Hi,

Thanks!
I understand that this patch does potentially affect boards with
external pull down.
To avoid this, I will move `enable-strobe-pulldown` to
rk3399-nanopi4.dtsi and send patch v2.


BR,
Jensen

On Wed, Aug 24, 2022 at 10:58 PM Doug Anderson [off-list ref] wrote:

Hi,

On Tue, Aug 23, 2022 at 8:11 PM Jensen Huang
[off-list ref] wrote:

quoted

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.

quoted

BR,
Jensen

On Tue, Aug 23, 2022 at 10:13 PM Doug Anderson [off-list ref] wrote:

quoted

Hi,

On Tue, Aug 23, 2022 at 4:53 AM Heiko Stübner [off-list ref] wrote:

quoted

Am Montag, 22. August 2022, 09:41:39 CEST schrieb Jensen Huang:

quoted

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 <redacted>

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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