mfd: add DB5500 PRCMU driver

This adds the DB5500 PRCMU driver. Right now this one is pretty
restricted in functionality, exposing a simple interface to send
I2C messages.

Acked-by: Samuel Ortiz <sameo@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

include/linux/mfd/db5500-prcmu.h

@@ -0,0 +1,45 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * License Terms: GNU General Public License v2
+ *
+ * U5500 PRCMU API.
+ */
+#ifndef __MACH_PRCMU_U5500_H
+#define __MACH_PRCMU_U5500_H
+
+#ifdef CONFIG_UX500_SOC_DB5500
+
+void db5500_prcmu_early_init(void);
+
+int db5500_prcmu_abb_read(u8 slave, u8 reg, u8 *value, u8 size);
+int db5500_prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size);
+
+#else /* !CONFIG_UX500_SOC_DB5500 */
+
+static inline void db5500_prcmu_early_init(void)
+{
+}
+
+static inline int db5500_prcmu_abb_read(u8 slave, u8 reg, u8 *value, u8 size)
+{
+	return -ENOSYS;
+}
+
+static inline int db5500_prcmu_abb_write(u8 slave, u8 reg, u8 *value, u8 size)
+{
+	return -ENOSYS;
+}
+
+#endif /* CONFIG_UX500_SOC_DB5500 */
+
+static inline int db5500_prcmu_config_abb_event_readout(u32 abb_events)
+{
+#ifdef CONFIG_MACH_U5500_SIMULATOR
+	return 0;
+#else
+	return -1;
+#endif
+}
+
+#endif /* __MACH_PRCMU_U5500_H */