dm: led: Add a driver for GPIO-controlled LEDs

Add a simple driver which allows use of LEDs attached to GPIOs. The linux
device tree binding is used.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/led/Kconfig b/drivers/led/Kconfig
index e4d9a84..de5feea 100644
--- a/drivers/led/Kconfig
+++ b/drivers/led/Kconfig
@@ -15,3 +15,12 @@
 	  If this is acceptable and you have a need to use LEDs in SPL,
 	  enable this option. You will need to enable device tree in SPL
 	  for this to work.
+
+config LED_GPIO
+	bool "LED support for GPIO-connected LEDs"
+	depends on LED && DM_GPIO
+	help
+	  Enable support for LEDs which are connected to GPIO lines. These
+	  GPIOs may be on the SoC or some other device which provides GPIOs.
+	  The GPIO driver must used driver model. LEDs are configured using
+	  the device tree.