On Fri, 29 Dec 2006, David Brownell wrote:
> Here's a version that compiles ...
This patch is completely broken.
> Arch-neutral GPIO calls for PXA.
This is not PXA but SA1100 to start with.
> Signed-off-by: David Brownell <[email protected]>
>
> Index: pxa/include/asm-arm/arch-sa1100/gpio.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ pxa/include/asm-arm/arch-sa1100/gpio.h 2006-12-29
> 18:21:00.000000000 -0800
> @@ -0,0 +1,100 @@
[...]
> +static inline int gpio_direction_input(unsigned gpio)
> +{
> + if (gpio > GPIO_MAX)
> + return -EINVAL;
> + GPDR = (GPDR_In << gpio);
This is crap. It will expand to GPDR = 0 effectively making _all_ gpios
as input.
What you want here is:
GPDR &= ~(1 << gpio);
and you most probably need to protect the implied read-modify-write
cycle with a spinlock unless the generic gpio API expects this
protection is the responsibility of the caller.
> +static inline int gpio_direction_output(unsigned gpio)
> +{
> + if (gpio > GPIO_MAX)
> + return -EINVAL;
> + GPDR = (GPDR_Out << gpio);
Same issue, although this would make all gpios as input except for the
specified one.
What you want is:
GPDR |= (1 << gpio);
And again spinlock protection is probably needed.
> +static inline int __gpio_get_value(unsigned gpio)
> +{
> + return GPLR & GPIO_GPIO(gpio);
> +}
> +
> +#define gpio_get_value(gpio) \
> + (__builtin_constant_p(gpio) \
> + ? __gpio_get_value(gpio) \
> + : sa1100_gpio_get_value(gpio))
> +
Please drop the out of line version. It will always be more costly than
the inline version even for non constant gpio values. And I think the
usage of GPIO_GPIO(gpio) is more obfuscating than directly using
(1 << gpio).
> +static inline void __gpio_set_value(unsigned gpio, int value)
> +{
> + if (value)
> + GPSR = GPIO_GPIO(gpio);
> + else
> + GPCR = GPIO_GPIO(gpio);
> +}
> +
> +#define gpio_set_value(gpio,value) \
> + (__builtin_constant_p(gpio) \
> + ? __gpio_set_value(gpio, value) \
> + : sa1100_gpio_set_value(gpio, value))
Same as above.
Nicolas
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