arm64: dts: rockchip: disable HS400 on RK3588 Tiger

We've had reports from the field that some RK3588 Tiger have random
issues with eMMC errors.

Applying commit a28352cf2d2f ("mmc: sdhci-of-dwcmshc: Change
DLL_STRBIN_TAPNUM_DEFAULT to 0x4") didn't help and seemed to have made
things worse for our board.

Our HW department checked the eMMC lines and reported that they are too
long and don't look great so signal integrity is probably not the best.

Note that not all Tigers with the same eMMC chip have errors, so the
suspicion is that we're really on the edge in terms of signal integrity
and only a handful devices are failing. Additionally, we have RK3588
Jaguars with the same eMMC chip but the layout is different and we also
haven't received reports about those so far.

Lowering the max-frequency to 150MHz from 200MHz instead of simply
disabling HS400 was briefly tested and seem to work as well. We've
disabled HS400 downstream and haven't received reports since so we'll go
with that instead of lowering the max-frequency.

Signed-off-by: Quentin Schulz <quentin.schulz@cherry.de>
Fixes: 6173ef24b35b ("arm64: dts: rockchip: add RK3588-Q7 (Tiger) SoM")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251112-tiger-hs200-v1-1-b50adac107c0@cherry.de
[added Fixes tag and stable-cc from 2nd mail]
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

0 files changed, 0 insertions, 0 deletions