linux-kernel - Re: [PATCH v4 6/8] mtd: maps: gpio-addr-flash: Convert to gpiod

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Date:   Wed, 3 Oct 2018 17:56:03 +0200
From:   Ricardo Ribalda Delgado <ricardo.ribalda@...il.com>
To:     Boris Brezillon <boris.brezillon@...tlin.com>
Cc:     Zhouyang Jia <jiazhouyang09@...il.com>,
        LKML <linux-kernel@...r.kernel.org>,
        Marek Vasut <marek.vasut@...il.com>,
        linux-mtd@...ts.infradead.org, Richard Weinberger <richard@....at>,
        Brian Norris <computersforpeace@...il.com>,
        David Woodhouse <dwmw2@...radead.org>
Subject: Re: [PATCH v4 6/8] mtd: maps: gpio-addr-flash: Convert to gpiod

Hi Boris
On Wed, Oct 3, 2018 at 5:17 PM Boris Brezillon
<boris.brezillon@...tlin.com> wrote:
>
> On Wed, 3 Oct 2018 17:11:14 +0200
> Boris Brezillon <boris.brezillon@...tlin.com> wrote:
>
> > Hi Ricardo,
> >
> > On Mon,  1 Oct 2018 14:43:49 +0200
> > Ricardo Ribalda Delgado <ricardo.ribalda@...il.com> wrote:
> >
> > > @@ -248,14 +252,19 @@ static int gpio_flash_probe(struct platform_device *pdev)
> > >
> > >     i = 0;
> > >     do {
> > > -           if (devm_gpio_request(&pdev->dev, state->gpio_addrs[i],
> > > -                                 DRIVER_NAME)) {
> > > +           unsigned int *gpio_id = (unsigned int *)gpios->start;
> > > +
> > > +           if (devm_gpio_request_one(&pdev->dev, gpio_id[i], GPIOD_OUT_LOW,
> > > +                                   DRIVER_NAME)) {
> > >                     dev_err(&pdev->dev, "failed to request gpio %d\n",
> > > -                           state->gpio_addrs[i]);
> > > +                           gpio_id[i]);
> > >                     return -EBUSY;
> > >             }
> > > -           gpio_direction_output(state->gpio_addrs[i], 0);
> > > -   } while (++i < state->gpio_count);
> > > +
> > > +           state->gpios->desc[i] = gpio_to_desc(gpio_id[i]);
> > > +           if (!state->gpios->desc[i])
> > > +                   return -EINVAL;
> > > +   } while (++i < state->gpios->ndescs);
> >
> > Actually, I was thinking about using devm_gpiod_get_array() here and
> > defining a gpio lookup table in the board file registering the device.
> > This way, adding support for DT based parsing is transparent.
>
> It's actually easier than I thought since no one is registering such a
> device, so all you have to do is call devm_gpiod_get_array() and have a
> struct gpio_descs pointer in struct async_state.

That is what I do in patch 8/8 for DT based parsing.

I am am doing the gpio_to_desc and other to maintain compatibility
with old platform board files (in and out tree).

I think is important to maintain that compatibility, but you decide ;)

Cheers

-- 
Ricardo Ribalda