Re: Add to_irq fields to gpiolib (with sample implementation)

[Ramax Lo]

2008/7/22 Ben Dooks <ben-linux@xxxxxxxxx>:
> On Mon, Jul 21, 2008 at 06:43:02PM +0800, Ramax Lo wrote:
>> 2008/7/18 Ben Dooks <ben-linux@xxxxxxxxx>:
>> > The two patches form a pair of patches to show
>> > that we should consider adding an to_irq field
>> > to the gpio_chip structure and gpiolib support.
>> >
>>
>> Indeed, it's necessary to add a new field to provide
>> a general interface.
>>
>> > The reason is that if we add support for devices
>> > registering gpio to also register interrputs, then
>> > a single arch-dependant interrupt mapping is not
>> > going to be sufficient.
>> >
>> > Note, this set does not remove any clashing
>> > definitions that may have of gpio_to_irq.
>> >
>> > ---
>> > GPIO: Add generic gpio_to_irq call.
>> >
>> > Add gpio_to_irq() implementation allowing the
>> > gpio_chip registration to also specify an function
>> > to map GPIO offsets into IRQs.
>> >
>> > Signed-off-by: Ben Dooks <ben-linux@xxxxxxxxx>
>> >
>> > Index: linux-2.6.26-quilt3/drivers/gpio/gpiolib.c
>> > ===================================================================
>> > --- linux-2.6.26-quilt3.orig/drivers/gpio/gpiolib.c     2008-07-18 00:40:52.000000000 +0100
>> > +++ linux-2.6.26-quilt3/drivers/gpio/gpiolib.c  2008-07-18 00:52:07.000000000 +0100
>> > @@ -339,6 +339,36 @@ const char *gpiochip_is_requested(struct
>> >  }
>> >  EXPORT_SYMBOL_GPL(gpiochip_is_requested);
>> >
>> > +int gpio_to_irq(unsigned gpio)
>> > +{
>> > +       struct gpio_chip        *chip;
>> > +       struct gpio_desc        *desc = &gpio_desc[gpio];
>> > +       unsigned long           flags;
>> > +       int                     status = -EINVAL;
>> > +
>> > +       spin_lock_irqsave(&gpio_lock, flags);
>> > +
>> > +       if (!gpio_is_valid(gpio))
>> > +               goto fail;
>> > +
>> > +       chip = desc->chip;
>> > +       if (!chip || !chip->to_irq)
>> > +               goto fail;
>> > +
>> > +       gpio -= chip->base;
>> > +       if (gpio >= chip->ngpio)
>> > +               goto fail;
>> > +
>> > +       status = chip->to_irq(chip, gpio);
>> > +
>> > + fail:
>> > +       spin_unlock_irqrestore(&gpio_lock, flags);
>> > +       if (status)
>> > +               pr_debug("%s: gpio-%d status %d\n",
>> > +                       __func__, gpio, status);
>> > +       return status;
>> > +}
>> > +EXPORT_SYMBOL_GPL(gpio_to_irq);
>> >
>>
>> Is it possible to define it as __gpio_to_irq(), and let people
>> define their macro or inline function, like the case of
>> __gpio_get_value(), to maintain compatibility?
>
> Ok, should I resubmit with this changed?
>

Yes, thanks.

