounce_period_us) {
+		attr = config.num_attrs;
+		config.num_attrs++;
+		for (i = 0; i < num_lines; i++)
+			gpiotools_set_bit(&config.attrs[attr].mask, i);
+		config.attrs[attr].attr.id = GPIO_V2_LINE_ATTR_ID_DEBOUNCE;
+		config.attrs[attr].attr.debounce_period_us = debounce_period_us;
+	}
+
+	if (!device_name || num_lines == 0) {
+		print_usage();
+		return -1;
+	}
+	if (!(config.flags & EDGE_FLAGS)) {
+		printf("No flags specified, listening on both rising and "
+		       "falling edges\n");
+		config.flags |= EDGE_FLAGS;
+	}
+	return monitor_device(device_name, lines, num_lines, &config, loops);
+}
diff --git a/tools/gpio/gpio-hammer.c b/tools/gpio/gpio-hammer.c
new file mode 100644
index 000000000..ba0866eb3
--- /dev/null
+++ b/tools/gpio/gpio-hammer.c
@@ -0,0 +1,176 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * gpio-hammer - example swiss army knife to shake GPIO lines on a system
+ *
+ * Copyright (C) 2016 Linus Walleij
+ *
+ * Usage:
+ *	gpio-hammer -n <device-name> -o <offset1> -o <offset2>
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <errno.h>
+#include <string.h>
+#include <poll.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <linux/gpio.h>
+#include "gpio-utils.h"
+
+int hammer_device(const char *device_name, unsigned int *lines, int num_lines,
+		  unsigned int loops)
+{
+	struct gpio_v2_line_values values;
+	struct gpio_v2_line_config config;
+	char swirr[] = "-\\|/";
+	int fd;
+	int ret;
+	int i, j;
+	unsigned int iteration = 0;
+
+	memset(&config, 0, sizeof(config));
+	config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
+
+	ret = gpiotools_request_line(device_name, lines, num_lines,
+				     &config, "gpio-hammer");
+	if (ret < 0)
+		goto exit_error;
+	else
+		fd = ret;
+
+	values.mask = 0;
+	values.bits = 0;
+	for (i = 0; i < num_lines; i++)
+		gpiotools_set_bit(&values.mask, i);
+
+	ret = gpiotools_get_values(fd, &values);
+	if (ret < 0)
+		goto exit_close_error;
+
+	fprintf(stdout, "Hammer lines [");
+	for (i = 0; i < num_lines; i++) {
+		fprintf(stdout, "%u", lines[i]);
+		if (i != (num_lines - 1))
+			fprintf(stdout, ", ");
+	}
+	fprintf(stdout, "] on %s, initial states: [", device_name);
+	for (i = 0; i < num_lines; i++) {
+		fprintf(stdout, "%d", gpiotools_test_bit(values.bits, i));
+		if (i != (num_lines - 1))
+			fprintf(stdout, ", ");
+	}
+	fprintf(stdout, "]\n");
+
+	/* Hammertime! */
+	j = 0;
+	while (1) {
+		/* Invert all lines so we blink */
+		for (i = 0; i < num_lines; i++)
+			gpiotools_change_bit(&values.bits, i);
+
+		ret = gpiotools_set_values(fd, &values);
+		if (ret < 0)
+			goto exit_close_error;
+
+		/* Re-read values to get status */
+		ret = gpiotools_get_values(fd, &values);
+		if (ret < 0)
+			goto exit_close_error;
+
+		fprintf(stdout, "[%c] ", swirr[j]);
+		j++;
+		if (j == sizeof(swirr) - 1)
+			j = 0;
+
+		fprintf(stdout, "[");
+		for (i = 0; i < num_lines; i++) {
+			fprintf(stdout, "%u: %d", lines[i],
+				gpiotools_test_bit(values.bits, i));
+			if (i != (num_lines - 1))
+				fprintf(stdout, ", ");
+		}
+		fprintf(stdout, "]\r");
+		fflush(stdout);
+		sleep(1);
+		iteration++;
+		if (loops && iteration == loops)
+			break;
+	}
+	fprintf(stdout, "\n");
+	ret = 0;
+
+exit_close_error:
+	gpiotools_release_line(fd);
+exit_error:
+	return ret;
+}
+
+void print_usage(void)
+{
+	fprintf(stderr, "Usage: gpio-hammer [options]...\n"
+		"Hammer GPIO lines, 0->1->0->1...\n"
+		"  -n <name>  Hammer GPIOs on a named device (must be stated)\n"
+		"  -o <n>     Offset[s] to hammer, at least one, several can be stated\n"
+		" [-c <n>]    Do <n> loops (optional, infinite loop if not stated)\n"
+		"  -?         This helptext\n"
+		"\n"
+		"Example:\n"
+		"gpio-hammer -n gpiochip0 -o 4\n"
+	);
+}
+
+int main(int argc, char **argv)
+{
+	const char *device_name = NULL;
+	unsigned int lines[GPIOHANDLES_MAX];
+	unsigned int loops = 0;
+	int num_lines;
+	int c;
+	int i;
+
+	i = 0;
+	while ((c = getopt(argc, argv, "c:n:o:?")) != -1) {
+		switch (c) {
+		case 'c':
+			loops = strtoul(optarg, NULL, 10);
+			break;
