[RFC] ns16550: support for UART with broken FIFO

[Jean-Christophe PLAGNIOL-VILLARD]

On 17:27 Tue 17 Jan     , Antony Pavlov wrote:
> On 17 January 2012 17:09, Sascha Hauer <s.hauer at pengutronix.de> wrote:
> > On Tue, Jan 17, 2012 at 02:39:06PM +0400, Antony Pavlov wrote:
> >> Signed-off-by: Antony Pavlov <antonynpavlov at gmail.com>
> >> ---
> >>  drivers/serial/serial_ns16550.c |   19 +++++++++++++++++--
> >>  include/ns16550.h               |    2 ++
> >>  2 files changed, 19 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
> >> index 1217a5f..01de964 100644
> >> --- a/drivers/serial/serial_ns16550.c
> >> +++ b/drivers/serial/serial_ns16550.c
> >> @@ -139,6 +139,8 @@ static unsigned int ns16550_calc_divisor(struct console_device *cdev,
> >>  static void ns16550_serial_init_port(struct console_device *cdev)
> >>  {
> >>       unsigned int baud_divisor;
> >> +     struct NS16550_plat *plat = (struct NS16550_plat *)
> >> +         cdev->dev->platform_data;
> >>
> >>       /* Setup the serial port with the defaults first */
> >>       baud_divisor = ns16550_calc_divisor(cdev, CONFIG_BAUDRATE);
> >> @@ -153,7 +155,13 @@ static void ns16550_serial_init_port(struct console_device *cdev)
> >>       ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
> >>       ns16550_write(cdev, LCRVAL, lcr);
> >>       ns16550_write(cdev, MCRVAL, mcr);
> >> -     ns16550_write(cdev, FCRVAL, fcr);
> >> +
> >> +     if (plat->flags & NS16650_FLAG_DISABLE_FIFO) {
> >> +             ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
> >> +     } else {
> >> +             ns16550_write(cdev, FCRVAL, fcr);
> >> +     }
> >
> > unnecessary braces here..
> >
> >> +
> >>  #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
> >>       ns16550_write(cdev, 0x00,  mdr1);
> >>  #endif
> >> @@ -211,6 +219,8 @@ static int ns16550_tstc(struct console_device *cdev)
> >>  static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
> >>  {
> >>       unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
> >> +     struct NS16550_plat *plat = (struct NS16550_plat *)
> >> +         cdev->dev->platform_data;
> >>
> >>       ns16550_write(cdev, 0x00, ier);
> >>       ns16550_write(cdev, LCR_BKSE, lcr);
> >> @@ -218,7 +228,12 @@ static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
> >>       ns16550_write(cdev, (baud_divisor >> 8) & 0xff, dlm);
> >>       ns16550_write(cdev, LCRVAL, lcr);
> >>       ns16550_write(cdev, MCRVAL, mcr);
> >> -     ns16550_write(cdev, FCRVAL, fcr);
> >> +     if (plat->flags & NS16650_FLAG_DISABLE_FIFO) {
> >> +             ns16550_write(cdev, FCRVAL & ~FCR_FIFO_EN, fcr);
> >> +     } else {
> >> +             ns16550_write(cdev, FCRVAL, fcr);
> >> +     }
> >
> > and here. Otherwise this looks ok.
> 
> Ok, I shall remove the braces.
> 
> Sascha!
> 
> We have special OMAP code, e.g.:
> 
> #ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
>         ns16550_write(cdev, 0x07, mdr1);        /* Disable */
> #endif
> 
> I think, that we can change it to something like this:
> 
>     if (plat->flags & NS16650_FLAG_OMAP_EXTENSIONS)
>         ns16550_write(cdev, 0x07, mdr1);        /* Disable */
I don't like to add dead code in the binary
just use
	if (IS_ENABLED(CONFIG_...)

Best Regards,
J.