irqchip: renesas-intc-irqpin: DT binding for sense bitfield width

Most Renesas irqpin controllers have 4-bit sense fields, however, some
have different widths. This patch adds a DT binding to optionally
specify such non-standard values.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/drivers/irqchip/irq-renesas-intc-irqpin.c b/drivers/irqchip/irq-renesas-intc-irqpin.c
index 5a68e5a..4aca1b2 100644
--- a/drivers/irqchip/irq-renesas-intc-irqpin.c
+++ b/drivers/irqchip/irq-renesas-intc-irqpin.c
@@ -18,6 +18,7 @@
  */
 
 #include <linux/init.h>
+#include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/spinlock.h>
 #include <linux/interrupt.h>
@@ -349,6 +350,9 @@
 	/* deal with driver instance configuration */
 	if (pdata)
 		memcpy(&p->config, pdata, sizeof(*pdata));
+	else
+		of_property_read_u32(pdev->dev.of_node, "sense-bitfield-width",
+				     &p->config.sense_bitfield_width);
 	if (!p->config.sense_bitfield_width)
 		p->config.sense_bitfield_width = 4; /* default to 4 bits */