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 14:43:55 +0800
From:	Frank Wang <frank.wang@...k-chips.com>
To:	Guenter Roeck <linux@...ck-us.net>, 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, frank.wang@...k-chips.com
Subject: Re: [PATCH v6 2/2] phy: rockchip-inno-usb2: add a new driver for
 Rockchip usb2phy

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;

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


>> +    ret = property_enable(rphy, &rport->port_cfg->phy_sus, false);
>> +    if (ret)
>> +        return ret;
>> +
>> +    rport->suspended = false;
>> +    return 0;
>> +}
>> +
>> +static int rockchip_usb2phy_suspend(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 suspend\n");
>> +
>> +    if (rport->suspended)
>> +        goto exit;
>> +
>
> I know I am nitpicking, but
>         return 0;
> would be fine here, be more consistent with the rest of the code,
>

Yeah, please see above changes.

BR.
Frank

>> +    ret = property_enable(rphy, &rport->port_cfg->phy_sus, true);
>> +    if (ret)
>> +        return ret;
>> +
>> +    rport->suspended = true;
>> +    clk_disable_unprepare(rphy->clk480m);
>> +
>> +exit:
>> +    return 0;
>
> and this label is really unnecessary.
>
>> +}
>> +
>
> [ ... ]
>