]> git.baikalelectronics.ru Git - kernel.git/commit
can: mcba_usb: Fix termination command argument
authorYasushi SHOJI <yasushi.shoji@gmail.com>
Thu, 24 Nov 2022 15:25:03 +0000 (00:25 +0900)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 19 Dec 2022 11:24:16 +0000 (12:24 +0100)
commita90b7946b568a041b0df738b23edaf528cca8e51
tree6ad51fe98fad973ac9581e8a476aec413af86407
parent872f485c53b2cb5a903b78f9162f43ae78c062e6
can: mcba_usb: Fix termination command argument

[ Upstream commit e31a0e2ac106aa74682e796c75b3f760d7cddbf2 ]

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 <yashi@spacecubics.com>
Link: https://lore.kernel.org/all/20221124152504.125994-1-yashi@spacecubics.com
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
drivers/net/can/usb/mcba_usb.c