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.reic...@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-in...@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-in...@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/ -- Sebastian
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