mfd/tc3589x: fix random interrupt misses

On the TC35892, a random delayed interrupt clear (GPIO IC) write locks up the
child interrupts. In such a case, the original interrupt is active and not yet
acknowledged. Re-check the IRQST bit for any pending interrupts and handle
those.

Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Sundar Iyer <sundar.iyer@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>

diff --git a/drivers/mfd/tc3589x.c b/drivers/mfd/tc3589x.c
index 0ed9669d95fa18d8c6199ca1c06a52f2140932ae..708349a5c0e397fed0657bc0199adbc2e419af8d 100644 (file)
--- a/drivers/mfd/tc3589x.c
+++ b/drivers/mfd/tc3589x.c
@@ -142,6 +142,7 @@ static irqreturn_t tc3589x_irq(int irq, void *data)
        struct tc3589x *tc3589x = data;
        int status;
 
+again:
        status = tc3589x_reg_read(tc3589x, TC3589x_IRQST);
        if (status < 0)
                return IRQ_NONE;
@@ -156,9 +157,12 @@ static irqreturn_t tc3589x_irq(int irq, void *data)
        /*
         * A dummy read or write (to any register) appears to be necessary to
         * have the last interrupt clear (for example, GPIO IC write) take
-        * effect.
+        * effect. In such a case, recheck for any interrupt which is still
+        * pending.
         */
-       tc3589x_reg_read(tc3589x, TC3589x_IRQST);
+       status = tc3589x_reg_read(tc3589x, TC3589x_IRQST);
+       if (status)
+               goto again;
 
        return IRQ_HANDLED;
 }