From: Bartosz Golaszewski <bartekgola@gmail.com>
Date: Fri, 29 Sep 2017 16:47:51 +0000 (+0200)
Subject: core: provide gpiod_line_get()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1cef8332aea84a400193f21a986109b092654ffe;p=qemu-gpiodev%2Flibgpiod.git

core: provide gpiod_line_get()

Provide a routine which simplifies the process of getting the handle
for a single GPIO line by encapsulating the calls opening the chip and
retrieving the line handle in a single function.

Implement test cases as well.

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

diff --git a/include/gpiod.h b/include/gpiod.h
index e1b9f91..aa5376e 100644
--- a/include/gpiod.h
+++ b/include/gpiod.h
@@ -879,6 +879,21 @@ int gpiod_line_set_value(struct gpiod_line *line, int value) GPIOD_API;
 int gpiod_line_set_value_bulk(struct gpiod_line_bulk *bulk,
 			      int *values) GPIOD_API;
 
+/**
+ * @brief Get a GPIO line handle by GPIO chip description and offset.
+ * @param device String describing the gpiochip.
+ * @param offset The offset of the GPIO line.
+ * @return GPIO line handle or NULL if an error occurred.
+ *
+ * This routine provides a shorter alternative to calling
+ * ::gpiod_chip_open_lookup and ::gpiod_chip_get_line.
+ *
+ * If this function succeeds, the caller is responsible for closing the
+ * associated GPIO chip.
+ */
+struct gpiod_line *
+gpiod_line_get(const char *device, unsigned int offset) GPIOD_API;
+
 /**
  * @brief Find a GPIO line by its name.
  * @param name Name of the GPIO line.
diff --git a/src/lib/core.c b/src/lib/core.c
index 5b41f1d..eabee89 100644
--- a/src/lib/core.c
+++ b/src/lib/core.c
@@ -921,6 +921,24 @@ int gpiod_line_set_value_bulk(struct gpiod_line_bulk *bulk, int *values)
 	return 0;
 }
 
+struct gpiod_line * gpiod_line_get(const char *device, unsigned int offset)
+{
+	struct gpiod_chip *chip;
+	struct gpiod_line *line;
+
+	chip = gpiod_chip_open_lookup(device);
+	if (!chip)
+		return NULL;
+
+	line = gpiod_chip_get_line(chip, offset);
+	if (!line) {
+		gpiod_chip_close(chip);
+		return NULL;
+	}
+
+	return line;
+}
+
 struct gpiod_line * gpiod_line_find(const char *name)
 {
 	struct gpiod_chip_iter *iter;
diff --git a/tests/tests-line.c b/tests/tests-line.c
index 8e283b6..41b78fd 100644
--- a/tests/tests-line.c
+++ b/tests/tests-line.c
@@ -278,6 +278,30 @@ TEST_DEFINE(line_set_value,
 	    "gpiod_line_set_value() - good",
 	    0, { 8 });
 
+static void line_get_good(void)
+{
+	TEST_CLEANUP(test_line_close_chip) struct gpiod_line *line = NULL;
+
+	line = gpiod_line_get(test_chip_name(2), 18);
+	TEST_ASSERT_NOT_NULL(line);
+	TEST_ASSERT_EQ(gpiod_line_offset(line), 18);
+}
+TEST_DEFINE(line_get_good,
+	    "gpiod_line_get() - good",
+	    TEST_FLAG_NAMED_LINES, { 16, 16, 32, 16 });
+
+static void line_get_invalid_offset(void)
+{
+	TEST_CLEANUP(test_line_close_chip) struct gpiod_line *line = NULL;
+
+	line = gpiod_line_get(test_chip_name(3), 18);
+	TEST_ASSERT_NULL(line);
+	TEST_ASSERT_ERRNO_IS(EINVAL);
+}
+TEST_DEFINE(line_get_invalid_offset,
+	    "gpiod_line_get() - invalid offset",
+	    TEST_FLAG_NAMED_LINES, { 16, 16, 32, 16 });
+
 static void line_find_good(void)
 {
 	TEST_CLEANUP(test_line_close_chip) struct gpiod_line *line = NULL;