[PATCH 3/6] staging: wfx: fix CONFIG_MMC=m with CONFIG_WFX=y

[Jerome Pouiller <Jerome.Pouiller@silabs.com>]

From: Jérôme Pouiller <jerome.pouiller@silabs.com>

If CONFIG_MMC=m and CONFIG_WFX=y, compilation complains with undefined
references:

    drivers/staging/wfx/main.o: In function `wfx_core_init': /linux/drivers/staging/wfx/main.c:488: undefined reference to `sdio_register_driver'
    drivers/staging/wfx/main.o: In function `wfx_core_exit': /linux/drivers/staging/wfx/main.c:496: undefined reference to `sdio_unregister_driver'
    drivers/staging/wfx/main.o:(.debug_addr+0x1a8): undefined reference to `sdio_register_driver'
    drivers/staging/wfx/main.o:(.debug_addr+0x6f0): undefined reference to `sdio_unregister_driver'

Indeed, symbols sdio_* are not present in kernel image.

This patch disallows CONFIG_WFX=y if CONFIG_MMC=m.

This solution impacts users who want to use SPI bus with configuration:
CONFIG_WFX=y + CONFIG_SPI=y + CONFIG_MMC=m. However, I think this is a
twisted case. So, I think it won't be missed.

Reported-by: zhong jiang <zhongjiang@huawei.com>
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
---
 drivers/staging/wfx/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/wfx/Kconfig b/drivers/staging/wfx/Kconfig
index 9b8a1c7a9e90..83ee4d0ca8c6 100644
--- a/drivers/staging/wfx/Kconfig
+++ b/drivers/staging/wfx/Kconfig
@@ -1,6 +1,7 @@
 config WFX
 	tristate "Silicon Labs wireless chips WF200 and further"
 	depends on MAC80211
+	depends on MMC || !MMC # do not allow WFX=y if MMC=m
 	depends on (SPI || MMC)
 	help
 	  This is a driver for Silicons Labs WFxxx series (WF200 and further)
-- 
2.20.1