SIM卡相关配置
1.
GPIO90---》BPI8
GPIO91---》BPI9
GPIO92---》BPI10
2.ProjectConfig.mk：MTK_PROTOCOL1_RAT_CONFIG = Lf/Lt/W/G
3.单卡
device.mk：PRODUCT_PROPERTY_OVERRIDES += persist.radio.multisim.config=ss
ProjectConfig.mk：MTK_MULTI_SIM_SUPPORT = ss
如果硬件没有接外部sim switch即单卡，则配置如下（不置空会出现SIM卡不识别问题）：
alps/kernel-3.10/arch/arm/configs/k95v21_defconfig
CONFIG_CUSTOM_KERNEL_SSW=" "
alps/device/mediatek/k95v21/ProjectConfig.mk
CUSTOM_KERNEL_SSW =
4.热插拔
ProjectConfig.mk: MTK_SIM_HOT_SWAP = yes
MTK_SIM_HOT_SWAP_COMMON_SLOT = no