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| author |   Alexey Starikovskiy <aystarik@gmail.com> | 2016-09-21 12:44:14 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-09-27 12:54:03 +0200 |
| commit | 36131cdfef5aef7f4a9a36423a7a338bd6f68ad6 (patch) | |
| tree | 7d75168490b71e02d839a8f56446238aead9f083 /drivers/tty | |
| parent | devpts: Change the owner of /dev/pts/ptmx to the mounter of /dev/pts (diff) | |
| download | linux-dev-36131cdfef5aef7f4a9a36423a7a338bd6f68ad6.tar.xz linux-dev-36131cdfef5aef7f4a9a36423a7a338bd6f68ad6.zip | |
tty/serial: atmel: fix fractional baud rate computation
The problem with previous code was it rounded values in wrong
place and produced wrong baud rate in some cases.
Signed-off-by: Alexey Starikovskiy <aystarik@gmail.com>
[nicolas.ferre@atmel.com: port to newer kernel and add commit log]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reviewed-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Reviewed-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/atmel_serial.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 5f550d9feed9..fd8aa1f4ba78 100644 --- a/drivers/tty/serial/atmel_serial.c +++ b/drivers/tty/serial/atmel_serial.c @@ -2170,13 +2170,15 @@ static void atmel_set_termios(struct uart_port *port, struct ktermios *termios, * accurately. This feature is enabled only when using normal mode. * baudrate = selected clock / (8 * (2 - OVER) * (CD + FP / 8)) * Currently, OVER is always set to 0 so we get - * baudrate = selected clock (16 * (CD + FP / 8)) + * baudrate = selected clock / (16 * (CD + FP / 8)) + * then + * 8 CD + FP = selected clock / (2 * baudrate) */ if (atmel_port->has_frac_baudrate && (mode & ATMEL_US_USMODE) == ATMEL_US_USMODE_NORMAL) { - div = DIV_ROUND_CLOSEST(port->uartclk, baud); - cd = div / 16; - fp = DIV_ROUND_CLOSEST(div % 16, 2); + div = DIV_ROUND_CLOSEST(port->uartclk, baud * 2); + cd = div >> 3; + fp = div & ATMEL_US_FP_MASK; } else { cd = uart_get_divisor(port, baud); } |