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Subject: Re: [PATCH v4 03/10] input: elants: remove unused axes
To:     =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= <mirq-linux@rere.qmqm.pl>,
        David Heidelberg <david@ixit.cz>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Henrik Rydberg <rydberg@bitmath.org>,
        James Chen <james.chen@emc.com.tw>,
        Johnny Chuang <johnny.chuang@emc.com.tw>,
        Rob Herring <robh+dt@kernel.org>,
        Scott Liu <scott.liu@emc.com.tw>
Cc:     linux-input@vger.kernel.org, linux-kernel@vger.kernel.org
References: <cover.1587916846.git.mirq-linux@rere.qmqm.pl>
 <b6cb0f810eec2d5c6245d6128502eebd342ca02a.1587916846.git.mirq-linux@rere.qmqm.pl>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <0f66e93c-9c71-73d0-90b8-15e0802a79c5@gmail.com>
Date:   Sun, 26 Apr 2020 19:35:47 +0300
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26.04.2020 19:11, Michał Mirosław пишет:
> Driver only ever reports MT events and input_mt_init_slots() sets up
> emulated axes already.  Clear the capabilities not generated directly
> and move MT axes setup, so they are visible by input_mt_init_slots().
> 
> Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
> Tested-by: Dmitry Osipenko <digetx@gmail.com>
> ---
> v4: reword commitmsg; reorder axis setup
> ---

Legacy pointer emulation doesn't work using v4. I think it will be
better to drop this patch for now and add this hunk to the patch #4:

--- >8 ---
diff --git a/drivers/input/touchscreen/elants_i2c.c
b/drivers/input/touchscreen/elants_i2c.c
index 060c60c04f25..3644b5b48081 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -1414,6 +1414,8 @@ static int elants_i2c_probe(struct i2c_client *client,
 	input_abs_set_res(ts->input, ABS_X, ts->x_res);
 	input_abs_set_res(ts->input, ABS_Y, ts->y_res);

+	touchscreen_parse_properties(ts->input, false, &ts->prop);
+
 	/* Multitouch input params setup */
 	error = input_mt_init_slots(ts->input, MAX_CONTACT_NUM,
 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
--- >8 ---

This hunk makes the DT properties to be applied for the legacy pointer,
fixing the cursor position on Nexus 7 device using Ubuntu 12.04. The MT
still works fine using Ubuntu 20.04.

Maybe input_mt_init_slots() could be changed to set up all the
properties that are needed for the legacy pointer, but I'm not 100% sure
because not very familiar with that code. Perhaps Dmitry Torokhov could
clarify?