mfd: da9052/53 lockup fix

An issue has been reported where the PMIC either locks up or fails to
respond following a system Reset. This could result in a second write
in which the bus writes the current content of the write buffer to address
of the last I2C access.

The failure case is where this unwanted write transfers incorrect data to
a critical register.

This patch fixes this issue to by following any read or write with a dummy read
to a safe register address. A safe register address is one where the contents
will not affect the operation of the system.

Signed-off-by: Ashish Jangam <ashish.jangam@kpitcummins.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

include/linux/mfd/da9052/reg.h

@@ -34,6 +34,9 @@
 #define DA9052_STATUS_C_REG		3
 #define DA9052_STATUS_D_REG		4
 
+/* PARK REGISTER */
+#define DA9052_PARK_REGISTER		DA9052_STATUS_D_REG
+
 /* EVENT REGISTERS */
 #define DA9052_EVENT_A_REG		5
 #define DA9052_EVENT_B_REG		6