Re: [PATCH v2 3/5] mmc: mmci: stm32: use the delay block above 100 MHz on stm32mp25 SoC

From: Christophe KERELLO

Date: Thu Nov 05 2026 - 03:20:02 EST


Hello Mateusz,

On 11/4/26 16:27, Mateusz Nowicki wrote:
From: Christophe Kerello<christophe.kerello@xxxxxxxxxxx>

On stm32mp25 SoC, the delay block has to be used only for an external
data frequency above 100 MHz. Skip the tuning up to that frequency, keep
50 MHz for stm32mp15 as before.

Fixes: b5c3eb385797 ("mmc: mmci: stm32: add delay block support for STM32MP25")
Cc:stable@xxxxxxxxxxxxxxx
Signed-off-by: Christophe Kerello<christophe.kerello@xxxxxxxxxxx>
[Mateusz: reworded the commit message, check dlyb before reading
min_freq, added Fixes and Cc stable]

Thanks for the fix.

Signed-off-by: Mateusz Nowicki<mateusz.nowicki@xxxxxxxxxx>
---

Notes:
On the STM32MP257F-DK (SDMMC2 kernel clock 200 MHz, eMMC in HS200 at
100 MHz) the writes failed with I/O errors in all 9 test runs without
this change, with sdmmc2 pins_a or pins_b and with or without NEGEDGE.
With it all 6 runs were correct, on both pin groups.

drivers/mmc/host/mmci_stm32_sdmmc.c | 16 +++++++++++-----
1 file changed, 11 insertions(+), 5 deletions(-)

Reviewed-by: Christophe Kerello <christophe.kerello@xxxxxxxxxxx>

Regards,
Christophe Kerello.