linux-kernel - Re: [PATCH v6 2/2] phy: rockchip-inno-usb2: add a new driver for Rockchip usb2phy

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Date:	Fri, 17 Jun 2016 06:20:45 -0700
From:	Guenter Roeck <linux@...ck-us.net>
To:	Frank Wang <frank.wang@...k-chips.com>, heiko@...ech.de
Cc:	dianders@...omium.org, groeck@...omium.org, jwerner@...omium.org,
	kishon@...com, robh+dt@...nel.org, pawel.moll@....com,
	mark.rutland@....com, ijc+devicetree@...lion.org.uk,
	galak@...eaurora.org, linux-kernel@...r.kernel.org,
	devicetree@...r.kernel.org, linux-usb@...r.kernel.org,
	linux-rockchip@...ts.infradead.org, xzy.xu@...k-chips.com,
	kever.yang@...k-chips.com, huangtao@...k-chips.com,
	william.wu@...k-chips.com
Subject: Re: [PATCH v6 2/2] phy: rockchip-inno-usb2: add a new driver for
 Rockchip usb2phy

Hi Frank,

On 06/16/2016 11:43 PM, Frank Wang wrote:
> Hi Guenter,
>
> On 2016/6/17 12:59, Guenter Roeck wrote:
>> On 06/16/2016 07:09 PM, Frank Wang wrote:
>>> The newer SoCs (rk3366, rk3399) take a different usb-phy IP block
>>> than rk3288 and before, and most of phy-related registers are also
>>> different from the past, so a new phy driver is required necessarily.
>>>
>>> Signed-off-by: Frank Wang <frank.wang@...k-chips.com>
>>> Suggested-by: Guenter Roeck <linux@...ck-us.net>
>>> Suggested-by: Doug Anderson <dianders@...omium.org>
>>> Reviewed-by: Heiko Stuebner <heiko@...ech.de>
>>> Tested-by: Heiko Stuebner <heiko@...ech.de>
>>> ---
>>
>> [ ... ]
>>
>>> +
>>> +static int rockchip_usb2phy_resume(struct phy *phy)
>>> +{
>>> +    struct rockchip_usb2phy_port *rport = phy_get_drvdata(phy);
>>> +    struct rockchip_usb2phy *rphy = dev_get_drvdata(phy->dev.parent);
>>> +    int ret;
>>> +
>>> +    dev_dbg(&rport->phy->dev, "port resume\n");
>>> +
>>> +    ret = clk_prepare_enable(rphy->clk480m);
>>> +    if (ret)
>>> +        return ret;
>>> +
>> If suspend can be called multiple times, resume can be called
>> multiple times as well. Doesn't this cause a clock imbalance
>> if you call clk_prepare_enable() multiple times on resume,
>> but clk_disable_unprepare() only once on suspend ?
>>
>
> Well, what you said is reasonable, How does something like below?
>
> @@ -307,6 +307,9 @@ static int rockchip_usb2phy_resume(struct phy *phy)
>
>          dev_dbg(&rport->phy->dev, "port resume\n");
>
> +       if (!rport->suspended)
> +               return 0;
> +
>          ret = clk_prepare_enable(rphy->clk480m);
>          if (ret)
>                  return ret;
> @@ -327,12 +330,16 @@ static int rockchip_usb2phy_suspend(struct phy *phy)
>
>          dev_dbg(&rport->phy->dev, "port suspend\n");
>
> +       if (rport->suspended)
> +               return 0;
> +
>          ret = property_enable(rphy, &rport->port_cfg->phy_sus, true);
>          if (ret)
>                  return ret;
>
>          rport->suspended = true;
>          clk_disable_unprepare(rphy->clk480m);
> +
>          return 0;
>   }
>
> @@ -485,6 +492,7 @@ static int rockchip_usb2phy_host_port_init(struct rockchip_usb2phy *rphy,
>
>          rport->port_id = USB2PHY_PORT_HOST;
>          rport->port_cfg = &rphy->phy_cfg->port_cfgs[USB2PHY_PORT_HOST];
> +       rport->suspended = true;
>

Why does it start in suspended mode ? That seems odd.

Guenter

>          mutex_init(&rport->mutex);
>          INIT_DELAYED_WORK(&rport->sm_work, rockchip_usb2phy_sm_work);
>