Re: [PATCH 1/5] gpiolib: devres: Introduce the function devm_request_gpio_array

[Rob Jones]

On 09/07/14 12:52, Julia Lawall wrote:
> On Wed, 9 Jul 2014, Rob Jones wrote:
>
> > Please note that I submitted a patch on 02/07/14 to create this
> > function which was acked by Linus Walleij on 05/07/14.
> >
> > Great minds think alike, and all that.
> >
> > However, I think that the version I submitted better replicates the
> > original (non devm) functionality, see below.

<snip>

> > > +int devm_gpio_request_array(struct device *dev, const struct gpio *array,
> > > +			    size_t num)
> > > +{
> > > +	int i, err;
> > > +
> > > +	for (i = 0; i < num; i++, array++) {
> > > +		err = devm_gpio_request_one(dev, array->gpio, array->flags,
> > > +					    array->label);
> > > +		if (err)
> > > +			return err;
> >
> > The failure path in the version I submitted frees up any already
> > allocated gpios on the first failure.
>
> Himangi first proposed doing that, but I thought it was not really in the
> spirit of devm functions, which is to leave that implicit.  No strong
> opinion on the matter, though.

Interestingly, we came at it from the other direction: I originally
didn't have the unwind in and our internal review guys suggested that
it was in the original function so putting it in would:

1. make this a better analogue of the original
2. help avoid deadlocks
3. allow the driver to retry, perhaps requesting reduced functionality.

> julia

<snip>

--
Rob Jones
Codethink Ltd
mailto:rob.jones@xxxxxxxxxxxxxxx
tel:+44 161 236 5575
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