serial: 8250_dw: Fix LCR workaround regression

Commit c49436b657d0 (serial: 8250_dw: Improve unwritable LCR workaround)
caused a regression. It added a check that the LCR was written properly
to detect and workaround the busy quirk, but the behaviour of bit 5
(UART_LCR_SPAR) differs between IP versions 3.00a and 3.14c per the
docs. On older versions this caused the check to fail and it would
repeatedly force idle and rewrite the LCR register, causing delays and
preventing any input from serial being received.

This is fixed by masking out UART_LCR_SPAR before making the comparison.

Signed-off-by: James Hogan <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Jiri Slaby <[email protected]>
Cc: Tim Kryger <[email protected]>
Cc: Ezequiel Garcia <[email protected]>
Cc: Matt Porter <[email protected]>
Cc: Markus Mayer <[email protected]>
Tested-by: Tim Kryger <[email protected]>
Tested-by: Ezequiel Garcia <[email protected]>
Tested-by: Heikki Krogerus <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

0 files changed, 0 insertions, 0 deletions