[PATCH 2/2] phy: rockchip-emmc: try to get drive impedance from DT

Shawn Lin shawn.lin at rock-chips.com
Thu Jan 5 17:09:53 PST 2017

On 2017/1/6 8:51, Doug Anderson wrote:
> Hi,
> On Thu, Jan 5, 2017 at 1:31 AM, Shawn Lin <shawn.lin at rock-chips.com> wrote:
>> Try to get drive impedance from DT and use it, otherwise
>> use 50ohm by default in order not to break the existing boards
>> as 50ohm works fine for them already.
>> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
>> ---
>>  drivers/phy/phy-rockchip-emmc.c | 29 ++++++++++++++++++++++++++++-
>>  1 file changed, 28 insertions(+), 1 deletion(-)
> I could have sworn that you somehow needed to make sure that the eMMC
> part itself needed to also be updated to be told the matching drive
> impedance so you don't get a mismatch.  How do you make that work?

No I didn't. So that means the eMMC part itself still couldn't be
updated. The intention for me to introduce this only for emmc phy is
that I got report that the default drive impedance of one eMMC is not
50ohms, so now we haven't been able to update it for eMMC part but maybe
we could just update it for the phy itself to match them in between.

> ...or am I just confused.  I meant to try to dig more, but ran out of
> time today.  :(
> -Doug

Best Regards
Shawn Lin

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