[PATCH 2/2] power: regulator: rk8xx: Add 500us delay after LDO regulator is enabled

[Kever Yang]

Hi Jonas,

On 2023/7/2 20:41, Jonas Karlman wrote:
> A quick power cycle of a LDO regulator during dw-mmc signal voltage
> change has shown that SD-card does not always get recognized.
>
> Linux driver use an enable_time of 400us for LDO regulators. Apply a
> 500us delay when a LDO regulator is enabled to fix possible issues.

Does 400us not enough for the board you test?

Hi Elaine,

     Could help to check this change?


Thanks,

- Kever

>
> Fixes: 94afc1cb466a ("power: regulator: rk8xx: update the driver for rk808 and rk818")
> Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
> ---
>   drivers/power/regulator/rk8xx.c | 4 ++++
>   1 file changed, 4 insertions(+)
>
> diff --git a/drivers/power/regulator/rk8xx.c b/drivers/power/regulator/rk8xx.c
> index 0ee07ad299d7..e95640a39b0a 100644
> --- a/drivers/power/regulator/rk8xx.c
> +++ b/drivers/power/regulator/rk8xx.c
> @@ -12,6 +12,7 @@
>   #include <dm.h>
>   #include <errno.h>
>   #include <log.h>
> +#include <linux/delay.h>
>   #include <power/rk8xx_pmic.h>
>   #include <power/pmic.h>
>   #include <power/regulator.h>
> @@ -616,6 +617,9 @@ static int _ldo_set_enable(struct udevice *pmic, int ldo, bool enable)
>   		break;
>   	}
>   
> +	if (enable)
> +		udelay(500);
> +
>   	return ret;
>   }
>