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

[zhangqing]

hi，

Reviewed-by: elaine.zhang<elaine.zhang at rock-chips.com>

在 2023/7/26 16:40, Jonas Karlman 写道:
> Hi Kever,
> On 2023-07-26 10:36, Kever Yang wrote:
>> 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?
> It probably is, linux apply a 400-500us range sleep so I went with upper
> limit of 500us for this patch.

This looks okay.

>
> Regards,
> Jonas
>
>> 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;
>>>    }
>>>    

-- 
张晴
瑞芯微电子股份有限公司
Rockchip Electronics Co.,Ltd
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