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Message-id: <52FE3A91.1090107@samsung.com>
Date: Fri, 14 Feb 2014 16:47:29 +0100
From: Tomasz Figa <t.figa@...sung.com>
To: Vivek Gautam <gautamvivek1987@...il.com>
Cc: Vivek Gautam <gautam.vivek@...sung.com>,
Linux USB Mailing List <linux-usb@...r.kernel.org>,
"linux-samsung-soc@...r.kernel.org"
<linux-samsung-soc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
linux-doc@...r.kernel.org, Greg KH <gregkh@...uxfoundation.org>,
Kukjin Kim <kgene.kim@...sung.com>,
Felipe Balbi <balbi@...com>, kishon <kishon@...com>,
Kamil Debski <k.debski@...sung.com>,
Sylwester Nawrocki <s.nawrocki@...sung.com>,
Julius Werner <jwerner@...omium.org>,
Jingoo Han <jg1.han@...sung.com>
Subject: Re: [PATCH v3] phy: Add new Exynos5 USB 3.0 PHY driver
Hi Vivek,
On 14.02.2014 14:53, Vivek Gautam wrote:
>>> Changes from v2:
>>> 1) Added support for multiple PHYs (UTMI+ and PIPE3) and
>>> related changes in the driver structuring.
>>
>>
>> I'm a bit skeptical about this separation. Can the PHY operate with just the
>> UTMI+ or PIPE3 part enabled alone without the other? Can any PHY consumer
>> operate this way?
>
> Yes :-)
> As also pointed by Kishon the PHY consumer (which is DWC3 in case of
> Exynos5 SoC series)
> should theoretically be able use either UTMI+ phy for High speed
> operations or both (UTMI+ and PIPE3)
> for Super Speed operations.
OK, that's fine then. This is the explanation I needed, thanks.
>>
>> I believe the right thing to do here is to do all the initialization in
>> .power_on() and let the driver simply call phy_power_on() when it needs the
>> PHY and phy_power_off() otherwise.
>
> If this is what we should be doing then what will be the purpose of
> two separate APIs :
> phy_power_on() and phy_init().
> Am i missing while understanding the things.
>
I don't understand this separation as well. Operations that should be
done together shouldn't be separated. Is there any case when you can
call one of phy_power_on() and phy_init() without calling another one
right before/after it?
Best regards,
Tomasz
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