Messages in this thread | | | Date | Mon, 4 Jul 2011 09:44:47 -0600 | From | Grant Likely <> | Subject | Re: [PATCH 1/2] gpio/gpio-generic: read set register for caching if available |
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On Mon, Jun 27, 2011 at 09:26:22AM +0200, Sebastian Andrzej Siewior wrote: > The ->data is a shadow copy which is used during the ->set callback in > order to avoid a read of the register before write. > If ->reg_set is set then we write to this location therefore we should > cache that value. > > Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> > --- > drivers/gpio/gpio-generic.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/drivers/gpio/gpio-generic.c b/drivers/gpio/gpio-generic.c > index 231714d..9f8b5c6 100644 > --- a/drivers/gpio/gpio-generic.c > +++ b/drivers/gpio/gpio-generic.c > @@ -398,7 +398,10 @@ int __devinit bgpio_init(struct bgpio_chip *bgc, > if (ret) > return ret; > > - bgc->data = bgc->read_reg(bgc->reg_dat); > + if (bgc->reg_set) > + bgc->data = bgc->read_reg(bgc->reg_set);
On most of the gpio controllers that I've seen, the 'set' register isn't something that you can actually read. I don't think this is something that can be done for all gpio controllers.
g.
> + else > + bgc->data = bgc->read_reg(bgc->reg_dat); > > return ret; > } > -- > 1.7.4.4 >
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