[PATCH 0/3] mmc: sdhci_am654: Fix DDR50 mode for cards without tuning support

[Diogo Ivo (Schneider Electric)]

DDR50 mode is not required to support the tuning command CMD19 by the
eMMC/SD specification, meaning that calibration may fail on cards that
do not implement it. This series fixes three issues discovered when
using such cards:

  - Patch 1 ensures the command/data line reset is always performed
    after tuning, even on failure, preventing stale data in the
    controller buffer.

  - Patch 2 clears the ITAPDLY enable and delay values on tuning
    failure so that leftover calibration values do not interfere with
    subsequent I/O.

  - Patch 3 falls back to the DT-provided itap delay value for DDR50
    when tuning fails in this mode, making a best-effort attempt at a
    known-good delay being programmed.

Together these changes make DDR50 functional on TI J721E SoCs with
cards that lack CMD19 tuning support.

Signed-off-by: Diogo Ivo (Schneider Electric) <diogo.ivo@xxxxxxxxxxx>
---
Diogo Ivo (Schneider Electric) (3):
      mmc: sdhci_am654: Reset command and data lines on failed tuning
      mmc: sdhci_am654: Clear ITAPDLY on tuning failure
      mmc: sdhci_am654: Fallback to DT-provided itap delay on DDR50 tuning failure

 drivers/mmc/host/sdhci_am654.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)
---
base-commit: 62cc90241548d5570ee68e01aaba6506964e9811
change-id: 20260728-am654-sdhci-85094d458bae

Best regards,
--  
Diogo Ivo <diogo.ivo@xxxxxxxxxxx>