From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH v3] input: keyboard: snvs_pwrkey: Send key events for i.MX6 S, DL and Q Date: Mon, 16 Sep 2019 16:37:01 -0700 Message-ID: <20190916233701.GH237523@dtor-ws> References: <20190904062329.97520-1-robin@protonic.nl> <20190912201300.GA636@penguin> <803592d161b9ca75d6ac1c2c54e891a1@protonic.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Robin Gong Cc: robin , "linux-input @ vger . kernel . org" , "linux-kernel @ vger . kernel . org" , Pengutronix Kernel Team , Marco Felsch , Shawn Guo , Adam Ford , "linux-arm-kernel @ lists . infradead . org" List-Id: linux-input@vger.kernel.org On Mon, Sep 16, 2019 at 07:45:37AM +0000, Robin Gong wrote: > On 2019/9/13 15:31 robin 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 > > >> --- > > >> @@ -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). Thanks. -- Dmitry