On Thu, 7 Jul 2022 17:09:45 +0200
Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, Jul 07, 2022 at 04:53:50PM +0200, Marek Behún wrote:
> > From: Pali Rohár <pali@xxxxxxxxxx>
> >
> > As a code cleanup for future changes, extract divisor code for SIO chip
> > into new function ftdi_sio_baud_to_divisor().
> >
> > No functional change.
> >
> > Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> > Tested-by: Marek Behún <kabel@xxxxxxxxxx>
> > ---
> > drivers/usb/serial/ftdi_sio.c | 34 ++++++++++++++++++++--------------
> > 1 file changed, 20 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
> > index 717b97f4e094..45a4eeb1fc70 100644
> > --- a/drivers/usb/serial/ftdi_sio.c
> > +++ b/drivers/usb/serial/ftdi_sio.c
> > @@ -1150,6 +1150,23 @@ static struct usb_serial_driver * const serial_drivers[] = {
> > * ***************************************************************************
> > */
> >
> > +static u32 ftdi_sio_baud_to_divisor(int baud)
> > +{
> > + switch (baud) {
> > + case 300: return ftdi_sio_b300;
> > + case 600: return ftdi_sio_b600;
> > + case 1200: return ftdi_sio_b1200;
> > + case 2400: return ftdi_sio_b2400;
> > + case 4800: return ftdi_sio_b4800;
> > + case 9600: return ftdi_sio_b9600;
> > + case 19200: return ftdi_sio_b19200;
> > + case 38400: return ftdi_sio_b38400;
> > + case 57600: return ftdi_sio_b57600;
> > + case 115200: return ftdi_sio_b115200;
> > + default: return -1;
>
> Why not just return 9600 as a default here like the original code did?
It keeps at 9600 as original code.
Before:
div_value = ftdi_sio_b9600;
baud = 9600;
After:
baud = 9600;
div_value = ftdi_sio_baud_to_divisor(baud);
The new function that converts between the enum values and real values
now indicates when conversion is not possible.
> And returning a negative number for a u32 is not a good idea for the
> obvious reasons you found when you tried to test for it...
Would s32 be ok?
