[media] smiapp: Add register diversion quirk

Add a quirk for diverting registers for on some sensors, even the standard
registers are not where they can be expected to be found. Add a quirk to
to help using such sensors.

smiapp_write_no_quirk() and smiapp_read_no_quirk() functions are provided
for the use of quirk implementations.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>

drivers/media/i2c/smiapp/smiapp-quirk.h

@@ -35,6 +35,17 @@ struct smiapp_sensor;
  * @post_poweron: Called always after the sensor has been fully powered on.
  * @pre_streamon: Called just before streaming is enabled.
  * @post_streamon: Called right after stopping streaming.
+ * @reg_access: Register access quirk. The quirk may divert the access
+ *		to another register, or no register at all.
+ *
+ *		@write: Is this read (false) or write (true) access?
+ *		@reg: Pointer to the register to access
+ *		@value: Register value, set by the caller on write, or
+ *			by the quirk on read
+ *
+ *		@return: 0 on success, -ENOIOCTLCMD if no register
+ *			 access may be done by the caller (default read
+ *			 value is zero), else negative error code on error
  */
 struct smiapp_quirk {
 	int (*limits)(struct smiapp_sensor *sensor);
@@ -42,6 +53,8 @@ struct smiapp_quirk {
 	int (*pre_streamon)(struct smiapp_sensor *sensor);
 	int (*post_streamoff)(struct smiapp_sensor *sensor);
 	unsigned long (*pll_flags)(struct smiapp_sensor *sensor);
+	int (*reg_access)(struct smiapp_sensor *sensor, bool write, u32 *reg,
+			  u32 *val);
 	unsigned long flags;
 };