simple gpio driver
hs at denx.de
Tue Aug 18 15:25:11 EST 2009
Anton Vorontsov wrote:
> Oops, I missed that patch, sorry.
> On Mon, Aug 17, 2009 at 03:18:37PM -0600, Grant Likely wrote:
>> On Wed, Aug 12, 2009 at 11:49 PM, Heiko Schocher<hs at denx.de> wrote:
>>> Hello Anton,
>>> i am trying to use the arch/powerpc/sysdev/simple_gpio.c driver,
>>> for accessing some gpios, and found, that u8_gpio_get()
>>> returns not only a 1 or a 0, instead it returns the real bit
>>> position from the gpio:
>>> gpio return
>>> base value
>>> 0 0/0x01
>>> 1 0/0x02
>>> 2 0/0x04
>>> 3 0/0x08
>>> 4 0/0x10
>>> 5 0/0x20
>>> 6 0/0x40
>>> 7 0/0x80
>>> I also use the arch/powerpc/platforms/52xx/mpc52xx_gpio.c and
>>> mpc52xx_gpt.c drivers, they all return for a gpio just a 1 or 0,
> There is also arch/powerpc/sysdev/qe_lib/gpio.c and
> arch/powerpc/sysdev/mpc8xxx_gpio.c that don't do that.
>>> which seems correct to me, because a gpio can have only 1 or 0
>>> as state ... what do you think?
>> I think returning '1' is perhaps slightly 'better' (however you define
>> that), but I don't think the caller should make any assumptions beyond
> Yep. So I don't think that the patch is needed.
Yes, if the gpio lib only differs in zero versus non zero.
Thanks for the info
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