core: new gpiod_chip_open() flavor

Implement gpiod_chip_open_by_label() which allows to find and open
a GPIO chip by its in-kernel label.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>

diff --git a/include/gpiod.h b/include/gpiod.h
index b62932291cf793ccdd7537f8684fad5c7a642811..0cb5d1a3294831e9b223dc1617de30d43f7fafb3 100644 (file)
--- a/include/gpiod.h
+++ b/include/gpiod.h
@@ -870,6 +870,14 @@ struct gpiod_chip * gpiod_chip_open_by_name(const char *name) GPIOD_API;
  */
 struct gpiod_chip * gpiod_chip_open_by_number(unsigned int num) GPIOD_API;
 
+/**
+ * @brief Open a gpiochip by label.
+ * @param label Label of the gpiochip to open.
+ * @return GPIO chip handle or NULL if the chip with given label was not found
+ *         or an error occured.
+ */
+struct gpiod_chip * gpiod_chip_open_by_label(const char *label) GPIOD_API;
+
 /**
  * @brief Open a gpiochip based on the best guess what the path is.
  * @param descr String describing the gpiochip.

diff --git a/src/lib/core.c b/src/lib/core.c
index 9ad5d0577094a71bea4b4a778203d7f5774aba44..9b541280df99852db9bb384c13bef881680d866a 100644 (file)
--- a/src/lib/core.c
+++ b/src/lib/core.c
@@ -960,6 +960,30 @@ struct gpiod_chip * gpiod_chip_open_by_number(unsigned int num)
        return chip;
 }
 
+struct gpiod_chip * gpiod_chip_open_by_label(const char *label)
+{
+       struct gpiod_chip_iter *iter;
+       struct gpiod_chip *chip;
+
+       iter = gpiod_chip_iter_new();
+       if (!iter)
+               return NULL;
+
+       gpiod_foreach_chip(iter, chip) {
+               if (gpiod_chip_iter_err(iter))
+                       goto out;
+
+               if (strcmp(label, gpiod_chip_label(chip)) == 0) {
+                       gpiod_chip_iter_free_noclose(iter);
+                       return chip;
+               }
+       }
+
+out:
+       gpiod_chip_iter_free(iter);
+       return  NULL;
+}
+
 struct gpiod_chip * gpiod_chip_open_lookup(const char *descr)
 {
        if (is_unsigned_int(descr))

diff --git a/tests/unit/tests-chip.c b/tests/unit/tests-chip.c
index bfba6f798869d729bf5d3c471451354a375774be..0690e4a39d21c8bcc467332f56d0f33bf30e50d5 100644 (file)
--- a/tests/unit/tests-chip.c
+++ b/tests/unit/tests-chip.c
@@ -80,6 +80,29 @@ GU_DEFINE_TEST(chip_open_lookup,
               "gpiod_chip_open_lookup()",
               GU_LINES_UNNAMED, { 8 });
 
+static void chip_open_by_label_good(void)
+{
+       GU_CLEANUP(gu_close_chip) struct gpiod_chip *chip = NULL;
+
+       chip = gpiod_chip_open_by_label("gpio-mockup-D");
+       GU_ASSERT_NOT_NULL(chip);
+       GU_ASSERT_STR_EQ(gpiod_chip_name(chip), gu_chip_name(3));
+}
+GU_DEFINE_TEST(chip_open_by_label_good,
+              "chip_open_by_label() good",
+              GU_LINES_UNNAMED, { 4, 4, 4, 4, 4 });
+
+static void chip_open_by_label_bad(void)
+{
+       GU_CLEANUP(gu_close_chip) struct gpiod_chip *chip = NULL;
+
+       chip = gpiod_chip_open_by_label("nonexistent_gpio_chip");
+       GU_ASSERT_NULL(chip);
+}
+GU_DEFINE_TEST(chip_open_by_label_bad,
+              "chip_open_by_label() bad",
+              GU_LINES_UNNAMED, { 4, 4, 4, 4, 4 });
+
 static void chip_name(void)
 {
        GU_CLEANUP(gu_close_chip) struct gpiod_chip *chip0 = NULL;