From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mo4-p02-ob.smtp.rzone.de (mo4-p02-ob.smtp.rzone.de [85.215.255.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 765B42848AA for ; Fri, 21 Nov 2025 19:35:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=85.215.255.81 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763753745; cv=pass; b=dZODBFN3pWvQNh/OeRIVMgjzU3H9O1DOBGixijQ/tyaTjOv/V8vlxQkk523Qw7yk0jmp5fM3ruFp7jMP2tknEVFfxnB7s1JISzrQk5Q1qEdztbLINNrFkQMC4nDjjU2nR1ndToCypVkzd4MOD356aRj7wydRzyhgqPJXOr9r5m8= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763753745; c=relaxed/simple; bh=0AaIpZeLvXk4TmubDn+FdpydKuHP3+59DDLYTYxLW9Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=uu8ZpDoNNND4pFG+d6I9hawqUHsenqzclWEUYgKP/f88vk449p7pbr3KI5vrcUg2Z5ZvFZ9C2AB8L+fOIRCSXUOZLrz6YrHeqhzBN4qOPda5JZ1lH577SmB6kxSQAggv0VLezq5mfjZpFkwKrnX6caG1sO60VDoSrDMTScMvwQA= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=hartkopp.net; spf=pass smtp.mailfrom=hartkopp.net; dkim=pass (2048-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b=c8QKgs5z; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b=wfmSlVlP; arc=pass smtp.client-ip=85.215.255.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=hartkopp.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=hartkopp.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="c8QKgs5z"; dkim=permerror (0-bit key) header.d=hartkopp.net header.i=@hartkopp.net header.b="wfmSlVlP" ARC-Seal: i=1; a=rsa-sha256; t=1763753730; cv=none; d=strato.com; s=strato-dkim-0002; b=snbuJCxgtghCcdO6e6pGNaFJu+tUOrEkosBypGgYGtAHeWQb/8J2jjoQJxZJkzUwHq PwLSKNWjMzZ+Q1kYa2eRtOBY+15gjq1FC6iLHLiJub+7V1r8JRKy529uowPPcKtMChDA ODPeUEC8muqa7NH6vrmylEJ7KSSzn0EC+417L9pzIsLHCX71WH5cpJ0TOSXDZYX40Tiv Fy6yii3hjaEundhUUFwZrXFf1uZzsKsKXYrE2u5VH3bFbb6jewNlca+cQxkGxaC2mgdb EkuWk+dt6HLjq1zBQNo8pn62Hfo/Q/aHlIS/ovDn4yT/QUSRoHcF0Hxn4cvBqB/IhbtZ D2Mg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; t=1763753730; s=strato-dkim-0002; d=strato.com; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=kjd+hHKGoaYbEP0miptzBTsChrI/eNkwTx1XU2+Zcs0=; b=WsGP94JcJb6OsIUmg6WWIvqy7SJUnRvikvsS8vJjc+y4MDkFvXJwEj+UbHpQuTxoNr M+Ec7SdY1VbLVTn9Yklg4GNiYmrgBn9BOYG70soCuHlGzwfgbf2qXcLKNPnpcZ2rhzWb 2hYKBXZG8phZWXgAiYg7Mbj/Z5KJ464GBTF6PlnYg5+zSOwO3isvRHEA9/48tdNdCpgX w4YOol4d4Kd+Xc6uPrvfpNr+fMkQyvC7rZ3Egesal2Ztulon6Jur62us/CapXwOqX+Hd VOOgPrOLqnDNf32mzZuMjdeeVSFkdTJs3y15XadSNtfkfl5Ob4Frh/8MQ0BQzNpUjbE0 STyg== ARC-Authentication-Results: i=1; strato.com; arc=none; dkim=none X-RZG-CLASS-ID: mo02 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1763753730; s=strato-dkim-0002; d=hartkopp.net; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=kjd+hHKGoaYbEP0miptzBTsChrI/eNkwTx1XU2+Zcs0=; b=c8QKgs5zpy4HE/wDh+V3Xx88Ijf4xYWYnUqcmEHfoTOgLqykrasL0whgGiYi9vqTpG tfIBzP1NJ6Xu0GiBAijYPWhygtwtw/QJLLiCKEzQv+lUGuP7WpZYzy5a0Ms31LqjLEu+ WiFkESeEQgE1adt0cJR+f7TzWNT8M1VrCJv+7dYM1fGCnh8mxDH9GUq05286TtKkrZSA pwuDs3jHM88z0v4E1qVnNoGpysnuTgh9ySPHm3imSYHnfABix1erejxmCBjYRKu4BaQL 2UgKOa1TXxLbfmFsDxIKZ73cvBQxhRTu10F5yy9R4YlRxs2HUeRsMq8MEsLUnpYkfmIm 2L/A== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; t=1763753730; s=strato-dkim-0003; d=hartkopp.net; h=References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From:Cc:Date: