The symbol MHI_BUS_EP neither depends on HAS_IOMEM, nor on INDIRECT_IOMEM. But, the function mhi_ep_ring_num_elems in drivers/bus/mhi/ep/ring.c is using a IO memcpy operation. So, when building for UM which doesn't have CONFIG_HAS_IOMEM=y, the build fails. Reviewed-by: Yann Sionneau <ysionneau@xxxxxxxxxxxxx> Signed-off-by: Julian Vetter <jvetter@xxxxxxxxxxxxx> --- Changes for v8: - New patch --- drivers/bus/mhi/ep/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/bus/mhi/ep/Kconfig b/drivers/bus/mhi/ep/Kconfig index 90ab3b040672..dba95fb95eeb 100644 --- a/drivers/bus/mhi/ep/Kconfig +++ b/drivers/bus/mhi/ep/Kconfig @@ -1,5 +1,6 @@ config MHI_BUS_EP tristate "Modem Host Interface (MHI) bus Endpoint implementation" + depends on HAS_IOMEM || INDIRECT_IOMEM help Bus driver for MHI protocol. Modem Host Interface (MHI) is a communication protocol used by a host processor to control -- 2.34.1