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SubjectRe: [v2 2/4] platform: (TS-5500) add GPIO support
On Mon, 29 Aug 2011 23:11:33 +0100,
Mark Brown <broonie@opensource.wolfsonmicro.com> wrote:
> On Fri, Aug 26, 2011 at 07:40:25PM -0400, Vivien Didelot wrote:
> > + bitno = line_to_bit_map[offset];
> > +
> > + mutex_lock(&drvdata->gpio_lock);
> > + byte = inb(ioaddr);
> > + mutex_unlock(&drvdata->gpio_lock);
>
> Do you really need the lock to do a read?

Is there any chance for this function to be preempted before reading the
register, allowing a call to ts5500_gpio_direction_output to occur
before ts5500_gpio_get is completed?

Vivien.


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