Re: [PATCH 2/6] gpio / ACPI: Allocate ACPI specific data directly in acpi_gpiochip_add()

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Tue, Feb 25, 2014 at 03:21:55PM +0100, Rafael J. Wysocki wrote:
> On Monday, February 24, 2014 06:00:07 PM Mika Westerberg wrote:
> > We are going to add more ACPI specific data to accompany GPIO chip so
> > instead of allocating it per each use-case we allocate it once when
> > acpi_gpiochip_add() is called and release it when acpi_gpiochip_remove() is
> > called.
> > 
> > Doing this allows us to add more ACPI specific data by merely adding new
> > fields to struct acpi_gpio_chip.
> > 
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  drivers/gpio/gpiolib-acpi.c | 83 ++++++++++++++++++++++++++++++++-------------
> >  1 file changed, 59 insertions(+), 24 deletions(-)
> > 
> > diff --git a/drivers/gpio/gpiolib-acpi.c b/drivers/gpio/gpiolib-acpi.c
> > index b7db098ba060..5f5f107c2099 100644
> > --- a/drivers/gpio/gpiolib-acpi.c
> > +++ b/drivers/gpio/gpiolib-acpi.c
> > @@ -26,6 +26,11 @@ struct acpi_gpio_evt_pin {
> >  	unsigned int irq;
> >  };
> >  
> > +struct acpi_gpio_chip {
> > +	struct gpio_chip *chip;
> > +	struct list_head *evt_pins;
> 
> Hmm.  Why exactly evt_pins has to be a pointer?
> 
> > +};
> > +
> >  static int acpi_gpiochip_find(struct gpio_chip *gc, void *data)
> >  {
> >  	if (!gc->dev)
> > @@ -81,14 +86,14 @@ static irqreturn_t acpi_gpio_irq_handler_evt(int irq, void *data)
> >  	return IRQ_HANDLED;
> >  }
> >  
> > -static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
> > +static void acpi_gpio_chip_dh(acpi_handle handle, void *data)
> >  {
> >  	/* The address of this function is used as a key. */
> >  }
> >  
> >  /**
> >   * acpi_gpiochip_request_interrupts() - Register isr for gpio chip ACPI events
> > - * @chip:      gpio chip
> > + * @achip:      ACPI GPIO chip
> >   *
> >   * ACPI5 platforms can use GPIO signaled ACPI events. These GPIO interrupts are
> >   * handled by ACPI event methods which need to be called from the GPIO
> > @@ -96,9 +101,10 @@ static void acpi_gpio_evt_dh(acpi_handle handle, void *data)
> >   * gpio pins have acpi event methods and assigns interrupt handlers that calls
> >   * the acpi event methods for those pins.
> >   */
> > -static void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
> > +static void acpi_gpiochip_request_interrupts(struct acpi_gpio_chip *achip)
> 
> I would call the argument "acpi_gpio" instead of achip (and analogously below),
> because the structure is a "chip plus some additional info".

OK.

> 
> >  {
> >  	struct acpi_buffer buf = {ACPI_ALLOCATE_BUFFER, NULL};
> > +	struct gpio_chip *chip = achip->chip;
> >  	struct acpi_resource *res;
> >  	acpi_handle handle, evt_handle;
> >  	struct list_head *evt_pins = NULL;
> > @@ -123,12 +129,7 @@ static void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
> >  		evt_pins = kzalloc(sizeof(*evt_pins), GFP_KERNEL);
> >  		if (evt_pins) {
> >  			INIT_LIST_HEAD(evt_pins);
> > -			status = acpi_attach_data(handle, acpi_gpio_evt_dh,
> > -						  evt_pins);
> > -			if (ACPI_FAILURE(status)) {
> > -				kfree(evt_pins);
> > -				evt_pins = NULL;
> > -			}
> > +			achip->evt_pins = evt_pins;
> 
> What about doing INIT_LIST_HEAD(&acpi_gpio->evt_pins) instead (if it's not a
> pointer)?
> 
> >  		}
> >  	}
> >  
> > @@ -197,30 +198,24 @@ static void acpi_gpiochip_request_interrupts(struct gpio_chip *chip)
> >  
> >  /**
> >   * acpi_gpiochip_free_interrupts() - Free GPIO _EVT ACPI event interrupts.
> > - * @chip:      gpio chip
> > + * @achip:      ACPI GPIO chip
> >   *
> >   * Free interrupts associated with the _EVT method for the given GPIO chip.
> >   *
> >   * The remaining ACPI event interrupts associated with the chip are freed
> >   * automatically.
> >   */
> > -static void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
> > +static void acpi_gpiochip_free_interrupts(struct acpi_gpio_chip *achip)
> 
> 
> 
> >  {
> > -	acpi_handle handle;
> > -	acpi_status status;
> >  	struct list_head *evt_pins;
> >  	struct acpi_gpio_evt_pin *evt_pin, *ep;
> > +	struct gpio_chip *chip = achip->chip;
> >  
> > -	if (!chip->dev || !chip->to_irq)
> > -		return;
> > -
> > -	handle = ACPI_HANDLE(chip->dev);
> > -	if (!handle)
> > +	if (!chip->dev || !chip->to_irq || !achip->evt_pins)
> >  		return;
> >  
> > -	status = acpi_get_data(handle, acpi_gpio_evt_dh, (void **)&evt_pins);
> > -	if (ACPI_FAILURE(status))
> > -		return;
> > +	evt_pins = achip->evt_pins;
> > +	achip->evt_pins = NULL;
> >  
> >  	list_for_each_entry_safe_reverse(evt_pin, ep, evt_pins, node) {
> >  		devm_free_irq(chip->dev, evt_pin->irq, evt_pin);
> > @@ -228,7 +223,6 @@ static void acpi_gpiochip_free_interrupts(struct gpio_chip *chip)
> >  		kfree(evt_pin);
> >  	}
> >  
> > -	acpi_detach_data(handle, acpi_gpio_evt_dh);
> >  	kfree(evt_pins);
> >  }
> >  
> > @@ -312,10 +306,51 @@ struct gpio_desc *acpi_get_gpiod_by_index(struct device *dev, int index,
> >  
> >  void acpi_gpiochip_add(struct gpio_chip *chip)
> >  {
> > -	acpi_gpiochip_request_interrupts(chip);
> > +	struct acpi_gpio_chip *achip;
> > +	acpi_handle handle;
> > +	acpi_status status;
> > +
> > +	handle = ACPI_HANDLE(chip->dev);
> > +	if (!handle)
> > +		return;
> > +
> > +	achip = kzalloc(sizeof(*achip), GFP_KERNEL);
> > +	if (!achip) {
> > +		dev_err(chip->dev,
> > +			"Failed to allocate memory for ACPI GPIO chip\n");
> > +		return;
> > +	}
> > +
> > +	achip->chip = chip;
> > +
> > +	status = acpi_attach_data(handle, acpi_gpio_chip_dh, achip);
> 
> To be honest, I'd prefer that to be associated with struct acpi_device rather
> than with the handle, but that's not a big deal for now.

OK, we can do that later if needed.