linux-kernel - Re: [PATCH 3/6] input: elants: support common touchscreen DT properties

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Message-ID: <2c9cd83c-518f-2f22-c3e7-ac629a181b8d@gmail.com>
Date:   Tue, 10 Dec 2019 18:21:02 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     linux-input@...r.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/6] input: elants: support common touchscreen DT
 properties

10.12.2019 05:38, Michał Mirosław пишет:
> On Tue, Dec 10, 2019 at 04:03:18AM +0300, Dmitry Osipenko wrote:
>> 10.12.2019 03:19, Michał Mirosław пишет:
>>> Support common DT properties like axis inversions to complement
>>> information obtained from device's firmware.a
> [...]
>>> @@ -498,10 +498,10 @@ static int elants_i2c_query_ts_info(struct elants_data *ts)
>>>  			 rows, cols, osr);
>>>  	} else {
>>>  		/* translate trace number to TS resolution */
>>> -		ts->x_max = ELAN_TS_RESOLUTION(rows, osr);
>>> -		ts->x_res = DIV_ROUND_CLOSEST(ts->x_max, phy_x);
>>> -		ts->y_max = ELAN_TS_RESOLUTION(cols, osr);
>>> -		ts->y_res = DIV_ROUND_CLOSEST(ts->y_max, phy_y);
>>> +		ts->prop.max_x = ELAN_TS_RESOLUTION(rows, osr);
>>> +		ts->x_res = DIV_ROUND_CLOSEST(ts->prop.max_x, phy_x);
>>> +		ts->prop.max_y = ELAN_TS_RESOLUTION(cols, osr);
>>> +		ts->y_res = DIV_ROUND_CLOSEST(ts->prop.max_y, phy_y);
>>>  	}
>>>  
>>>  	return 0;
>>> @@ -833,8 +833,7 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf,
>>>  
>>>  			input_mt_slot(input, i);
>>>  			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
>>> -			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
>>> -			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
>>> +			touchscreen_report_pos(input, &ts->prop, x, y, true);
>>>  			input_event(input, EV_ABS, ABS_MT_PRESSURE, p);
>>>  			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, w);
>>>  
>>> @@ -1251,13 +1250,15 @@ static int elants_i2c_probe(struct i2c_client *client,
>>>  	ts->input->name = "Elan Touchscreen";
>>>  	ts->input->id.bustype = BUS_I2C;
>>>  
>>> +	touchscreen_parse_properties(ts->input, true, &ts->prop);
>>
>> Shouldn't this function be invoked after setting the max x/y sizes with
>> the hardware values? That's what all other drivers do and then you won't
>> need to set the ts->prop.max_x/y above in the code.
> 
> This is done later in the series - this patch only adds axis inversion
> support and ignores DT-provided sizes.

What is the reason of splitting it into two patches?

Perhaps I'm still missing something, but why something a bit more simple
like this wouldn't yield exactly the same result:

diff --git a/drivers/input/touchscreen/elants_i2c.c
b/drivers/input/touchscreen/elants_i2c.c
index d4ad24ea54c8..8763a3b25c29 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -32,6 +32,7 @@
 #include <linux/slab.h>
 #include <linux/firmware.h>
 #include <linux/input/mt.h>
+#include <linux/input/touchscreen.h>
 #include <linux/acpi.h>
 #include <linux/of.h>
 #include <linux/gpio/consumer.h>
@@ -147,6 +148,8 @@ struct elants_data {

 	/* Must be last to be used for DMA operations */
 	u8 buf[MAX_PACKET_SIZE] ____cacheline_aligned;
+
+	struct touchscreen_properties prop;
 };

 static int elants_i2c_send(struct i2c_client *client,
@@ -807,8 +810,7 @@ static void elants_i2c_mt_event(struct elants_data
*ts, u8 *buf)

 			input_mt_slot(input, i);
 			input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
-			input_event(input, EV_ABS, ABS_MT_POSITION_X, x);
-			input_event(input, EV_ABS, ABS_MT_POSITION_Y, y);
+			touchscreen_report_pos(ts->input, &ts->prop, x, y, true);
 			input_event(input, EV_ABS, ABS_MT_PRESSURE, p);
 			input_event(input, EV_ABS, ABS_MT_TOUCH_MAJOR, w);

@@ -1249,6 +1251,8 @@ static int elants_i2c_probe(struct i2c_client *client,
 	input_abs_set_res(ts->input, ABS_MT_POSITION_X, ts->x_res);
 	input_abs_set_res(ts->input, ABS_MT_POSITION_Y, ts->y_res);

+	touchscreen_parse_properties(ts->input, true, &ts->prop);
+
 	error = input_register_device(ts->input);
 	if (error) {
 		dev_err(&client->dev,