From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 370D1C433EF for ; Sat, 14 May 2022 20:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232382AbiENUNh (ORCPT ); Sat, 14 May 2022 16:13:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59098 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229759AbiENUNh (ORCPT ); Sat, 14 May 2022 16:13:37 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA0BF140E5 for ; Sat, 14 May 2022 13:13:35 -0700 (PDT) Received: from gallifrey.ext.pengutronix.de ([2001:67c:670:201:5054:ff:fe8d:eefb] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1npy8r-00010h-Ek; Sat, 14 May 2022 22:13:33 +0200 Received: from pengutronix.de (unknown [IPv6:2a01:4f8:1c1c:29e9:22:41ff:fe00:1400]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id 5CA4D7E427; Sat, 14 May 2022 20:13:32 +0000 (UTC) Date: Sat, 14 May 2022 22:13:31 +0200 From: Marc Kleine-Budde To: Matej Vasilevski Cc: devicetree@vger.kernel.org, linux-can@vger.kernel.org, pisa@cmp.felk.cvut.cz, ondrej.ille@gmail.com, netdev@vger.kernel.org, martin.jerabek01@gmail.com Subject: Re: [RFC PATCH 1/3] can: ctucanfd: add HW timestamps to RX and error CAN frames Message-ID: <20220514201331.xv5ofxbzrv5ti3bi@pengutronix.de> References: <20220512232706.24575-1-matej.vasilevski@seznam.cz> <20220512232706.24575-2-matej.vasilevski@seznam.cz> <20220513114135.lgbda6armyiccj3o@pengutronix.de> <20220514091741.GA203806@hopium> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="qf7flepnkiv2qd3k" Content-Disposition: inline In-Reply-To: <20220514091741.GA203806@hopium> X-SA-Exim-Connect-IP: 2001:67c:670:201:5054:ff:fe8d:eefb X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: devicetree@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org --qf7flepnkiv2qd3k Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On 14.05.2022 11:18:08, Matej Vasilevski wrote: > > > + timecounter_init(&priv->tc, &priv->cc, 0); > >=20 > > You here set the offset of the HW clock to 1.1.1970. The mcp driver sets > > the offset to current time. I think it's convenient to have the current > > time here....What do you think. >=20 > I actually searched in the mailing list and read your conversation with > Vincent on timestamps starting from 0 or synced to current time. > https://lore.kernel.org/linux-can/CAMZ6RqL+n4tRy-B-W+fzW5B3QV6Bedrko57pU_= 0TE023Oxw_5w@mail.gmail.com/ Thanks for looking up that discussion. Back than I was arguing for the start from 0, but in the mean time I added TS support for the mcp251xfd, which starts with the current time :) > Then I discussed it with Pavel Pisa and he requested to start from 0. > Reasons are that system time can change (NTP, daylight saving time, > user settings etc.), so when it starts from 0 it is clear that it is > "timestamp time". >=20 > Are there a lot of CAN drivers synced to system time? I think this would > be a good argument for syncing, to keep things nice and cohesive in > the CAN subsystem. >=20 > Overall I wouldn't want to block this patch over such a minutiae. ACK regards, Marc --=20 Pengutronix e.K. | Marc Kleine-Budde | Embedded Linux | https://www.pengutronix.de | Vertretung West/Dortmund | Phone: +49-231-2826-924 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | --qf7flepnkiv2qd3k Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEBsvAIBsPu6mG7thcrX5LkNig010FAmKADWkACgkQrX5LkNig 010EaQf+P4PDQgB1q9NTsep6x1FkFyAyBf5nFcWP7FYQjvbfOq/3Tuq5/LZsZuKQ /ac++Fw7u6iHtZQAHWg9vtmqlDTHR3UQlBEux7siRQXnUNoNopekN8qYKic5bx71 2aVhD4EmFxOb0jFFhBaOisIi9xmRRXG/kgUyJHQMBPL+gljx3mvbA/PfiIjvCT4L KNOizvTR0V0DpdhAl7oceu9AJg97qJ+RSOyyZx7q3vke/LB+8uXWSmdGkms1wcbI duCDQ0sFHOqsUdWnqbxfYh9Ph1aep47fqd5cOygN7zbXPA5XpY1VppQYbdsoU0ez bfH19KOUpJGU4DPhjj0zXG2bWh78nw== =6ZCc -----END PGP SIGNATURE----- --qf7flepnkiv2qd3k--