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From: David Engraf <david.engraf@sysgo.com>
To: richard.genoud@gmail.com, gregkh@linuxfoundation.org,
	jslaby@suse.com, nicolas.ferre@microchip.com,
	alexandre.belloni@bootlin.com, ludovic.desroches@microchip.com
Cc: linux-serial@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	David Engraf <david.engraf@sysgo.com>
Subject: [PATCH] tty/serial: atmel: fix out of range clock divider handling
Date: Wed, 11 Dec 2019 17:29:54 +0100	[thread overview]
Message-ID: <20191211162954.8393-1-david.engraf@sysgo.com> (raw)

Use MCK_DIV8 when the clock divider is > 65535. Unfortunately the mode
register was already written thus the clock selection is ignored.

Fix by writing the mode register after calculating the baudrate.

Signed-off-by: David Engraf <david.engraf@sysgo.com>
---
 drivers/tty/serial/atmel_serial.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index a8dc8af83f39..9983e2fabbac 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2270,9 +2270,6 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 		mode |= ATMEL_US_USMODE_NORMAL;
 	}
 
-	/* set the mode, clock divisor, parity, stop bits and data size */
-	atmel_uart_writel(port, ATMEL_US_MR, mode);
-
 	/*
 	 * when switching the mode, set the RTS line state according to the
 	 * new mode, otherwise keep the former state
@@ -2315,6 +2312,9 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 	}
 	quot = cd | fp << ATMEL_US_FP_OFFSET;
 
+	/* set the mode, clock divisor, parity, stop bits and data size */
+	atmel_uart_writel(port, ATMEL_US_MR, mode);
+
 	if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
 		atmel_uart_writel(port, ATMEL_US_BRGR, quot);
 	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
-- 
2.17.1


             reply	other threads:[~2019-12-11 16:30 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11 16:29 David Engraf [this message]
2019-12-13  9:57 ` [PATCH] tty/serial: atmel: fix out of range clock divider handling Richard Genoud
2019-12-13 13:49   ` David Engraf
2019-12-13 14:03     ` [PATCH v2] " David Engraf
2019-12-13 16:07       ` Greg KH
2019-12-16  8:34         ` David Engraf
2019-12-16  8:54           ` [PATCH v3] " David Engraf
2019-12-16 10:03             ` Richard Genoud
2019-12-16 10:26             ` Ludovic Desroches

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