Re: [PATCH] gpio: tegra186: Add support for T186 GPIO

From: Thierry Reding
Date: Tue Nov 08 2016 - 12:58:17 EST


On Tue, Nov 08, 2016 at 09:49:27AM -0700, Stephen Warren wrote:
> On 11/08/2016 08:55 AM, Thierry Reding wrote:
> > On Mon, Nov 07, 2016 at 05:42:33PM -0800, Olof Johansson wrote:
> > > On Mon, Nov 7, 2016 at 5:21 AM, Thierry Reding <thierry.reding@xxxxxxxxx> wrote:
> > > > On Mon, Nov 07, 2016 at 08:53:37AM +0100, Linus Walleij wrote:
> > > > > On Wed, Nov 2, 2016 at 11:48 AM, Suresh Mangipudi <smangipudi@xxxxxxxxxx> wrote:
> > > > >
> > > > > > Add GPIO driver for T186 based platforms.
> > > > > > Adds support for MAIN and AON GPIO's from T186.
> > > > > >
> > > > > > Signed-off-by: Suresh Mangipudi <smangipudi@xxxxxxxxxx>
> > > > >
> > > > > Stephen/Thierry/Alexandre:
> > > > > Can I get your review on this Tegra thing?
> > > >
> > > > Can we hold off on this for a bit? I've got my own implementation of
> > > > this in my Tegra186 tree because I thought nobody else was working on
> > > > it. From a brief look they seem mostly similar but there are a couple
> > > > of differences that I need to take a closer look at (and do some more
> > > > intensive testing on).
> > >
> > > Be careful about discouraging other developers internally from
> > > participating upstream, Thierry.
> >
> > That was certainly not my intention. I do welcome any contributions,
> > internal or external.
> >
> > > Please don't become a bottleneck for your company's contributions.
> > > Rewriting stuff on your own isn't a scalable model.
> >
> > Like I said, I didn't rewrite this, I merely wrote the GPIO driver
> > because there wasn't one at the time and I wasn't aware of anyone else
> > working on one. Waiting for a GPIO driver to emerge would've prevented
> > me from making progress on other fronts.
>
> One issue here is that there are lots of patches destined for upstream in
> your own personal tree, but they aren't actually upstream yet. I think
> pushing more of your work into linux-next (and further upstream) faster
> would help people out. linux-next and other "standard" repos should be
> easily discoverable by anyway following any upstreaming HOWTOs, but those
> HOWTOs aren't going to mention your personal trees, so patches there
> effectively don't exist. Making the already extant work more discoverable
> will help prevent people duplicating work.

I had assumed that I had properly communicated what the canonical
temporary location for Tegra186 patches would be, but you're right that
it's probably easy to miss, and linux-next would be a more obvious
target.

> Related to this, I've been waiting rather a while for the Tegra186 DT
> binding patches I sent to be applied. I'd love to see them go in ASAP even
> if there's no kernel driver behind them. The bindings have been reviewed,
> ack'd, and they're in use in U-Boot already.

It's true, I've been promising this for weeks now. I'll get around to it
within the week. Please do prod me in case I don't. I promise I won't
get mad =)

> A thought on Tegra186: For a older supported SoCs, we obviously don't want
> to push changes upstream that aren't too well baked. However, for a new SoC
> that doesn't work yet, I'm tend to prioritize getting as much early work
> upstream as fast as possible (to try and unblock people working in other
> areas) over getting those patches perfect first. Release early, release
> often will help unblock people and parallelize work. Pipeline your own work
> rather than batching it all up to release at once.

I'm always hesitant to merge code that isn't functional or tested, but
perhaps I'm being a little overzealous here, and I'm evidently not doing
so great, so let me try to be more aggressive.

> P.S. don't take this email too personally or anything; I'm not trying to be
> complaining/critical or anything like that. It's just a few mild thoughts.

No offense taken, thanks for being constructive about it.

Thierry

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