[media] Input: synaptics-rmi4 - add support for F54 diagnostics

Function 54 implements access to various RMI4 diagnostic features.

This patch adds support for retrieving this data. It registers a V4L2
device to output the data to user space.
Signed-off-by: Nick Dyer <nick@shmanahar.org>
Tested-by: Andrew Duggan <aduggan@synaptics.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

drivers/input/rmi4/Kconfig

@@ -61,3 +61,14 @@ config RMI4_F30
 
 	  Function 30 provides GPIO and LED support for RMI4 devices. This
 	  includes support for buttons on TouchPads and ClickPads.
+
+config RMI4_F54
+	bool "RMI4 Function 54 (Analog diagnostics)"
+	depends on RMI4_CORE
+	depends on VIDEO_V4L2
+	select VIDEOBUF2_VMALLOC
+	help
+	  Say Y here if you want to add support for RMI4 function 54
+
+	  Function 54 provides access to various diagnostic features in certain
+	  RMI4 touch sensors.

drivers/input/rmi4/Makefile

@@ -7,6 +7,7 @@ rmi_core-$(CONFIG_RMI4_2D_SENSOR) += rmi_2d_sensor.o
 rmi_core-$(CONFIG_RMI4_F11) += rmi_f11.o
 rmi_core-$(CONFIG_RMI4_F12) += rmi_f12.o
 rmi_core-$(CONFIG_RMI4_F30) += rmi_f30.o
+rmi_core-$(CONFIG_RMI4_F54) += rmi_f54.o
 
 # Transports
 obj-$(CONFIG_RMI4_I2C) += rmi_i2c.o

drivers/input/rmi4/rmi_bus.c

@@ -312,6 +312,9 @@ static struct rmi_function_handler *fn_handlers[] = {
 #ifdef CONFIG_RMI4_F30
 	&rmi_f30_handler,
 #endif
+#ifdef CONFIG_RMI4_F54
+	&rmi_f54_handler,
+#endif
 };
 
 static void __rmi_unregister_function_handlers(int start_idx)

drivers/input/rmi4/rmi_driver.h

@@ -102,4 +102,5 @@ extern struct rmi_function_handler rmi_f01_handler;
 extern struct rmi_function_handler rmi_f11_handler;
 extern struct rmi_function_handler rmi_f12_handler;
 extern struct rmi_function_handler rmi_f30_handler;
+extern struct rmi_function_handler rmi_f54_handler;
 #endif