From:Subject:Sender; bh=kjd+hHKGoaYbEP0miptzBTsChrI/eNkwTx1XU2+Zcs0=; b=wfmSlVlP9m47eYHbkVEw9axLmYeAAAQB1Y4Ka62utjXhU5xl0apAyn2ZuRV4cdciU8 VEgMeWdWyUtJqsR0UhDg== X-RZG-AUTH: ":P2MHfkW8eP4Mre39l357AZT/I7AY/7nT2yrDxb8mjH4JKvMdQv2tTUsMrZpkO3Mw3lZ/t54cFxeEQ7s8bGWj0Q==" Received: from lenov17.lan by smtp.strato.de (RZmta 54.0.0 AUTH) with ESMTPSA id Ke2b461ALJZUEnE (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256 bits)) (Client did not present a certificate); Fri, 21 Nov 2025 20:35:30 +0100 (CET) From: Oliver Hartkopp To: linux-can@vger.kernel.org Cc: Vincent Mailhol , Oliver Hartkopp Subject: [canxl v5 13/17] can: calc_bittiming: add can_calc_sample_point_nrz() Date: Fri, 21 Nov 2025 20:35:09 +0100 Message-ID: <20251121193513.2097-14-socketcan@hartkopp.net> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20251121193513.2097-1-socketcan@hartkopp.net> References: <20251121193513.2097-1-socketcan@hartkopp.net> Precedence: bulk X-Mailing-List: linux-can@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="us-ascii" From: Vincent Mailhol CAN XL optimal sample point for PWM encoding (when TMS is on) differs from the NRZ optimal one. There is thus a need to calculate a different sample point depending whether TMS is on or off. This is a preparation change: move the sample point calculation from can_calc_bittiming() into the new can_calc_sample_point_nrz() function. In an upcoming change, a function will be added to calculate the sample point for PWM encoding. Signed-off-by: Vincent Mailhol Signed-off-by: Oliver Hartkopp --- drivers/net/can/dev/calc_bittiming.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/net/can/dev/calc_bittiming.c b/drivers/net/can/dev/calc_bittiming.c index 46f6f5942abb..35db90be9c9a 100644 --- a/drivers/net/can/dev/calc_bittiming.c +++ b/drivers/net/can/dev/calc_bittiming.c @@ -8,10 +8,22 @@ #include #include #define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */ +/* CiA recommended sample points for Non Return to Zero encoding. */ +static int can_calc_sample_point_nrz(const struct can_bittiming *bt) +{ + if (bt->bitrate > 800 * KILO /* BPS */) + return 750; + + if (bt->bitrate > 500 * KILO /* BPS */) + return 800; + + return 875; +} + /* Bit-timing calculation derived from: * * Code based on LinCAN sources and H8S2638 project * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz * Copyright 2005 Stanislav Marek @@ -76,21 +88,14 @@ int can_calc_bittiming(const struct net_device *dev, struct can_bittiming *bt, unsigned int best_brp = 0; /* current best value for brp */ unsigned int brp, tsegall, tseg, tseg1 = 0, tseg2 = 0; u64 v64; int err; - /* Use CiA recommended sample points */ - if (bt->sample_point) { + if (bt->sample_point) sample_point = bt->sample_point; - } else { - if (bt->bitrate > 800 * KILO /* BPS */) - sample_point = 750; - else if (bt->bitrate > 500 * KILO /* BPS */) - sample_point = 800; - else - sample_point = 875; - } + else + sample_point = can_calc_sample_point_nrz(bt); /* tseg even = round down, odd = round up */ for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1; tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) { tsegall = CAN_SYNC_SEG + tseg / 2; -- 2.47.3