[RFC] ns16550: support for UART with broken FIFO

[Antony Pavlov]

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 */

-- 
Best regards,
  Antony Pavlov