dsa: Allow tag drivers to be built as modules

Make the CONFIG symbols tristate and add help text.

The broadcom and Microchip KSZ tag drivers support two different
tagging protocols in one driver. Add a configuration option for the
drivers, and then options to select the protocol.

Create a submenu for the tagging drivers.
Signed-off-by: Andrew Lunn <andrew@lunn.ch>

v2:
tab/space cleanup
Help text wording
NET_DSA_TAG_BRCM_COMMON and NET_DSA_TAG_KZS_COMMON hidden

v3:
More tabification
Punctuation

v4:
trailler->trailer
Signed-off-by: David S. Miller <davem@davemloft.net>

net/dsa/Kconfig

@@ -4,7 +4,7 @@ config HAVE_NET_DSA
 
 # Drivers must select NET_DSA and the appropriate tagging format
 
-config NET_DSA
+menuconfig NET_DSA
 	tristate "Distributed Switch Architecture"
 	depends on HAVE_NET_DSA
 	depends on BRIDGE || BRIDGE=n
@@ -26,39 +26,84 @@ config NET_DSA_LEGACY
 
 	  This feature is scheduled for removal in 4.17.
 
-# tagging formats
+config NET_DSA_TAG_BRCM_COMMON
+	tristate
+	default n
+
 config NET_DSA_TAG_BRCM
-	bool
+	tristate "Tag driver for Broadcom switches using in-frame headers"
+	select NET_DSA_TAG_BRCM_COMMON
+	help
+	  Say Y if you want to enable support for tagging frames for the
+	  Broadcom switches which place the tag after the MAC source address.
+
 
 config NET_DSA_TAG_BRCM_PREPEND
-	bool
+	tristate "Tag driver for Broadcom switches using prepended headers"
+	select NET_DSA_TAG_BRCM_COMMON
+	help
+	  Say Y if you want to enable support for tagging frames for the
+	  Broadcom switches which places the tag before the Ethernet header
+	  (prepended).
+
+config NET_DSA_TAG_GSWIP
+	tristate "Tag driver for Lantiq / Intel GSWIP switches"
+	help
+	  Say Y or M if you want to enable support for tagging frames for the
+	  Lantiq / Intel GSWIP switches.
 
 config NET_DSA_TAG_DSA
-	bool
+	tristate "Tag driver for Marvell switches using DSA headers"
+	help
+	  Say Y or M if you want to enable support for tagging frames for the
+	  Marvell switches which use DSA headers.
 
 config NET_DSA_TAG_EDSA
-	bool
+	tristate "Tag driver for Marvell switches using EtherType DSA headers"
+	help
+	  Say Y or M if you want to enable support for tagging frames for the
+	  Marvell switches which use EtherType DSA headers.
 
-config NET_DSA_TAG_GSWIP
-	bool
+config NET_DSA_TAG_MTK
+	tristate "Tag driver for Mediatek switches"
+	help
+	  Say Y or M if you want to enable support for tagging frames for
+	  Mediatek switches.
+
+config NET_DSA_TAG_KSZ_COMMON
+	tristate
+	default n
 
 config NET_DSA_TAG_KSZ
-	bool
+	tristate "Tag driver for Microchip 9893 family of switches"
+	select NET_DSA_TAG_KSZ_COMMON
+	help
+	  Say Y if you want to enable support for tagging frames for the
+	  Microchip 9893 family of switches.
 
 config NET_DSA_TAG_KSZ9477
-	bool
-	select NET_DSA_TAG_KSZ
+	tristate "Tag driver for Microchip 9477 family of switches"
+	select NET_DSA_TAG_KSZ_COMMON
+	help
+	  Say Y if you want to enable support for tagging frames for the
+	  Microchip 9477 family of switches.
 
-config NET_DSA_TAG_LAN9303
-	bool
+config NET_DSA_TAG_QCA
+	tristate "Tag driver for Qualcomm Atheros QCA8K switches"
+	help
+	  Say Y or M if you want to enable support for tagging frames for
+	  the Qualcomm Atheros QCA8K switches.
 
-config NET_DSA_TAG_MTK
-	bool
+config NET_DSA_TAG_LAN9303
+	tristate "Tag driver for SMSC/Microchip LAN9303 family of switches"
+	help
+	  Say Y or M if you want to enable support for tagging frames for the
+	  SMSC/Microchip LAN9303 family of switches.
 
 config NET_DSA_TAG_TRAILER
-	bool
-
-config NET_DSA_TAG_QCA
-	bool
+	tristate "Tag driver for switches using a trailer tag"
+	help
+	  Say Y or M if you want to enable support for tagging frames at
+	  with a trailed. e.g. Marvell 88E6060.
 
 endif

net/dsa/Makefile

@@ -5,13 +5,12 @@ dsa_core-y += dsa.o dsa2.o master.o port.o slave.o switch.o
 dsa_core-$(CONFIG_NET_DSA_LEGACY) += legacy.o
 
 # tagging formats
-dsa_core-$(CONFIG_NET_DSA_TAG_BRCM) += tag_brcm.o
-dsa_core-$(CONFIG_NET_DSA_TAG_BRCM_PREPEND) += tag_brcm.o
-dsa_core-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
-dsa_core-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
-dsa_core-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
-dsa_core-$(CONFIG_NET_DSA_TAG_KSZ) += tag_ksz.o
-dsa_core-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
-dsa_core-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
-dsa_core-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
-dsa_core-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o
+obj-$(CONFIG_NET_DSA_TAG_BRCM_COMMON) += tag_brcm.o
+obj-$(CONFIG_NET_DSA_TAG_DSA) += tag_dsa.o
+obj-$(CONFIG_NET_DSA_TAG_EDSA) += tag_edsa.o
+obj-$(CONFIG_NET_DSA_TAG_GSWIP) += tag_gswip.o
+obj-$(CONFIG_NET_DSA_TAG_KSZ_COMMON) += tag_ksz.o
+obj-$(CONFIG_NET_DSA_TAG_LAN9303) += tag_lan9303.o
+obj-$(CONFIG_NET_DSA_TAG_MTK) += tag_mtk.o
+obj-$(CONFIG_NET_DSA_TAG_QCA) += tag_qca.o
+obj-$(CONFIG_NET_DSA_TAG_TRAILER) += tag_trailer.o