build: define PWM_SUPPORT arch feature flag

As the PWM has its own sub-system in the Linux kernel,
I think it should be handled in the same way as GPIO, RTC, PCI...

This patch introduces a specific feature flag "pwm" and the
"leds-pwm" kernel module as the first customer.

Signed-off-by: Christian Lamparter <[email protected]>

package/kernel/linux/modules/leds.mk

@@ -159,3 +159,19 @@ define KernelPackage/leds-pca963x/description
 endef
 
 $(eval $(call KernelPackage,leds-pca963x))
+
+
+define KernelPackage/leds-pwm
+  SUBMENU:=$(LEDS_MENU)
+  TITLE:=PWM driven LED Support
+  KCONFIG:=CONFIG_LEDS_PWM
+  DEPENDS:= @PWM_SUPPORT
+  FILES:=$(LINUX_DIR)/drivers/leds/leds-pwm.ko
+  AUTOLOAD:=$(call AutoLoad,60,leds-pwm,1)
+endef
+
+define KernelPackage/leds-pwm/description
+ This option enables support for pwm driven LEDs
+endef
+
+$(eval $(call KernelPackage,leds-pwm))

scripts/target-metadata.pl

@@ -20,6 +20,7 @@ sub target_config_features(@) {
 		/^usb$/ and $ret .= "\tselect USB_SUPPORT\n";
 		/^usbgadget$/ and $ret .= "\tselect USB_GADGET_SUPPORT\n";
 		/^pcmcia$/ and $ret .= "\tselect PCMCIA_SUPPORT\n";
+		/^pwm$/ and $ret .= "\select PWM_SUPPORT\n";
 		/^rtc$/ and $ret .= "\tselect RTC_SUPPORT\n";
 		/^squashfs$/ and $ret .= "\tselect USES_SQUASHFS\n";
 		/^jffs2$/ and $ret .= "\tselect USES_JFFS2\n";

target/Config.in

@@ -29,6 +29,9 @@ config PCIE_SUPPORT
 config PCMCIA_SUPPORT
 	bool
 
+config PWM_SUPPORT
+	bool
+
 config USB_SUPPORT
 	select AUDIO_SUPPORT
 	bool