gpio: For ARC EM Starterkit, a 4-port GPIO implementation is being added

The file gpio_dw_registers.h already had the 4-port GPIO
registers defined, yet the gpio_dw.c implementation didn't
support it properly. There are 4 ports here, not 2, and only
PORTA can support interrupts and debounce.

On the em_starterkit board, for example, PORTA
has 3 bits for buttons: A, L and R. The other 3 ports should not
be used with interrupts & debounce.

I've re-worked this file to derive the port number from the
base address given. The lower 6 bits are divided by 12 to
derive the port number. From this, the registers EXT_PORTA,
EXT_PORTB, EXT_PORTC or EXT_PORTD can be read.

Also, for those ports that don't support interrupts,
set irq_num to 0, and that code will be avoided. I've verified
that I can access GPIO now correctly on the EM Starterkit. The
em_starterkit board support will be submitted soon but I'm
staging in this change first.

Change-Id: I98dbe083e03e046b40e07b4b14a99a39a6d0f0be
Signed-off-by: Chuck Jordan <[email protected]>

drivers/gpio/Kconfig.dw

@@ -150,4 +150,104 @@ config GPIO_DW_1_IRQ_PRI
 	help
 	IRQ priority
 
+config GPIO_DW_2
+       bool "Designware GPIO block 1"
+       depends on GPIO_DW
+       default n
+       help
+       Include Designware GPIO driver
+
+config GPIO_DW_2_NAME
+       string "Driver name"
+       depends on GPIO_DW_2
+       default "GPIO_2"
+
+config GPIO_DW_2_CLOCK_GATE_SUBSYS
+	int "Clock controller's subsystem"
+	depends on GPIO_DW_CLOCK_GATE && GPIO_DW_2
+
+choice
+	prompt "Port 1 Interrupts via"
+	default GPIO_DW_2_IRQ_DIRECT
+	depends on GPIO_DW_2
+
+config GPIO_DW_2_IRQ_DIRECT
+	bool "Direct Hardware Interrupt"
+	help
+	  When interrupts fire, the driver's ISR function is being called directly.
+
+config GPIO_DW_2_IRQ_SHARED
+	bool "Shared IRQ"
+	depends on SHARED_IRQ
+	select GPIO_DW_SHARED_IRQ
+	help
+	  When interrupts fire, the shared IRQ driver is notified. Then the shared IRQ
+	  driver dispatches the interrupt to other drivers.
+
+endchoice
+
+config GPIO_DW_2_IRQ_SHARED_NAME
+	string "Device name for Shared IRQ"
+	depends on GPIO_DW_2_IRQ_SHARED
+	help
+	  Specify the device name for the shared IRQ driver. It is used to register
+	  this driver with the shared IRQ driver, so interrupts can be dispatched
+	  correctly.
+
+config GPIO_DW_2_IRQ_PRI
+       int "Controller interrupt priority"
+       depends on GPIO_DW_2 && GPIO_DW_2_IRQ_DIRECT
+       help
+       IRQ priority
+
+config GPIO_DW_3
+       bool "Designware GPIO block 1"
+       depends on GPIO_DW
+       default n
+       help
+       Include Designware GPIO driver
+
+config GPIO_DW_3_NAME
+       string "Driver name"
+       depends on GPIO_DW_3
+       default "GPIO_3"
+
+config GPIO_DW_3_CLOCK_GATE_SUBSYS
+	int "Clock controller's subsystem"
+	depends on GPIO_DW_CLOCK_GATE && GPIO_DW_3
+
+choice
+	prompt "Port 1 Interrupts via"
+	default GPIO_DW_3_IRQ_DIRECT
+	depends on GPIO_DW_3
+
+config GPIO_DW_3_IRQ_DIRECT
+	bool "Direct Hardware Interrupt"
+	help
+	  When interrupts fire, the driver's ISR function is being called directly.
+
+config GPIO_DW_3_IRQ_SHARED
+	bool "Shared IRQ"
+	depends on SHARED_IRQ
+	select GPIO_DW_SHARED_IRQ
+	help
+	  When interrupts fire, the shared IRQ driver is notified. Then the shared IRQ
+	  driver dispatches the interrupt to other drivers.
+
+endchoice
+
+config GPIO_DW_3_IRQ_SHARED_NAME
+	string "Device name for Shared IRQ"
+	depends on GPIO_DW_3_IRQ_SHARED
+	help
+	  Specify the device name for the shared IRQ driver. It is used to register
+	  this driver with the shared IRQ driver, so interrupts can be dispatched
+	  correctly.
+
+config GPIO_DW_3_IRQ_PRI
+       int "Controller interrupt priority"
+       depends on GPIO_DW_3 && GPIO_DW_3_IRQ_DIRECT
+       help
+       IRQ priority
+
 endif # GPIO_DW