Re: [PATCH 3/4] phy: rockchip-emmc: configure default output tap delay
From: Heiko Stuebner
Date: Thu Jun 16 2016 - 19:36:51 EST
Am Donnerstag, 12. Mai 2016, 15:43:05 schrieb Brian Norris:
> The output tap delay controls helps maintain the hold requirements for
> eMMC. The exact value is dependent on the SoC and other factors, though
> it isn't really an exact science. But the default of 0 is not very good,
> as it doesn't give the eMMC much hold time, so let's bump up to 4
> (approx 90 degree phase?). If we need to configure this any further
> (e.g., based on board or speed factors), we may need to consider a
> device tree representation.
>
> Suggested-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
on my rk3399-evb board the emmc still runs nicely with this patch, so
Tested-by: Heiko Stuebner <heiko@xxxxxxxxx>