serial: 8250_of: assume reg-shift of 2 for mrvl,mmp-uart

commit f4817843e39ce78aace0195a57d4e8500a65a898 upstream.

There are two other drivers that bind to mrvl,mmp-uart and both of them
assume register shift of 2 bits. There are device trees that lack the
property and rely on that assumption.

If this driver wins the race to bind to those devices, it should behave
the same as the older deprecated driver.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_of.c b/drivers/tty/serial/8250/8250_of.c
index 877fd7f8a8ed14e708ec952afbf49790d6a4d09b..98125de2f0a6c615351db1525f84c03393f745d4 100644 (file)
--- a/drivers/tty/serial/8250/8250_of.c
+++ b/drivers/tty/serial/8250/8250_of.c
@@ -130,6 +130,10 @@ static int of_platform_serial_setup(struct platform_device *ofdev,
                port->flags |= UPF_IOREMAP;
        }
 
+       /* Compatibility with the deprecated pxa driver and 8250_pxa drivers. */
+       if (of_device_is_compatible(np, "mrvl,mmp-uart"))
+               port->regshift = 2;
+
        /* Check for registers offset within the devices address range */
        if (of_property_read_u32(np, "reg-shift", &prop) == 0)
                port->regshift = prop;