[RESEND PATCH v3 6/9] tty: xuartps: Don't write IRQ disable register to enable interrupts

[Soren Brinkmann]

A comment states, that, according to the data sheet, to enable
interrupts the disable register should be written, but the enable
register could be left untouched. And it suspsects a HW bug requiring
to write both.
Reviewing the data sheet, these statements seem wrong. Just as one would
expect. Writing to the enable/disable register enables/disables
interrupts.
Hence the misleading comment and needless write to the disable register
are removed from the enable sequence.

Signed-off-by: Soren Brinkmann <soren.brinkmann at xilinx.com>
Tested-by: Michal Simek <michal.simek at xilinx.com>
---
I added a few lines to comment the change and altered the summary line.
In case this causes issues it should show up a little easier as a
candidate to revert.

Changes in v3: None
Changes in v2: None

---
 drivers/tty/serial/xilinx_uartps.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index b182ab8cfd07..f9a2c2fc03c4 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1085,11 +1085,7 @@ static void xuartps_console_write(struct console *co, const char *s,
 
 	xuartps_writel(ctrl, XUARTPS_CR_OFFSET);
 
-	/* restore interrupt state, it seems like there may be a h/w bug
-	 * in that the interrupt enable register should not need to be
-	 * written based on the data sheet
-	 */
-	xuartps_writel(~imr, XUARTPS_IDR_OFFSET);
+	/* restore interrupt state */
 	xuartps_writel(imr, XUARTPS_IER_OFFSET);
 
 	if (locked)
-- 
1.9.1.1.gbb9f595