mfd: Support configuration of WM831x /IRQ output in CMOS mode

Provide platform data allowing the system to set the /IRQ pin into
CMOS mode rather than the default open drain. The default value of
this platform data reflects the default hardware configuration so
there should be no change to existing users.
Signed-off-by: NMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

drivers/mfd/wm831x-irq.c

@@ -520,6 +520,14 @@ int wm831x_irq_init(struct wm831x *wm831x, int irq)
 		return 0;
 	}
 
+	if (pdata->irq_cmos)
+		i = 0;
+	else
+		i = WM831X_IRQ_OD;
+
+	wm831x_set_bits(wm831x, WM831X_IRQ_CONFIG,
+			WM831X_IRQ_OD, i);
+
 	/* Try to flag /IRQ as a wake source; there are a number of
 	 * unconditional wake sources in the PMIC so this isn't
 	 * conditional but we don't actually care *too* much if it

include/linux/mfd/wm831x/pdata.h

@@ -109,6 +109,9 @@ struct wm831x_pdata {
 	/** Called after subdevices are set up */
 	int (*post_init)(struct wm831x *wm831x);
 
+	/** Put the /IRQ line into CMOS mode */
+	bool irq_cmos;
+
 	int irq_base;
 	int gpio_base;
 	struct wm831x_backlight_pdata *backlight;