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Subject: Re: [PATCH v3 10/12] hikey960: Support usb functionality of Hikey960
To:     Chunfeng Yun <chunfeng.yun@mediatek.com>
References: <20190302090505.65542-1-chenyu56@huawei.com>
 <20190302090505.65542-11-chenyu56@huawei.com>
 <1551664069.2210.64.camel@mhfsdcap03>
From:   Chen Yu <chenyu56@huawei.com>
Message-ID: <2708b188-d318-6758-a5fd-8573559b2e70@huawei.com>
Date:   Mon, 4 Mar 2019 09:55:37 +0800
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Hi Chunfeng Yun,

On 2019/3/4 9:47, Chunfeng Yun wrote:

>> +
>> +	hisi_hikey_usb->role_sw = usb_role_switch_get(dev);
>> +	if (!hisi_hikey_usb->role_sw)
>> +		return -EPROBE_DEFER;
> Here return EPROBE_DEFFER means the related device_connection is
> registered after this probe is called, right?
> if not, use IS_ERR_OR_NULL then return PTR_ERR is enough
Yes, the driver which register the usb_role_switch may finish probe after
this driver is probed for the first time.
>> +	else if (IS_ERR(hisi_hikey_usb->role_sw))
>> +		return PTR_ERR(hisi_hikey_usb->role_sw);
>> +
>> +	ret = usb_role_switch_register_notifier(hisi_hikey_usb->role_sw,
>> +			&hisi_hikey_usb->nb);
>> +	if (ret) {
>> +		usb_role_switch_put(hisi_hikey_usb->role_sw);
>> +		return ret;
>> +	}
>> +
>> +	platform_set_drvdata(pdev, hisi_hikey_usb);
>> +
>> +	return 0;
>> +}
>> +

> 
> 
> .
>