Re: [RFC/RFT PATCH 2/2] gpio: omap: ensure that runtime pm will disable unused gpio banks

[Tony Lindgren <tony@atomide.com>]

* Tony Lindgren <tony@atomide.com> [150307 00:08]:
> * grygorii.strashko@linaro.org <grygorii.strashko@linaro.org> [150306 11:27]:
> > From: Grygorii Strashko <grygorii.strashko@linaro.org>
> > 
> > Now there are two points related to Runtime PM usage:
> > 1) bank state doesn't need to be checked in places where
> > Rintime PM is used, bacause Runtime PM maintains its
> > own usage counter:
> >       if (!BANK_USED(bank))
> >                pm_runtime_get_sync(bank->dev);
> > so, it's safe to drop such checks.
> > 
> > 2) There is a call of pm_runtime_get_sync() in omap_gpio_irq_type(),
> > but no corresponding put. As result, GPIO devices could be
> > powered on forever if at least one GPIO was used as IRQ.
> > Hence, allow powering off GPIO banks by adding missed
> > pm_runtime_put(bank->dev) at the end of omap_gpio_irq_type().
> 
> Nice to see this happening, but I think before merging this we need
> to test to be sure that the pm_runtime calls actually match.. I'm
> not convinced right now.. We may still have uninitialized entry
> points similar to 3d009c8c61f9 ("gpio: omap: Fix bad device
> access with setup_irq()").

OK so I finally got around testing this along with your bank
removal set. Looks like this patch causes a regression at least
with n900 keyboard LEDs with off-idle. The LED won't come back
on after restore from off-idle. Anyways, now we have something
reproducable :) So I'll try to debug it further at some point,
might be few days before I get to it.

Regards,

Tony

 
> > Signed-off-by: Grygorii Strashko <grygorii.strashko@linaro.org>
> > ---
> >  drivers/gpio/gpio-omap.c | 17 +++++++----------
> >  1 file changed, 7 insertions(+), 10 deletions(-)
> > 
> > diff --git a/drivers/gpio/gpio-omap.c b/drivers/gpio/gpio-omap.c
> > index 2b2fc4b..b1176c5 100644
> > --- a/drivers/gpio/gpio-omap.c
> > +++ b/drivers/gpio/gpio-omap.c
> > @@ -497,8 +497,7 @@ static int omap_gpio_irq_type(struct irq_data *d, unsigned type)
> >  	unsigned long flags;
> >  	unsigned offset;
> >  
> > -	if (!BANK_USED(bank))
> > -		pm_runtime_get_sync(bank->dev);
> > +	pm_runtime_get_sync(bank->dev);
> >  
> >  #ifdef CONFIG_ARCH_OMAP1
> >  	if (d->irq > IH_MPUIO_BASE)
> > @@ -530,6 +529,8 @@ static int omap_gpio_irq_type(struct irq_data *d, unsigned type)
> >  	else if (type & (IRQ_TYPE_EDGE_FALLING | IRQ_TYPE_EDGE_RISING))
> >  		__irq_set_handler_locked(d->irq, handle_edge_irq);
> >  
> > +	pm_runtime_put(bank->dev);
> > +
> >  	return retval;
> >  }
> >  
> > @@ -680,8 +681,7 @@ static int omap_gpio_request(struct gpio_chip *chip, unsigned offset)
> >  	 * If this is the first gpio_request for the bank,
> >  	 * enable the bank module.
> >  	 */
> > -	if (!BANK_USED(bank))
> > -		pm_runtime_get_sync(bank->dev);
> > +	pm_runtime_get_sync(bank->dev);
> >  
> >  	spin_lock_irqsave(&bank->lock, flags);
> >  	/* Set trigger to none. You need to enable the desired trigger with
> > @@ -713,8 +713,7 @@ static void omap_gpio_free(struct gpio_chip *chip, unsigned offset)
> >  	 * If this is the last gpio to be freed in the bank,
> >  	 * disable the bank module.
> >  	 */
> > -	if (!BANK_USED(bank))
> > -		pm_runtime_put(bank->dev);
> > +	pm_runtime_put(bank->dev);
> >  }
> >  
> >  /*
> > @@ -807,8 +806,7 @@ static unsigned int omap_gpio_irq_startup(struct irq_data *d)
> >  	unsigned long flags;
> >  	unsigned offset = GPIO_INDEX(bank, gpio);
> >  
> > -	if (!BANK_USED(bank))
> > -		pm_runtime_get_sync(bank->dev);
> > +	pm_runtime_get_sync(bank->dev);
> >  
> >  	spin_lock_irqsave(&bank->lock, flags);
> >  	omap_gpio_init_irq(bank, gpio, offset);
> > @@ -835,8 +833,7 @@ static void omap_gpio_irq_shutdown(struct irq_data *d)
> >  	 * If this is the last IRQ to be freed in the bank,
> >  	 * disable the bank module.
> >  	 */
> > -	if (!BANK_USED(bank))
> > -		pm_runtime_put(bank->dev);
> > +	pm_runtime_put(bank->dev);
> >  }
> >  
> >  static void omap_gpio_ack_irq(struct irq_data *d)
> > -- 
> > 1.9.1
> > 
> --
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