spl: Allow timer drivers to be used in SPL

Add a new Kconfig option to allow timer drivers to be used in SPL.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

common/spl/Kconfig

@@ -537,6 +537,15 @@ config SPL_SPI_SUPPORT
 	  enable SPI drivers that are needed for other purposes also, such
 	  as a SPI PMIC.
 
+config SPL_TIMER_SUPPORT
+	bool "Support timer drivers"
+	depends on SPL
+	help
+	  Enable support for timer drivers in SPL. These can be used to get
+	  a timer value when in SPL, or perhaps for implementing a delay
+	  function. This enables the drivers in drivers/timer as part of an
+	  SPL build.
+
 config SPL_USB_HOST_SUPPORT
 	bool "Support USB host drivers"
 	depends on SPL

drivers/Makefile

@@ -35,6 +35,7 @@ obj-$(CONFIG_SPL_ETH_SUPPORT) += net/phy/
 obj-$(CONFIG_SPL_USBETH_SUPPORT) += net/phy/
 obj-$(CONFIG_SPL_PCI_SUPPORT) += pci/
 obj-$(CONFIG_SPL_RTC_SUPPORT) += rtc/
+obj-$(CONFIG_SPL_TIMER_SUPPORT) += timer/
 obj-$(CONFIG_SPL_MUSB_NEW_SUPPORT) += usb/musb-new/
 obj-$(CONFIG_SPL_USB_GADGET_SUPPORT) += usb/gadget/
 obj-$(CONFIG_SPL_USB_GADGET_SUPPORT) += usb/gadget/udc/