From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 A0B4A5692 for ; Thu, 15 Dec 2022 18:11:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0FE57C433F2; Thu, 15 Dec 2022 18:11:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1671127867; bh=25iNAoRPgXGfNeYb4wh8vl8JMGQM/UoBj2wGDcQyI/M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=B4OL+jIUXKw+lnKBPjEleF0ZCVj8AhSYGc97oinZhlHWWpdn8dvrHQqnjG+zzWzny Nvf9E4++EOb78N/s7Q7PBouwtF8va0qtqpPulBODJ+US6QMXFiAgZ4gYpyN94UEu+5 zEH9dK8amVIIo5kNISCvN9TmReRpQq6KuKn80AQ0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yasushi SHOJI , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 5.4 9/9] can: mcba_usb: Fix termination command argument Date: Thu, 15 Dec 2022 19:10:36 +0100 Message-Id: <20221215172905.792898044@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20221215172905.468656378@linuxfoundation.org> References: <20221215172905.468656378@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Yasushi SHOJI [ Upstream commit 1a8e3bd25f1e789c8154e11ea24dc3ec5a4c1da0 ] Microchip USB Analyzer can activate the internal termination resistors by setting the "termination" option ON, or OFF to to deactivate them. As I've observed, both with my oscilloscope and captured USB packets below, you must send "0" to turn it ON, and "1" to turn it OFF. >>From the schematics in the user's guide, I can confirm that you must drive the CAN_RES signal LOW "0" to activate the resistors. Reverse the argument value of usb_msg.termination to fix this. These are the two commands sequence, ON then OFF. > No. Time Source Destination Protocol Length Info > 1 0.000000 host 1.3.1 USB 46 URB_BULK out > > Frame 1: 46 bytes on wire (368 bits), 46 bytes captured (368 bits) > USB URB > Leftover Capture Data: a80000000000000000000000000000000000a8 > > No. Time Source Destination Protocol Length Info > 2 4.372547 host 1.3.1 USB 46 URB_BULK out > > Frame 2: 46 bytes on wire (368 bits), 46 bytes captured (368 bits) > USB URB > Leftover Capture Data: a80100000000000000000000000000000000a9 Signed-off-by: Yasushi SHOJI Link: https://lore.kernel.org/all/20221124152504.125994-1-yashi@spacecubics.com Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- drivers/net/can/usb/mcba_usb.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c index 957e51a77d4d..16fb4fc26518 100644 --- a/drivers/net/can/usb/mcba_usb.c +++ b/drivers/net/can/usb/mcba_usb.c @@ -47,6 +47,10 @@ #define MCBA_VER_REQ_USB 1 #define MCBA_VER_REQ_CAN 2 +/* Drive the CAN_RES signal LOW "0" to activate R24 and R25 */ +#define MCBA_VER_TERMINATION_ON 0 +#define MCBA_VER_TERMINATION_OFF 1 + #define MCBA_SIDL_EXID_MASK 0x8 #define MCBA_DLC_MASK 0xf #define MCBA_DLC_RTR_MASK 0x40 @@ -469,7 +473,7 @@ static void mcba_usb_process_ka_usb(struct mcba_priv *priv, priv->usb_ka_first_pass = false; } - if (msg->termination_state) + if (msg->termination_state == MCBA_VER_TERMINATION_ON) priv->can.termination = MCBA_TERMINATION_ENABLED; else priv->can.termination = MCBA_TERMINATION_DISABLED; @@ -789,9 +793,9 @@ static int mcba_set_termination(struct net_device *netdev, u16 term) }; if (term == MCBA_TERMINATION_ENABLED) - usb_msg.termination = 1; + usb_msg.termination = MCBA_VER_TERMINATION_ON; else - usb_msg.termination = 0; + usb_msg.termination = MCBA_VER_TERMINATION_OFF; mcba_usb_xmit_cmd(priv, (struct mcba_usb_msg *)&usb_msg); -- 2.35.1