[PATCH v2] mmc: mtk-sd: Fix register settings for hs400(es) mode

[AngeloGioacchino Del Regno]

Il 23/01/25 10:26, Andy-ld Lu ha scritto:
> For hs400(es) mode, the 'hs400-ds-delay' is typically configured in the
> dts. However, some projects may only define 'mediatek,hs400-ds-dly3',
> which can lead to initialization failures in hs400es mode. CMD13 reported
> response crc error in the mmc_switch_status() just after switching to
> hs400es mode.
> 
> [    1.914038][   T82] mmc0: mmc_select_hs400es failed, error -84
> [    1.914954][   T82] mmc0: error -84 whilst initialising MMC card
> 
> Currently, the hs400_ds_dly3 value is set within the tuning function. This
> means that the PAD_DS_DLY3 field is not configured before tuning process,
> which is the reason for the above-mentioned CMD13 response crc error.
> 
> Move the PAD_DS_DLY3 field configuration into msdc_prepare_hs400_tuning(),
> and add a value check of hs400_ds_delay to prevent overwriting by zero when
> the 'hs400-ds-delay' is not set in the dts. In addition, since hs400(es)
> only tune the PAD_DS_DLY1, the PAD_DS_DLY2_SEL bit should be cleared to
> bypass it.
> 
> Fixes: c4ac38c6539b ("mmc: mtk-sd: Add HS400 online tuning support")
> Signed-off-by: Andy-ld Lu <andy-ld.lu at mediatek.com>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>