[PATCH v8] reset: Add driver for gpio-controlled reset pins

[Philipp Zabel]

Am Dienstag, den 16.07.2013, 09:47 -0600 schrieb Stephen Warren:
> On 07/16/2013 12:51 AM, Shawn Guo wrote:
> > On Tue, Jul 16, 2013 at 09:50:42AM +0800, Shawn Guo wrote:
> >> Hi Philipp,
> >>
> >> On Thu, May 30, 2013 at 11:09:00AM +0200, Philipp Zabel wrote:
> >>> This driver implements a reset controller device that toggle a gpio
> >>> connected to a reset pin of a peripheral IC. The delay between assertion
> >>> and de-assertion of the reset signal can be configured via device tree.
> >>>
> >>> Signed-off-by: Philipp Zabel <p.zabel at pengutronix.de>
> >>> Reviewed-by: Stephen Warren <swarren at nvidia.com>
> >>
> >> I see this patch is very useful, as GPIOs are widely used to reset
> >> components/devices on board.  But I do not find the patch in v3.11-rc1.
> >> What's your plan about it?
> >>
> >> Also, I'm wondering if we should register the driver a little bit
> >> early.  Please see the following patch.  If it makes sense to you,
> >> I can send the patch to you, or you can just quash it into yours.
> > 
> > And here is another change request.
> 
> > diff --git a/drivers/reset/gpio-reset.c b/drivers/reset/gpio-reset.c
> 
> > -	gpio_set_value(drvdata->gpio, value);
> > +	if (gpio_cansleep(drvdata->gpio))
> > +		gpio_set_value_cansleep(drvdata->gpio, value);
> > +	else
> > +		gpio_set_value(drvdata->gpio, value);
> 
> That's not right. Calling gpio_set_value() v.s.
> gpio_set_value_cansleep() should be based on the properties of the
> calling context, not the GPIO being controlled. In other words, if it's
> permissible to call gpio_set_value_cansleep() at this point in the code,
> simply always call that, and remove the conditional logic.

In which case I'd say let's just call the _cansleep variant here
unconditionally and declare that reset_control_assert/deassert() may
sleep, just as reset_control_reset() has to anyway.

regards
Philipp