mfd: Add AUXADC support for WM8350

The auxiliary ADC in the WM8350 is shared between several subdevices
so access to it needs to be arbitrated by the core driver.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

include/linux/mfd/wm8350/comparator.h

@@ -164,4 +164,12 @@
 #define WM8350_AUXADC_BATT			6
 #define WM8350_AUXADC_TEMP			7
 
+struct wm8350;
+
+/*
+ * AUX ADC Readback
+ */
+int wm8350_read_auxadc(struct wm8350 *wm8350, int channel, int scale,
+		       int vref);
+
 #endif

include/linux/mfd/wm8350/core.h

@@ -573,6 +573,8 @@ struct wm8350 {
 			 void *src);
 	u16 *reg_cache;
 
+	struct mutex auxadc_mutex;
+
 	/* Interrupt handling */
 	struct work_struct irq_work;
 	struct mutex irq_mutex; /* IRQ table mutex */