Hikey960 with kernel 4.9 on spi (SPI2 and SPI3) is giving read error on higher frequency(20MHz)

Hikey960 with kernel 4.9 on spi (SPI2(LS) and SPI3(HS)) is giving read error on higher frequency(20MHz). Has anyone tried it out prior ? Any help appreciated.

Read is completely unsuccessful, never worked on higher frequency. But on kernel 4.4 when we had tried last time it was working good on 20 MHz.

spi_read is returning 0 but no data. @Loic @guodong Any clue. Let me know if you need more information. I have tested the slave device on another host platform and it was running at 20MHz.

Is your question related to https://bugs.96boards.org/show_bug.cgi?id=555
?

-Guodong

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I can check by enabling dma support in SPI3 node on HS. Which dmaX shall I use for SPI3 ? dma0/dma1… ?

For SPI3, RX 12, TX 13, use these channels.

DMA seems to be enabled. When I try with 19.2MHz, in CRO it reads 13.4MHz. I have to get this SPI interface up with ~20MHz. Can anyone shed some light ? @guodong @Loic