+		case 'n':
+			device_name = optarg;
+			break;
+		case 'o':
+			/*
+			 * Avoid overflow. Do not immediately error, we want to
+			 * be able to accurately report on the amount of times
+			 * '-o' was given to give an accurate error message
+			 */
+			if (i < GPIOHANDLES_MAX)
+				lines[i] = strtoul(optarg, NULL, 10);
+
+			i++;
+			break;
+		case '?':
+			print_usage();
+			return -1;
+		}
+	}
+
+	if (i >= GPIOHANDLES_MAX) {
+		fprintf(stderr,
+			"Only %d occurrences of '-o' are allowed, %d were found\n",
+			GPIOHANDLES_MAX, i + 1);
+		return -1;
+	}
+
+	num_lines = i;
+
+	if (!device_name || !num_lines) {
+		print_usage();
+		return -1;
+	}
+	return hammer_device(device_name, lines, num_lines, loops);
+}
diff --git a/tools/gpio/gpio-sloppy-logic-analyzer.sh b/tools/gpio/gpio-sloppy-logic-analyzer.sh
new file mode 100755
index 000000000..3ef2278e4
--- /dev/null
+++ b/tools/gpio/gpio-sloppy-logic-analyzer.sh
@@ -0,0 +1,246 @@
+#!/bin/sh -eu
+# SPDX-License-Identifier: GPL-2.0
+#
+# Helper script for the Linux Kernel GPIO sloppy logic analyzer
+#
+# Copyright (C) Wolfram Sang <wsa@sang-engineering.com>
+# Copyright (C) Renesas Electronics Corporation
+
+samplefreq=1000000
+numsamples=250000
+cpusetdefaultdir='/sys/fs/cgroup'
+cpusetprefix='cpuset.'
+debugdir='/sys/kernel/debug'
+ladirname='gpio-sloppy-logic-analyzer'
+outputdir="$PWD"
+neededcmds='taskset zip'
+max_chans=8
+duration=
+initcpu=
+listinstances=0
+lainstance=
+lasysfsdir=
+triggerdat=
+trigger_bindat=
+progname="${0##*/}"
+print_help()
+{
+	cat << EOF
+$progname - helper script for the Linux Kernel Sloppy GPIO Logic Analyzer
+Available options:
+	-c|--cpu <n>: which CPU to isolate for sampling. Only needed once. Default <1>.
+		      Remember that a more powerful CPU gives you higher sampling speeds.
+		      Also CPU0 is not recommended as it usually does extra bookkeeping.
+	-d|--duration-us <SI-n>: number of microseconds to sample. Overrides -n, no default value.
+	-h|--help: print this help
+	-i|--instance <str>: name of the logic analyzer in case you have multiple instances. Default
+			     to first instance found
+	-k|--kernel-debug-dir <str>: path to the kernel debugfs mountpoint. Default: <$debugdir>
+	-l|--list-instances: list all available instances
+	-n|--num_samples <SI-n>: number of samples to acquire. Default <$numsamples>
+	-o|--output-dir <str>: directory to put the result files. Default: current dir
+	-s|--sample_freq <SI-n>: desired sampling frequency. Might be capped if too large.
+				 Default: <1000000>
+	-t|--trigger <str>: pattern to use as trigger. <str> consists of two-char pairs. First
+			    char is channel number starting at "1". Second char is trigger level:
+			    "L" - low; "H" - high; "R" - rising; "F" - falling
+			    These pairs can be combined with "+", so "1H+2F" triggers when probe 1
+			    is high while probe 2 has a falling edge. You can have multiple triggers
+			    combined with ",". So, "1H+2F,1H+2R" is like the example before but it
+			    waits for a rising edge on probe 2 while probe 1 is still high after the
+			    first trigger has been met.
+			    Trigger data will only be used for the next capture and then be erased.
+
+<SI-n> is an integer value where SI units "T", "G", "M", "K" are recognized, e.g. '1M500K' is 1500000.
+
+Examples:
+Samples $numsamples values at 1MHz with an already prepared CPU or automatically prepares CPU1 if needed,
+use the first logic analyzer instance found:
+	'$progname'
+Samples 50us at 2MHz waiting for a falling edge on channel 2. CPU and instance as above:
+	'$progname -d 50 -s 2M -t "2F"'
+
+Note that the process exits after checking all parameters but a sub-process still works in
+the background. The result is only available once the sub-process finishes.
+
+Result is a .sr file to be consumed with PulseView from the free Sigrok project. It is
+a zip file which also contains the binary sample data which may be consumed by others.
+The filename is the logic analyzer instance name plus a since-epoch timestamp.
