Re: [PATCH v2 1/5] arm64: dts: ti: k3-am6*: Set eMMC clock parents to default

[Judith Mendez]

Hi Nishanth,

On 4/22/25 7:37 AM, Nishanth Menon wrote:
> On 09:36-20250421, Judith Mendez wrote:
> > Hi Udit,
> >
> > On 4/19/25 10:00 AM, Kumar, Udit wrote:
> > > On 4/18/2025 5:00 AM, Judith Mendez wrote:
> > > > Set eMMC clock parents to the defaults which is MAIN_PLL0_HSDIV5_CLKOUT
> > > > for eMMC. This change is necessary since DM is not implementing the
> > > > correct procedure to switch PLL clock source for eMMC and we have a
> > > > non-glich-free mux. To remove any potential issues, lets switch back to
> > > > the defaults.
> > >
> > > IMO, we need to fix DM  if not then documentation [0] .
> >
> > DM cannot be fixed for only one IP and documentation says what clock
> > parents are supported, it does not have to say what are the issues
> > that come with using a specific clock parent.
>
> As I understand the arasan IP requirement is that the IP must be held in
> reset while the clock is switched, which is not reasonable to implement
> given decoupled systems like DM and Linux OS.
>
> > > Then only this patch is ok because as per document [0]
> > >
> > > removed clock by this patch is valid parent for eMMC.
> >
> > The clock parent currently set is a valid parent, but we have non-
> > glitch-free muxes and to avoid any potential issues with these, we
> > should switch back to the defaults. It seems like we randomly switched
> > from the default for no good reason and it has been copy paste per
> > platforms since then, so we are switching back to the defaults now.
> >
> > ~ Judith
> >
> > > [0] https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/j722s/clocks.html
> > >
> > > Thanks
> > >
> > > Udit
> > >
> > > > Fixes: c37c58fdeb8a ("arm64: dts: ti: k3-am62: Add more peripheral
> > > > nodes")
> > > > Fixes: d3ae4e8d8b6a ("arm64: dts: ti: k3-am62a-main: Add sdhci0
> > > > instance")
> > > > Fixes: b5080c7c1f7e ("arm64: dts: ti: k3-am62p: Add nodes for more IPs")
>
> Please follow ./Documentation/process/stable-kernel-rules.rst - this is
> easier to backport if these were to be split into 3 different patches.
> Please do not forget to add Cc: stable@xxxxxxxxxxxxxxx as per the rules
> as well.

Understood, will split-up this series and respin, thanks.

~ Judith

> > > > Signed-off-by: Judith Mendez <jm@xxxxxx>
> > > > ---
> > > >    arch/arm64/boot/dts/ti/k3-am62-main.dtsi               | 2 --
> > > >    arch/arm64/boot/dts/ti/k3-am62a-main.dtsi              | 2 --
> > > >    arch/arm64/boot/dts/ti/k3-am62p-j722s-common-main.dtsi | 2 --
> > > >    3 files changed, 6 deletions(-)
> > > >
> > > > [..]