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Message-ID: <20080724115139.GC8301@fluff.org.uk>
Date: Thu, 24 Jul 2008 12:51:39 +0100
From: Ben Dooks <ben-linux@...ff.org>
To: Ben Dooks <ben-linux@...ff.org>
Cc: linux-kernel@...r.kernel.org, david-b@...bell.net
Subject: Re: GPIO: Add generic gpio_to_irq call.
On Thu, Jul 24, 2008 at 12:46:27PM +0100, Ben Dooks wrote:
> 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 13:50:32.000000000 +0100
> +++ linux-2.6.26-quilt3/drivers/gpio/gpiolib.c 2008-07-22 15:20:26.000000000 +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);
hmm, this should have a check for chip->to_irq
being non-null before it.
> +
> + 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);
>
> /* 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 13:50:32.000000000 +0100
> +++ linux-2.6.26-quilt3/include/asm-generic/gpio.h 2008-07-22 15:21:05.000000000 +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,
> Index: linux-2.6.26-quilt3/Documentation/gpio.txt
> ===================================================================
> --- linux-2.6.26-quilt3.orig/Documentation/gpio.txt 2008-07-22 15:22:08.000000000 +0100
> +++ linux-2.6.26-quilt3/Documentation/gpio.txt 2008-07-22 15:27:14.000000000 +0100
> @@ -273,8 +273,9 @@ some GPIOs can't be used as IRQs.) It i
> number that wasn't set up as an input using gpio_direction_input(), or
> to use an IRQ number that didn't originally come from gpio_to_irq().
>
> -These two mapping calls are expected to cost on the order of a single
> -addition or subtraction. They're not allowed to sleep.
> +These two mapping calls are expected to cost on between the order of a
> +single addition or subtraction to obtaining an spinlock and using the
> +to_irq method of the relevant gpio chip. They're not allowed to sleep.
>
> Non-error values returned from gpio_to_irq() can be passed to request_irq()
> or free_irq(). They will often be stored into IRQ resources for platform
> @@ -400,6 +401,7 @@ They may also want to provide a custom v
> Trivial implementations of those functions can directly use framework
> code, which always dispatches through the gpio_chip:
>
> + #define gpio_to_irq __gpio_to_irq
> #define gpio_get_value __gpio_get_value
> #define gpio_set_value __gpio_set_value
> #define gpio_cansleep __gpio_cansleep
>
> --
> Ben (ben@...ff.org, http://www.fluff.org/)
>
> 'a smiley only costs 4 bytes'
> --
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--
Ben (ben@...ff.org, http://www.fluff.org/)
'a smiley only costs 4 bytes'
--
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