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Message-ID: <CACRpkdYn3WWAKeKa0dUjXg3QtMYdTrysGGK3aND5VwBH=NPqTA@mail.gmail.com>
Date: Thu, 26 May 2016 11:06:48 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Masahiro Yamada <yamada.masahiro@...ionext.com>
Cc: "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Alexandre Courbot <gnurou@...il.com>
Subject: Re: [PATCH v3] gpio: UniPhier: add driver for UniPhier GPIO controller
On Fri, May 20, 2016 at 6:30 AM, Masahiro Yamada
<yamada.masahiro@...ionext.com> wrote:
> So, I'd like to know the recommended driver coding style
> based on 4.7-rc1.
Sure, best is to look at other recently added drivers
I guess.
> Diving into the git-log so far, I came up the following list:
>
> [1] The "dev" member of gpiochip was renamed to "parent"
Yes.
> [2] The most recommended register function is now
> devm_gpiochip_add_data()
Yes, saves some code.
> [3] Pass the driver private data to the
> 3rd argument of devm_gpiochip_add_data().
Yes.
> [4] Do not use container_of() to covert
> from gpiochip to driver private data.
> Instead, gpiochip_get_data() should be used.
Yes.
> (I used of_mm_gpio_chip in v3,
> but I needed to use container_of() to
> convert from gpiochip to of_mm_gpio_chip.
> I am wondering if you are happy with it or not.)
We will see when we look at the code ;)
I guess it is OK. The alternative is to use gpio-generic instead,
see commit 42178e2a1e42b480ada954750f248b53d3fb5940
"drivers/gpio: Switch gpio-mpc8xxx to use gpio-generic"
for an example of that approach.
> [5] gpiochip.owner is being deprecated.
> So, platform drivers need not set
> "gpiochip.owner = THIS_MODULE".
Yes.
> Correct?
Yes.
> Is there anything else missing?
I advice to add a .get_direction() callback if possible and
also .set_single_ended() if the GPIO chip supports open
drain / open source in hardware.
Yours,
Linus Walleij
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