linux-kernel - Re: [PATCH 2/2] Input: omap-keypad: Fix idle configration to not block SoC idle states

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Date:   Mon, 3 Dec 2018 11:23:51 -0800
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Tony Lindgren <tony@...mide.com>
Cc:     linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-omap@...r.kernel.org, Axel Haslam <axelhaslam@...com>,
        Illia Smyrnov <illia.smyrnov@...com>,
        Marcel Partap <mpartap@....net>,
        Merlijn Wajer <merlijn@...zup.org>,
        Michael Scott <hashcode0f@...il.com>,
        NeKit <nekit1000@...il.com>, Pavel Machek <pavel@....cz>,
        Sebastian Reichel <sre@...nel.org>
Subject: Re: [PATCH 2/2] Input: omap-keypad: Fix idle configration to not
 block SoC idle states

On Sun, Dec 02, 2018 at 05:29:33PM -0800, Tony Lindgren wrote:
> With PM enabled, I noticed that pressing a key on the droid4 keyboard will
> block deeper idle states for the SoC. Looks like we can fix this by
> managing the idle register to gether with the interrupt similar to what
> we already do for the GPIO controller.
> 
> Note that we now must also disable OMAP4_DEF_IRQENABLE_LONGKEY as it
> should not be used together with debounce according to the TRM.
> 
> Cc: Axel Haslam <axelhaslam@...com>
> Cc: Illia Smyrnov <illia.smyrnov@...com>
> Cc: Marcel Partap <mpartap@....net>
> Cc: Merlijn Wajer <merlijn@...zup.org>
> Cc: Michael Scott <hashcode0f@...il.com>
> Cc: NeKit <nekit1000@...il.com>
> Cc: Pavel Machek <pavel@....cz>
> Cc: Sebastian Reichel <sre@...nel.org>
> Reported-by: Pavel Machek <pavel@....cz>
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>  drivers/input/keyboard/omap4-keypad.c | 28 ++++++++++++++-------------
>  1 file changed, 15 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/input/keyboard/omap4-keypad.c b/drivers/input/keyboard/omap4-keypad.c
> --- a/drivers/input/keyboard/omap4-keypad.c
> +++ b/drivers/input/keyboard/omap4-keypad.c
> @@ -53,11 +53,12 @@
>  /* OMAP4 bit definitions */
>  #define OMAP4_DEF_IRQENABLE_EVENTEN	BIT(0)
>  #define OMAP4_DEF_IRQENABLE_LONGKEY	BIT(1)
> -#define OMAP4_DEF_WUP_EVENT_ENA		BIT(0)
> -#define OMAP4_DEF_WUP_LONG_KEY_ENA	BIT(1)
>  #define OMAP4_DEF_CTRL_NOSOFTMODE	BIT(1)
>  #define OMAP4_DEF_CTRL_PTV_SHIFT	2
>  
> +#define OMAP4_KBD_IRQ_MASK		(OMAP4_DEF_IRQENABLE_LONGKEY | \
> +					 OMAP4_DEF_IRQENABLE_EVENTEN)
> +
>  /* OMAP4 values */
>  #define OMAP4_VAL_IRQDISABLE		0x0
>  
> @@ -127,9 +128,11 @@ static irqreturn_t omap4_keypad_irq_handler(int irq, void *dev_id)
>  	struct omap4_keypad *keypad_data = dev_id;
>  
>  	if (kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS)) {
> -		/* Disable interrupts */
> +		/* Disable interrupts and wake-up events */
>  		kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
>  				 OMAP4_VAL_IRQDISABLE);

I wonder, do we need to turn off interrupts at keyboard controller
level, or we should simply use IRQF_ONESHOT?

> +		kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE, 0);

So we are saying that disabling wakeup for the time between hard
interrupt firing, and when interrupt thread runs, makes much difference?
It is surprising to me... How long does it take to schedule interrupt
thread?

Thanks.

-- 
Dmitry