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Subject[PATCH 3.2 003/115] 8250: use callbacks to access UART_DLL/UART_DLM
3.2.80-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Sebastian Frias <sf84@laposte.net>

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)

Fixes: b32b19b8ffc0 ("[SERIAL] 8250: set divisor register correctly ...")

Signed-off-by: Sebastian Frias <sf84@laposte.net>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
- Adjust filename
- We're using serial_{in,out}p for 8-bit I/O]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/tty/serial/8250.c | 18 ++++++------------
1 file changed, 6 insertions(+), 12 deletions(-)

--- a/drivers/tty/serial/8250.c
+++ b/drivers/tty/serial/8250.c
@@ -777,22 +777,16 @@ 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_inp(p, UART_LCR);
serial_outp(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_inp(p, UART_DLL);
- old_dlm = serial_inp(p, UART_DLM);
-
- serial_outp(p, UART_DLL, 0);
- serial_outp(p, UART_DLM, 0);
-
- id = serial_inp(p, UART_DLL) | serial_inp(p, UART_DLM) << 8;
-
- serial_outp(p, UART_DLL, old_dll);
- serial_outp(p, UART_DLM, old_dlm);
serial_outp(p, UART_LCR, old_lcr);

return id;
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