[PATCH v2] pinctrl: cherryview: Add a quirk to make Acer Chromebook keyboard work again

[Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>]

After commit 47c950d10202 ("pinctrl: cherryview: Do not add all
southwest and north GPIOs to IRQ domain") the driver does not add all
GPIOs to the irqdomain. The reason for that is that those GPIOs cannot
generate IRQs at all, only GPEs (General Purpose Events). This causes
Linux virtual IRQ numbering to change.

However, it seems some CYAN Chromebooks, including Acer Chromebook
hardcodes these Linux IRQ numbers in the ACPI tables of the machine.
Since the numbering is different now, the IRQ meant for keyboard does
not match the Linux virtual IRQ number anymore making the keyboard
non-functional.

Work this around by adding special quirk just for these machines where
we add back all GPIOs to the irqdomain. Rest of the Cherryview/Braswell
based machines will not be affected by the change.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=194945
Fixes: 47c950d10202 ("pinctrl: cherryview: Do not add all southwest and north GPIOs to IRQ domain")
Reported-by: Adam S Levy <theadamlevy@xxxxxxxxx>
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
Changes from v1:
 - Add BIOS date to DMI match string to keep this quirk from affecting
   future BIOS versions where the issue might be fixed already.

Marc, Linus,

I went for adding the quirk here instead of quirking it in i8042 keyboard
driver because there might be other devices hard-coding the Linux IRQ
number. This way we only need to touch one driver.

Adam,

Can you please try if this patch still fixes the problem for you? Thanks.

 drivers/pinctrl/intel/pinctrl-cherryview.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/intel/pinctrl-cherryview.c b/drivers/pinctrl/intel/pinctrl-cherryview.c
index f80134e3e0b6..9ff790174906 100644
--- a/drivers/pinctrl/intel/pinctrl-cherryview.c
+++ b/drivers/pinctrl/intel/pinctrl-cherryview.c
@@ -13,6 +13,7 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/dmi.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -1524,10 +1525,31 @@ static void chv_gpio_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
+/*
+ * Certain machines seem to hardcode Linux IRQ numbers in their ACPI
+ * tables. Since we leave GPIOs that are not capable of generating
+ * interrupts out of the irqdomain the numbering will be different and
+ * cause devices using the hardcoded IRQ numbers fail. In order not to
+ * break such machines we will only mask pins from irqdomain if the machine
+ * is not listed below.
+ */
+static const struct dmi_system_id chv_no_valid_mask[] = {
+	{
+		/* See https://bugzilla.kernel.org/show_bug.cgi?id=194945 */
+		.ident = "Acer Chromebook (CYAN)",
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "GOOGLE"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Edgar"),
+			DMI_MATCH(DMI_BIOS_DATE, "05/21/2016"),
+		},
+	}
+};
+
 static int chv_gpio_probe(struct chv_pinctrl *pctrl, int irq)
 {
 	const struct chv_gpio_pinrange *range;
 	struct gpio_chip *chip = &pctrl->chip;
+	bool need_valid_mask = !dmi_check_system(chv_no_valid_mask);
 	int ret, i, offset;
 
 	*chip = chv_gpio_chip;
@@ -1536,7 +1558,7 @@ static int chv_gpio_probe(struct chv_pinctrl *pctrl, int irq)
 	chip->label = dev_name(pctrl->dev);
 	chip->parent = pctrl->dev;
 	chip->base = -1;
-	chip->irq_need_valid_mask = true;
+	chip->irq_need_valid_mask = need_valid_mask;
 
 	ret = devm_gpiochip_add_data(pctrl->dev, chip, pctrl);
 	if (ret) {
@@ -1567,7 +1589,7 @@ static int chv_gpio_probe(struct chv_pinctrl *pctrl, int irq)
 		intsel &= CHV_PADCTRL0_INTSEL_MASK;
 		intsel >>= CHV_PADCTRL0_INTSEL_SHIFT;
 
-		if (intsel >= pctrl->community->nirqs)
+		if (need_valid_mask && intsel >= pctrl->community->nirqs)
 			clear_bit(i, chip->irq_valid_mask);
 	}
 
-- 
2.11.0

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