linux-kernel - Re: [PATCH v3 2/2] phy: rockchip-inno-usb2: correct 480MHz output clock stable time

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Message-ID: <4919785a-2460-145d-e2e4-944ae7940633@rock-chips.com>
Date:   Tue, 15 Nov 2016 11:23:26 +0800
From:   wlf <wulf@...k-chips.com>
To:     Doug Anderson <dianders@...gle.com>
Cc:     Kishon Vijay Abraham I <kishon@...com>,
        Heiko Stübner <heiko@...ech.de>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Frank Wang <frank.wang@...k-chips.com>,
        黄涛 <huangtao@...k-chips.com>,
        Brian Norris <briannorris@...gle.com>,
        Guenter Roeck <groeck@...gle.com>
Subject: Re: [PATCH v3 2/2] phy: rockchip-inno-usb2: correct 480MHz output
 clock stable time

Hi Doug,

在 2016年11月15日 02:17, Doug Anderson 写道:
> William,
>
> On Mon, Nov 14, 2016 at 1:27 AM, William Wu <wulf@...k-chips.com> wrote:
>> We found that the system crashed due to 480MHz output clock of
>> USB2 PHY was unstable after clock had been enabled by gpu module.
>>
>> Theoretically, 1 millisecond is a critical value for 480MHz
>> output clock stable time, so we try to change the delay time
>> to 1.2 millisecond to avoid this issue.
>>
>> And the commit ed907fb1d7c3 ("phy: rockchip-inno-usb2: correct
>> clk_ops callback") used prepare callbacks instead of enable
>> callbacks to support gate a clk if the operation may sleep. So
>> we can switch from delay to sleep functions.
>>
>> Signed-off-by: William Wu <wulf@...k-chips.com>
>> ---
>> Changes in v3:
>> - fix kbuild test error: too few arguments to function 'usleep_range'
>>
>> Changes in v2:
>> - use usleep_range() function instead of mdelay()
>>
>>   drivers/phy/phy-rockchip-inno-usb2.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/phy/phy-rockchip-inno-usb2.c b/drivers/phy/phy-rockchip-inno-usb2.c
>> index 365e077..0e52b25 100644
>> --- a/drivers/phy/phy-rockchip-inno-usb2.c
>> +++ b/drivers/phy/phy-rockchip-inno-usb2.c
>> @@ -166,7 +166,7 @@ static int rockchip_usb2phy_clk480m_prepare(struct clk_hw *hw)
>>                          return ret;
>>
>>                  /* waitting for the clk become stable */
>> -               mdelay(1);
>> +               usleep_range(1200, 1300);
> Sight nit that you could also fix the spelling from "waitting" to "waiting".
>
> ...but that's pre-existing, so:
>
> Reviewed-by: Douglas Anderson <dianders@...omium.org>
Thanks! I'll add  Reviewed-by and fix the spelling issue.
>
>
>