+EOF
+}
+
+fail()
+{
+	echo "$1"
+	exit 1
+}
+
+parse_si()
+{
+	conv_si="$(printf $1 | sed 's/[tT]+\?/*1000G+/g; s/[gG]+\?/*1000M+/g; s/[mM]+\?/*1000K+/g; s/[kK]+\?/*1000+/g; s/+$//')"
+	si_val="$((conv_si))"
+}
+set_newmask()
+{
+	for f in $(find "$1" -iname "$2"); do echo "$newmask" > "$f" 2>/dev/null || true; done
+}
+
+init_cpu()
+{
+	isol_cpu="$1"
+
+	[ -d "$lacpusetdir" ] || mkdir "$lacpusetdir"
+
+	cur_cpu=$(cat "${lacpusetfile}cpus")
+	[ "$cur_cpu" = "$isol_cpu" ] && return
+	[ -z "$cur_cpu" ] || fail "CPU$isol_cpu requested but CPU$cur_cpu already isolated"
+
+	echo "$isol_cpu" > "${lacpusetfile}cpus" || fail "Could not isolate CPU$isol_cpu. Does it exist?"
+	echo 1 > "${lacpusetfile}cpu_exclusive"
+	echo 0 > "${lacpusetfile}mems"
+
+	oldmask=$(cat /proc/irq/default_smp_affinity)
+	newmask=$(printf "%x" $((0x$oldmask & ~(1 << isol_cpu))))
+
+	set_newmask '/proc/irq' '*smp_affinity'
+	set_newmask '/sys/devices/virtual/workqueue/' 'cpumask'
+
+	# Move tasks away from isolated CPU
+	for p in $(ps -o pid | tail -n +2); do
+		mask=$(taskset -p "$p") || continue
+		# Ignore tasks with a custom mask, i.e. not equal $oldmask
+		[ "${mask##*: }" = "$oldmask" ] || continue
+		taskset -p "$newmask" "$p" || continue
+	done 2>/dev/null >/dev/null
+
+	# Big hammer! Working with 'rcu_momentary_eqs()' for a more fine-grained solution
+	# still printed warnings. Same for re-enabling the stall detector after sampling.
+	echo 1 > /sys/module/rcupdate/parameters/rcu_cpu_stall_suppress
+
+	cpufreqgov="/sys/devices/system/cpu/cpu$isol_cpu/cpufreq/scaling_governor"
+	[ -w "$cpufreqgov" ] && echo 'performance' > "$cpufreqgov" || true
+}
+
+parse_triggerdat()
+{
+	oldifs="$IFS"
+	IFS=','; for trig in $1; do
+		mask=0; val1=0; val2=0
+		IFS='+'; for elem in $trig; do
+			chan=${elem%[lhfrLHFR]}
+			mode=${elem#$chan}
+			# Check if we could parse something and the channel number fits
+			[ "$chan" != "$elem" ] && [ "$chan" -le $max_chans ] || fail "Trigger syntax error: $elem"
+			bit=$((1 << (chan - 1)))
+			mask=$((mask | bit))
+			case $mode in
+				[hH]) val1=$((val1 | bit)); val2=$((val2 | bit));;
+				[fF]) val1=$((val1 | bit));;
+				[rR]) val2=$((val2 | bit));;
+			esac
+		done
+		trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val1)"
+		[ $val1 -ne $val2 ] && trigger_bindat="$trigger_bindat$(printf '\\%o\\%o' $mask $val2)"
+	done
+	IFS="$oldifs"
+}
+
+do_capture()
+{
+	taskset "$1" echo 1 > "$lasysfsdir"/capture || fail "Capture error! Check kernel log"
+
+	srtmp=$(mktemp -d)
+	echo 1 > "$srtmp"/version
+	cp "$lasysfsdir"/sample_data "$srtmp"/logic-1-1
+	cat > "$srtmp"/metadata << EOF
+[global]
+sigrok version=0.2.0
+
+[device 1]
+capturefile=logic-1
+total probes=$(wc -l < "$lasysfsdir"/meta_data)
+samplerate=${samplefreq}Hz
+unitsize=1
+EOF
+	cat "$lasysfsdir"/meta_data >> "$srtmp"/metadata
+
+	zipname="$outputdir/${lasysfsdir##*/}-$(date +%s).sr"
+	zip -jq "$zipname" "$srtmp"/*
+	rm -rf "$srtmp"
+	delay_ack=$(cat "$lasysfsdir"/delay_ns_acquisition)
+	[ "$delay_ack" -eq 0 ] && delay_ack=1
+	echo "Logic analyzer done. Saved '$zipname'"
+	echo "Max sample frequency this time: $((1000000000 / delay_ack))Hz."
