selftests: gpio: add a helper for reading GPIO line names

Add a simple program that allows to read GPIO line names from the
character device. This will be used in gpio-sim selftests.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

diff --git a/tools/testing/selftests/gpio/.gitignore b/tools/testing/selftests/gpio/.gitignore
index 4ea4f58dab1a0cd8e274f1b6e1d938dbfc685794..ededb077a3a69c5335d2d4785a7cb6dc5951ba9d 100644 (file)
--- a/tools/testing/selftests/gpio/.gitignore
+++ b/tools/testing/selftests/gpio/.gitignore
@@ -1,3 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
 gpio-mockup-cdev
 gpio-chip-info
+gpio-line-name

diff --git a/tools/testing/selftests/gpio/Makefile b/tools/testing/selftests/gpio/Makefile
index 84b48547f94c1572b7eeb846deae18e1135710ee..d7d8f1985d992d6a289359d8d1545f520dc16b1b 100644 (file)
--- a/tools/testing/selftests/gpio/Makefile
+++ b/tools/testing/selftests/gpio/Makefile
@@ -2,6 +2,6 @@
 
 TEST_PROGS := gpio-mockup.sh
 TEST_FILES := gpio-mockup-sysfs.sh
-TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info
+TEST_GEN_PROGS_EXTENDED := gpio-mockup-cdev gpio-chip-info gpio-line-name
 
 include ../lib.mk

diff --git a/tools/testing/selftests/gpio/gpio-line-name.c b/tools/testing/selftests/gpio/gpio-line-name.c
new file mode 100644 (file)
index 0000000..e635cfa
--- /dev/null
+++ b/tools/testing/selftests/gpio/gpio-line-name.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * GPIO character device helper for reading line names.
+ *
+ * Copyright (C) 2021 Bartosz Golaszewski <brgl@bgdev.pl>
+ */
+
+#include <fcntl.h>
+#include <linux/gpio.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/types.h>
+
+static void print_usage(void)
+{
+       printf("usage:\n");
+       printf("  gpio-line-name <chip path> <line offset>\n");
+}
+
+int main(int argc, char **argv)
+{
+       struct gpio_v2_line_info info;
+       int fd, ret;
+       char *endp;
+
+       if (argc != 3) {
+               print_usage();
+               return EXIT_FAILURE;
+       }
+
+       fd = open(argv[1], O_RDWR);
+       if (fd < 0) {
+               perror("unable to open the GPIO chip");
+               return EXIT_FAILURE;
+       }
+
+       memset(&info, 0, sizeof(info));
+       info.offset = strtoul(argv[2], &endp, 10);
+       if (*endp != '\0') {
+               print_usage();
+               return EXIT_FAILURE;
+       }
+
+       ret = ioctl(fd, GPIO_V2_GET_LINEINFO_IOCTL, &info);
+       if (ret) {
+               perror("line info ioctl failed");
+               return EXIT_FAILURE;
+       }
+
+       printf("%s\n", info.name);
+
+       return EXIT_SUCCESS;
+}