Re: [PATCH] hw/ssi: imx_spi: Improve chip select handling

[Guenter Roeck]

On 9/17/21 8:09 PM, Cheng, Xuzhou wrote:
> > > I got some free time in the past days to investigate this issue. Guenter is 
> > > right, the Linux imx-spi driver does not work on QEMU.
> > >
> > > The reason is that the state of m25p80 machine loops in STATE_READING_DATA 
> > > state after receiving RDSR command, the new command is ignored. Before sending 
> > > a new command, the CS line should be pulled to high, this make the state of 
> > > m25p80 back to IDLE.
> > >
> > > I have same point with Guenter, it's that set CS to 1 when burst is zero. But i 
> > > don't think it is necessary to set CS to 0 in imx_spi_flush_txfifo(). I will 
> > > send a new patch to fix this issue.
> >
> > Thanks a lot for looking into this. If you have a better solution than mine, by 
> > all means, please go for it. As I mentioned in my patch, I didn't really like 
> > it, but I was unable to find a better solution.
> I am doing some experiment to verify that the new patch is reasonable, so the 
> new patch will be delayed few days.

No problem. Note that I'll be traveling for the next 2-3 weeks, and I won't be 
able
to test any patches during that time.

Guenter