Re: [PATCHv3 4/5] Input: EXC3000: Add support to query model and fw_version

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

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.

Thanks.

-- 
Dmitry