Re: [PATCH 2/2] spi: bcm-mspi: Add support for Broadcom MSPI driver.

From: Mark Brown
Date: Thu May 14 2015 - 15:08:50 EST

On Thu, May 14, 2015 at 11:19:01AM -0700, Scott Branden wrote:
> On 15-05-14 03:31 AM, Mark Brown wrote:

> >Chip vendors often say this sort of thing and then get surprised by what
> >their users choose to do, and even if it only ever gets used with flash
> >all it would take is some new flash command which can use full duplex
> >for something. Please write the code so it at least tries to handle
> >full duplex operation, if you can't test it fully that's not the end of
> >the world. It doesn't look like it should be particularly difficult.

> Yes, there is always room for improvements in code. In this case - it
> really is not worth our time to add code we can't test. We try to deliver
> code that we can test and actually works. Yes, if anyone needs to use the

While I try to not apply code that has obvious problems with silent data
corruption in it which is what we have just now.

> mspi for full duplex operation code can be added in the future - it is
> software. This block has gone through many generations of our SoCs and has
> only been used for this purpose - the bootROM boots from this SPI only. It
> is dedicated for this purpose.

All it takes is one hardware engineer who sees a SPI controller and a
GPIO they can use for chip select; I wouldn't be so sure that nobody
ever fixed this up locally (or happened to use a device that only needed
single duplex).

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