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

[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 ?

Best regards,
Stefano Babic

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