gpio: omap: convert to use irq_domain_add_simple()

The GPIO OMAP driver supports different OMAP SoC families and
not all of them have the needed support to use the linear IRQ
domain mapping like OMAP1 that use the legacy domain mapping.

But this special check is not necessary since the simple IRQ
domain mapping is able to handle both cases. Having a zero
IRQ offset will be interpreted as a linear domain case while
a non-zero value will be interpreted as a legacy domain case.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/gpio/gpio-omap.c

@@ -1138,9 +1138,7 @@ static int omap_gpio_probe(struct platform_device *pdev)
 	const struct omap_gpio_platform_data *pdata;
 	struct resource *res;
 	struct gpio_bank *bank;
-#ifdef CONFIG_ARCH_OMAP1
-	int irq_base;
-#endif
+	int irq_base = 0;
 
 	match = of_match_device(of_match_ptr(omap_gpio_match), dev);
 
@@ -1185,21 +1183,16 @@ static int omap_gpio_probe(struct platform_device *pdev)
 #ifdef CONFIG_ARCH_OMAP1
 	/*
 	 * REVISIT: Once we have OMAP1 supporting SPARSE_IRQ, we can drop
-	 * irq_alloc_descs() and irq_domain_add_legacy() and just use a
-	 * linear IRQ domain mapping for all OMAP platforms.
+	 * irq_alloc_descs() since a base IRQ offset will no longer be needed.
 	 */
 	irq_base = irq_alloc_descs(-1, 0, bank->width, 0);
 	if (irq_base < 0) {
 		dev_err(dev, "Couldn't allocate IRQ numbers\n");
 		return -ENODEV;
 	}
-
-	bank->domain = irq_domain_add_legacy(node, bank->width, irq_base,
-					     0, &irq_domain_simple_ops, NULL);
-#else
-	bank->domain = irq_domain_add_linear(node, bank->width,
-					     &irq_domain_simple_ops, NULL);
 #endif
+	bank->domain = irq_domain_add_simple(node, bank->width, irq_base,
+					     &irq_domain_simple_ops, NULL);
 	if (!bank->domain) {
 		dev_err(dev, "Couldn't register an IRQ domain\n");
 		return -ENODEV;