Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Peter Rosin]

[CC'd linux-i2c@ and Wolfram Sang as the branch might end up with him]

On 2016-08-23 16:38, jic23-tko9wxEg+fIOOJlXag/Snyp2UmYkHbXO@public.gmane.org wrote:
> On 23.08.2016 09:37, Peter Rosin wrote:
>> On 2016-08-21 20:32, Jonathan Cameron wrote:
>>> On 15/08/16 19:38, Linus Walleij wrote:
>>>> Since the MPU-3050 has an outgoing I2C port it needs to act as
>>>> an I2C mux. This means that the device is switching I2C traffic
>>>> to devices beyond it. On my system this is the only way to reach
>>>> the accelerometer. The "sensor fusion" ability of the MPU-3050
>>>> to directly talk to the device on the outgoing I2C port is
>>>> currently not used by the driver, but it has code to allow I2C
>>>> traffic to pass through so that the Linux kernel can reach the
>>>> device on the other side with a kernel driver.
>>> Cc'd Peter Rosin as he's maintaining the i2c mux code now.
>>
>> The i2c-mux handling looks sane, with the current code, but I had
>> an update in mind for the next merge window that affects this:
>>
>> [PATCH v2 0/8] devicetree cleanup for i2c muxes/arbs/gates
>> https://lkml.org/lkml/2016/8/15/569
>>
>> Specifically patch 3/8 is relevant
>>
>> [PATCH v2 3/8] dt-bindings: i2c: add support for 'i2c-gate' subnode
>> https://lkml.org/lkml/2016/8/15/270
>>
>> (implemented in 5/7)
>>
>> The above is not in next (yet). I don't know how this situation is
>> best handled?
>>
>> Cheers,
>> Peter
> Hmm. Depends a bit on timing.  The merge window close for IIO is in
> perhaps 3 weeks time.  If this driver isn't ready reasonably quickly
> I'll probably hold it for next window anyway.
> 
> If we do want to do the mux stuff and this in the same window then
> the standard trick is a branch with just the relevant patches that
> are the dependency in it and we both merge that into our trees.
> Key thing is that we then don't touch this branch at all.
> 
> Git then sorts the mess out just fine when that works it's way to
> Linus.  The two trees will have the same commit id's for the patches
> so he'll get them via which ever tree he merges first.

Ok, but if the driver is ready in time, then this i2c-mux-dt-branch
needs to have soaked in next for at least a week before we start
relying on it. No?

Therefore, I better prepare the i2c-mux-dt-branch right away so that
there is also time to make use of it. My plan is that I make the branch
in the i2c-mux repo, then get it added to next somehow for soaking. I
do not currently have a branch registered to be included in next, and I
know it's just a matter of asking, but it seems rather pointless to add
one just for this one-off occurrence? And since my series is closer to
i2c than it is to iio, it feels righter to have it soak in next via the
i2c tree.

Wolfram, is that ok with you? Or should I just bite the bullet and ask
Stephen to include a brand new for-next branch from the i2c-mux repo
instead?

And a final question before I start with the i2c-mux-dt-branch; Is any
base better than any other for it? I know i2c/for-next is based on
v4.8-rc3 (at least currently, but I don't think Wolfram rebases
willy-nillilly). So, would v4.8-rc3 be ok as a base for everyone?

Cheers,
Peter

Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Wolfram Sang]

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> Wolfram, is that ok with you? Or should I just bite the bullet and ask
> Stephen to include a brand new for-next branch from the i2c-mux repo
> instead?

I had a glimpse of the series in question and it looks good to me. Looks
like I'll pull it in today or tomorrow.

But it may be nice to have a branch in your mux-repo that people can
pull anyhow? I usually don't like pulling all of linux-next when I only
want one specific feature.


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Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Peter Rosin]

On 2016-08-25 14:44, Linus Walleij wrote:
> On Tue, Aug 23, 2016 at 10:37 AM, Peter Rosin <peda@axentia.se> wrote:
> 
>> Specifically patch 3/8 is relevant
>>
>> [PATCH v2 3/8] dt-bindings: i2c: add support for 'i2c-gate' subnode
>> https://lkml.org/lkml/2016/8/15/270
> 
> Yup the gate is what I'm using.

You need to update the dt bindings to the new simpler form, and then
add the flag I2C_MUX_GATE to your i2c_mux_alloc call.

>> The above is not in next (yet). I don't know how this situation is
>> best handled?
> 
> I can put these patches into my development branch to get
> a working driver using the gate. But I'd prefer them be in -next
> when I pick them.
> 
> Then the rest is merge mechanics, dunno the best there,
> Jonathan can decide.

I waited a bit for someone to scream about v4.8-rc3 being a bad base
for some reason, but there was only silence. I have now pushed the
series, and it can be pulled by anyone interested.

