* [PATCH RESEND] tty: serial: 8250_mtk: Fix quot calculation
@ 2014-10-31 16:36 Matthias Brugger
2014-10-31 16:48 ` Arnd Bergmann
0 siblings, 1 reply; 3+ messages in thread
From: Matthias Brugger @ 2014-10-31 16:36 UTC (permalink / raw)
To: gregkh
Cc: linux-kernel, jslaby, alan, matthias.bgg, heiko, yingjoe.chen,
ibanezchen, linux-serial, linux-arm-kernel
From: Matthias Brugger <matthias.bgg@gmail.com>
The calculation of value quot for highspeed register set to three
was wrong. This patch fixes the calculation so that the serial port
for baudrates bigger then 576000 baud is working correctly.
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>
---
drivers/tty/serial/8250/8250_mtk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_mtk.c b/drivers/tty/serial/8250/8250_mtk.c
index 8f37d57..de7aae5 100644
--- a/drivers/tty/serial/8250/8250_mtk.c
+++ b/drivers/tty/serial/8250/8250_mtk.c
@@ -81,7 +81,7 @@ mtk8250_set_termios(struct uart_port *port, struct ktermios *termios,
/* Set to highest baudrate supported */
if (baud >= 1152000)
baud = 921600;
- quot = DIV_ROUND_CLOSEST(port->uartclk, 256 * baud);
+ quot = (port->uartclk / (256 * baud)) + 1;
}
/*
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH RESEND] tty: serial: 8250_mtk: Fix quot calculation
2014-10-31 16:36 [PATCH RESEND] tty: serial: 8250_mtk: Fix quot calculation Matthias Brugger
@ 2014-10-31 16:48 ` Arnd Bergmann
2014-11-03 2:27 ` eddie huang
0 siblings, 1 reply; 3+ messages in thread
From: Arnd Bergmann @ 2014-10-31 16:48 UTC (permalink / raw)
To: linux-arm-kernel
Cc: Matthias Brugger, gregkh, heiko, yingjoe.chen, linux-kernel,
ibanezchen, linux-serial, jslaby, alan
On Friday 31 October 2014 17:36:35 Matthias Brugger wrote:
> - quot = DIV_ROUND_CLOSEST(port->uartclk, 256 * baud);
> + quot = (port->uartclk / (256 * baud)) + 1;
Should this be DIV_ROUND_UP then?
Arnd
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH RESEND] tty: serial: 8250_mtk: Fix quot calculation
2014-10-31 16:48 ` Arnd Bergmann
@ 2014-11-03 2:27 ` eddie huang
0 siblings, 0 replies; 3+ messages in thread
From: eddie huang @ 2014-11-03 2:27 UTC (permalink / raw)
To: Arnd Bergmann
Cc: linux-arm-kernel, heiko, yingjoe.chen, gregkh, linux-kernel,
ibanezchen, linux-serial, Matthias Brugger, jslaby, alan
On Fri, 2014-10-31 at 17:48 +0100, Arnd Bergmann wrote:
> On Friday 31 October 2014 17:36:35 Matthias Brugger wrote:
> > - quot = DIV_ROUND_CLOSEST(port->uartclk, 256 * baud);
> > + quot = (port->uartclk / (256 * baud)) + 1;
>
> Should this be DIV_ROUND_UP then?
>
> Arnd
>
I think DIV_ROUND_UP is more suitable in this case, and I already do
this and test OK on my MTK platform
http://lists.infradead.org/pipermail/linux-arm-kernel/2014-October/296149.html
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2014-11-03 2:27 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2014-10-31 16:36 [PATCH RESEND] tty: serial: 8250_mtk: Fix quot calculation Matthias Brugger
2014-10-31 16:48 ` Arnd Bergmann
2014-11-03 2:27 ` eddie huang
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).