Hello again Yiping,
Thanks you for your reply, and sorry for the Subject of the Question. By mistake, I wrote 2.14 instead of 4.14.
I explain you my context. We are using QorIQ LS1021A processor, in specific we use TQMLS1021xA board. For yocto project we use a BSP layer provided by TQ (https://github.com/tq-systems/meta-tq.git). Our kernel is 4.14.78-TQMLS102xA.BSP.SW.0110. Sorry for the confusion.
We have tested the SPI master mode successfully but we have not get SPI slave mode working. And we wonder if it is possible actually.
Thanks vey much