+}
+
+rep=$(getopt -a -l cpu:,duration-us:,help,instance:,list-instances,kernel-debug-dir:,num_samples:,output-dir:,sample_freq:,trigger: -o c:d:hi:k:ln:o:s:t: -- "$@") || exit 1
+eval set -- "$rep"
+while true; do
+	case "$1" in
+	-c|--cpu) initcpu="$2"; shift;;
+	-d|--duration-us) parse_si $2; duration=$si_val; shift;;
+	-h|--help) print_help; exit 0;;
+	-i|--instance) lainstance="$2"; shift;;
+	-k|--kernel-debug-dir) debugdir="$2"; shift;;
+	-l|--list-instances) listinstances=1;;
+	-n|--num_samples) parse_si $2; numsamples=$si_val; shift;;
+	-o|--output-dir) outputdir="$2"; shift;;
+	-s|--sample_freq) parse_si $2; samplefreq=$si_val; shift;;
+	-t|--trigger) triggerdat="$2"; shift;;
+	--) break;;
+	*) fail "error parsing command line: $*";;
+	esac
+	shift
+done
+
+for f in $neededcmds; do
+	command -v "$f" >/dev/null || fail "Command '$f' not found"
+done
+
+# print cpuset mountpoint if any, errorcode > 0 if noprefix option was found
+cpusetdir=$(awk '$3 == "cgroup" && $4 ~ /cpuset/ { print $2; exit (match($4, /noprefix/) > 0) }' /proc/self/mounts) || cpusetprefix=''
+if [ -z "$cpusetdir" ]; then
+	cpusetdir="$cpusetdefaultdir"
+	[ -d $cpusetdir ] || mkdir $cpusetdir
+	mount -t cgroup -o cpuset none $cpusetdir || fail "Couldn't mount cpusets. Not in kernel or already in use?"
+fi
+
+lacpusetdir="$cpusetdir/$ladirname"
+lacpusetfile="$lacpusetdir/$cpusetprefix"
+sysfsdir="$debugdir/$ladirname"
+
+[ "$samplefreq" -ne 0 ] || fail "Invalid sample frequency"
+
+[ -d "$sysfsdir" ] || fail "Could not find logic analyzer root dir '$sysfsdir'. Module loaded?"
+[ -x "$sysfsdir" ] || fail "Could not access logic analyzer root dir '$sysfsdir'. Need root?"
+
+[ $listinstances -gt 0 ] && find "$sysfsdir" -mindepth 1 -type d | sed 's|.*/||' && exit 0
+
+if [ -n "$lainstance" ]; then
+	lasysfsdir="$sysfsdir/$lainstance"
+else
+	lasysfsdir=$(find "$sysfsdir" -mindepth 1 -type d -print -quit)
+fi
+[ -d "$lasysfsdir" ] || fail "Logic analyzer directory '$lasysfsdir' not found!"
+[ -d "$outputdir" ] || fail "Output directory '$outputdir' not found!"
+
+[ -n "$initcpu" ] && init_cpu "$initcpu"
+[ -d "$lacpusetdir" ] || { echo "Auto-Isolating CPU1"; init_cpu 1; }
+
+ndelay=$((1000000000 / samplefreq))
+echo "$ndelay" > "$lasysfsdir"/delay_ns
+
+[ -n "$duration" ] && numsamples=$((samplefreq * duration / 1000000))
+echo $numsamples > "$lasysfsdir"/buf_size
+
+if [ -n "$triggerdat" ]; then
+	parse_triggerdat "$triggerdat"
+	printf "$trigger_bindat" > "$lasysfsdir"/trigger 2>/dev/null || fail "Trigger data '$triggerdat' rejected"
+fi
+
+workcpu=$(cat "${lacpusetfile}effective_cpus")
+[ -n "$workcpu" ] || fail "No isolated CPU found"
+cpumask=$(printf '%x' $((1 << workcpu)))
+instance=${lasysfsdir##*/}
+echo "Setting up '$instance': $numsamples samples at ${samplefreq}Hz with ${triggerdat:-no} trigger using CPU$workcpu"
+do_capture "$cpumask" &
diff --git a/tools/gpio/gpio-utils.c b/tools/gpio/gpio-utils.c
new file mode 100644
index 000000000..4096bcd51
--- /dev/null
+++ b/tools/gpio/gpio-utils.c
@@ -0,0 +1,284 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * GPIO tools - helpers library for the GPIO tools
+ *
+ * Copyright (C) 2015 Linus Walleij
+ * Copyright (C) 2016 Bamvor Jian Zhang
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <linux/gpio.h>
+#include "gpio-utils.h"
+
+#define CONSUMER "gpio-utils"
+
+/**
+ * DOC: Operation of gpio
+ *
+ * Provide the api of gpiochip for chardev interface. There are two
+ * types of api.  The first one provide as same function as each
+ * ioctl, including request and release for lines of gpio, read/write
+ * the value of gpio. If the user want to do lots of read and write of
+ * lines of gpio, user should use this type of api.
+ *
+ * The second one provide the easy to use api for user. Each of the
+ * following api will request gpio lines, do the operation and then
+ * release these lines.
+ */
+
+/**
+ * gpiotools_request_line() - request gpio lines in a gpiochip
+ * @device_name:	The name of gpiochip without prefix "/dev/",
+ *			such as "gpiochip0"
+ * @lines:		An array desired lines, specified by offset
+ *			index for the associated GPIO device.
