[PATCH LINUX v5 4/8] tty: xuartps: Clear interrupt status register in shutdown

From: Soren Brinkmann
Date: Sat Dec 26 2015 - 05:44:48 EST


When shutting down the UART, clear the interrupt status register. Bits
in the ISR are cleared by writing them as '1'.

Signed-off-by: Soren Brinkmann <soren.brinkmann@xxxxxxxxxx>
Reviewed-by: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Moritz Fischer <moritz.fischer@xxxxxxxxx>
---
v4:
- clarify workings of the ISR in the commit message
---
drivers/tty/serial/xilinx_uartps.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index 6a7cd4e057ae..ef114d7a0623 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -828,6 +828,7 @@ static void cdns_uart_shutdown(struct uart_port *port)
/* Disable interrupts */
status = readl(port->membase + CDNS_UART_IMR_OFFSET);
writel(status, port->membase + CDNS_UART_IDR_OFFSET);
+ writel(0xffffffff, port->membase + CDNS_UART_ISR_OFFSET);

/* Disable the TX and RX */
writel(CDNS_UART_CR_TX_DIS | CDNS_UART_CR_RX_DIS,
--
2.6.3.3.g9bb996a

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