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Message-ID: <901c91090807210343r3c483656p6c9b2ef77ffee2a0@mail.gmail.com>
Date: Mon, 21 Jul 2008 18:43:02 +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)
2008/7/18 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?
> /* 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
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>
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