mfd: Emulate active low IRQs as well as active high IRQs for wm831x

As with the existing emulation this should not be used in production
systems but is useful for test purposes.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm831x-irq.c

@@ -413,22 +413,25 @@ static int wm831x_irq_set_type(struct irq_data *data, unsigned int type)
 	 * do the update here as we can be called with the bus lock
 	 * held.
 	 */
+	wm831x->gpio_level_low[irq] = false;
+	wm831x->gpio_level_high[irq] = false;
 	switch (type) {
 	case IRQ_TYPE_EDGE_BOTH:
 		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_INT_MODE;
-		wm831x->gpio_level[irq] = false;
 		break;
 	case IRQ_TYPE_EDGE_RISING:
 		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_POL;
-		wm831x->gpio_level[irq] = false;
 		break;
 	case IRQ_TYPE_EDGE_FALLING:
 		wm831x->gpio_update[irq] = 0x10000;
-		wm831x->gpio_level[irq] = false;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
 		wm831x->gpio_update[irq] = 0x10000 | WM831X_GPN_POL;
-		wm831x->gpio_level[irq] = true;
+		wm831x->gpio_level_high[irq] = true;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		wm831x->gpio_update[irq] = 0x10000;
+		wm831x->gpio_level_low[irq] = true;
 		break;
 	default:
 		return -EINVAL;
@@ -517,7 +520,7 @@ static irqreturn_t wm831x_irq_thread(int irq, void *data)
 		 * status.  This is sucky but improves interoperability.
 		 */
 		if (primary == WM831X_GP_INT &&
-		    wm831x->gpio_level[i - WM831X_IRQ_GPIO_1]) {
+		    wm831x->gpio_level_high[i - WM831X_IRQ_GPIO_1]) {
 			ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
 			while (ret & 1 << (i - WM831X_IRQ_GPIO_1)) {
 				handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
@@ -526,6 +529,17 @@ static irqreturn_t wm831x_irq_thread(int irq, void *data)
 						      WM831X_GPIO_LEVEL);
 			}
 		}
+
+		if (primary == WM831X_GP_INT &&
+		    wm831x->gpio_level_low[i - WM831X_IRQ_GPIO_1]) {
+			ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
+			while (!(ret & 1 << (i - WM831X_IRQ_GPIO_1))) {
+				handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
+								   i));
+				ret = wm831x_reg_read(wm831x,
+						      WM831X_GPIO_LEVEL);
+			}
+		}
 	}
 
 out:

include/linux/mfd/wm831x/core.h

@@ -384,7 +384,8 @@ struct wm831x {
 
 	/* Used by the interrupt controller code to post writes */
 	int gpio_update[WM831X_NUM_GPIO_REGS];
-	bool gpio_level[WM831X_NUM_GPIO_REGS];
+	bool gpio_level_high[WM831X_NUM_GPIO_REGS];
+	bool gpio_level_low[WM831X_NUM_GPIO_REGS];
 
 	struct mutex auxadc_lock;
 	struct list_head auxadc_pending;