Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
MIME-Version: 1.0
References: <20190302090505.65542-1-chenyu56@huawei.com> <20190302090505.65542-11-chenyu56@huawei.com>
 <CAHp75VdaNn4OQAQt1cU8CZ+Cton90kxmwQSG5Du7KUzPR3hSCg@mail.gmail.com> <386ac0cf-cee7-bc1b-d22c-80dedff391cf@huawei.com>
In-Reply-To: <386ac0cf-cee7-bc1b-d22c-80dedff391cf@huawei.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 4 Mar 2019 08:55:30 +0200
Message-ID: <CAHp75VcjQjBV8xsuJyZ1RBnNQAV_k8z9Hp-3S_JnYDRpJZ2UXw@mail.gmail.com>
Subject: Re: [PATCH v3 10/12] hikey960: Support usb functionality of Hikey960
To:     Chen Yu <chenyu56@huawei.com>
Cc:     liuyu712@hisilicon.com, USB <linux-usb@vger.kernel.org>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        John Stultz <john.stultz@linaro.org>,
        Suzhuangluan <suzhuangluan@hisilicon.com>,
        Kongfei <kongfei@hisilicon.com>, wanghu17@hisilicon.com,
        butao@hisilicon.com, Yao Chen <chenyao11@huawei.com>,
        fangshengzhou@hisilicon.com, lipengcheng8@huawei.com,
        songxiaowei <songxiaowei@hisilicon.com>,
        xu yiping <xuyiping@hisilicon.com>, xuyoujun4@huawei.com,
        yudongbin@hisilicon.com, zangleigang@hisilicon.com,
        Chunfeng Yun <chunfeng.yun@mediatek.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Binghui Wang <wangbinghui@hisilicon.com>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>
Content-Type: text/plain; charset="UTF-8"
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, Mar 4, 2019 at 4:35 AM Chen Yu <chenyu56@huawei.com> wrote:
> On 2019/3/3 0:01, Andy Shevchenko wrote:
> > On Sat, Mar 2, 2019 at 11:05 AM Yu Chen <chenyu56@huawei.com> wrote:

> >> +config HISI_HIKEY_USB
> >> +       tristate "USB functionality of HiSilicon Hikey Platform"
> >> +       depends on OF && GPIOLIB
> >> +       help
> >> +         If you say yes here you get support for usb functionality of HiSilicon Hikey Platform.
> >
> >> +#include <linux/of.h>
> >
> > It's hard to see why this have
> > depends on OF followed by above header inclusion.
> >
> This driver depends on devicetree, so I add "depends on OF".
> But is seems that "#include <linux/of.h>" can be removed after "of_" API
> have been removed. Thanks for your reminder!

So, it means that technically there is no such dependency, rather
administratively.

> >> +       hisi_hikey_usb->typec_vbus = devm_gpiod_get(dev, "typec-vbus",
> >> +                       GPIOD_OUT_LOW);
> >
> >> +       if (!hisi_hikey_usb->typec_vbus)
> >> +               return -ENOENT;
> >
> > Hmm... Is it possible to get NULL pointer from gpiod_get() at all?
> >
> >> +       if (!hisi_hikey_usb->otg_switch)
> >> +               return -ENOENT;
> >
> > Ditto.
> >
> I check the comments of devm_gpio_get API, it will not return NULL pointer.
> But is it more safe to keep the NULL checking? What is your advice?

Why do we need dead code?

-- 
With Best Regards,
Andy Shevchenko