ARM: 5628/1: ep93xx: Introduce Pulse Width Modulator (PWM) driver

The EP93xx features two PWMs (one on the EP9307) with the following
features:

  * Configurable dual output
  * Separate input clocks for each PWM output
  * 16-bit resolution
  * Programmable pulse width (duty cycle), interval (frequency), and
    polarity

This adds the necessary core support as well as the driver.  A sysfs
interface is provided to control the PWM outputs.

Signed-off-by: Matthieu Crapet <mcrapet@gmail.com>
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Acked-by: Ryan Mallon <ryan@bluewatersys.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/misc/Kconfig

@@ -233,6 +233,19 @@ config ISL29003
 	  This driver can also be built as a module.  If so, the module
 	  will be called isl29003.
 
+config EP93XX_PWM
+	tristate "EP93xx PWM support"
+	depends on ARCH_EP93XX
+	help
+	  This option enables device driver support for the PWM channels
+	  on the Cirrus EP93xx processors.  The EP9307 chip only has one
+	  PWM channel all the others have two, the second channel is an
+	  alternate function of the EGPIO14 pin.  A sysfs interface is
+	  provided to control the PWM channels.
+
+	  To compile this driver as a module, choose M here: the module will
+	  be called ep93xx_pwm.
+
 source "drivers/misc/c2port/Kconfig"
 source "drivers/misc/eeprom/Kconfig"
 source "drivers/misc/cb710/Kconfig"