pwm: add support for atmel-hlcdc-pwm device

The HLCDC IP available in some Atmel SoCs (i.e. at91sam9x5, at91sam9n12
or sama5d3 families for instance) provides a PWM device.

This driver add support for a PWM chip exposing a single PWM device (which
will most likely be used to drive a backlight device).

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Tested-by: Anthony Harivel <anthony.harivel@emtrion.de>
Tested-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index ddabe39..847a57d 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -50,6 +50,17 @@
 	  To compile this driver as a module, choose M here: the module
 	  will be called pwm-atmel.
 
+config PWM_ATMEL_HLCDC_PWM
+	tristate "Atmel HLCDC PWM support"
+	depends on MFD_ATMEL_HLCDC
+	help
+	  Generic PWM framework driver for the PWM output of the HLCDC
+	  (Atmel High-end LCD Controller). This PWM output is mainly used
+	  to control the LCD backlight.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called pwm-atmel-hlcdc.
+
 config PWM_ATMEL_TCB
 	tristate "Atmel TC Block PWM support"
 	depends on ATMEL_TCLIB && OF