[PATCH] PL061 GPIO: Changing *_irq_chip_data with *_irq_data for real irqs.

[Baruch Siach]

Hi Viresh,

On Wed, Apr 21, 2010 at 01:14:51PM +0530, Viresh KUMAR wrote:
> On 4/21/2010 1:07 PM, Baruch Siach wrote:
> > Hi Viresh,
> > 
> > On Wed, Apr 21, 2010 at 12:30:01PM +0530, Viresh KUMAR wrote:
> >> PL061 driver is using set_irq_chip_data and get_irq_chip_data for real irq
> >> lines. It must be using *_irq_data functions instead. As chip_data is used by
> >> interrupt controllers also, which makes vic write at incorrect addresses.
> >>
> >> Also, pl061_direction_output doesn't set value of gpio to value passed to 
> >> it.  Adding code to set value of GPIO pin to requrested value.
> > 
> > Please split this patch into two separate patches. The two fixes are unrelated 
> > to each other.
> 
> OK.
> 
> > 
> >>
> >> Signed-off-by: Viresh Kumar <viresh.kumar at st.com>
> >> ---
> >>  drivers/gpio/pl061.c |    8 ++++----
> >>  1 files changed, 4 insertions(+), 4 deletions(-)
> >>
> >> diff --git a/drivers/gpio/pl061.c b/drivers/gpio/pl061.c
> >> index 3ad1eeb..0a30124 100644
> >> --- a/drivers/gpio/pl061.c
> >> +++ b/drivers/gpio/pl061.c
> >> @@ -86,10 +86,10 @@ static int pl061_direction_output(struct gpio_chip *gc, unsigned offset,
> >>  		return -EINVAL;
> >>  
> >>  	spin_lock_irqsave(&chip->lock, flags);
> >> -	writeb(!!value << offset, chip->base + (1 << (offset + 2)));
> > 
> > I'm still for keeping this line.
> 
> I will do that, but i am still not sure why should we keep it.
> Changing value before changing direction will have no effect.
> And if in future releases of pl061 IP, this bug is resolved then also the
> changing value after direction will be fine.

Wrong. Changing the value after direction may cause the GPIO line to output 
the wrong value for a short period of time (between the first writeb() and the 
second). Preventing this is the whole point of having the value parameter in 
the .direction_output method, instead of calling gpio_direction_output() and 
then gpio_set_value().

baruch

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