>> >  /* Drivers MUST set GPIO direction before making get/set calls.  In
>> >  * some cases this is done in early boot, before IRQs are enabled.
>> > Index: linux-2.6.26-quilt3/include/asm-generic/gpio.h
>> > ===================================================================
>> > --- linux-2.6.26-quilt3.orig/include/asm-generic/gpio.h 2008-07-18 00:40:52.000000000 +0100
>> > +++ linux-2.6.26-quilt3/include/asm-generic/gpio.h      2008-07-18 00:46:32.000000000 +0100
>> > @@ -40,6 +40,7 @@ struct module;
>> >  * @dbg_show: optional routine to show contents in debugfs; default code
>> >  *     will be used when this is omitted, but custom code can show extra
>> >  *     state (such as pullup/pulldown configuration).
>> > + * @to_irq: convert gpio offset to IRQ number.
>> >  * @base: identifies the first GPIO number handled by this chip; or, if
>> >  *     negative during registration, requests dynamic ID allocation.
>> >  * @ngpio: the number of GPIOs handled by this controller; the last GPIO
>> > @@ -71,6 +72,9 @@ struct gpio_chip {
>> >                                                unsigned offset, int value);
>> >        void                    (*dbg_show)(struct seq_file *s,
>> >                                                struct gpio_chip *chip);
>> > +       int                     (*to_irq)(struct gpio_chip *chip,
>> > +                                         unsigned offset);
>> > +
>> >        int                     base;
>> >        u16                     ngpio;
>> >        unsigned                can_sleep:1;
>> > @@ -97,6 +101,7 @@ extern int gpio_direction_output(unsigne
>> >  extern int gpio_get_value_cansleep(unsigned gpio);
>> >  extern void gpio_set_value_cansleep(unsigned gpio, int value);
>> >
>> > +extern int gpio_to_irq(unsigned gpio);
>> >
>> >  /* A platform's <asm/gpio.h> code may want to inline the I/O calls when
>> >  * the GPIO is constant and refers to some always-present controller,
>> >
>> >
>> > S3C24XX: Add gpio_to_irq implementation
>> >
>> > Add the necessary to_irq fields for the S3C24XX
>> > GPIO banks that support IRQs.
>> >
>> > Signed-off-by: Ben Dooks <ben-linux@xxxxxxxxx>
>> >
>> > Index: linux-2.6.26-quilt3/arch/arm/plat-s3c24xx/gpiolib.c
>> > ===================================================================
>> > --- linux-2.6.26-quilt3.orig/arch/arm/plat-s3c24xx/gpiolib.c    2008-07-18 12:35:15.000000000 +0100
>> > +++ linux-2.6.26-quilt3/arch/arm/plat-s3c24xx/gpiolib.c 2008-07-18 12:37:39.000000000 +0100
>> > @@ -150,6 +150,19 @@ static int s3c24xx_gpiolib_banka_output(
>> >        return 0;
>> >  }
>> >
>> > +static int s3c24xx_gpiolib_bankf_toirq(struct gpio_chip *chip, unsigned offset)
>> > +{
>> > +       if (offset < 4)
>> > +               return IRQ_EINT0 + offset;
>> > +
>> > +       return IRQ_EINT4 + (offset - 4);
>> > +}
>> > +
>> > +static int s3c24xx_gpiolib_bankg_toirq(struct gpio_chip *chip, unsigned offset)
>> > +{
>> > +       return IRQ_EINT8 + offset;
>> > +}
>> > +
>> >
>> >  struct s3c24xx_gpio_chip gpios[] = {
>> >        [0] = {
>> > @@ -228,6 +241,7 @@ struct s3c24xx_gpio_chip gpios[] = {
>> >                        .direction_output       = s3c24xx_gpiolib_output,
>> >                        .set                    = s3c24xx_gpiolib_set,
>> >                        .get                    = s3c24xx_gpiolib_get,
>> > +                       .to_irq                 = s3c24xx_gpiolib_bankf_toirq,
>> >                },
>> >        },
>> >        [6] = {
>> > @@ -241,6 +255,7 @@ struct s3c24xx_gpio_chip gpios[] = {
>> >                        .direction_output       = s3c24xx_gpiolib_output,
>> >                        .set                    = s3c24xx_gpiolib_set,
>> >                        .get                    = s3c24xx_gpiolib_get,
>> > +                       .to_irq                 = s3c24xx_gpiolib_bankg_toirq,
>> >                },
>> >        },
>> >  };
>> >
>> >
>> > --
>> > Ben (ben@xxxxxxxxx, http://www.fluff.org/)
>> >
>> >  'a smiley only costs 4 bytes'
>> >
>> > -------------------------------------------------------------------
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>> >
>>
>> -------------------------------------------------------------------
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>
> --
> --
> Ben
>
> Q:      What's a light-year?
> A:      One-third less calories than a regular year.
>
>
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