+ * @num_lines:		The number of lines to request.
+ * @config:		The new config for requested gpio. Reference
+ *			"linux/gpio.h" for config details.
+ * @consumer:		The name of consumer, such as "sysfs",
+ *			"powerkey". This is useful for other users to
+ *			know who is using.
+ *
+ * Request gpio lines through the ioctl provided by chardev. User
+ * could call gpiotools_set_values() and gpiotools_get_values() to
+ * read and write respectively through the returned fd. Call
+ * gpiotools_release_line() to release these lines after that.
+ *
+ * Return:		On success return the fd;
+ *			On failure return the errno.
+ */
+int gpiotools_request_line(const char *device_name, unsigned int *lines,
+			   unsigned int num_lines,
+			   struct gpio_v2_line_config *config,
+			   const char *consumer)
+{
+	struct gpio_v2_line_request req;
+	char *chrdev_name;
+	int fd;
+	int i;
+	int ret;
+
+	ret = asprintf(&chrdev_name, "/dev/%s", device_name);
+	if (ret < 0)
+		return -ENOMEM;
+
+	fd = open(chrdev_name, 0);
+	if (fd == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to open %s, %s\n",
+			chrdev_name, strerror(errno));
+		goto exit_free_name;
+	}
+
+	memset(&req, 0, sizeof(req));
+	for (i = 0; i < num_lines; i++)
+		req.offsets[i] = lines[i];
+
+	req.config = *config;
+	strcpy(req.consumer, consumer);
+	req.num_lines = num_lines;
+
+	ret = ioctl(fd, GPIO_V2_GET_LINE_IOCTL, &req);
+	if (ret == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to issue %s (%d), %s\n",
+			"GPIO_GET_LINE_IOCTL", ret, strerror(errno));
+	}
+
+	if (close(fd) == -1)
+		perror("Failed to close GPIO character device file");
+exit_free_name:
+	free(chrdev_name);
+	return ret < 0 ? ret : req.fd;
+}
+
+/**
+ * gpiotools_set_values() - Set the value of gpio(s)
+ * @fd:			The fd returned by
+ *			gpiotools_request_line().
+ * @values:		The array of values want to set.
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_set_values(const int fd, struct gpio_v2_line_values *values)
+{
+	int ret;
+
+	ret = ioctl(fd, GPIO_V2_LINE_SET_VALUES_IOCTL, values);
+	if (ret == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to issue %s (%d), %s\n",
+			"GPIOHANDLE_SET_LINE_VALUES_IOCTL", ret,
+			strerror(errno));
+	}
+
+	return ret;
+}
+
+/**
+ * gpiotools_get_values() - Get the value of gpio(s)
+ * @fd:			The fd returned by
+ *			gpiotools_request_line().
+ * @values:		The array of values get from hardware.
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_get_values(const int fd, struct gpio_v2_line_values *values)
+{
+	int ret;
+
+	ret = ioctl(fd, GPIO_V2_LINE_GET_VALUES_IOCTL, values);
+	if (ret == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to issue %s (%d), %s\n",
+			"GPIOHANDLE_GET_LINE_VALUES_IOCTL", ret,
+			strerror(errno));
+	}
+
+	return ret;
+}
+
+/**
+ * gpiotools_release_line() - Release the line(s) of gpiochip
+ * @fd:			The fd returned by
+ *			gpiotools_request_line().
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_release_line(const int fd)
+{
+	int ret;
+
+	ret = close(fd);
+	if (ret == -1) {
+		perror("Failed to close GPIO LINE device file");
+		ret = -errno;
+	}
+
+	return ret;
+}
+
+/**
+ * gpiotools_get() - Get value from specific line
+ * @device_name:	The name of gpiochip without prefix "/dev/",
+ *			such as "gpiochip0"
+ * @line:		number of line, such as 2.
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_get(const char *device_name, unsigned int line)
+{
+	int ret;
+	unsigned int value;
+	unsigned int lines[] = {line};
+
+	ret = gpiotools_gets(device_name, lines, 1, &value);
+	if (ret)
+		return ret;
+	return value;
+}
+
+
+/**
+ * gpiotools_gets() - Get values from specific lines.
+ * @device_name:	The name of gpiochip without prefix "/dev/",
+ *			such as "gpiochip0".
+ * @lines:		An array desired lines, specified by offset
+ *			index for the associated GPIO device.
+ * @num_lines:		The number of lines to request.
+ * @values:		The array of values get from gpiochip.
