staging: iio: resolver: new driver for AD2S1210 devices

Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/resolver/Kconfig

@@ -17,3 +17,38 @@ config AD2S120X
 	  Say yes here to build support for Analog Devices spi resolver
 	  to digital converters, ad2s1200 and ad2s1205, provides direct access
 	  via sysfs.
+
+config AD2S1210
+	tristate "Analog Devices ad2s1210 driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices spi resolver
+	  to digital converters, ad2s1210, provides direct access via sysfs.
+
+choice
+	prompt "Resolution Control"
+	depends on AD2S1210
+	default AD2S1210_GPIO_NONE
+	help
+	  In normal mode, the resolution of the digital output is selected
+	  using the RES0 and RES1 input pins. In configuration mode, the
+	  resolution is selected by setting the RES0 and RES1 bits in the
+	  control regsiter. When switching between normal mode and configuration
+	  mode, there are some schemes to keep them matchs.
+
+config AD2S1210_GPIO_INPUT
+	bool "read resolution from gpio pins"
+	help
+	  GPIO pins are sampling RES0 and RES1 pins, read the resolution
+	  settings from the GPIO pins.
+
+config AD2S1210_GPIO_OUTPUT
+	bool "set gpio pins to set resolution"
+	help
+	  RES0 and RES1 pins are controlled by GPIOs, setting GPIO pins to
+	  set the resolution.
+
+config AD2S1210_GPIO_NONE
+	bool "take the responsibility by user"
+
+endchoice

drivers/staging/iio/resolver/Makefile

@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_AD2S90) += ad2s90.o
 obj-$(CONFIG_AD2S120X) += ad2s120x.o
+obj-$(CONFIG_AD2S1210) += ad2s1210.o