在 2022/2/15 20:36, Mark Brown 写道:
On Tue, Feb 15, 2022 at 11:00:54AM +0800, Jon Lin wrote:
在 2022/2/14 20:49, Mark Brown 写道:
As covered in the documentation setup() for one device may run while
another is active, therefore if multiple devices are configured in the
same register you should use a lock to ensure there can't be multiple
writes. Note that the above appears to not just be setting the mode but
also the chip select so if you've got two SPI_CS_HIGH devices then
they'll both be going in and separately setting cr0.
Is the io_mutex in function spi_setup is good enough?
It's not supposed to be for that but looking at the code quickly I
*think* setup() is never called with io_mutex held so it might well be
fine - you should double check though. If not you'd need to add another
lock in your driver data.
》setup() is never called with io_mutex held
I think so. and I think the io_mutex is enough for me.
