Re: [PATCH v2] imx6: Re-add mmc aliases

[Detlev Casanova <detlev.casanova@collabora.com>]

On Friday, December 9, 2022 6:01:13 A.M. EST Peter Robinson wrote:
> On Thu, Dec 8, 2022 at 3:23 PM Detlev Casanova
> 
> <detlev.casanova@collabora.com> wrote:
> > In commit d0399a46e7cda63c07e3eb8558bef84cfb068028, the device tree was
> > synchronized from linux and the aliases were dropped.
> 
> Is there a reason not to get this change upstreamed in to Linux and
> then this wouldn't be a problem moving forward?

Yes, please check this conversation: http://patchwork.ozlabs.org/comment/3016037/[1]

> > They need to be kept so that the mmc cards are in the right order.
> > Without the aliases, u-boot reports:
> > MMC:   FSL_SDHC: 2, FSL_SDHC: 3
> > 
> > With the aliases, u-boot reports:
> > MMC:   FSL_SDHC: 0, FSL_SDHC: 1
> > 
> > The upstream linux device tree does not contain the same aliases than
> > u-boot (It keeps the devices order with /dev/mmcblk2 and /dev/mmcblk3).
> > Because this board has been using different aliases in u-boot
> > and linux, a imx6q-sabrelite-u-boot.dtsi file is added to be
> > automatically included in imx6q-sabrelite.dts.
> > 
> > This way, linux and u-boot each keep their own aliases and there
> > is no breakage on current installations.
> > 
> > This should never be done for new boards as we want to keep linux and
> > u-boot with the same aliases as much as possible.
> > This patch is only necessary to avoid breaking existing setups.
> > 
> > Signed-off-by: Detlev Casanova <detlev.casanova@collabora.com>
> > 
> > Gbp-Pq: Topic apertis/imx6
> > Gbp-Pq: Name 0010-imx6-Re-add-mmc-aliases.patch
> > ---
> > 
> >  arch/arm/dts/imx6q-sabrelite-u-boot.dtsi | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> >  create mode 100644 arch/arm/dts/imx6q-sabrelite-u-boot.dtsi
> > 
> > diff --git a/arch/arm/dts/imx6q-sabrelite-u-boot.dtsi
> > b/arch/arm/dts/imx6q-sabrelite-u-boot.dtsi new file mode 100644
> > index 0000000000..706ec9ba25
> > --- /dev/null
> > +++ b/arch/arm/dts/imx6q-sabrelite-u-boot.dtsi
> > @@ -0,0 +1,15 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (C) 2022 Collabora
> > + */
> > +
> > +#include "imx6qdl-u-boot.dtsi"
> > +
> > +/ {
> > +       aliases {
> > +               mmc0 = &usdhc3;
> > +               mmc1 = &usdhc4;
> > +               pwm_lcd = &pwm1;
> > +               pwm_lvds = &pwm4;
> > +       };
> > +};
> > --
> > 2.38.1



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[1] http://patchwork.ozlabs.org/comment/3016037/