linux-kernel - Re: [PATCH v3] input: keyboard: snvs_pwrkey: Send key events for i.MX6 S, DL and Q

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Message-ID: <20191122224840.GE248138@dtor-ws>
Date:   Fri, 22 Nov 2019 14:48:40 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Robin Gong <yibin.gong@....com>
Cc:     robin <robin@...tonic.nl>, Marco Felsch <m.felsch@...gutronix.de>,
        "linux-input @ vger . kernel . org" <linux-input@...r.kernel.org>,
        "linux-kernel @ vger . kernel . org" <linux-kernel@...r.kernel.org>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Shawn Guo <shawnguo@...nel.org>,
        Adam Ford <aford173@...il.com>,
        "linux-arm-kernel @ lists . infradead . org" 
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v3] input: keyboard: snvs_pwrkey: Send key events for
 i.MX6 S, DL and Q

On Thu, Nov 21, 2019 at 01:17:56PM +0000, Robin Gong wrote:
> 
> On 2019-11-21 0:33, robin <robin@...tonic.nl> wrote:
> > On 2019-11-20 10:27, Marco Felsch wrote:
> > > Hi Robin,
> > >
> > > On 19-09-16 16:37, Dmitry Torokhov wrote:
> > >> On Mon, Sep 16, 2019 at 07:45:37AM +0000, Robin Gong wrote:
> > >> > On 2019/9/13 15:31 robin <robin@...tonic.nl> wrote:>
> > >> > > Hi Dmitry,
> > >> > >
> > >> > > On 2019-09-12 22:13, Dmitry Torokhov wrote:
> > >> > > > Hi Robin,
> > >> > > >
> > >> > > > On Wed, Sep 04, 2019 at 06:23:29AM +0000, Robin van der Gracht
> > wrote:
> > >> > > >> The first generation i.MX6 processors does not send an
> > >> > > >> interrupt when the power key is pressed. It sends a power down
> > >> > > >> request interrupt if the key is released before a hard
> > >> > > >> shutdown (5 second press). This should allow software to bring down
> > the SoC safely.
> > >> > > >>
> > >> > > >> For this driver to work as a regular power key with the older
> > >> > > >> SoCs, we need to send a keypress AND release when we get the
> > >> > > >> power down request irq.
> > >> > > >>
> > >> > > >> Signed-off-by: Robin van der Gracht <robin@...tonic.nl>
> > >> > > >> ---
> > >> > > >> @@ -67,13 +83,17 @@ static irqreturn_t
> > >> > > >> imx_snvs_pwrkey_interrupt(int irq, void *dev_id)  {
> > >> > > >>  	struct platform_device *pdev = dev_id;
> > >> > > >>  	struct pwrkey_drv_data *pdata = platform_get_drvdata(pdev);
> > >> > > >> +	unsigned long expire = jiffies;
> > >> > > >>  	u32 lp_status;
> > >> > > >>
> > >> > > >>  	pm_wakeup_event(pdata->input->dev.parent, 0);
> > >> > > >>
> > >> > > >>  	regmap_read(pdata->snvs, SNVS_LPSR_REG, &lp_status);
> > >> > > >> -	if (lp_status & SNVS_LPSR_SPO)
> > >> > > >> -		mod_timer(&pdata->check_timer, jiffies +
> > >> > > >> msecs_to_jiffies(DEBOUNCE_TIME));
> > >> > > >> +	if (lp_status & SNVS_LPSR_SPO) {
> > >> > > >> +		if (pdata->minor_rev > 0)
> > >> > > >> +			expire = jiffies + msecs_to_jiffies(DEBOUNCE_TIME);
> > >> > > >> +		mod_timer(&pdata->check_timer, expire);
> > >> > > >
> > >> > > > Why do we even need to fire the timer in case of the first
> > >> > > > generation hardware? Just send press and release events directly from
> > the ISR.
> > >> > That timer looks like a software debounce to prevent unexpected and
> > >> > meaningless interrupt/event caused by quick press/release.
> > >>
> > >> Right, but in case of the first generation hardware we schedule the
> > >> timer immediately (expire == 0) and do not check state of the
> > >> hardware in the timer handler, but rather simply emit down/up events,
> > >> so we do not really get any benefit from the timer (again, I am
> > >> talking about first generation hardware only).
> > >
> > > Did you prepared a v4? Just ask to avoid a duplicated work :)
> > 
> > No I haven't. Not sure what the public wants. Use timer, don't use timer..
> > 
> > v3 has had long term testing though ;)
> Sorry for that I miss the mail.
> Understood a little bit confusion about immediate timer for
> the first press, just stand on the view of clean code shape.
> But I'm okay if you prefer to remove timer in the first interrupt
> generation.

Yes, please prepare v4 without the timer for the first generation of the
hardware.

Thanks.

-- 
Dmitry