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

[Peng Fan]

Hi Christoph

Thanks for your patch.

> Subject: [PATCH] mmc: Fix missing 1 ms delay after mmc power up
...
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -2878,11 +2878,18 @@ static int mmc_power_cycle(struct mmc
> *mmc)
>  		return ret;
> 
>  	/*
> -	 * SD spec recommends at least 1ms of delay. Let's wait for
> 2ms
> -	 * to be on the safer side.
> +	 * SD spec recommends at least 1ms of 'power on' delay.
> +	 * Let's wait for 2ms to be on the safer side.
>  	 */
>  	udelay(2000);
> -	return mmc_power_on(mmc);
> +	ret = mmc_power_on(mmc);
> +
> +	/*
> +	 * SD spec recommends at least 1ms of 'stable supply voltage'
> delay.
> +	 * Let's wait for 2ms to be on the safer side.
> +	 */
> +	udelay(2000);

Per spec,                                                                                                  
>From Figure 6-4: Power-up Diagram of Card 
the 1ms is voltageSupply ramp up time, so I am thinking the fix 
should be in your regulator side, saying startup-delay-us property
in your regulator node.

Thanks,
Peng.

> +	return ret;
>  }
> 
>  int mmc_get_op_cond(struct mmc *mmc, bool quiet)
> --
> 2.43.0