| Message ID | 1657676339-6055-1-git-send-email-hayashi.kunihiko@socionext.com |
|---|---|
| State | Deferred |
| Delegated to: | Tom Rini |
| Headers | show |
| Series | serial: zynq: Use DIV_ROUND_CLOSEST() to calcurate divider value | expand |
On 7/13/22 03:38, Kunihiko Hayashi wrote: > Since the calulation of "bgen" is rounded down, using a higher > baudrate will result in a larger difference from the actual > baudrate. Should use DIV_ROUND_CLOSEST() like the Linux driver. > > Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> > --- > drivers/serial/serial_zynq.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c > index 83adfb5fb98a..857c570c5836 100644 > --- a/drivers/serial/serial_zynq.c > +++ b/drivers/serial/serial_zynq.c > @@ -75,7 +75,7 @@ static void _uart_zynq_serial_setbrg(struct uart_zynq *regs, > * Find acceptable values for baud generation. > */ > for (bdiv = 4; bdiv < 255; bdiv++) { > - bgen = clock / (baud * (bdiv + 1)); > + bgen = DIV_ROUND_CLOSEST(clock, (baud * (bdiv + 1))); Applied but I have removed one level of () in second parameter which is not needed. Thanks, Michal
Hi Michal, On 2022/07/15 19:48, Michal Simek wrote: > > > On 7/13/22 03:38, Kunihiko Hayashi wrote: >> Since the calulation of "bgen" is rounded down, using a higher >> baudrate will result in a larger difference from the actual >> baudrate. Should use DIV_ROUND_CLOSEST() like the Linux driver. >> >> Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> >> --- >> drivers/serial/serial_zynq.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c >> index 83adfb5fb98a..857c570c5836 100644 >> --- a/drivers/serial/serial_zynq.c >> +++ b/drivers/serial/serial_zynq.c >> @@ -75,7 +75,7 @@ static void _uart_zynq_serial_setbrg(struct uart_zynq >> *regs, >> * Find acceptable values for baud generation. >> */ >> for (bdiv = 4; bdiv < 255; bdiv++) { >> - bgen = clock / (baud * (bdiv + 1)); >> + bgen = DIV_ROUND_CLOSEST(clock, (baud * (bdiv + 1))); > > Applied but I have removed one level of () in second parameter which is not > needed. Sorry I forgot to remove it. Thanks for pointing out. --- Best Regards Kunihiko Hayashi
diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c index 83adfb5fb98a..857c570c5836 100644 --- a/drivers/serial/serial_zynq.c +++ b/drivers/serial/serial_zynq.c @@ -75,7 +75,7 @@ static void _uart_zynq_serial_setbrg(struct uart_zynq *regs, * Find acceptable values for baud generation. */ for (bdiv = 4; bdiv < 255; bdiv++) { - bgen = clock / (baud * (bdiv + 1)); + bgen = DIV_ROUND_CLOSEST(clock, (baud * (bdiv + 1))); if (bgen < 2 || bgen > 65535) continue;
Since the calulation of "bgen" is rounded down, using a higher baudrate will result in a larger difference from the actual baudrate. Should use DIV_ROUND_CLOSEST() like the Linux driver. Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com> --- drivers/serial/serial_zynq.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)