linux-kernel - Re: [PATCH v1] Input: tegra-kbc - report wakeup key for some platforms.

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Date:	Wed, 30 Nov 2011 13:20:22 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	riyer@...dia.com
Cc:	rydberg@...omail.se, swarren@...dia.com, ldewangan@...dia.com,
	linux-kernel@...r.kernel.org, linux-input@...r.kernel.org,
	linux-tegra@...r.kernel.org
Subject: Re: [PATCH v1] Input: tegra-kbc - report wakeup key for some
 platforms.

Hi Rakesh,

On Wed, Nov 30, 2011 at 12:43:31PM -0800, riyer@...dia.com wrote:
> From: Rakesh Iyer <riyer@...dia.com>
> 
> Tegra kbc cannot detect exact keypress causing wakeup in interrupt mode.
> Allow wakeup keypress to be reported for certain platforms.
> 
> Signed-off-by: Rakesh Iyer <riyer@...dia.com>
> ---
>  arch/arm/mach-tegra/include/mach/kbc.h |    1 +
>  drivers/input/keyboard/tegra-kbc.c     |   20 ++++++++++++++++----
>  2 files changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/arch/arm/mach-tegra/include/mach/kbc.h b/arch/arm/mach-tegra/include/mach/kbc.h
> index 4f3572a..20bb054 100644
> --- a/arch/arm/mach-tegra/include/mach/kbc.h
> +++ b/arch/arm/mach-tegra/include/mach/kbc.h
> @@ -53,6 +53,7 @@ struct tegra_kbc_platform_data {
>  	struct tegra_kbc_pin_cfg pin_cfg[KBC_MAX_GPIO];
>  	const struct matrix_keymap_data *keymap_data;
>  
> +	u32 wakeup_key;
>  	bool wakeup;
>  	bool use_fn_map;
>  	bool use_ghost_filter;
> diff --git a/drivers/input/keyboard/tegra-kbc.c b/drivers/input/keyboard/tegra-kbc.c
> index cf3228b..ceb1185 100644
> --- a/drivers/input/keyboard/tegra-kbc.c
> +++ b/drivers/input/keyboard/tegra-kbc.c
> @@ -52,6 +52,7 @@
>  /* KBC Interrupt Register */
>  #define KBC_INT_0	0x4
>  #define KBC_INT_FIFO_CNT_INT_STATUS	(1 << 2)
> +#define KBC_INT_KEYPRESS_INT_STATUS	(1 << 0)
>  
>  #define KBC_ROW_CFG0_0	0x8
>  #define KBC_COL_CFG0_0	0x18
> @@ -74,10 +75,12 @@ struct tegra_kbc {
>  	unsigned int cp_to_wkup_dly;
>  	bool use_fn_map;
>  	bool use_ghost_filter;
> +	bool keypress_caused_wake;
>  	const struct tegra_kbc_platform_data *pdata;
>  	unsigned short keycode[KBC_MAX_KEY * 2];
>  	unsigned short current_keys[KBC_MAX_KPENT];
>  	unsigned int num_pressed_keys;
> +	u32 wakeup_key;
>  	struct timer_list timer;
>  	struct clk *clk;
>  };
> @@ -409,6 +412,9 @@ static irqreturn_t tegra_kbc_isr(int irq, void *args)
>  		 */
>  		tegra_kbc_set_fifo_interrupt(kbc, false);
>  		mod_timer(&kbc->timer, jiffies + kbc->cp_dly_jiffies);
> +	} else if (val & KBC_INT_KEYPRESS_INT_STATUS) {
> +		/* We can be here only through system resume path */
> +		kbc->keypress_caused_wake = true;
>  	}
>  
>  	spin_unlock_irqrestore(&kbc->lock, flags);
> @@ -674,9 +680,10 @@ static int __devinit tegra_kbc_probe(struct platform_device *pdev)
>  	keymap_data = pdata->keymap_data ?: &tegra_kbc_default_keymap_data;
>  	matrix_keypad_build_keymap(keymap_data, KBC_ROW_SHIFT,
>  				   input_dev->keycode, input_dev->keybit);
> +	kbc->wakeup_key = pdata->wakeup_key;
>  
> -	err = request_irq(kbc->irq, tegra_kbc_isr, IRQF_TRIGGER_HIGH,
> -			  pdev->name, kbc);
> +	err = request_irq(kbc->irq, tegra_kbc_isr,
> +			  IRQF_NO_SUSPEND | IRQF_TRIGGER_HIGH, pdev->name, kbc);
>  	if (err) {
>  		dev_err(&pdev->dev, "failed to request keyboard IRQ\n");
>  		goto err_put_clk;
> @@ -738,7 +745,6 @@ static int tegra_kbc_suspend(struct device *dev)
>  
>  	mutex_lock(&kbc->idev->mutex);
>  	if (device_may_wakeup(&pdev->dev)) {
> -		disable_irq(kbc->irq);
>  		del_timer_sync(&kbc->timer);
>  		tegra_kbc_set_fifo_interrupt(kbc, false);

This disturbs locking rules and allows timer to run past this point.
Instead of keeping interrupt enabled can't you simply read controller
state in tegra_kbc_resume (before enabling interrupt) and emit the
keycode if you detect KBC_INT_KEYPRESS_INT_STATUS condition?

Thanks.

-- 
Dmitry
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