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

[robin <robin@xxxxxxxxxxx>]

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@xxxxxxxxxxx>
> > ---
> >
> > Changes v2 -> v3:
> >  - Drop alt compatible string for identifying first revision snvs 
> > hardware,
> >    read minor revision from register instead.
> >  - Drop imx6qdl.dtsi modification and device-tree binding 
> > documentation.
> >  - Add an additional input_sync() to create 2 seperate input reports 
> > for press
> >    and release.
> >
> >  drivers/input/keyboard/Kconfig       |  2 +-
> >  drivers/input/keyboard/snvs_pwrkey.c | 28 
> > ++++++++++++++++++++++++++--
> >  2 files changed, 27 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/input/keyboard/Kconfig 
> > b/drivers/input/keyboard/Kconfig
> > index 7c4f19dab34f..937e58da5ce1 100644
> > --- a/drivers/input/keyboard/Kconfig
> > +++ b/drivers/input/keyboard/Kconfig
> > @@ -436,7 +436,7 @@ config KEYBOARD_SNVS_PWRKEY
> >  	depends on OF
> >  	help
> >  	  This is the snvs powerkey driver for the Freescale i.MX 
> > application
> > -	  processors that are newer than i.MX6 SX.
> > +	  processors.
> >
> >  	  To compile this driver as a module, choose M here; the
> >  	  module will be called snvs_pwrkey.
> > diff --git a/drivers/input/keyboard/snvs_pwrkey.c 
> > b/drivers/input/keyboard/snvs_pwrkey.c
> > index 5342d8d45f81..828580eee0d2 100644
> > --- a/drivers/input/keyboard/snvs_pwrkey.c
> > +++ b/drivers/input/keyboard/snvs_pwrkey.c
> > @@ -19,6 +19,7 @@
> >  #include <linux/mfd/syscon.h>
> >  #include <linux/regmap.h>
> >
> > +#define SNVS_HPVIDR1_REG 0xF8
> >  #define SNVS_LPSR_REG	0x4C	/* LP Status Register */
> >  #define SNVS_LPCR_REG	0x38	/* LP Control Register */
> >  #define SNVS_HPSR_REG	0x14
> > @@ -37,6 +38,7 @@ struct pwrkey_drv_data {
> >  	int wakeup;
> >  	struct timer_list check_timer;
> >  	struct input_dev *input;
> > +	u8 minor_rev;
> >  };
> >
> >  static void imx_imx_snvs_check_for_events(struct timer_list *t)
> > @@ -45,6 +47,20 @@ static void imx_imx_snvs_check_for_events(struct 
> > timer_list *t)
> >  	struct input_dev *input = pdata->input;
> >  	u32 state;
> >
> > +	if (pdata->minor_rev == 0) {
> > +		/*
> > +		 * The first generation i.MX6 SoCs only sends an interrupt on
> > +		 * button release. To mimic power-key usage, we'll prepend a
> > +		 * press event.
> > +		 */
> > +		input_report_key(input, pdata->keycode, 1);
> > +		input_sync(input);
> > +		input_report_key(input, pdata->keycode, 0);
> > +		input_sync(input);
> > +		pm_relax(input->dev.parent);
> > +		return;
> > +	}
> > +
> >  	regmap_read(pdata->snvs, SNVS_HPSR_REG, &state);
> >  	state = state & SNVS_HPSR_BTN ? 1 : 0;
> >
> > @@ -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.

Robin Gong proposed to move the code to imx_imx_snvs_check_for_events()
to improve readability and unload the ISR.

But since I, eventually, couldn't use the existing handling in
imx_imx_snvs_check_for_events(), I do see why you're asking.

I'll move the code to the ISR and submit a new patch.

Robin van der Gracht