[PATCH v3] gpio-mlxbf2: only get IRQ for device instances 0 and 3

[David Thompson <davthompson@nvidia.com>]

The gpio-mlxbf2 driver interfaces with four GPIO controllers,
device instances 0-3. There are two IRQ resources shared between
the four controllers, and they are found in the ACPI table for
device instances 0 and 3.  The driver should not attempt to get
an IRQ resource when probing device instance 1 or 2, otherwise
the following error is logged:
  mlxbf2_gpio MLNXBF22:01: error -ENXIO: IRQ index 0 not found

Fixes: 2b725265cb08 ("gpio: mlxbf2: Introduce IRQ support")
Cc: stable@vger.kernel.org
Signed-off-by: David Thompson <davthompson@nvidia.com>
Reviewed-by: Shravan Kumar Ramani <shravankr@nvidia.com>
---
v3: added version history
v2: added tag "Cc: stable@vger.kernel.org"

 drivers/gpio/gpio-mlxbf2.c | 56 ++++++++++++++++++++++++--------------
 1 file changed, 36 insertions(+), 20 deletions(-)

diff --git a/drivers/gpio/gpio-mlxbf2.c b/drivers/gpio/gpio-mlxbf2.c
index 6f3dda6b635f..fc56ac81e344 100644
--- a/drivers/gpio/gpio-mlxbf2.c
+++ b/drivers/gpio/gpio-mlxbf2.c
@@ -353,7 +353,9 @@ mlxbf2_gpio_probe(struct platform_device *pdev)
 	struct gpio_chip *gc;
 	unsigned int npins;
 	const char *name;
+	char *colon_ptr;
 	int ret, irq;
+	long num;
 
 	name = dev_name(dev);
 
@@ -397,26 +399,40 @@ mlxbf2_gpio_probe(struct platform_device *pdev)
 	gc->ngpio = npins;
 	gc->owner = THIS_MODULE;
 
-	irq = platform_get_irq(pdev, 0);
-	if (irq >= 0) {
-		girq = &gs->gc.irq;
-		gpio_irq_chip_set_chip(girq, &mlxbf2_gpio_irq_chip);
-		girq->handler = handle_simple_irq;
-		girq->default_type = IRQ_TYPE_NONE;
-		/* This will let us handle the parent IRQ in the driver */
-		girq->num_parents = 0;
-		girq->parents = NULL;
-		girq->parent_handler = NULL;
-
-		/*
-		 * Directly request the irq here instead of passing
-		 * a flow-handler because the irq is shared.
-		 */
-		ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler,
-				       IRQF_SHARED, name, gs);
-		if (ret) {
-			dev_err(dev, "failed to request IRQ");
-			return ret;
+	colon_ptr = strchr(dev_name(dev), ':');
+	if (!colon_ptr) {
+		dev_err(dev, "invalid device name format\n");
+		return -EINVAL;
+	}
+
+	ret = kstrtol(++colon_ptr, 16, &num);
+	if (ret) {
+		dev_err(dev, "invalid device instance\n");
+		return ret;
+	}
+
+	if (!num || num == 3) {
+		irq = platform_get_irq(pdev, 0);
+		if (irq >= 0) {
+			girq = &gs->gc.irq;
+			gpio_irq_chip_set_chip(girq, &mlxbf2_gpio_irq_chip);
+			girq->handler = handle_simple_irq;
+			girq->default_type = IRQ_TYPE_NONE;
+			/* This will let us handle the parent IRQ in the driver */
+			girq->num_parents = 0;
+			girq->parents = NULL;
+			girq->parent_handler = NULL;
+
+			/*
+			 * Directly request the irq here instead of passing
+			 * a flow-handler because the irq is shared.
+			 */
+			ret = devm_request_irq(dev, irq, mlxbf2_gpio_irq_handler,
+					       IRQF_SHARED, name, gs);
+			if (ret) {
+				dev_err(dev, "failed to request IRQ");
+				return ret;
+			}
 		}
 	}
 
-- 
2.30.1