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Message-ID: <901c91090807222047p46f8efcas493602c06a44e2ad@mail.gmail.com>
Date: Wed, 23 Jul 2008 11:47:48 +0800
From: "Ramax Lo" <ramaxlo@...il.com>
To: "Ben Dooks" <ben-linux@...ff.org>
Cc: linux-arm-kernel@...ts.arm.linux.org.uk,
linux-kernel@...r.kernel.org
Subject: Re: Add to_irq fields to gpiolib (with sample implementation)
2008/7/22 Ben Dooks <ben-linux@...ff.org>:
> On Mon, Jul 21, 2008 at 06:43:02PM +0800, Ramax Lo wrote:
>> 2008/7/18 Ben Dooks <ben-linux@...ff.org>:
>> > 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@...ff.org>
>> >
>> > 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@...ff.org>
>> >
>> > 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@...ff.org, http://www.fluff.org/)
>> >
>> > 'a smiley only costs 4 bytes'
>> >
>> > -------------------------------------------------------------------
>> > List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel
>> > FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php
>> > Etiquette: http://www.arm.linux.org.uk/mailinglists/etiquette.php
>> >
>>
>> -------------------------------------------------------------------
>> List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm-kernel
>> FAQ: http://www.arm.linux.org.uk/mailinglists/faq.php
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>
> --
> --
> Ben
>
> Q: What's a light-year?
> A: One-third less calories than a regular year.
>
>
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