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

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Message-ID: <887EB3E7-D753-441D-9D84-1FCBB4C5E033@gmail.com>
Date:   Tue, 04 Dec 2018 11:15:06 -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 December 4, 2018 11:09:32 AM PST, Tony Lindgren <tony@...mide.com> wrote:
>Hi,
>
>* Dmitry Torokhov <dmitry.torokhov@...il.com> [181204 04:00]:
>> Hi Tony,
>> 
>> On Mon, Dec 03, 2018 at 03:12:51PM -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.
>> 
>> Can you show me where exactly we are doing this? I can't seem to find
>> the matching code.
>
>With your change it now becomes the fix, and we're just missing the
>clearing of the OMAP4_KBD_WAKEUPENABLE register in omap4_keypad_close.
>
>Does the following minimal version with updated comments make
>more sense now?

Awesome, thank you Tony.

>
>Regards,
>
>Tony
>
>8< --------------
>>From tony Mon Sep 17 00:00:00 2001
>From: Tony Lindgren <tony@...mide.com>
>Date: Tue, 4 Dec 2018 11:07:56 -0800
>Subject: [PATCH] Input: omap-keypad: Fix idle configration to not block
> SoC idle states
>
>With PM enabled, I noticed that pressing a key on the droid4 keyboard
>will
>block deeper idle states for the SoC. Let's fix this by using
>IRQF_ONESHOT
>and stop constantly toggling the device OMAP4_KBD_IRQENABLE register as
>suggested by Dmitry Torokhov <dmitry.torokhov@...il.com>.
>
>>From the hardware point of view, looks like we need to manage the
>registers
>for OMAP4_KBD_IRQENABLE and OMAP4_KBD_WAKEUPENABLE together to avoid
>blocking deeper SoC idle states. And with toggling of
>OMAP4_KBD_IRQENABLE
>register now gone with IRQF_ONESHOT, also the SoC idle state problem is
>gone during runtime. We still also need to clear OMAP4_KBD_WAKEUPENABLE
>in
>omap4_keypad_close() though to pair it with omap4_keypad_open() to
>prevent
>blocking deeper SoC idle states after rmmod omap4-keypad.
>
>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 | 16 ++++------------
> 1 file changed, 4 insertions(+), 12 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
>@@ -126,12 +126,8 @@ 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 */
>-		kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
>-				 OMAP4_VAL_IRQDISABLE);
>+	if (kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS))
> 		return IRQ_WAKE_THREAD;
>-	}
> 
> 	return IRQ_NONE;
> }
>@@ -173,11 +169,6 @@ static irqreturn_t omap4_keypad_irq_thread_fn(int
>irq, void *dev_id)
> 	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
> 			 kbd_read_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS));
> 
>-	/* enable interrupts */
>-	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
>-		OMAP4_DEF_IRQENABLE_EVENTEN |
>-				OMAP4_DEF_IRQENABLE_LONGKEY);
>-
> 	return IRQ_HANDLED;
> }
> 
>@@ -214,9 +205,10 @@ static void omap4_keypad_close(struct input_dev
>*input)
> 
> 	disable_irq(keypad_data->irq);
> 
>-	/* Disable interrupts */
>+	/* Disable interrupts and wake-up events */
> 	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQENABLE,
> 			 OMAP4_VAL_IRQDISABLE);
>+	kbd_writel(keypad_data, OMAP4_KBD_WAKEUPENABLE, 0);
> 
> 	/* clear pending interrupts */
> 	kbd_write_irqreg(keypad_data, OMAP4_KBD_IRQSTATUS,
>@@ -365,7 +357,7 @@ static int omap4_keypad_probe(struct
>platform_device *pdev)
> 	}
> 
>	error = request_threaded_irq(keypad_data->irq,
>omap4_keypad_irq_handler,
>-				     omap4_keypad_irq_thread_fn, 0,
>+				     omap4_keypad_irq_thread_fn, IRQF_ONESHOT,
> 				     "omap4-keypad", keypad_data);
> 	if (error) {
> 		dev_err(&pdev->dev, "failed to register interrupt\n");



-- 
Dmitry