linux-kernel - [PATCH 5.15 172/230] Revert "serial: sc16is7xx: Clear RS485 bits in the shutdown"

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Date:   Mon, 11 Jul 2022 11:07:08 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Hui Wang <hui.wang@...onical.com>
Subject: [PATCH 5.15 172/230] Revert "serial: sc16is7xx: Clear RS485 bits in the shutdown"

From: Hui Wang <hui.wang@...onical.com>

commit 41c606879f89623dd5269eaffea640b915e9e17c upstream.

This reverts commit 927728a34f11b5a27f4610bdb7068317d6fdc72a.

Once the uart_port->rs485->flag is set to SER_RS485_ENABLED, the port
should always work in RS485 mode. If users want the port to leave
RS485 mode, they need to call ioctl() to clear SER_RS485_ENABLED.

So here we shouldn't clear the RS485 bits in the shutdown().

Fixes: 927728a34f11 ("serial: sc16is7xx: Clear RS485 bits in the shutdown")
Signed-off-by: Hui Wang <hui.wang@...onical.com>
Link: https://lore.kernel.org/r/20220418094339.678144-1-hui.wang@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/tty/serial/sc16is7xx.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1055,12 +1055,10 @@ static void sc16is7xx_shutdown(struct ua
 
 	/* Disable all interrupts */
 	sc16is7xx_port_write(port, SC16IS7XX_IER_REG, 0);
-	/* Disable TX/RX, clear auto RS485 and RTS invert */
+	/* Disable TX/RX */
 	sc16is7xx_port_update(port, SC16IS7XX_EFCR_REG,
 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
-			      SC16IS7XX_EFCR_TXDISABLE_BIT |
-			      SC16IS7XX_EFCR_AUTO_RS485_BIT |
-			      SC16IS7XX_EFCR_RTS_INVERT_BIT,
+			      SC16IS7XX_EFCR_TXDISABLE_BIT,
 			      SC16IS7XX_EFCR_RXDISABLE_BIT |
 			      SC16IS7XX_EFCR_TXDISABLE_BIT);