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authorStefan Tatschner <rumpelsepp@sevenbyte.org>2015-11-24 15:06:29 +0100
committerJonathan Corbet <corbet@lwn.net>2015-12-10 19:29:11 +0100
commitaecd89e85534d31b161bbe16e31d98f67947e1eb (patch)
treeeff6df8fafb57c543a94a518dfa56568e094cc4c /Documentation/networking/can.txt
parentFix CFQ I/O scheduler parameter name in documentation (diff)
downloadlinux-aecd89e85534d31b161bbe16e31d98f67947e1eb.tar.xz
linux-aecd89e85534d31b161bbe16e31d98f67947e1eb.zip
can-doc: Add hint about getting timestamps
This patch adds a hint about how to get timestamps of received CAN frames with ioctl(2). This hint has been applied to the former SocketCAN Documentation, but it got lost during mainlining the first bits and pieces to linux kernel. Signed-off-by: Stefan Tatschner <rumpelsepp@sevenbyte.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/networking/can.txt')
-rw-r--r--Documentation/networking/can.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/networking/can.txt b/Documentation/networking/can.txt
index 05fd83bb3596..6ab619fcc517 100644
--- a/Documentation/networking/can.txt
+++ b/Documentation/networking/can.txt
@@ -372,6 +372,15 @@ solution for a couple of reasons:
nbytes = sendto(s, &frame, sizeof(struct can_frame),
0, (struct sockaddr*)&addr, sizeof(addr));
+ An accurate timestamp can be obtained with an ioctl(2) call after reading
+ a message from the socket:
+
+ struct timeval tv;
+ ioctl(s, SIOCGSTAMP, &tv);
+
+ The timestamp has a resolution of one microsecond and is set automatically
+ at the reception of a CAN frame.
+
Remark about CAN FD (flexible data rate) support:
Generally the handling of CAN FD is very similar to the formerly described