serial: mxs-auart: fix gpio change detection on interrupt

mxs_auart_modem_status() did't detect gpio's state change
because s->mctrl_prev was modified before by mctrl_gpio_get().
The patch introduces mctrl_temp variable to fix the bug.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 0262a6a50834..21b3b3569461 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -799,6 +799,7 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 {
         u32 istat;
         struct mxs_auart_port *s = context;
+        u32 mctrl_temp = s->mctrl_prev;
         u32 stat = readl(s->port.membase + AUART_STAT);
 
         istat = readl(s->port.membase + AUART_INTR);
@@ -818,7 +819,7 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
             irq == s->gpio_irq[UART_GPIO_DSR] ||
             irq == s->gpio_irq[UART_GPIO_RI])
                 mxs_auart_modem_status(s,
-                                mctrl_gpio_get(s->gpios, &s->mctrl_prev));
+                                mctrl_gpio_get(s->gpios, &mctrl_temp));
 
         if (istat & AUART_INTR_CTSMIS) {
                 if (CTS_AT_AUART() && s->ms_irq_enabled)