gpio: intel-mid: Move hardware initialization to callback

The driver wants to initialize related registers before IRQ chip will be added.
That's why move it to a corresponding callback. It also fixes the NULL pointer
dereference.

Fixes: 8069e69 ("gpio: intel-mid: Pass irqchip when adding gpiochip")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-intel-mid.c

@@ -293,8 +293,9 @@ static void intel_mid_irq_handler(struct irq_desc *desc)
 	chip->irq_eoi(data);
 }
 
-static void intel_mid_irq_init_hw(struct intel_mid_gpio *priv)
+static int intel_mid_irq_init_hw(struct gpio_chip *chip)
 {
+	struct intel_mid_gpio *priv = gpiochip_get_data(chip);
 	void __iomem *reg;
 	unsigned base;
 
@@ -309,6 +310,8 @@ static void intel_mid_irq_init_hw(struct intel_mid_gpio *priv)
 		reg = gpio_reg(&priv->chip, base, GEDR);
 		writel(~0, reg);
 	}
+
+	return 0;
 }
 
 static int __maybe_unused intel_gpio_runtime_idle(struct device *dev)
@@ -372,6 +375,7 @@ static int intel_gpio_probe(struct pci_dev *pdev,
 
 	girq = &priv->chip.irq;
 	girq->chip = &intel_mid_irqchip;
+	girq->init_hw = intel_mid_irq_init_hw;
 	girq->parent_handler = intel_mid_irq_handler;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(&pdev->dev, girq->num_parents,
@@ -384,9 +388,8 @@ static int intel_gpio_probe(struct pci_dev *pdev,
 	girq->default_type = IRQ_TYPE_NONE;
 	girq->handler = handle_simple_irq;
 
-	intel_mid_irq_init_hw(priv);
-
 	pci_set_drvdata(pdev, priv);
+
 	retval = devm_gpiochip_add_data(&pdev->dev, &priv->chip, priv);
 	if (retval) {
 		dev_err(&pdev->dev, "gpiochip_add error %d\n", retval);