USB: cdc_subset: only build when one driver is enabled

This avoids a harmless randconfig warning I get when USB_NET_CDC_SUBSET
is enabled, but all of the more specific drivers are not:

drivers/net/usb/cdc_subset.c:241:2: #warning You need to configure some hardware for this driver

The current behavior is clearly intentional, giving a warning when
a user picks a configuration that won't do anything good. The only
reason for even addressing this is that I'm getting close to
eliminating all 'randconfig' warnings on ARM, and this came up
a couple of times.

My workaround is to not even build the module when none of the
configurations are enable.

Alternatively we could simply remove the #warning (nothing wrong
for compile-testing), turn it into a runtime warning, or
change the Kconfig options into a menu to hide CONFIG_USB_NET_CDC_SUBSET.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/usb/Kconfig b/drivers/net/usb/Kconfig
index 7f83504..cdde590 100644 (file)
--- a/drivers/net/usb/Kconfig
+++ b/drivers/net/usb/Kconfig
@@ -395,6 +395,10 @@ config USB_NET_RNDIS_HOST
          The protocol specification is incomplete, and is controlled by
          (and for) Microsoft; it isn't an "Open" ecosystem or market.
 
+config USB_NET_CDC_SUBSET_ENABLE
+       tristate
+       depends on USB_NET_CDC_SUBSET
+
 config USB_NET_CDC_SUBSET
        tristate "Simple USB Network Links (CDC Ethernet subset)"
        depends on USB_USBNET
@@ -413,6 +417,7 @@ config USB_NET_CDC_SUBSET
 config USB_ALI_M5632
        bool "ALi M5632 based 'USB 2.0 Data Link' cables"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        help
          Choose this option if you're using a host-to-host cable
          based on this design, which supports USB 2.0 high speed.
@@ -420,6 +425,7 @@ config USB_ALI_M5632
 config USB_AN2720
        bool "AnchorChips 2720 based cables (Xircom PGUNET, ...)"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        help
          Choose this option if you're using a host-to-host cable
          based on this design.  Note that AnchorChips is now a
@@ -428,6 +434,7 @@ config USB_AN2720
 config USB_BELKIN
        bool "eTEK based host-to-host cables (Advance, Belkin, ...)"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        default y
        help
          Choose this option if you're using a host-to-host cable
@@ -437,6 +444,7 @@ config USB_BELKIN
 config USB_ARMLINUX
        bool "Embedded ARM Linux links (iPaq, ...)"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        default y
        help
          Choose this option to support the "usb-eth" networking driver
@@ -454,6 +462,7 @@ config USB_ARMLINUX
 config USB_EPSON2888
        bool "Epson 2888 based firmware (DEVELOPMENT)"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        help
          Choose this option to support the usb networking links used
          by some sample firmware from Epson.
@@ -461,6 +470,7 @@ config USB_EPSON2888
 config USB_KC2190
        bool "KT Technology KC2190 based cables (InstaNet)"
        depends on USB_NET_CDC_SUBSET
+       select USB_NET_CDC_SUBSET_ENABLE
        help
          Choose this option if you're using a host-to-host cable
          with one of these chips.

diff --git a/drivers/net/usb/Makefile b/drivers/net/usb/Makefile
index b5f0406..37fb46a 100644 (file)
--- a/drivers/net/usb/Makefile
+++ b/drivers/net/usb/Makefile
@@ -23,7 +23,7 @@ obj-$(CONFIG_USB_NET_GL620A)  += gl620a.o
 obj-$(CONFIG_USB_NET_NET1080)  += net1080.o
 obj-$(CONFIG_USB_NET_PLUSB)    += plusb.o
 obj-$(CONFIG_USB_NET_RNDIS_HOST)       += rndis_host.o
-obj-$(CONFIG_USB_NET_CDC_SUBSET)       += cdc_subset.o
+obj-$(CONFIG_USB_NET_CDC_SUBSET_ENABLE)        += cdc_subset.o
 obj-$(CONFIG_USB_NET_ZAURUS)   += zaurus.o
 obj-$(CONFIG_USB_NET_MCS7830)  += mcs7830.o
 obj-$(CONFIG_USB_USBNET)       += usbnet.o