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From: Dave Penkler <dpenkler@gmail.com>
To: gregkh@linuxfoundation.org, linux-staging@lists.linux.dev,
	linux-kernel@vger.kernel.org
Cc: marcello.carla@gmx.com, Dave Penkler <dpenkler@gmail.com>
Subject: [PATCH 8/8] staging: gpib: Set control lines in attach
Date: Fri, 18 Apr 2025 19:34:34 +0200	[thread overview]
Message-ID: <20250418173434.2892-9-dpenkler@gmail.com> (raw)
In-Reply-To: <20250418173434.2892-1-dpenkler@gmail.com>

When the driver is attached the state of the main control lines
is not defined and can lead to hangs. Set the control lines to
a known state (logic false).

Fixes: 4cd654f84769 ("staging: gpib: Add gpio bitbang GPIB driver")
Tested-by: Dave Penkler <dpenkler@gmail.com>
Signed-off-by: Dave Penkler <dpenkler@gmail.com>
---
 drivers/staging/gpib/gpio/gpib_bitbang.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/staging/gpib/gpio/gpib_bitbang.c b/drivers/staging/gpib/gpio/gpib_bitbang.c
index 5c134cfb6d61..625fef24a0bf 100644
--- a/drivers/staging/gpib/gpio/gpib_bitbang.c
+++ b/drivers/staging/gpib/gpio/gpib_bitbang.c
@@ -1262,6 +1262,10 @@ static int bb_attach(struct gpib_board *board, const struct gpib_board_config *c
 		gpiod_direction_output(TE, 1);
 		gpiod_direction_output(PE, 1);
 	}
+/* Set main control lines to a known state */
+	gpiod_direction_output(IFC, 1);
+	gpiod_direction_output(REN, 1);
+	gpiod_direction_output(_ATN, 1);
 
 	if (strcmp(PINMAP_2, pin_map) == 0) { /* YOGA: enable level shifters */
 		gpiod_direction_output(YOGA_ENABLE, 1);
-- 
2.49.0


      parent reply	other threads:[~2025-04-18 17:35 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-18 17:34 [PATCH 0/8] staging: gpib: Fixes and cleanup for gpio driver Dave Penkler
2025-04-18 17:34 ` [PATCH 1/8] staging: gpib: Fix request_system_control in gpio Dave Penkler
2025-04-18 17:34 ` [PATCH 2/8] staging: gpib: Fix setting controller-in-charge Dave Penkler
2025-04-18 17:34 ` [PATCH 3/8] staging: gpib: Enable SRQ irq on request_system_control Dave Penkler
2025-04-18 17:34 ` [PATCH 4/8] staging: gpib: Remove dependency on LED subsystem Dave Penkler
2025-04-18 17:34 ` [PATCH 5/8] staging: gpib: Remove atn_asserted global variable Dave Penkler
2025-04-18 17:34 ` [PATCH 6/8] staging: gpib: Change error code for no listener Dave Penkler
2025-04-18 17:34 ` [PATCH 7/8] staging: gpib: Cleanup allocate_gpios code Dave Penkler
2025-04-18 17:34 ` Dave Penkler [this message]

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