On Monday 26 February 2007 5:35 am, Milan Svoboda wrote:
> > There is one problem, thought. Original code used:
> >
> > static inline void udc_gpio_init_pullup(unsigned gpio)
> > {
> > pxa_gpio_mode((gpio & GPIO_MD_MASK_NR) | GPIO_OUT |
GPIO_DFLT_LOW);
> > }
> >
> > But new generic gpio doesn't allows us to specify GPIO_DFLT_LOW. I'm
not
> > sure if this is a problem. Any thoughts?
>
> Specifically here, not a problem -- since the pullup is forced low
> shortly after that call. The worst that would happen is that a
> host sees a brief glitch on the D+ line, which would end up being
> ignored (since that can happen anyway during enumeration).
>
> In general, that's a potential problem. Not including a default
> value for gpio_direction_output() was an oversight, and that should
> probably get fixed before 2.6.21-final. Andrew Victor raised that
> issue offline in the context of AT91 (and AVR32).
>
> If you felt like fixing that for the ixp4xx and pxa, I expect that
> fixes could soon be forthcoming for other platforms and the docs.
>
How to fix it?
1. Use default value, e.g. line after gpio_direction_output shall be
always low?
Or
2. Change the gpio_direction_output(int gpio) to
gpio_direction_output(int gpio, int level) and let the user to decide
if he want's low or high level?
What's preferable?
Milan
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