Linux 4.19.31

[thirdparty/kernel/stable-queue.git] / releases / 4.19.31 / serial-8250_of-assume-reg-shift-of-2-for-mrvl-mmp-uart.patch

From f4817843e39ce78aace0195a57d4e8500a65a898 Mon Sep 17 00:00:00 2001
From: Lubomir Rintel <lkundrak@v3.sk>
Date: Sun, 24 Feb 2019 13:00:53 +0100
Subject: serial: 8250_of: assume reg-shift of 2 for mrvl,mmp-uart

From: Lubomir Rintel <lkundrak@v3.sk>

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>

---
 drivers/tty/serial/8250/8250_of.c |    4 ++++
 1 file changed, 4 insertions(+)

--- 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(stru
 		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;