Hi Heiko
On 2017Äê12ÔÂ02ÈÕ 05:58, Heiko Stuebner wrote:
Am Freitag, 1. Dezember 2017, 13:42:46 CET schrieb Doug Anderson:
Hi,
On Wed, Nov 29, 2017 at 6:27 PM, Chris Zhong <zyw@xxxxxxxxxxxxxx> wrote:
Hi Doug
Thank you for mentioning this patch.
I think the focus of the discussion is: can we put the grf control bit to
dts.
The RK3399 has 2 Type-C phy, but only one DP controller, this "uphy_dp_sel"
can help to switch these 2 phy. So I think this bit can be considered as a
part of
Type-C phy, these 2 phy have different bits, just similar to other bits
(such as "pipe-status").
Put them to DTS file might be a accepted practice.
I guess the first step would be finding the person to make a decision.
Is that Heiko? Olof? Kishon? Rob?. As I see it there are a few
options:
1. Land this series as-is. This makes the new bit work just like all
the other ones next to it. If anyone happens to try to use an old
device tree on a new kernel they'll break. Seems rather unlikely
given that the whole type C PHY is not really fully functional
upstream, but technically this is a no-no from a device tree
perspective.
2. Change the series to make this property optional. If it's not
there then the code behaves like it always did. This would address
the "compatibility" problem but likely wouldn't actually help any real
people, and it would be extra work.
3. Redo the driver to deprecate all the old offsets / bits and just
put the table in the driver, keyed off the compatible string and base
address if the IO memory.
I can't make this decision. It's up to those folks who would be
landing the patch and I'd be happy with any of them. What I'm less
happy with, however, is the indecision preventing forward progress.
We should pick one of the above things and land it. My own personal
bias is #1: just land the series. No real people will be hurt and
it's just adding another property that matches the ones next to it.
I'd second that #1 . That whole type-c phy thingy never fully worked in
the past (some for the never used dp output), so personally I don't have
issues with going that route.
From a long term perspective (AKA how I'd write the next driver like
this) I personally lean towards to "tables in the driver, not in the
device tree" but quite honestly I'm happy to take whatever direction
the maintainers give.
It looks like we're in agreement here :-) . GRF stuff should not leak into
the devicetree, as it causes endless headaches later. But I guess we'll
need to live with the ones that happened so far.
So, the first step is: move all the private property of tcphy to
drivers/phy/rockchip/phy-rockchip-typec.c.
Second step: new a member: uphy-dp-sel.
In my mind, we should have discussed these properties before, and then I
moved them all into DTS.
--
Chris Zhong
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