Messages in this thread | | | From | Doug Anderson <> | Date | Wed, 24 Aug 2022 07:57:44 -0700 | Subject | Re: [PATCH] arm64: dts: rockchip: add enable-strobe-pulldown to emmc phy on rk3399 |
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Hi,
On Tue, Aug 23, 2022 at 8:11 PM Jensen Huang <jensenhuang@friendlyarm.com> wrote: > > Hi, > > Sorry for sending an email in HTML format. > > I realized that only some devices may be affected, so I considered > modifying rk3399-nanopi4.dtsi only, > but other boards without external pull-down should still need this patch.
I guess the other alternative would be to change how the dt property works. You could say:
1. If `enable-strobe-pulldown` is set then enable the strobe pulldown.
2. If `enable-strobe-pulldown` is not set then don't touch the pin in the kernel.
3. If someone later needs to explicitly disable the strobe pulldown they could add a new property like `disable-strobe-pulldown`.
Obviously there are tradeoffs between that and what you've done and I'm happy to let others make the call of which they'd prefer.
> BR, > Jensen > > On Tue, Aug 23, 2022 at 10:13 PM Doug Anderson <dianders@chromium.org> wrote: > > > > Hi, > > > > On Tue, Aug 23, 2022 at 4:53 AM Heiko Stübner <heiko@sntech.de> wrote: > > > > > > Am Montag, 22. August 2022, 09:41:39 CEST schrieb Jensen Huang: > > > > Internal pull-down for strobe line (GRF_EMMCPHY_CON2[9]) was disabled > > > > by commit 8b5c2b45b8f0, which causes I/O error in HS400 mode. > > > > > > > > Tested on NanoPC-T4. > > > > > > > > Fixes: 8b5c2b45b8f0 ("phy: rockchip: set pulldown for strobe line in dts") > > > > Signed-off-by: Jensen Huang <jensenhuang@friendlyarm.com> > > > > > > ok, so this looks like it restores previous functionality. > > > > > > I'm just wondering as the "offending" patch is from 2020, why this > > > only turns up now. Any ideas? > > > > Ah, I see. So before the offending patch we used to just leave the > > pull state at whatever the default was when the kernel was booted. > > After the offending patch we chose a default. > > > > On kevin I see an external pull down on this line. Enabling both the > > internal and external is probably not a huge deal, it'll just affect > > the strength of the pull. > > > > On bob I _think_ the external pull down is also stuffed. > > > > ...so I guess that would explain why it didn't cause a problem for at > > least those two boards? > > > > -Doug
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