Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 03abeac0 authored by Andrew Victor's avatar Andrew Victor Committed by Russell King
Browse files

[ARM] 4357/1: AT91: Support slower serial baud-rates 



Allow slower serial baud-rates by switching the UART clock from MCK to
MCK/8.

Based on patches by Mike Wolfram and Russell King.

Signed-off-by: default avatarAndrew Victor <andrew@sanpeople.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 7c73628f

drivers/serial/atmel_serial.c

+7 −2
Original line number Diff line number Diff line
@@ -484,11 +484,16 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios * termios, 
	unsigned long flags;

	unsigned int mode, imr, quot, baud;



	/* Get current mode register */

	mode = UART_GET_MR(port) & ~(ATMEL_US_USCLKS | ATMEL_US_CHRL | ATMEL_US_NBSTOP | ATMEL_US_PAR);



	baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk/16);

	quot = uart_get_divisor(port, baud);



	/* Get current mode register */

	mode = UART_GET_MR(port) & ~(ATMEL_US_CHRL | ATMEL_US_NBSTOP | ATMEL_US_PAR);

	if (quot > 65535) {		/* BRGR is 16-bit, so switch to slower clock */

		quot /= 8;

		mode |= ATMEL_US_USCLKS_MCK_DIV8;

	}



	/* byte size */

	switch (termios->c_cflag & CSIZE) {

drivers/serial/atmel_serial.h

+3 −0
Original line number Diff line number Diff line
@@ -46,6 +46,9 @@ 
#define			ATMEL_US_USMODE_ISO7816_T1	6

#define			ATMEL_US_USMODE_IRDA		8

#define		ATMEL_US_USCLKS		(3   <<  4)		/* Clock Selection */

#define			ATMEL_US_USCLKS_MCK		(0 <<  4)

#define			ATMEL_US_USCLKS_MCK_DIV8	(1 <<  4)

#define			ATMEL_US_USCLKS_SCK		(3 <<  4)

#define		ATMEL_US_CHRL		(3   <<  6)		/* Character Length */

#define			ATMEL_US_CHRL_5			(0 <<  6)

#define			ATMEL_US_CHRL_6			(1 <<  6)