Wolfram, please merge it into i2c/for-next

Linus/Jonathan, technically you don't need all patches and can skip
the last three, but it seems a bit over the top to be super anal
about that detail...

Cheers,
Peter


The following changes since commit fa8410b355251fd30341662a40ac6b22d3e38468:

  Linux 4.8-rc3 (2016-08-21 16:14:10 -0700)

are available in the git repository at:

  https://github.com/peda-r/i2c-mux.git i2c-mux-dt-3

for you to fetch changes up to 8a191a7ad4ca9022bb838387b20d3de6acc88b72:

  i2c: pca954x: add device tree binding (2016-08-25 22:11:04 +0200)

----------------------------------------------------------------
Peter Rosin (8):
      dt-bindings: i2c: add support for 'i2c-mux' subnode
      dt-bindings: i2c: add support for 'i2c-arb' subnode
      dt-bindings: i2c: add support for 'i2c-gate' subnode
      dt-bindings: i2c: add bindings for nxp,pca9541
      i2c: mux: add support for 'i2c-mux', 'i2c-arb' and 'i2c-gate' DT subnodes
      i2c: mux: inform the i2c mux core about how it is used
      i2c: pca9541: add device tree binding
      i2c: pca954x: add device tree binding

 .../bindings/i2c/i2c-arb-gpio-challenge.txt        |  8 +---
 Documentation/devicetree/bindings/i2c/i2c-arb.txt  | 35 ++++++++++++++++
 Documentation/devicetree/bindings/i2c/i2c-gate.txt | 41 +++++++++++++++++++
 Documentation/devicetree/bindings/i2c/i2c-mux.txt  | 23 ++++++++---
 .../devicetree/bindings/i2c/nxp,pca9541.txt        | 29 ++++++++++++++
 MAINTAINERS                                        |  2 +
 drivers/i2c/i2c-mux.c                              | 44 +++++++++++++++++----
 drivers/i2c/muxes/i2c-arb-gpio-challenge.c         |  2 +-
 drivers/i2c/muxes/i2c-mux-pca9541.c                | 11 +++++-
 drivers/i2c/muxes/i2c-mux-pca954x.c                | 46 ++++++++++++++++------
 include/linux/i2c-mux.h                            |  8 +++-
 11 files changed, 214 insertions(+), 35 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb.txt
 create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gate.txt
 create mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9541.txt

Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Wolfram Sang]

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> Wolfram, please merge it into i2c/for-next

Pulled, thanks!


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Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Linus Walleij]

On Thu, Aug 25, 2016 at 10:32 PM, Peter Rosin <peda-koto5C5qi+TLoDKTGw+V6w@public.gmane.org> wrote:
> On 2016-08-25 14:44, Linus Walleij wrote:

>> Then the rest is merge mechanics, dunno the best there,
>> Jonathan can decide.
>
> I waited a bit for someone to scream about v4.8-rc3 being a bad base
> for some reason, but there was only silence. I have now pushed the
> series, and it can be pulled by anyone interested.
>
> Wolfram, please merge it into i2c/for-next
>
> Linus/Jonathan, technically you don't need all patches and can skip
> the last three, but it seems a bit over the top to be super anal
> about that detail...

OK I'll pull this into my development branch. At least we can
merge the bindings, whether to merge the driver this or next merge
window (or simply apply the patch to the I2C tree!) is another issue.

Yours,
Linus Walleij

Re: [PATCH 2/2] iio: gyro: Add driver for the MPU-3050 gyroscope

[Jonathan Cameron]

On 26/08/16 08:39, Linus Walleij wrote:
> On Thu, Aug 25, 2016 at 10:32 PM, Peter Rosin <peda@axentia.se> wrote:
>> On 2016-08-25 14:44, Linus Walleij wrote:
> 
>>> Then the rest is merge mechanics, dunno the best there,
>>> Jonathan can decide.
>>
>> I waited a bit for someone to scream about v4.8-rc3 being a bad base
>> for some reason, but there was only silence. I have now pushed the
>> series, and it can be pulled by anyone interested.
>>
>> Wolfram, please merge it into i2c/for-next
>>
>> Linus/Jonathan, technically you don't need all patches and can skip
>> the last three, but it seems a bit over the top to be super anal
>> about that detail...
> 
> OK I'll pull this into my development branch. At least we can
> merge the bindings, whether to merge the driver this or next merge
> window (or simply apply the patch to the I2C tree!) is another issue.
> 
> Yours,
> Linus Walleij
When you post future versions Linus, please include a mention of 
the dependency and a link to Peter's tree.

Peter, please can keep that branch around for now.

If we get this sorted in time to be prior to the next merge window
I'll pull your tree into IIO as well as Wolfram having already
pulled it into i2c.  Both will work there way upstream and
all will be fine.  My pull request tag will simply have a description
of why we are doing this.

Jonathan
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