Patch "8250: use callbacks to access UART_DLL/UART_DLM" has been added to the 3.14-stable tree

This is a note to let you know that I've just added the patch titled

8250: use callbacks to access UART_DLL/UART_DLM

to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
8250-use-callbacks-to-access-uart_dll-uart_dlm.patch
and it can be found in the queue-3.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sebastian Frias <[email protected]>
Date: Fri, 18 Dec 2015 17:40:05 +0100
Subject: 8250: use callbacks to access UART_DLL/UART_DLM

From: Sebastian Frias <[email protected]>

commit 0b41ce991052022c030fd868e03877700220b090 upstream.

Some UART HW has a single register combining UART_DLL/UART_DLM (this was probably forgotten in the change that introduced the callbacks, commit b32b19b8ffc05cbd3bf91c65e205f6a912ca15d9)

---
 drivers/tty/serial/8250/8250_core.c |   18 ++++++------------
 1 file changed, 6 insertions(+), 12 deletions(-)

@@ -686,22 +686,16 @@ static int size_fifo(struct uart_8250_po
  */
 static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
 {
-	unsigned char old_dll, old_dlm, old_lcr;
-	unsigned int id;
+	unsigned char old_lcr;
+	unsigned int id, old_dl;
 
 	old_lcr = serial_in(p, UART_LCR);
 	serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
+	old_dl = serial_dl_read(p);
+	serial_dl_write(p, 0);
+	id = serial_dl_read(p);
+	serial_dl_write(p, old_dl);
 
-	old_dll = serial_in(p, UART_DLL);
-	old_dlm = serial_in(p, UART_DLM);
-
-	serial_out(p, UART_DLL, 0);
-	serial_out(p, UART_DLM, 0);
-
-	id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
-
-	serial_out(p, UART_DLL, old_dll);
-	serial_out(p, UART_DLM, old_dlm);
 	serial_out(p, UART_LCR, old_lcr);
 
 	return id;

Patches currently in stable-queue which might be from [email protected] are

queue-3.14/8250-use-callbacks-to-access-uart_dll-uart_dlm.patch