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

[Tony Lindgren <tony@atomide.com>]

* 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()").

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
>