[U-Boot] [PATCH v3 5/5] ARM: dm: spi: Add support DM/DTS for i.MX28 mxs SPI driver (DM_SPI conversion)

Lukasz Majewski
2019-06-17T12:27:38Z

Hi Marek,

> On 6/17/19 8:49 AM, Lukasz Majewski wrote:
> > Hi Marek,
> >
> >> On 6/16/19 12:34 AM, Lukasz Majewski wrote:
> >>> This commit converts mxs_spi driver to support DM/DTS.
> >>>
> >>> Signed-off-by: Lukasz Majewski <lukma@denx.de>
> >>
> >> Is the non-DM part needed for anything ?
> >
> > Do you mean the non-DM part of the mxs_gpio driver? Yes, it is used
> > by not converted boards.
>
> This is a SPI driver though.
>
> >> I recall the SPL jumps back
> >> to BootROM when loading the U-Boot proper. So if not, drop it.
> >>
> >> Also, please don't do partial conversion for iMX28 only, do the
> >> iMX23 part as well, it cannot be hard.
> >
> > Maybe it is not hard, but I cannot test it properly as I don't have
> > i.MX23 device. If you are offering your help with testing (i.e. you
> > do have the access to i.MX23 device and you will test those
> > changes) I can add support for it.
> >
> > Otherwise, NO, I will not add ANY new untested code.
>
> In general, you don't have to add any code, the iMX23/28 SPI IP is
> very much the same hardware, DTTO for most of the other blocks. If
> there are any differences between iMX23/28, they are already handled
> in the existing driver(s).
>
> Half-way converted drivers in fact increase maintenance burden,
> because then we have to deal with two different variants of the code,
> instead of only one.

I cannot agree with this sentence. The conversion would be done for
i.MX28, which is then tested and validated (and clearly stated in the
cover letter/commit message that only supported was i.MX28).

If I don't need to adjust common, reused code (which already supports
both variants as it is the case with mxs_spi.c), then I don't mind.

For more intrusive changes - the driver needs to be tested and
validated (by somebody who has the HW for testing).

> That's why I would like to see this practice go
> away wherever possible, and in this case it is possible.

In this particular case it is possible to add support for both as SoC
specific changes (i.MX23 vs i.MX28) is performed in common code (e.g.
mxs_spi_xfer_dma).

>
> If you need someone to test your changes, CC the board maintainers,
> that's standard practice.

As fair as I remember only Angelo and Michael had also interest in
testing converted code for i.MX28 based board.

There was NO reply from other people when this (and few others) driver
was marked as DEPRECATED.

> If they don't respond, that cannot be
> helped.
>

Best regards,

Lukasz Majewski

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