powerpc/legacy_serial: Bail if reg-offset/shift properties are present

The legacy serial driver does not work with an 8250 type UART that is
described in the device tree with the reg-offset and reg-shift
properties.  This change makes legacy_serial ignore these devices.

Signed-off-by: John Linn <john.linn@xilinx.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 5 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/legacy_serial.c b/arch/powerpc/kernel/legacy_serial.c
index 61dd17449ddc..cf37f5ca4b71 100644
--- a/arch/powerpc/kernel/legacy_serial.c
+++ b/arch/powerpc/kernel/legacy_serial.c
@@ -136,6 +136,11 @@ static int __init add_legacy_soc_port(struct device_node *np,
         if (of_get_property(np, "clock-frequency", NULL) == NULL)
                 return -1;
 
+        /* if reg-shift or offset, don't try to use it */
+        if ((of_get_property(np, "reg-shift", NULL) != NULL) ||
+                (of_get_property(np, "reg-offset", NULL) != NULL))
+                return -1;
+
         /* if rtas uses this device, don't try to use it as well */
         if (of_get_property(np, "used-by-rtas", NULL) != NULL)
                 return -1;