I noticed on Nexus 7 that after rebooting from downstream kernel to
upstream, the GPIO interrupt is triggering non-stop despite of interrupts
being disabled for all of GPIOs. This happens because Nexus 7 uses a
soft-reboot, meaning that bootloader should take care of resetting
hardware, but bootloader doesn't do it well. In a result, GPIO interrupt
may be left ON at a boot time. Let's mask all GPIO interrupts at the
driver's probe time in order to resolve the issue.
Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
---
drivers/gpio/gpio-max77620.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/drivers/gpio/gpio-max77620.c b/drivers/gpio/gpio-max77620.c
index 313bd02dd893..473b4e900bbb 100644
--- a/drivers/gpio/gpio-max77620.c
+++ b/drivers/gpio/gpio-max77620.c
@@ -260,6 +260,25 @@ static int max77620_gpio_set_config(struct gpio_chip *gc, unsigned int offset,
return -ENOTSUPP;
}
+static void max77620_gpio_initialize(struct max77620_gpio *mgpio)
+{
+ unsigned int i;
+ int err;
+
+ /*
+ * GPIO interrupts may be left ON after bootloader, hence let's
+ * pre-initialize hardware to the expected state by disabling all
+ * interrupts.
+ */
+ for (i = 0; i < MAX77620_GPIO_NR; i++) {
+ err = regmap_update_bits(mgpio->rmap, GPIO_REG_ADDR(i),
+ MAX77620_CNFG_GPIO_INT_MASK, 0);
+ if (err < 0)
+ dev_err(mgpio->dev, "failed to disable interrupt: %d\n",
+ err);
+ }
+}
+
static int max77620_gpio_probe(struct platform_device *pdev)
{
struct max77620_chip *chip = dev_get_drvdata(pdev->dev.parent);
@@ -292,6 +311,7 @@ static int max77620_gpio_probe(struct platform_device *pdev)
mgpio->gpio_chip.of_node = pdev->dev.parent->of_node;
#endif
+ max77620_gpio_initialize(mgpio);
platform_set_drvdata(pdev, mgpio);
ret = devm_gpiochip_add_data(&pdev->dev, &mgpio->gpio_chip, mgpio);
--
2.26.0
