serial: samsung: enable clock before clearing pending interrupts during init

Ensure that the uart controller clock is enabled prior to writing to the
interrupt mask and pending registers in the s3c24xx_serial_init_port
function.

Signed-off-by: Chander Kashyap <chander.kashyap@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c
index 89429410a245..0c8a9fa2be6c 100644
--- a/drivers/tty/serial/samsung.c
+++ b/drivers/tty/serial/samsung.c
@@ -1166,6 +1166,18 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
                 ourport->tx_irq = ret;
 
         ourport->clk    = clk_get(&platdev->dev, "uart");
+        if (IS_ERR(ourport->clk)) {
+                pr_err("%s: Controller clock not found\n",
+                                dev_name(&platdev->dev));
+                return PTR_ERR(ourport->clk);
+        }
+
+        ret = clk_prepare_enable(ourport->clk);
+        if (ret) {
+                pr_err("uart: clock failed to prepare+enable: %d\n", ret);
+                clk_put(ourport->clk);
+                return ret;
+        }
 
         /* Keep all interrupts masked and cleared */
         if (s3c24xx_serial_has_interrupt_mask(port)) {
@@ -1180,6 +1192,7 @@ static int s3c24xx_serial_init_port(struct s3c24xx_uart_port *ourport,
 
         /* reset the fifos (and setup the uart) */
         s3c24xx_serial_resetport(port, cfg);
+        clk_disable_unprepare(ourport->clk);
         return 0;
 }