serial: uart: add hw flow control support configuration
authorMurali Karicheri <m-karicheri2@ti.com>
Thu, 1 May 2014 19:04:53 +0000 (15:04 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 28 May 2014 20:04:46 +0000 (13:04 -0700)
commit06aa82e498c144c7784a6f3d3b55458b272d6146
tree0055d789f294f29287ec4386ef3b81ef9eb4a181
parentab5e4e4108ca5d8326cb6b4b3a21b096a002f68f
serial: uart: add hw flow control support configuration

8250 uart driver currently supports only software assisted hw flow
control. The software assisted hw flow control maintains a hw_stopped
flag in the tty structure to stop and start transmission and use modem
status interrupt for the event to drive the handshake signals. This is
not needed if hw has flow control capabilities. This patch adds a
DT attribute for enabling hw flow control for a uart port. Also skip
stop and start if this flag is present in flag field of the port
structure.

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Jiri Slaby <jslaby@suse.cz>
CC: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Documentation/devicetree/bindings/serial/of-serial.txt
drivers/tty/serial/8250/8250_core.c
drivers/tty/serial/of_serial.c
drivers/tty/serial/serial_core.c