linux-kernel - RE: [PATCH] Input: elan_i2c - Implement inhibit/uninhibit functions.

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Date:   Fri, 28 Apr 2023 10:21:53 +0800
From:   "Jingle.Wu" <jingle.wu@....com.tw>
To:     "'Dmitry Torokhov'" <dmitry.torokhov@...il.com>
Cc:     <linux-kernel@...r.kernel.org>, <linux-input@...r.kernel.org>,
        <phoenix@....com.tw>, <josh.chen@....com.tw>,
        <dave.wang@....com.tw>
Subject: RE: [PATCH] Input: elan_i2c - Implement inhibit/uninhibit functions.

Hi Dmitry:
	During the initial process and when the users open/close device,
having the elan uninhibit/inhibit commands (low power mode) was not what
Elan expects to happen. Due to that touchpad would do the calibration in
uninhibit moment , we don't want the calibration to be affected by fingers
on the touchpad.
	However, the LID inhibit/uninhibit functions in the Linux kernel
driver calls open/close(), so we need to separate the inhibit/uninhibit
behavior from open/close() function
	
https://elixir.bootlin.com/linux/latest/source/drivers/input/input.c#L1783
	
https://elixir.bootlin.com/linux/latest/source/drivers/input/input.c#L1813

THANKS
JINGLE

-----Original Message-----
From: 'Dmitry Torokhov' [mailto:dmitry.torokhov@...il.com] 
Sent: Thursday, April 27, 2023 6:58 AM
To: Jingle.Wu <jingle.wu@....com.tw>
Cc: linux-kernel@...r.kernel.org; linux-input@...r.kernel.org;
phoenix@....com.tw; josh.chen@....com.tw; dave.wang@....com.tw
Subject: Re: [PATCH] Input: elan_i2c - Implement inhibit/uninhibit
functions.

Hi Jingle,

On Mon, Apr 10, 2023 at 09:26:04AM +0800, Jingle.Wu wrote:
> HI Dmitry:
> 
> > +static void elan_close(struct input_dev *input_dev) {
> > +	if ((input_dev->users) && (!input_dev->inhibited))
> > +		elan_inhibit(input_dev);
> 
> This check is for "only inhibit request", and elan_open() its check is 
> for "only uninhibit request".
> Because input_dev-> open() close() will be executed 2-3 times when
initial.

I do not see why this would be an issue if what you are doing is putting the
device into a low power mode.

If this issue is about need to re-calibrate after opening the lid on certain
devices, then I think we need to do the same that we did for the I2C-HID
connected devices on Redrix and hook this functionality to a LID handler.

Thanks.

--
Dmitry