clk: sunxi-ng: Move all clock types to a library

We've run into kconfig missing dependency errors in the sunxi-ng
code a couple times now. Each time the fix is to find the missing
select statement and add it to the Kconfig entry for a particular
SoC driver. Given that all this code is builtin (non-modular) we
don't need to do this complicated dependency tracking in Kconfig.
Instead we can move all the "library"ish code to be compiled as
lib-y instead of obj-y, let the linker throw away unused code in
the resulting vmlinux, and drop all the Kconfig stuff we use to
track clock types.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
[Maxime: added lib.a to obj-y, added the comment]
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

1 files changed, 22 insertions, 13 deletions

diff --git a/drivers/clk/sunxi-ng/Makefile b/drivers/clk/sunxi-ng/Makefile
index 0185c6f..0c45fa5 100644
--- a/drivers/clk/sunxi-ng/Makefile
+++ b/drivers/clk/sunxi-ng/Makefile
@@ -1,21 +1,21 @@
 # Common objects
-obj-$(CONFIG_SUNXI_CCU)		+= ccu_common.o
-obj-$(CONFIG_SUNXI_CCU)		+= ccu_reset.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_common.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_reset.o
 
 # Base clock types
-obj-$(CONFIG_SUNXI_CCU_DIV)	+= ccu_div.o
-obj-$(CONFIG_SUNXI_CCU_FRAC)	+= ccu_frac.o
-obj-$(CONFIG_SUNXI_CCU_GATE)	+= ccu_gate.o
-obj-$(CONFIG_SUNXI_CCU_MUX)	+= ccu_mux.o
-obj-$(CONFIG_SUNXI_CCU_MULT)	+= ccu_mult.o
-obj-$(CONFIG_SUNXI_CCU_PHASE)	+= ccu_phase.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_div.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_frac.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_gate.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_mux.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_mult.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_phase.o
 
 # Multi-factor clocks
-obj-$(CONFIG_SUNXI_CCU_NK)	+= ccu_nk.o
-obj-$(CONFIG_SUNXI_CCU_NKM)	+= ccu_nkm.o
-obj-$(CONFIG_SUNXI_CCU_NKMP)	+= ccu_nkmp.o
-obj-$(CONFIG_SUNXI_CCU_NM)	+= ccu_nm.o
-obj-$(CONFIG_SUNXI_CCU_MP)	+= ccu_mp.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_nk.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_nkm.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_nkmp.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_nm.o
+lib-$(CONFIG_SUNXI_CCU)		+= ccu_mp.o
 
 # SoC support
 obj-$(CONFIG_SUN50I_A64_CCU)	+= ccu-sun50i-a64.o
@@ -31,3 +31,12 @@ obj-$(CONFIG_SUN8I_R_CCU)	+= ccu-sun8i-r.o
 obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80.o
 obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80-de.o
 obj-$(CONFIG_SUN9I_A80_CCU)	+= ccu-sun9i-a80-usb.o
+
+# The lib-y file goals is supposed to work only in arch/*/lib or lib/. In our
+# case, we want to use that goal, but even though lib.a will be properly
+# generated, it will not be linked in, eventually resulting in a linker error
+# for missing symbols.
+#
+# We can work around that by explicitly adding lib.a to the obj-y goal. This is
+# an undocumented behaviour, but works well for now.
+obj-$(CONFIG_SUNXI_CCU)		+= lib.a