[RFC PATCH 4/6] serio: serport: add support for buffered write and receive

[Rob Herring]

A tty ldisc naturally supports writing a buffer at a time, so convert the
serport driver to use the serio write_buf() function. For clients using
the existing interfaces, there is no change in functionality.

Signed-off-by: Rob Herring <r...@kernel.org>
---
 drivers/input/serio/serport.c | 43 +++++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 20 deletions(-)

diff --git a/drivers/input/serio/serport.c b/drivers/input/serio/serport.c
index a938c2b..5572c28 100644
--- a/drivers/input/serio/serport.c
+++ b/drivers/input/serio/serport.c
@@ -45,10 +45,10 @@ struct serport {
  * Callback functions from the serio code.
  */
 
-static int serport_serio_write(struct serio *serio, unsigned char data)
+static int serport_serio_write_buf(struct serio *serio, const unsigned char 
*data, size_t len)
 {
        struct serport *serport = serio->port_data;
-       return -(serport->tty->ops->write(serport->tty, &data, 1) != 1);
+       return serport->tty->ops->write(serport->tty, data, len);
 }
 
 static int serport_serio_open(struct serio *serio)
@@ -133,26 +133,29 @@ static void serport_ldisc_receive(struct tty_struct *tty, 
const unsigned char *c
        if (!test_bit(SERPORT_ACTIVE, &serport->flags))
                goto out;
 
-       for (i = 0; i < count; i++) {
-               if (fp) {
-                       switch (fp[i]) {
-                       case TTY_FRAME:
-                               ch_flags = SERIO_FRAME;
-                               break;
-
-                       case TTY_PARITY:
-                               ch_flags = SERIO_PARITY;
-                               break;
-
-                       default:
-                               ch_flags = 0;
-                               break;
+       if (serio_buffered_mode_enabled(serport->serio)) {
+               serio_receive_buf(serport->serio, cp, count);
+       } else {
+               for (i = 0; i < count; i++) {
+                       if (fp) {
+                               switch (fp[i]) {
+                               case TTY_FRAME:
+                                       ch_flags = SERIO_FRAME;
+                                       break;
+
+                               case TTY_PARITY:
+                                       ch_flags = SERIO_PARITY;
+                                       break;
+
+                               default:
+                                       ch_flags = 0;
+                                       break;
+                               }
                        }
-               }
 
-               serio_interrupt(serport->serio, cp[i], ch_flags);
+                       serio_interrupt(serport->serio, cp[i], ch_flags);
+               }
        }
-
 out:
        spin_unlock_irqrestore(&serport->lock, flags);
 }
@@ -179,7 +182,7 @@ static ssize_t serport_ldisc_read(struct tty_struct * tty, 
struct file * file, u
        snprintf(serio->phys, sizeof(serio->phys), "%s/serio0", tty_name(tty));
        serio->id = serport->id;
        serio->id.type = SERIO_RS232;
-       serio->write = serport_serio_write;
+       serio->write_buf = serport_serio_write_buf;
        serio->open = serport_serio_open;
        serio->close = serport_serio_close;
        serio->port_data = serport;
-- 
2.9.3