4.2.2 SDIO Card Detect

MMC slots have a card detect line that is used by Linux to indicate that an SDIO card was inserted, which can be used if ATWILC is connected through the MMC slot such as when ATWILC1000 SD board is used. However, not all setups would have this line connected. For example, ATWILC3000 Shield Board + SAMA5D4 Xplained setup uses the Arduino header for connection, which does not expose the card detect GPIO (PE3). In this case, it is essential to remove the dependency on the card detect line for the platform to detect ATWILC's SDIO controller.

Under the corresponding MMC entry in the dts file, remove the cd-gpios entry and add a non-removable property. For the MMC entry setting in the DT Overlay file, see 4.5 General Purpose IOs.

Note: Add the broken-cd property instead of non-removable in the dts file if there is no card detect line and the module cannot power up during system boot.