counter: 104-quad-8: Add Generic Counter interface support

This patch adds support for the Generic Counter interface to the
104-QUAD-8 driver. The existing 104-QUAD-8 device interface should not
be affected by this patch; all changes are intended as supplemental
additions as perceived by the user.

Generic Counter Counts are created for the eight quadrature channel
counts, as well as their respective quadrature A and B Signals (which
are associated via respective Synapse structures) and respective index
Signals.

The new Generic Counter interface sysfs attributes are intended to
expose the same functionality and data available via the existing
104-QUAD-8 IIO device interface; the Generic Counter interface serves
to provide the respective functionality and data in a standard way
expected of counter devices.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -268,12 +268,12 @@ L:	linux-gpio@vger.kernel.org
 S:	Maintained
 F:	drivers/gpio/gpio-104-idio-16.c
 
-ACCES 104-QUAD-8 IIO DRIVER
+ACCES 104-QUAD-8 DRIVER
 M:	William Breathitt Gray <vilhelm.gray@gmail.com>
 L:	linux-iio@vger.kernel.org
 S:	Maintained
 F:	Documentation/ABI/testing/sysfs-bus-iio-counter-104-quad-8
-F:	drivers/iio/counter/104-quad-8.c
+F:	drivers/counter/104-quad-8.c
 
 ACCES PCI-IDIO-16 GPIO DRIVER
 M:	William Breathitt Gray <vilhelm.gray@gmail.com>

drivers/counter/Kconfig

@@ -8,3 +8,24 @@ menuconfig COUNTER
 	  This enables counter device support through the Generic Counter
 	  interface. You only need to enable this, if you also want to enable
 	  one or more of the counter device drivers below.
+
+if COUNTER
+
+config 104_QUAD_8
+	tristate "ACCES 104-QUAD-8 driver"
+	depends on PC104 && X86 && IIO
+	select ISA_BUS_API
+	help
+	  Say yes here to build support for the ACCES 104-QUAD-8 quadrature
+	  encoder counter/interface device family (104-QUAD-8, 104-QUAD-4).
+
+	  A counter's respective error flag may be cleared by performing a write
+	  operation on the respective count value attribute. Although the
+	  104-QUAD-8 counters have a 25-bit range, only the lower 24 bits may be
+	  set, either directly or via the counter's preset attribute. Interrupts
+	  are not supported by this driver.
+
+	  The base port addresses for the devices may be configured via the base
+	  array module parameter.
+
+endif # COUNTER

drivers/counter/Makefile

@@ -3,3 +3,5 @@
 #
 
 obj-$(CONFIG_COUNTER) += counter.o
+
+obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o

drivers/iio/counter/Kconfig

@@ -5,23 +5,6 @@
 
 menu "Counters"
 
-config 104_QUAD_8
-	tristate "ACCES 104-QUAD-8 driver"
-	depends on PC104 && X86
-	select ISA_BUS_API
-	help
-	  Say yes here to build support for the ACCES 104-QUAD-8 quadrature
-	  encoder counter/interface device family (104-QUAD-8, 104-QUAD-4).
-
-	  Performing a write to a counter's IIO_CHAN_INFO_RAW sets the counter and
-	  also clears the counter's respective error flag. Although the counters
-	  have a 25-bit range, only the lower 24 bits may be set, either directly
-	  or via a counter's preset attribute. Interrupts are not supported by
-	  this driver.
-
-	  The base port addresses for the devices may be configured via the base
-	  array module parameter.
-
 config STM32_LPTIMER_CNT
 	tristate "STM32 LP Timer encoder counter driver"
 	depends on MFD_STM32_LPTIMER || COMPILE_TEST

drivers/iio/counter/Makefile

@@ -4,5 +4,4 @@
 
 # When adding new entries keep the list in alphabetical order
 
-obj-$(CONFIG_104_QUAD_8)	+= 104-quad-8.o
 obj-$(CONFIG_STM32_LPTIMER_CNT)	+= stm32-lptimer-cnt.o