regmap: Report if we actually handled an interrupt in regmap-irq

While the IRQ core doesn't currently support shared threaded interrupts
that's no reason for drivers not to do their bit and report IRQ_NONE when
they don't get an interrupt. This allows the core spurious/wedget interrupt
detection support to do its thing.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

drivers/base/regmap/regmap-irq.c

@@ -100,6 +100,7 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 	u8 *buf8 = data->status_reg_buf;
 	u16 *buf16 = data->status_reg_buf;
 	u32 *buf32 = data->status_reg_buf;
+	bool handled = false;
 
 	ret = regmap_bulk_read(map, chip->status_base, data->status_reg_buf,
 			       chip->num_regs);
@@ -146,10 +147,14 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
 		if (data->status_buf[chip->irqs[i].reg_offset] &
 		    chip->irqs[i].mask) {
 			handle_nested_irq(data->irq_base + i);
+			handled = true;
 		}
 	}
 
-	return IRQ_HANDLED;
+	if (handled)
+		return IRQ_HANDLED;
+	else
+		return IRQ_NONE;
 }
 
 /**