[PATCH] mmc: Fix missing 1 ms delay after mmc power up

[Peng Fan]

On Fri, Oct 31, 2025 at 03:59:51PM +0100, Christoph Stoidner wrote:
>mmc/sd specification requires a 1 ms delay (stable supply voltage)
>after vdd was enabled and before issuing first command.
>
>For most sdcard/soc combinations, the missing delay seems to be not a
>problem because the processing time between enabling vdd and the first
>command is often hundreds of microseconds or more. However, in our
>specific case, some sdcards were not detected by u-boot:
>* soc: NXP i.MX 93
>* sdcards: SanDisk Ultra, 64GB micro SDXC 1,
>           MediaRange, 8GB, SDHC
>* measured time between vdd and first command: approx. 784us
>* symptom: both sdcards did not respond at all to first commands,
>           u-boot mmc subsystem ran into timeout and stops to
>           initialize the cards
>
>Signed-off-by: Christoph Stoidner <c.stoidner at phytec.de>
>Cc: Peng Fan <peng.fan at nxp.com>
>Cc: Jaehoon Chung <jh80.chung at samsung.com>
>---

Applied.

Thanks,
Peng