pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler

commit cdca06e4e85974d8a3503ab15709dbbaf90d3dd1 upstream.

According to VLI64 Intel Atom E3800 Specification Update (#329901)
concurrent read accesses may result in returning 0xffffffff and write
accesses may be dropped silently.
To workaround all accesses must be protected by locks.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/pinctrl/intel/pinctrl-baytrail.c b/drivers/pinctrl/intel/pinctrl-baytrail.c
index 079015385fd8..7f2263d61063 100644
--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
+++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
@@ -1612,7 +1612,9 @@ static void byt_gpio_irq_handler(struct irq_desc *desc)
                         continue;
                 }
 
+                raw_spin_lock(&vg->lock);
                 pending = readl(reg);
+                raw_spin_unlock(&vg->lock);
                 for_each_set_bit(pin, &pending, 32) {
                         virq = irq_find_mapping(vg->chip.irqdomain, base + pin);
                         generic_handle_irq(virq);