[U-Boot] [PATCH 13/13] bootcount: i2c: Delay after writing

[Heiko Schocher]

Hello Stefano,

Am 13.03.2019 um 11:04 schrieb Stefano Babic:
> Hi Ian,
> 
> On 31/01/19 15:21, Ian Ray wrote:
>> Since 2018.11, the pattern of bootcount load and store has changed such
>> that bootcount_inc() and bootcount_error() will load, increment, store,
>> and load *again*.  The second load exposes a timing problem whereby the
>> i2c read fails.  The root cause _seems_ to relate to performance of the
>> 24c08 EEPROM.  Insert a delay after writing to work around this.
>>
>> Signed-off-by: Ian Ray <ian.ray at ge.com>
>> ---
>>   drivers/bootcount/bootcount_i2c.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/bootcount/bootcount_i2c.c b/drivers/bootcount/bootcount_i2c.c
>> index ed22389..dd86426 100644
>> --- a/drivers/bootcount/bootcount_i2c.c
>> +++ b/drivers/bootcount/bootcount_i2c.c
>> @@ -64,6 +64,10 @@ void bootcount_store(ulong a)
>>   			CONFIG_BOOTCOUNT_ALEN, buf, sizeof(buf));
>>   	if (ret != 0)
>>   		puts("Error writing bootcount\n");
>> +	else
>> +		/* Datasheet claims 2 ms typical write cycle time.
>> +		 * This delay ensures that next read will succeed. */
>> +		mdelay(5);
>>   
> 
> I see, but this is device specific while bootcount_i2c should be
> device-unaware. I know this driver is used with PMIC where no delay is
> required. Heiko, is it ok to put a fix delay here or should be
> configurable ?

I would prefer here to make this timeout configurable, thinking
about boottime constraints.

bye,
Heiko
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