From: Bartosz Golaszewski <bartekgola@gmail.com>
Date: Wed, 15 Nov 2017 13:39:58 +0000 (+0100)
Subject: core: don't allow open-source and open-drain flags at the same time
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=1749610c31cb701fb4864278167ed531ea1c7b63;p=qemu-gpiodev%2Flibgpiod.git

core: don't allow open-source and open-drain flags at the same time

If the hardware actually allowed it, the electrical result would be
disastrous. This has only recently been fixed in the kernel, so add
a relevant check to the library as well.

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

diff --git a/src/lib/core.c b/src/lib/core.c
index c17dffa..a1d6e0e 100644
--- a/src/lib/core.c
+++ b/src/lib/core.c
@@ -343,6 +343,12 @@ static int line_request_values(struct gpiod_line_bulk *bulk,
 		return -1;
 	}
 
+	if ((config->flags & GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN) &&
+	    (config->flags & GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE)) {
+		errno = EINVAL;
+		return -1;
+	}
+
 	memset(&req, 0, sizeof(req));
 
 	if (config->flags & GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN)
diff --git a/tests/tests-line.c b/tests/tests-line.c
index 2071e8e..bc15170 100644
--- a/tests/tests-line.c
+++ b/tests/tests-line.c
@@ -513,6 +513,28 @@ TEST_DEFINE(line_open_source_open_drain_input_invalid,
 	    "gpiod_line - open-source & open-drain for input mode (invalid)",
 	    0, { 8 });
 
+static void line_open_source_open_drain_simultaneously(void)
+{
+	TEST_CLEANUP(test_close_chip) struct gpiod_chip *chip = NULL;
+	struct gpiod_line *line;
+	int rv;
+
+	chip = gpiod_chip_open(test_chip_path(0));
+	TEST_ASSERT_NOT_NULL(chip);
+
+	line = gpiod_chip_get_line(chip, 2);
+	TEST_ASSERT_NOT_NULL(line);
+
+	rv = gpiod_line_request_output_flags(line, TEST_CONSUMER,
+				GPIOD_LINE_REQUEST_FLAG_OPEN_SOURCE |
+				GPIOD_LINE_REQUEST_FLAG_OPEN_DRAIN, 1);
+	TEST_ASSERT_EQ(rv, -1);
+	TEST_ASSERT_ERRNO_IS(EINVAL);
+}
+TEST_DEFINE(line_open_source_open_drain_simultaneously,
+	    "gpiod_line - open-source & open-drain flags simultaneously",
+	    0, { 8 });
+
 static void line_null_consumer(void)
 {
 	TEST_CLEANUP(test_close_chip) struct gpiod_chip *chip = NULL;