Re: Problem in setting the state of GPIO pin in PXA255

Nicolas,
    Thanks for the suggestion. Now I am able to
change the state of some GPIO pins. But I couldn't
change the state of following pins.
  GPIO pins:1, 13-15, 21-22, 29-31,48-55, 58-84.

Suppose if a pin is already configured for alternative
function, will this matter while changing
the state of pin?

  I have a written driver with IOCTL routine. The
IOCTL
routine supports GPIO_GET ( get the gpio pin state)
and
GPIO_SET (set the gpio pin state) commands from
user space programs.
   From user space program, I am able to change
the state of some GPIO pins. But one thing that I
observed is that, from user space program I
couldn't change the state of some GPIO pins, for
which I was able to change the state from the driver
directly.

    Any idea about this?

thanks,
Seshu
   
> > Hi,
> >     I am using Lubbock board (PXA255 based) and
> > linux-2.4.19-rmk7-pxa1.
> >     I am trying to set the state of GPIO pin using
> > GPSR/GPCR registers. But the state I am trying to
> set
> > is not reflected on the GPIO pin. The pin always
> > reatins its old state.
> > 
> > I am using the following piece of code in
> > the driver.
> > 
> >    set_GPIO_mode(81 | GPIO_OUT); 
> >    old_state = ( GPLR(81) & GPIO_bit(81))?1:0 ;
> >                   /* old_state is zero */
> >    GPSR(81) |= GPIO_bit(81); /*set pin state to
> 1*/
> 
> With GPSR and GPCR you only need to perform a direct
> assignment, e.g.:
> 
>       GPSR(81) = GPIO_bit(81);
> 
> >    new_state = ( GPLR(81) & GPIO_bit(81))?1:0 ;
> > 
> > But I always get new_state as zero.
> 
> What about the level on the actual GPIO line?
> 
> > I tried with other GPIO pins and found the same
> thing.
> > 
> >    Any idea why the GPIO pin state is not 
> > changing even after setting in GPSR/GPCR
> registers?
> >    Did I miss any settings in some other
> registers?
> 
> Your code seems to be right (besides the minor
> detail above).
> 
> 
> Nicolas
> 


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