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_gets(const char *device_name, unsigned int *lines,
+		   unsigned int num_lines, unsigned int *values)
+{
+	int fd, i;
+	int ret;
+	int ret_close;
+	struct gpio_v2_line_config config;
+	struct gpio_v2_line_values lv;
+
+	memset(&config, 0, sizeof(config));
+	config.flags = GPIO_V2_LINE_FLAG_INPUT;
+	ret = gpiotools_request_line(device_name, lines, num_lines,
+				     &config, CONSUMER);
+	if (ret < 0)
+		return ret;
+
+	fd = ret;
+	for (i = 0; i < num_lines; i++)
+		gpiotools_set_bit(&lv.mask, i);
+	ret = gpiotools_get_values(fd, &lv);
+	if (!ret)
+		for (i = 0; i < num_lines; i++)
+			values[i] = gpiotools_test_bit(lv.bits, i);
+	ret_close = gpiotools_release_line(fd);
+	return ret < 0 ? ret : ret_close;
+}
+
+/**
+ * gpiotools_set() - Set value to specific line
+ * @device_name:	The name of gpiochip without prefix "/dev/",
+ *			such as "gpiochip0"
+ * @line:		number of line, such as 2.
+ * @value:		The value of gpio, must be 0(low) or 1(high).
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_set(const char *device_name, unsigned int line,
+		  unsigned int value)
+{
+	unsigned int lines[] = {line};
+
+	return gpiotools_sets(device_name, lines, 1, &value);
+}
+
+/**
+ * gpiotools_sets() - Set values to specific lines.
+ * @device_name:	The name of gpiochip without prefix "/dev/",
+ *			such as "gpiochip0".
+ * @lines:		An array desired lines, specified by offset
+ *			index for the associated GPIO device.
+ * @num_lines:		The number of lines to request.
+ * @values:		The array of values set to gpiochip, must be
+ *			0(low) or 1(high).
+ *
+ * Return:		On success return 0;
+ *			On failure return the errno.
+ */
+int gpiotools_sets(const char *device_name, unsigned int *lines,
+		   unsigned int num_lines, unsigned int *values)
+{
+	int ret, i;
+	struct gpio_v2_line_config config;
+
+	memset(&config, 0, sizeof(config));
+	config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
+	config.num_attrs = 1;
+	config.attrs[0].attr.id = GPIO_V2_LINE_ATTR_ID_OUTPUT_VALUES;
+	for (i = 0; i < num_lines; i++) {
+		gpiotools_set_bit(&config.attrs[0].mask, i);
+		gpiotools_assign_bit(&config.attrs[0].attr.values,
+				     i, values[i]);
+	}
+	ret = gpiotools_request_line(device_name, lines, num_lines,
+				     &config, CONSUMER);
+	if (ret < 0)
+		return ret;
+
+	return gpiotools_release_line(ret);
+}
diff --git a/tools/gpio/gpio-utils.h b/tools/gpio/gpio-utils.h
new file mode 100644
index 000000000..8af7c8ee1
--- /dev/null
+++ b/tools/gpio/gpio-utils.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * GPIO tools - utility helpers library for the GPIO tools
+ *
+ * Copyright (C) 2015 Linus Walleij
+ *
+ * Portions copied from iio_utils and lssio:
+ * Copyright (c) 2010 Manuel Stahl <manuel.stahl@iis.fraunhofer.de>
+ * Copyright (c) 2008 Jonathan Cameron
+ * *
+ */
+#ifndef _GPIO_UTILS_H_
+#define _GPIO_UTILS_H_
+
+#include <stdbool.h>
+#include <string.h>
+#include <linux/types.h>
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+static inline int check_prefix(const char *str, const char *prefix)
+{
+	return strlen(str) > strlen(prefix) &&
+		strncmp(str, prefix, strlen(prefix)) == 0;
+}
+
+int gpiotools_request_line(const char *device_name,
+			   unsigned int *lines,
+			   unsigned int num_lines,
+			   struct gpio_v2_line_config *config,
+			   const char *consumer);
+int gpiotools_set_values(const int fd, struct gpio_v2_line_values *values);
+int gpiotools_get_values(const int fd, struct gpio_v2_line_values *values);
+int gpiotools_release_line(const int fd);
+
+int gpiotools_get(const char *device_name, unsigned int line);
+int gpiotools_gets(const char *device_name, unsigned int *lines,
+		   unsigned int num_lines, unsigned int *values);
+int gpiotools_set(const char *device_name, unsigned int line,
+		  unsigned int value);
+int gpiotools_sets(const char *device_name, unsigned int *lines,
