Linux Input Archive on lore.kernel.org
 help / color / Atom feed
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Sebastian Reichel <sebastian.reichel@collabora.com>
Cc: Ahmet Inan <inan@distec.de>,
	Martin Fuzzey <martin.fuzzey@flowbird.group>,
	linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel@collabora.com
Subject: Re: [PATCHv3 4/5] Input: EXC3000: Add support to query model and fw_version
Date: Wed, 20 May 2020 22:54:00 -0700
Message-ID: <20200521055400.GX89269@dtor-ws> (raw)
In-Reply-To: <20200520212540.t73my7ireicuwbrs@earth.universe>

On Wed, May 20, 2020 at 11:25:40PM +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Wed, May 20, 2020 at 10:49:52AM -0700, Dmitry Torokhov wrote:
> > Hi Sebastian,
> > 
> > On Wed, May 20, 2020 at 05:39:35PM +0200, Sebastian Reichel wrote:
> > > Expose model and fw_version via sysfs. Also query the model
> > > in probe to make sure, that the I2C communication with the
> > > device works before successfully probing the driver.
> > > 
> > > This is a bit complicated, since EETI devices do not have
> > > a sync interface. Sending the commands and directly reading
> > > does not work. Sending the command and waiting for some time
> > > is also not an option, since there might be touch events in
> > > the mean time.
> > > 
> > > Last but not least we do not cache the results, since this
> > > interface can be used to check the I2C communication is still
> > > working as expected.
> > > 
> > > Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
> > > ---
> > >  .../ABI/testing/sysfs-driver-input-exc3000    |  15 ++
> > >  drivers/input/touchscreen/exc3000.c           | 145 +++++++++++++++++-
> > >  2 files changed, 159 insertions(+), 1 deletion(-)
> > >  create mode 100644 Documentation/ABI/testing/sysfs-driver-input-exc3000
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-driver-input-exc3000 b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> > > new file mode 100644
> > > index 000000000000..d79da4f869af
> > > --- /dev/null
> > > +++ b/Documentation/ABI/testing/sysfs-driver-input-exc3000
> > > @@ -0,0 +1,15 @@
> > > +What:		/sys/class/input/inputX/fw_version
> > > +Date:		May 2020
> > > +Contact:	linux-input@vger.kernel.org
> > > +Description:	Reports the firmware version provided by the touchscreen, for example "00_T6" on a EXC80H60
> > > +
> > > +		Access: Read
> > > +		Valid values: Represented as string
> > > +
> > > +What:		/sys/class/input/inputX/model
> > > +Date:		May 2020
> > > +Contact:	linux-input@vger.kernel.org
> > > +Description:	Reports the model identification provided by the touchscreen, for example "Orion_1320" on a EXC80H60
> > > +
> > > +		Access: Read
> > > +		Valid values: Represented as string
> > 
> > These are properties of the controller (i2c device), not input
> > abstraction class on top of it, so the attributes should be attached to
> > i2c_client instance.
> > 
> > Please use devm_device_add_group() in probe to instantiate them at the
> > proper level.
> 
> As written in the cover letter using devm_device_add_group() in
> probe routine results in a udev race condition:
> 
> http://kroah.com/log/blog/2013/06/26/how-to-create-a-sysfs-file-correctly/

This race has been solved with the addition of KOBJ_BIND/KOBJ_UNBIND
uevents that signal when driver is bound or unbound from the device.
Granted, current systemd/udev drops them as it does not know how to
"add" to the device state, but this is on systemd to solve.

Thanks.

-- 
Dmitry

  reply index

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-20 15:39 [PATCHv3 0/5] EXC3000 Updates Sebastian Reichel
2020-05-20 15:39 ` [PATCHv3 1/5] dt-bindings: touchscreen: Convert EETI EXC3000 touchscreen to json-schema Sebastian Reichel
2020-05-20 15:39 ` [PATCHv3 2/5] Input: EXC3000: switch to i2c's probe_new API Sebastian Reichel
2020-05-20 16:50   ` Enric Balletbo i Serra
2020-05-20 17:31   ` Dmitry Torokhov
2020-05-20 15:39 ` [PATCHv3 3/5] Input: EXC3000: add EXC80H60 and EXC80H84 support Sebastian Reichel
2020-05-20 17:45   ` Dmitry Torokhov
2020-05-20 21:20     ` Sebastian Reichel
2020-05-21  6:12       ` Dmitry Torokhov
2020-05-20 15:39 ` [PATCHv3 4/5] Input: EXC3000: Add support to query model and fw_version Sebastian Reichel
2020-05-20 16:53   ` Enric Balletbo i Serra
2020-05-20 17:49   ` Dmitry Torokhov
2020-05-20 21:25     ` Sebastian Reichel
2020-05-21  5:54       ` Dmitry Torokhov [this message]
2020-05-20 15:39 ` [PATCHv3 5/5] Input: EXC3000: Add reset gpio support Sebastian Reichel
2020-05-20 16:54   ` Enric Balletbo i Serra

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200521055400.GX89269@dtor-ws \
    --to=dmitry.torokhov@gmail.com \
    --cc=inan@distec.de \
    --cc=kernel@collabora.com \
    --cc=linux-input@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=martin.fuzzey@flowbird.group \
    --cc=sebastian.reichel@collabora.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux Input Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-input/0 linux-input/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-input linux-input/ https://lore.kernel.org/linux-input \
		linux-input@vger.kernel.org
	public-inbox-index linux-input

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-input


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git