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@xxxxxxxxxxxxx> > > > --- > > > .../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@xxxxxxxxxxxxxxx > > > +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@xxxxxxxxxxxxxxx > > > +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