+		   unsigned int num_lines, unsigned int *values);
+
+/* helper functions for gpio_v2_line_values bits */
+static inline void gpiotools_set_bit(__u64 *b, int n)
+{
+	*b |= _BITULL(n);
+}
+
+static inline void gpiotools_change_bit(__u64 *b, int n)
+{
+	*b ^= _BITULL(n);
+}
+
+static inline void gpiotools_clear_bit(__u64 *b, int n)
+{
+	*b &= ~_BITULL(n);
+}
+
+static inline int gpiotools_test_bit(__u64 b, int n)
+{
+	return !!(b & _BITULL(n));
+}
+
+static inline void gpiotools_assign_bit(__u64 *b, int n, bool value)
+{
+	if (value)
+		gpiotools_set_bit(b, n);
+	else
+		gpiotools_clear_bit(b, n);
+}
+
+#endif /* _GPIO_UTILS_H_ */
diff --git a/tools/gpio/gpio-watch.c b/tools/gpio/gpio-watch.c
new file mode 100644
index 000000000..41e76d244
--- /dev/null
+++ b/tools/gpio/gpio-watch.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * gpio-watch - monitor unrequested lines for property changes using the
+ *              character device
+ *
+ * Copyright (C) 2019 BayLibre SAS
+ * Author: Bartosz Golaszewski <bgolaszewski@baylibre.com>
+ */
+
+#include <ctype.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <linux/gpio.h>
+#include <poll.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+int main(int argc, char **argv)
+{
+	struct gpio_v2_line_info_changed chg;
+	struct gpio_v2_line_info req;
+	struct pollfd pfd;
+	int fd, i, j, ret;
+	char *event, *end;
+	ssize_t rd;
+
+	if (argc < 3)
+		goto err_usage;
+
+	fd = open(argv[1], O_RDWR | O_CLOEXEC);
+	if (fd < 0) {
+		perror("unable to open gpiochip");
+		return EXIT_FAILURE;
+	}
+
+	for (i = 0, j = 2; i < argc - 2; i++, j++) {
+		memset(&req, 0, sizeof(req));
+
+		req.offset = strtoul(argv[j], &end, 0);
+		if (*end != '\0')
+			goto err_usage;
+
+		ret = ioctl(fd, GPIO_V2_GET_LINEINFO_WATCH_IOCTL, &req);
+		if (ret) {
+			perror("unable to set up line watch");
+			return EXIT_FAILURE;
+		}
+	}
+
+	pfd.fd = fd;
+	pfd.events = POLLIN | POLLPRI;
+
+	for (;;) {
+		ret = poll(&pfd, 1, 5000);
+		if (ret < 0) {
+			perror("error polling the linechanged fd");
+			return EXIT_FAILURE;
+		} else if (ret > 0) {
+			memset(&chg, 0, sizeof(chg));
+			rd = read(pfd.fd, &chg, sizeof(chg));
+			if (rd < 0 || rd != sizeof(chg)) {
+				if (rd != sizeof(chg))
+					errno = EIO;
+
+				perror("error reading line change event");
+				return EXIT_FAILURE;
+			}
+
+			switch (chg.event_type) {
+			case GPIO_V2_LINE_CHANGED_REQUESTED:
+				event = "requested";
+				break;
+			case GPIO_V2_LINE_CHANGED_RELEASED:
+				event = "released";
+				break;
+			case GPIO_V2_LINE_CHANGED_CONFIG:
+				event = "config changed";
+				break;
+			default:
+				fprintf(stderr,
+					"invalid event type received from the kernel\n");
+				return EXIT_FAILURE;
+			}
+
+			printf("line %u: %s at %" PRIu64 "\n",
+			       chg.info.offset, event, (uint64_t)chg.timestamp_ns);
+		}
+	}
+
+	return 0;
+
+err_usage:
+	printf("%s: <gpiochip> <line0> <line1> ...\n", argv[0]);
+	return EXIT_FAILURE;
+}
diff --git a/tools/gpio/lsgpio.c b/tools/gpio/lsgpio.c
new file mode 100644
index 000000000..52a0be454
--- /dev/null
+++ b/tools/gpio/lsgpio.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * lsgpio - example on how to list the GPIO lines on a system
+ *
+ * Copyright (C) 2015 Linus Walleij
+ *
+ * Usage:
+ *	lsgpio <-n device-name>
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <errno.h>
+#include <string.h>
+#include <poll.h>
+#include <fcntl.h>
+#include <getopt.h>
+#include <sys/ioctl.h>
+#include <linux/gpio.h>
+
+#include "gpio-utils.h"
+
+struct gpio_flag {
+	char *name;
+	unsigned long long mask;
+};
+
+struct gpio_flag flagnames[] = {
+	{
+		.name = "used",
+		.mask = GPIO_V2_LINE_FLAG_USED,
+	},
+	{
+		.name = "input",
+		.mask = GPIO_V2_LINE_FLAG_INPUT,
+	},
+	{
+		.name = "output",
+		.mask = GPIO_V2_LINE_FLAG_OUTPUT,
+	},
+	{
+		.name = "active-low",
+		.mask = GPIO_V2_LINE_FLAG_ACTIVE_LOW,
+	},
+	{
+		.name = "open-drain",
+		.mask = GPIO_V2_LINE_FLAG_OPEN_DRAIN,
+	},
+	{
