Re: [PATCH] OMAP GPIO - don't wake from suspend unless requested.

[NeilBrown]

On Thu, 6 Sep 2012 11:18:09 +0530 "Shilimkar, Santosh"
<santosh.shilimkar@xxxxxx> wrote:

> On Thu, Sep 6, 2012 at 8:35 AM, NeilBrown <neilb@xxxxxxx> wrote:
> > On Mon, 3 Sep 2012 22:59:06 -0700 "Shilimkar, Santosh"
> > <santosh.shilimkar@xxxxxx> wrote:

> >> After thinking bit more on this, the problem seems to be coming
> >> mainly because the gpio device is runtime suspended bit early than
> >> it should be. Similar issue seen with i2c driver as well. The i2c issue
> >> was discussed with Rafael at LPC last week. The idea is to move
> >> the pm_runtime_enable/disable() calls entirely up to the
> >> _late/_early stage of device suspend/resume.
> >> Will update this thread once I have further update.
> >
> > This won't be late enough.  IRQCHIP_MASK_ON_SUSPEND takes effect after all
> > the _late callbacks have been called.
> > I, too, spoke to Rafael about this in San Diego.  He seemed to agree with me
> > that the interrupt needs to be masked in the ->suspend callback.  any later
> > is too late.
> >
> Thanks for information about your discussion. Will wait for the patch then.
> 
> Regards
> santosh

I already sent a patch - that is what started this thread :-)

I include it below.
You said "The patch doesn't seems to be correct" but didn't expand on why.
Do you still think it is not correct?  I wouldn't be surprised if there is
some case that it doesn't handle quite right, but it seems right to me.

Thanks,
NeilBrown


From: NeilBrown <neilb@xxxxxxx>
Subject: [PATCH] OMAP GPIO - don't wake from suspend unless requested.

Current kernel will wake from suspend on an event on any active
GPIO even if enable_irq_wake() wasn't called.

There are two reasons that the hardware wake-enable bit should be set:

1/ while non-suspended the CPU might go into a deep sleep (off_mode)
  in which the wake-enable bit is needed for an interrupt to be
  recognised.
2/ while suspended the GPIO interrupt should wake from suspend if and
   only if irq_wake as been enabled.

The code currently doesn't keep these two reasons separate so they get
confused and sometimes the wakeup flags is set incorrectly.

This patch reverts:
 commit 9c4ed9e6c01e7a8bd9079da8267e1f03cb4761fc
    gpio/omap: remove suspend/resume callbacks
and
 commit 0aa2727399c0b78225021413022c164cb99fbc5e
    gpio/omap: remove suspend_wakeup field from struct gpio_bank

and makes some minor changes so that we have separate flags for "GPIO
should wake from deep idle" and "GPIO should wake from suspend".

With this patch, the GPIO from my touch screen doesn't wake my device
any more, which is what I want.

Cc: Kevin Hilman <khilman@xxxxxx>
Cc: Tony Lindgren <tony@xxxxxxxxxxx>
Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
Cc: Cousson Benoit <b-cousson@xxxxxx>
Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
Cc: Tarun Kanti DebBarma <tarun.kanti@xxxxxx>
Cc: Felipe Balbi <balbi@xxxxxx>
Cc: Govindraj.R <govindraj.raja@xxxxxx>

Signed-off-by: NeilBrown <neilb@xxxxxxx>

diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
index 4fbc208..fdbad70 100644
--- a/drivers/gpio/gpio-omap.c
+++ b/drivers/gpio/gpio-omap.c
@@ -57,6 +57,7 @@ struct gpio_bank {
 	u16 irq;
 	int irq_base;
 	struct irq_domain *domain;
+	u32 suspend_wakeup;
 	u32 non_wakeup_gpios;
 	u32 enabled_non_wakeup_gpios;
 	struct gpio_regs context;
@@ -522,11 +523,12 @@ static int _set_gpio_wakeup(struct gpio_bank *bank, int gpio, int enable)
 
 	spin_lock_irqsave(&bank->lock, flags);
 	if (enable)
-		bank->context.wake_en |= gpio_bit;
+		bank->suspend_wakeup |= gpio_bit;
 	else
-		bank->context.wake_en &= ~gpio_bit;
+		bank->suspend_wakeup &= ~gpio_bit;
 
-	__raw_writel(bank->context.wake_en, bank->base + bank->regs->wkup_en);
+	if (!bank->loses_context)
+		__raw_writel(bank->suspend_wakeup, bank->base + bank->regs->wkup_en);
 	spin_unlock_irqrestore(&bank->lock, flags);
 
 	return 0;
@@ -1157,6 +1159,51 @@ static int __devinit omap_gpio_probe(struct platform_device *pdev)
 #ifdef CONFIG_ARCH_OMAP2PLUS
 
 #if defined(CONFIG_PM_RUNTIME)
+
+#if defined(CONFIG_PM_SLEEP)
+static int omap_gpio_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct gpio_bank *bank = platform_get_drvdata(pdev);
+	void __iomem *base = bank->base;
+	unsigned long flags;
+
+	if (!bank->mod_usage || !bank->loses_context)
+		return 0;
+
+	if (!bank->regs->wkup_en || !bank->context.wake_en)
+		return 0;
+
+	spin_lock_irqsave(&bank->lock, flags);
+	_gpio_rmw(base, bank->regs->wkup_en, 0xffffffff, 0);
+	_gpio_rmw(base, bank->regs->wkup_en, bank->suspend_wakeup, 1);
+	spin_unlock_irqrestore(&bank->lock, flags);
+
+	return 0;
+}
+
+static int omap_gpio_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct gpio_bank *bank = platform_get_drvdata(pdev);
+	void __iomem *base = bank->base;
+	unsigned long flags;
+
+	if (!bank->mod_usage || !bank->loses_context)
+		return 0;
+
+	if (!bank->regs->wkup_en || !bank->context.wake_en)
+		return 0;
+
+	spin_lock_irqsave(&bank->lock, flags);
+	_gpio_rmw(base, bank->regs->wkup_en, 0xffffffff, 0);
+	_gpio_rmw(base, bank->regs->wkup_en, bank->context.wake_en, 1);
+	spin_unlock_irqrestore(&bank->lock, flags);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
 static void omap_gpio_restore_context(struct gpio_bank *bank);
 
 static int omap_gpio_runtime_suspend(struct device *dev)
@@ -1386,11 +1433,14 @@ static void omap_gpio_restore_context(struct gpio_bank *bank)
 }
 #endif /* CONFIG_PM_RUNTIME */
 #else
+#define omap_gpio_suspend NULL
+#define omap_gpio_resume NULL
 #define omap_gpio_runtime_suspend NULL
 #define omap_gpio_runtime_resume NULL
 #endif
 
 static const struct dev_pm_ops gpio_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(omap_gpio_suspend, omap_gpio_resume)
 	SET_RUNTIME_PM_OPS(omap_gpio_runtime_suspend, omap_gpio_runtime_resume,
 									NULL)
 };

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