gpio/langwell: Simplify demux loop

Use __ffs() to find the pending interrupt source instead of looping 32
times.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Alek Du <alek.du@intel.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

diff --git a/drivers/gpio/langwell_gpio.c b/drivers/gpio/langwell_gpio.c
index 6efc4e6..f658af0 100644 (file)
--- a/drivers/gpio/langwell_gpio.c
+++ b/drivers/gpio/langwell_gpio.c
@@ -191,19 +191,20 @@ static void lnw_irq_handler(unsigned irq, struct irq_desc *desc)
        struct lnw_gpio *lnw = irq_data_get_irq_handler_data(data);
        struct irq_chip *chip = irq_data_get_irq_chip(data);
        u32 base, gpio, gedr_v;
+       unsigned long pending;
        void __iomem *gedr;
 
        /* check GPIO controller to check which pin triggered the interrupt */
        for (base = 0; base < lnw->chip.ngpio; base += 32) {
                gedr = gpio_reg(&lnw->chip, base, GEDR);
-               gedr_v = readl(gedr);
+               gedr_v = pending = readl(gedr);
                if (!gedr_v)
                        continue;
-               for (gpio = base; gpio < base + 32; gpio++)
-                       if (gedr_v & BIT(gpio % 32)) {
-                               pr_debug("pin %d triggered\n", gpio);
-                               generic_handle_irq(lnw->irq_base + gpio);
-                       }
+               while (pending) {
+                       gpio = __ffs(pending) - 1;
+                       pending &= ~BIT(gpio);
+                       generic_handle_irq(lnw->irq_base + base + gpio);
+               }
                /* clear the edge detect status bit */
                writel(gedr_v, gedr);
        }