tools: gpioget: add new --dir-as-is option for GPO read-back

Both legacy sysfs and new character device API support querying line
state of a GPIO configured as output. But while sysfs /value can
be read for these output GPIOs, gpioget unconditionally muxes the
line as input. To ease migration to the new user API, add a new
--dir-as-is parameter that doesn't force the line to input.

This is especially useful for GPIO controllers that maintain their
last configured output state.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

diff --git a/tools/gpioget.c b/tools/gpioget.c
index ceeec566683a180f34d9e9e3aa7e80314a436cfb..51cecb6a18a9c410a7f5fa69f4e0194eb125a6d6 100644 (file)
--- a/tools/gpioget.c
+++ b/tools/gpioget.c
@@ -13,11 +13,12 @@ static const struct option longopts[] = {
        { "help",       no_argument,            NULL,   'h' },
        { "version",    no_argument,            NULL,   'v' },
        { "active-low", no_argument,            NULL,   'l' },
+       { "dir-as-is",  no_argument,            NULL,   'n' },
        { "bias",       required_argument,      NULL,   'B' },
        { GETOPT_NULL_LONGOPT },
 };
 
-static const char *const shortopts = "+hvlB:";
+static const char *const shortopts = "+hvlnB:";
 
 static void print_help(void)
 {
@@ -30,6 +31,7 @@ static void print_help(void)
        printf("  -h, --help:\t\tdisplay this message and exit\n");
        printf("  -v, --version:\tdisplay the version and exit\n");
        printf("  -l, --active-low:\tset the line active state to low\n");
+       printf("  -n, --dir-as-is:\tdon't force-reconfigure line direction\n");
        printf("  -B, --bias=[as-is|disable|pull-down|pull-up] (defaults to 'as-is'):\n");
        printf("                set the line bias\n");
        printf("\n");
@@ -38,6 +40,7 @@ static void print_help(void)
 
 int main(int argc, char **argv)
 {
+       int request_type = GPIOD_LINE_REQUEST_DIRECTION_INPUT;
        struct gpiod_line_request_config config;
        int *values, optc, opti, rv, flags = 0;
        unsigned int *offsets, i, num_lines;
@@ -60,6 +63,9 @@ int main(int argc, char **argv)
                case 'l':
                        flags |= GPIOD_LINE_REQUEST_FLAG_ACTIVE_LOW;
                        break;
+               case 'n':
+                       request_type = GPIOD_LINE_REQUEST_DIRECTION_AS_IS;
+                       break;
                case 'B':
                        flags |= bias_flags(optarg);
                        break;
@@ -104,7 +110,7 @@ int main(int argc, char **argv)
        memset(&config, 0, sizeof(config));
 
        config.consumer = "gpioget";
-       config.request_type = GPIOD_LINE_REQUEST_DIRECTION_INPUT;
+       config.request_type = request_type;
        config.flags = flags;
 
        rv = gpiod_line_request_bulk(lines, &config, NULL);