Re: [PATCH 4.9 11/66] spi/bcm63xx: make spi subsystem aware of message size limits

[Greg Kroah-Hartman]

On Fri, Jul 20, 2018 at 01:34:43PM +0100, Mark Brown wrote:
> On Fri, Jul 20, 2018 at 02:13:28PM +0200, Greg Kroah-Hartman wrote:
> 
> > The bcm63xx SPI controller does not allow manual control of the CS
> > lines and will toggle it automatically before and after sending data,
> > so we are limited to messages that fit in the FIFO buffer. Since the CS
> > lines aren't available as GPIOs either, we will need to make slave
> > drivers aware of this limitation so they can handle them accordingly.
> 
> Same review comment as before: this will ask other code (which
> presumably never worked?) to change how they use the hardware in order
> to cope with the limiations which seems a bit risky to me given that
> limits like this are fairly rare so that code isn't super well exercised
> in general.

Ok, now I think I understand this better.  I've now dropped this, and
the follow-on fixup patch from the 4.9 queue.  Thanks for being patient
with me.

greg k-h