[PATCH 4.9 08/66] pinctrl: baytrail: Add missing spinlock usage in byt_gpio_irq_handler

[Greg Kroah-Hartman]

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Stein <alexander.st...@systec-electronic.com>

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.st...@systec-electronic.com>
Acked-by: Mika Westerberg <mika.westerb...@linux.intel.com>
Signed-off-by: Linus Walleij <linus.wall...@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 drivers/pinctrl/intel/pinctrl-baytrail.c |    2 ++
 1 file changed, 2 insertions(+)

--- 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
                        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);