diff mbox series

[net,8/8] can: mcba_usb: Fix termination command argument

Message ID 20221124195708.1473369-9-mkl@pengutronix.de (mailing list archive)
State Accepted
Commit 1a8e3bd25f1e789c8154e11ea24dc3ec5a4c1da0
Delegated to: Netdev Maintainers
Headers show
Series [net,1/8] can: can327: can327_feed_frame_to_netdev(): fix potential skb leak when netdev is down | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Pull request is its own cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 5 maintainers not CCed: pabeni@redhat.com wg@grandegger.com edumazet@google.com mailhol.vincent@wanadoo.fr paskripkin@gmail.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/checkpatch warning WARNING: From:/Signed-off-by: email address mismatch: 'From: Yasushi SHOJI <yasushi.shoji@gmail.com>' != 'Signed-off-by: Yasushi SHOJI <yashi@spacecubics.com>' WARNING: Possible repeated word: 'to'
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Marc Kleine-Budde Nov. 24, 2022, 7:57 p.m. UTC 
From: Yasushi SHOJI <yasushi.shoji@gmail.com>

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>
---
 drivers/net/can/usb/mcba_usb.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/can/usb/mcba_usb.c b/drivers/net/can/usb/mcba_usb.c
index 218b098b261d..47619e9cb005 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
@@ -463,7 +467,7 @@  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;
@@ -785,9 +789,9 @@  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);