+		.name = "open-source",
+		.mask = GPIO_V2_LINE_FLAG_OPEN_SOURCE,
+	},
+	{
+		.name = "pull-up",
+		.mask = GPIO_V2_LINE_FLAG_BIAS_PULL_UP,
+	},
+	{
+		.name = "pull-down",
+		.mask = GPIO_V2_LINE_FLAG_BIAS_PULL_DOWN,
+	},
+	{
+		.name = "bias-disabled",
+		.mask = GPIO_V2_LINE_FLAG_BIAS_DISABLED,
+	},
+	{
+		.name = "clock-realtime",
+		.mask = GPIO_V2_LINE_FLAG_EVENT_CLOCK_REALTIME,
+	},
+};
+
+static void print_attributes(struct gpio_v2_line_info *info)
+{
+	int i;
+	const char *field_format = "%s";
+
+	for (i = 0; i < ARRAY_SIZE(flagnames); i++) {
+		if (info->flags & flagnames[i].mask) {
+			fprintf(stdout, field_format, flagnames[i].name);
+			field_format = ", %s";
+		}
+	}
+
+	if ((info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING) &&
+	    (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING))
+		fprintf(stdout, field_format, "both-edges");
+	else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_RISING)
+		fprintf(stdout, field_format, "rising-edge");
+	else if (info->flags & GPIO_V2_LINE_FLAG_EDGE_FALLING)
+		fprintf(stdout, field_format, "falling-edge");
+
+	for (i = 0; i < info->num_attrs; i++) {
+		if (info->attrs[i].id == GPIO_V2_LINE_ATTR_ID_DEBOUNCE)
+			fprintf(stdout, ", debounce_period=%dusec",
+				info->attrs[i].debounce_period_us);
+	}
+}
+
+int list_device(const char *device_name)
+{
+	struct gpiochip_info cinfo;
+	char *chrdev_name;
+	int fd;
+	int ret;
+	int i;
+
+	ret = asprintf(&chrdev_name, "/dev/%s", device_name);
+	if (ret < 0)
+		return -ENOMEM;
+
+	fd = open(chrdev_name, 0);
+	if (fd == -1) {
+		ret = -errno;
+		fprintf(stderr, "Failed to open %s\n", chrdev_name);
+		goto exit_free_name;
+	}
+
+	/* Inspect this GPIO chip */
+	ret = ioctl(fd, GPIO_GET_CHIPINFO_IOCTL, &cinfo);
+	if (ret == -1) {
+		ret = -errno;
+		perror("Failed to issue CHIPINFO IOCTL\n");
+		goto exit_close_error;
+	}
+	fprintf(stdout, "GPIO chip: %s, \"%s\", %u GPIO lines\n",
+		cinfo.name, cinfo.label, cinfo.lines);
+
+	/* Loop over the lines and print info */
+	for (i = 0; i < cinfo.lines; i++) {
+		struct gpio_v2_line_info linfo;
+
+		memset(&linfo, 0, sizeof(linfo));
+		linfo.offset = i;
+
+		ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &linfo);
+		if (ret == -1) {
+			ret = -errno;
+			perror("Failed to issue LINEINFO IOCTL\n");
+			goto exit_close_error;
+		}
+		fprintf(stdout, "\tline %2d:", linfo.offset);
+		if (linfo.name[0])
+			fprintf(stdout, " \"%s\"", linfo.name);
+		else
+			fprintf(stdout, " unnamed");
+		if (linfo.consumer[0])
+			fprintf(stdout, " \"%s\"", linfo.consumer);
+		else
+			fprintf(stdout, " unused");
+		if (linfo.flags) {
+			fprintf(stdout, " [");
+			print_attributes(&linfo);
+			fprintf(stdout, "]");
+		}
+		fprintf(stdout, "\n");
+
+	}
+
+exit_close_error:
+	if (close(fd) == -1)
+		perror("Failed to close GPIO character device file");
+exit_free_name:
+	free(chrdev_name);
+	return ret;
+}
+
+void print_usage(void)
+{
+	fprintf(stderr, "Usage: lsgpio [options]...\n"
+		"List GPIO chips, lines and states\n"
+		"  -n <name>  List GPIOs on a named device\n"
+		"  -?         This helptext\n"
+	);
+}
+
+int main(int argc, char **argv)
+{
+	const char *device_name = NULL;
+	int ret;
+	int c;
+
+	while ((c = getopt(argc, argv, "n:")) != -1) {
+		switch (c) {
+		case 'n':
+			device_name = optarg;
+			break;
+		case '?':
+			print_usage();
+			return -1;
+		}
+	}
+
+	if (device_name)
+		ret = list_device(device_name);
+	else {
+		const struct dirent *ent;
+		DIR *dp;
+
+		/* List all GPIO devices one at a time */
+		dp = opendir("/dev");
+		if (!dp) {
+			ret = -errno;
+			goto error_out;
+		}
+
+		ret = -ENOENT;
+		while (ent = readdir(dp), ent) {
+			if (check_prefix(ent->d_name, "gpiochip")) {
+				ret = list_device(ent->d_name);
+				if (ret)
+					break;
+			}
+		}
+
+		ret = 0;
+		if (closedir(dp) == -1) {
+			perror("scanning devices: Failed to close directory");
+			ret = -errno;
+		}
+	}
+error_out:
+	return ret;
+}