Hi Chris, Am Montag, 4. Dezember 2017, 10:47:08 CET schrieb Chris Zhong: > On 2017年12月02日 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 <z...@rock-chips.com> 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.
Actually, I was agreeing with Doug, that we probably don't need to rework the type-c phy driver. As most properties for it are in the devicetree right now we'll need to support them for backwards-compatiblity anyway. And yes, there probably was discussion over dts vs. driver-table when the type-c driver was introduced, but I either missed it or wasn't firm enough back then ;-) . Hence the "we'll need to live with it" for the type-c phy, but should not do similar things in future drivers. Heiko
