staging: mt7621-gpio: set different names for each gpio_chip and irq_chip

Currently the driver defines 3 gpiochips, one for each bank.

/sys/class/gpio/gpiochip416/label:1e000600.gpio
/sys/class/gpio/gpiochip448/label:1e000600.gpio
/sys/class/gpio/gpiochip480/label:1e000600.gpio

Unfortunately they all have the same label

Interrupts from /proc/interrupt show the same name which is
confusing:

/proc/interrupts:

17: 0  0  0  0  MIPS GIC  19  mt7621, mt7621, mt7621

which is the interrupt from the GPIO controller.
It is a little weird that all three banks are named "mt7621"
here. We also have:

26: 0  0  0  0  GPIO  18  reset

which is the interrupt from GPIO which provides the "reset"
button. I suspect that if I had interrupts form two different
banks they would both be called "GPIO" which would be a little
confusing.

In order to unify all of this set different names for each chip
Use a 'bank-based' name instead the same for all: 'mt7621-bank[0-2]'.
Create a new 'mediatek_gpio_bank_name' function which return the
name depending on the bank number. This function is allways called
with a valid index 0, 1 or 2.
Signed-off-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/mt7621-gpio/gpio-mt7621.c

@@ -190,13 +190,21 @@ mediatek_gpio_irq_type(struct irq_data *d, unsigned int type)
 }
 
 static struct irq_chip mediatek_gpio_irq_chip = {
-	.name			= "GPIO",
 	.irq_unmask		= mediatek_gpio_irq_unmask,
 	.irq_mask		= mediatek_gpio_irq_mask,
 	.irq_mask_ack		= mediatek_gpio_irq_mask,
 	.irq_set_type		= mediatek_gpio_irq_type,
 };
 
+static inline const char * const mediatek_gpio_bank_name(int bank)
+{
+	static const char * const bank_names[] = {
+		"mt7621-bank0", "mt7621-bank1", "mt7621-bank2",
+	};
+
+	return bank_names[bank];
+}
+
 static int
 mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 {
@@ -215,6 +223,7 @@ mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 	spin_lock_init(&rg->lock);
 	rg->chip.of_node = bank;
 	rg->bank = be32_to_cpu(*id);
+	rg->chip.label = mediatek_gpio_bank_name(rg->bank);
 
 	dat = gpio->gpio_membase + GPIO_REG_DATA + (rg->bank * GPIO_BANK_WIDE);
 	set = gpio->gpio_membase + GPIO_REG_DSET + (rg->bank * GPIO_BANK_WIDE);
@@ -242,7 +251,7 @@ mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 		 */
 		ret = devm_request_irq(&pdev->dev, gpio->gpio_irq,
 				       mediatek_gpio_irq_handler, IRQF_SHARED,
-				       "mt7621", &rg->chip);
+				       rg->chip.label, &rg->chip);
 
 		if (ret) {
 			dev_err(&pdev->dev, "Error requesting IRQ %d: %d\n",
@@ -250,6 +259,7 @@ mediatek_gpio_bank_probe(struct platform_device *pdev, struct device_node *bank)
 			return ret;
 		}
 
+		mediatek_gpio_irq_chip.name = rg->chip.label;
 		ret = gpiochip_irqchip_add(&rg->chip, &mediatek_gpio_irq_chip,
 					   0, handle_simple_irq, IRQ_TYPE_NONE);
 		if (ret) {