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tty/serial: atmel: fix out of range clock divider handling 

commit cb47b9f863 upstream.

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: 5bf5635ac1 ("tty/serial: atmel: add fractional baud rate support")
Signed-off-by: David Engraf <david.engraf@sysgo.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Richard Genoud <richard.genoud@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191216085403.17050-1-david.engraf@sysgo.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
David Engraf 2019-12-16 09:54:03 +01:00 committed by Greg Kroah-Hartman
parent 385fc1fb75
commit 3a2f322a2b
1 changed files with 22 additions and 21 deletions
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43
drivers/tty/serial/atmel_serial.c
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@ -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;