target/linux/brcm2708/patches-4.9/0087-amba_pl011-Don-t-use-DT-aliases-for-numbering.patch

   1 From b34475b447c7e97fa9c4a854849f6e856fe59931 Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 23 Feb 2016 17:26:48 +0000
   4 Subject: [PATCH] amba_pl011: Don't use DT aliases for numbering
   5
   6 The pl011 driver looks for DT aliases of the form "serial<n>",
   7 and if found uses <n> as the device ID. This can cause
   8 /dev/ttyAMA0 to become /dev/ttyAMA1, which is confusing if the
   9 other serial port is provided by the 8250 driver which doesn't
  10 use the same logic.
  11 ---
  12  drivers/tty/serial/amba-pl011.c | 5 +++++
  13  1 file changed, 5 insertions(+)
  14
  15 --- a/drivers/tty/serial/amba-pl011.c
  16 +++ b/drivers/tty/serial/amba-pl011.c
  17 @@ -2441,7 +2441,12 @@ static int pl011_setup_port(struct devic
  18         if (IS_ERR(base))
  19                 return PTR_ERR(base);
  20
  21 +       /* Don't use DT serial<n> aliases - it causes the device to
  22 +          be renumbered to ttyAMA1 if it is the second serial port in the
  23 +          system, even though the other one is ttyS0. The 8250 driver
  24 +          doesn't use this logic, so always remains ttyS0.
  25         index = pl011_probe_dt_alias(index, dev);
  26 +       */
  27
  28         uap->old_cr = 0;
  29         uap->port.dev = dev;