RE: [PATCH] tty: serial: fsl_lpuart: minimum baud rate support

From: Vabhav Sharma (OSS)
Date: Thu Jun 25 2020 - 06:13:02 EST




> -----Original Message-----
> From: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> Sent: Thursday, June 25, 2020 3:34 PM
> To: Vabhav Sharma (OSS) <vabhav.sharma@xxxxxxxxxxx>
> Cc: jslaby@xxxxxxxx; linux-serial@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Varun Sethi <V.Sethi@xxxxxxx>; Vabhav Sharma
> <vabhav.sharma@xxxxxxx>
> Subject: Re: [PATCH] tty: serial: fsl_lpuart: minimum baud rate support
>
> On Thu, Jun 25, 2020 at 03:19:05PM +0530, Vabhav Sharma wrote:
> > From: Vabhav Sharma <vabhav.sharma@xxxxxxx>
> >
> > The formula for the baud rate is
> > baud rate = "baud clock / ((OSR+1) × SBR)
> >
> > Algorithm used in function lpuart32_serial_setbrg() only changes the
> > SBR. Even with maxmum value put in, OSR stays at 0x7 and the lowest
> > baud rate would be ~ 2600 bps
> >
> > Update the algorithm to allow driver operation at 1200,2400 or
> > 600 bps
> >
> > Signed-off-by: Vabhav Sharma <vabhav.sharma@xxxxxxx>
> > ---
> > drivers/tty/serial/fsl_lpuart.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/tty/serial/fsl_lpuart.c
> > b/drivers/tty/serial/fsl_lpuart.c index 90298c4..0fd0fa5f 100644
> > --- a/drivers/tty/serial/fsl_lpuart.c
> > +++ b/drivers/tty/serial/fsl_lpuart.c
> > @@ -1925,6 +1925,10 @@ static void __lpuart32_serial_setbrg(struct
> uart_port *port,
> > tmp_sbr++;
> > }
> >
> > + if (tmp_sbr > UARTBAUD_SBR_MASK) {
> > + continue;
> > + }
>
> Always use scripts/checkpatch.pl on your patches so you do not get grumpy
> emails from maintainers telling you to use scripts/checkpatch.pl on your
> patches...
Indeed, I run the script before sending patch
./scripts/checkpatch.pl 0001-tty-serial-fsl_lpuart-minimum-baud-rate-support.patch
total: 0 errors, 0 warnings, 10 lines checked

0001-tty-serial-fsl_lpuart-minimum-baud-rate-support.patch has no obvious style problems and is ready for submission.