diff options
| author | Andrew Victor <andrew@sanpeople.com> | 2007-05-03 12:26:24 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2007-05-03 14:12:45 +0100 |
| commit | 03abeac0a222060ae8f02e8359c285df0971437e (patch) | |
| tree | 96fd9e6f11740a098ffa0958d218ff1f41e4b216 /drivers | |
| parent | 7c73628f24ea73479232d1b608359aa7d8d2c95d (diff) | |
[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: Andrew Victor <andrew@sanpeople.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/serial/atmel_serial.c | 9 | ||||
| -rw-r--r-- | drivers/serial/atmel_serial.h | 3 |
2 files changed, 10 insertions, 2 deletions
diff --git a/drivers/serial/atmel_serial.c b/drivers/serial/atmel_serial.c index 935f48fa501..3320bcd92c0 100644 --- a/drivers/serial/atmel_serial.c +++ b/drivers/serial/atmel_serial.c @@ -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) { diff --git a/drivers/serial/atmel_serial.h b/drivers/serial/atmel_serial.h index 11b44360e10..e0141776517 100644 --- a/drivers/serial/atmel_serial.h +++ b/drivers/serial/atmel_serial.h @@ -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) |