[PATCH 3/4] gpio: mt7621: be sure IRQ domain is created before exposing GPIO chips

[Sergio Paracuellos <sergio.paracuellos@gmail.com>]

Function 'mediatek_gpio_bank_probe()' registers three GPIO chips using
'devm_gpiochip_add_data()'. At this point, the chips become live and visible
to consumers. However, the IRQ domain isn't allocated and set up until
'mt7621_gpio_irq_setup()' is called after the GPIO chips setup finishes.
If a consumer requests a GPIO IRQ concurrently 'mt7621_gpio_to_irq()' can
be called and pass a NULL irq domain pointer irq_create_mapping(), that can
corrupt the mappings or cause a crash. Fix this possible problem seting up
irq domain before GPIO chips setup is performed.

Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
---
 drivers/gpio/gpio-mt7621.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/gpio/gpio-mt7621.c b/drivers/gpio/gpio-mt7621.c
index 57384ef74703..1b0b5247d3c9 100644
--- a/drivers/gpio/gpio-mt7621.c
+++ b/drivers/gpio/gpio-mt7621.c
@@ -466,12 +466,6 @@ mediatek_gpio_probe(struct platform_device *pdev)
 	mtk->num_gpios = MTK_BANK_WIDTH * MTK_BANK_CNT;
 	platform_set_drvdata(pdev, mtk);
 
-	for (i = 0; i < MTK_BANK_CNT; i++) {
-		ret = mediatek_gpio_bank_probe(dev, i);
-		if (ret)
-			return ret;
-	}
-
 	if (mtk->gpio_irq > 0) {
 		ret = mt7621_gpio_irq_setup(pdev, mtk);
 		if (ret)
@@ -482,6 +476,12 @@ mediatek_gpio_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	for (i = 0; i < MTK_BANK_CNT; i++) {
+		ret = mediatek_gpio_bank_probe(dev, i);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
 
-- 
2.43.0