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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 v3] tty/serial: atmel: fix out of range clock divider handling
Date: Mon, 16 Dec 2019 09:54:03 +0100	[thread overview]
Message-ID: <20191216085403.17050-1-david.engraf@sysgo.com> (raw)
In-Reply-To: <39e4d1c7-20b0-a024-3a46-e4d4369eed8e@sysgo.com>

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

Fix by doing the baud rate calulation before setting the mode.

Fixes: 5bf5635ac170 ("tty/serial: atmel: add fractional baud rate support")
Signed-off-by: David Engraf <david.engraf@sysgo.com>
---
Changes since v1: 
 - moves set baud rate block before setting the mode register because
   ATMEL_US_RTSDIS and ATMEL_US_RTSEN depend on ATMEL_US_MR.mode

---
 drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index a8dc8af83f39..1ba9bc667e13 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2270,27 +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
-	 */
-	if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
-		unsigned int rts_state;
-
-		if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
-			/* let the hardware control the RTS line */
-			rts_state = ATMEL_US_RTSDIS;
-		} else {
-			/* force RTS line to low level */
-			rts_state = ATMEL_US_RTSEN;
-		}
-
-		atmel_uart_writel(port, ATMEL_US_CR, rts_state);
-	}
-
 	/*
 	 * Set the baud rate:
 	 * Fractional baudrate allows to setup output frequency more
@@ -2317,6 +2296,28 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
 		atmel_uart_writel(port, ATMEL_US_BRGR, quot);
+
+	/* 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
+	 */
+	if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
+		unsigned int rts_state;
+
+		if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
+			/* let the hardware control the RTS line */
+			rts_state = ATMEL_US_RTSDIS;
+		} else {
+			/* force RTS line to low level */
+			rts_state = ATMEL_US_RTSEN;
+		}
+
+		atmel_uart_writel(port, ATMEL_US_CR, rts_state);
+	}
+
 	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
 	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
 	atmel_port->tx_stopped = false;
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
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: David Engraf <david.engraf@sysgo.com>,
	linux-arm-kernel@lists.infradead.org,
	linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v3] tty/serial: atmel: fix out of range clock divider handling
Date: Mon, 16 Dec 2019 09:54:03 +0100	[thread overview]
Message-ID: <20191216085403.17050-1-david.engraf@sysgo.com> (raw)
In-Reply-To: <39e4d1c7-20b0-a024-3a46-e4d4369eed8e@sysgo.com>

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

Fix by doing the baud rate calulation before setting the mode.

Fixes: 5bf5635ac170 ("tty/serial: atmel: add fractional baud rate support")
Signed-off-by: David Engraf <david.engraf@sysgo.com>
---
Changes since v1: 
 - moves set baud rate block before setting the mode register because
   ATMEL_US_RTSDIS and ATMEL_US_RTSEN depend on ATMEL_US_MR.mode

---
 drivers/tty/serial/atmel_serial.c | 43 ++++++++++++++++---------------
 1 file changed, 22 insertions(+), 21 deletions(-)

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index a8dc8af83f39..1ba9bc667e13 100644
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2270,27 +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
-	 */
-	if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
-		unsigned int rts_state;
-
-		if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
-			/* let the hardware control the RTS line */
-			rts_state = ATMEL_US_RTSDIS;
-		} else {
-			/* force RTS line to low level */
-			rts_state = ATMEL_US_RTSEN;
-		}
-
-		atmel_uart_writel(port, ATMEL_US_CR, rts_state);
-	}
-
 	/*
 	 * Set the baud rate:
 	 * Fractional baudrate allows to setup output frequency more
@@ -2317,6 +2296,28 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios,
 
 	if (!(port->iso7816.flags & SER_ISO7816_ENABLED))
 		atmel_uart_writel(port, ATMEL_US_BRGR, quot);
+
+	/* 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
+	 */
+	if ((old_mode & ATMEL_US_USMODE) != (mode & ATMEL_US_USMODE)) {
+		unsigned int rts_state;
+
+		if ((mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_HWHS) {
+			/* let the hardware control the RTS line */
+			rts_state = ATMEL_US_RTSDIS;
+		} else {
+			/* force RTS line to low level */
+			rts_state = ATMEL_US_RTSEN;
+		}
+
+		atmel_uart_writel(port, ATMEL_US_CR, rts_state);
+	}
+
 	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_RSTSTA | ATMEL_US_RSTRX);
 	atmel_uart_writel(port, ATMEL_US_CR, ATMEL_US_TXEN | ATMEL_US_RXEN);
 	atmel_port->tx_stopped = false;
-- 
2.17.1


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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-12-16  8:54 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-11 16:29 [PATCH] tty/serial: atmel: fix out of range clock divider handling David Engraf
2019-12-11 16:29 ` David Engraf
2019-12-13  9:57 ` Richard Genoud
2019-12-13  9:57   ` Richard Genoud
2019-12-13 13:49   ` David Engraf
2019-12-13 13:49     ` David Engraf
2019-12-13 14:03     ` [PATCH v2] " David Engraf
2019-12-13 14:03       ` David Engraf
2019-12-13 16:07       ` Greg KH
2019-12-13 16:07         ` Greg KH
2019-12-16  8:34         ` David Engraf
2019-12-16  8:34           ` David Engraf
2019-12-16  8:54           ` David Engraf [this message]
2019-12-16  8:54             ` [PATCH v3] " David Engraf
2019-12-16 10:03             ` Richard Genoud
2019-12-16 10:03               ` Richard Genoud
2019-12-16 10:26             ` Ludovic Desroches
2019-12-16 10:26               ` Ludovic Desroches

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