[PATCH AUTOSEL 4.14 022/186] pinctrl: baytrail: Do not clear IRQ flags on direct-irq enabled pins

[Sasha Levin <sashal@xxxxxxxxxx>]

From: Hans de Goede <hdegoede@xxxxxxxxxx>

[ Upstream commit a23680594da7a9e2696dbcf4f023e9273e2fa40b ]

Suspending Goodix touchscreens requires changing the interrupt pin to
output before sending them a power-down command. Followed by wiggling
the interrupt pin to wake the device up, after which it is put back
in input mode.

On Bay Trail devices with a Goodix touchscreen direct-irq mode is used
in combination with listing the pin as a normal GpioIo resource.

This works fine, until the goodix driver gets rmmod-ed and then insmod-ed
again. In this case byt_gpio_disable_free() calls
byt_gpio_clear_triggering() which clears the IRQ flags and after that the
(direct) IRQ no longer triggers.

This commit fixes this by adding a check for the BYT_DIRECT_IRQ_EN flag
to byt_gpio_clear_triggering().

Note that byt_gpio_clear_triggering() only gets called from
byt_gpio_disable_free() for direct-irq enabled pins, as these are excluded
from the irq_valid mask by byt_init_irq_valid_mask().

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Acked-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pinctrl/intel/pinctrl-baytrail.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/pinctrl/intel/pinctrl-baytrail.c b/drivers/pinctrl/intel/pinctrl-baytrail.c
index 9df5d29d708da..4fb3e44f91331 100644
--- a/drivers/pinctrl/intel/pinctrl-baytrail.c
+++ b/drivers/pinctrl/intel/pinctrl-baytrail.c
@@ -958,7 +958,13 @@ static void byt_gpio_clear_triggering(struct byt_gpio *vg, unsigned int offset)
 
 	raw_spin_lock_irqsave(&byt_lock, flags);
 	value = readl(reg);
-	value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL);
+
+	/* Do not clear direct-irq enabled IRQs (from gpio_disable_free) */
+	if (value & BYT_DIRECT_IRQ_EN)
+		/* nothing to do */ ;
+	else
+		value &= ~(BYT_TRIG_POS | BYT_TRIG_NEG | BYT_TRIG_LVL);
+
 	writel(value, reg);
 	raw_spin_unlock_irqrestore(&byt_lock, flags);
 }
-- 
2.20.1