counter: new TI eQEP driver

This adds a new counter driver for the Texas Instruments Enhanced
Quadrature Encoder Pulse (eQEP) module.

Only very basic functionality is currently implemented - only enough to
be able to read the position. The actual device has many more features
which can be added to the driver on an as-needed basis.

It is not possible to read the QEPA/B signal values in hardware, so
that feature is omitted.

The TI_PWMSS kernel option is selected in Kconfig to enable the parent
bus, which is needed for power management.

Signed-off-by: David Lechner <david@lechnology.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 2967d0a9..c80fa76 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -49,6 +49,17 @@
 	  To compile this driver as a module, choose M here: the
 	  module will be called stm32-lptimer-cnt.
 
+config TI_EQEP
+	tristate "TI eQEP counter driver"
+	depends on (SOC_AM33XX || COMPILE_TEST)
+	select REGMAP_MMIO
+	help
+	  Select this option to enable the Texas Instruments Enhanced Quadrature
+	  Encoder Pulse (eQEP) counter driver.
+
+	  To compile this driver as a module, choose M here: the module will be
+	  called ti-eqep.
+
 config FTM_QUADDEC
 	tristate "Flex Timer Module Quadrature decoder driver"
 	depends on HAS_IOMEM && OF