linux-kernel - RE: [PATCH v3] phy: rcar-gen3-usb2: fix implementation for runtime PM

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Date:   Tue, 4 Apr 2017 11:36:34 +0000
From:   Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To:     "kishon@...com" <kishon@...com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-renesas-soc@...r.kernel.org" 
        <linux-renesas-soc@...r.kernel.org>
Subject: RE: [PATCH v3] phy: rcar-gen3-usb2: fix implementation for runtime PM

Hi Kishon,

> From: Yoshihiro Shimoda, Sent: Tuesday, March 14, 2017 8:38 AM
> 
> This patch fixes an issue that this driver doesn't take care of the runtime
> PM. This code assumed that devm_phy_create() called pm_runtime_enable(dev),
> but it misunderstood the dev_phy_create()'s specification.
> This driver should call its own pm_runtime_enable() before dev_phy_create().
> 
> Fixes: f3b5a8d9b50d ("phy: rcar-gen3-usb2: Add R-Car Gen3 USB2 PHY driver")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> ---
>  Changes from v2:
>   - revise the commit log (s/pm_runtime_pm/pm_runtime_enable)
> 
>  Changes from v1:
>   - revise the commit log (s/the own/its own/)
>   - simplify return code in probe().

I'm afraid but would you review this patch?

Best regards,
Yoshihiro Shimoda

>  drivers/phy/phy-rcar-gen3-usb2.c | 31 ++++++++++++++++++++++++-------
>  1 file changed, 24 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/phy/phy-rcar-gen3-usb2.c b/drivers/phy/phy-rcar-gen3-usb2.c
> index afb4d04..54c3429 100644
> --- a/drivers/phy/phy-rcar-gen3-usb2.c
> +++ b/drivers/phy/phy-rcar-gen3-usb2.c
> @@ -20,6 +20,7 @@
>  #include <linux/of_address.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/workqueue.h>
> 
> @@ -395,7 +396,7 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  	struct rcar_gen3_chan *channel;
>  	struct phy_provider *provider;
>  	struct resource *res;
> -	int irq;
> +	int irq, ret = 0;
> 
>  	if (!dev->of_node) {
>  		dev_err(dev, "This driver needs device tree\n");
> @@ -434,17 +435,24 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  		}
>  	}
> 
> -	/* devm_phy_create() will call pm_runtime_enable(dev); */
> +	/*
> +	 * devm_phy_create() will call pm_runtime_enable(&phy->dev);
> +	 * And then, phy-core will manage runtime pm for this device.
> +	 */
> +	pm_runtime_enable(dev);
>  	channel->phy = devm_phy_create(dev, NULL, &rcar_gen3_phy_usb2_ops);
>  	if (IS_ERR(channel->phy)) {
>  		dev_err(dev, "Failed to create USB2 PHY\n");
> -		return PTR_ERR(channel->phy);
> +		ret = PTR_ERR(channel->phy);
> +		goto error;
>  	}
> 
>  	channel->vbus = devm_regulator_get_optional(dev, "vbus");
>  	if (IS_ERR(channel->vbus)) {
> -		if (PTR_ERR(channel->vbus) == -EPROBE_DEFER)
> -			return PTR_ERR(channel->vbus);
> +		if (PTR_ERR(channel->vbus) == -EPROBE_DEFER) {
> +			ret = PTR_ERR(channel->vbus);
> +			goto error;
> +		}
>  		channel->vbus = NULL;
>  	}
> 
> @@ -454,15 +462,22 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>  	if (IS_ERR(provider)) {
>  		dev_err(dev, "Failed to register PHY provider\n");
> +		ret = PTR_ERR(provider);
> +		goto error;
>  	} else if (channel->has_otg) {
>  		int ret;
> 
>  		ret = device_create_file(dev, &dev_attr_role);
>  		if (ret < 0)
> -			return ret;
> +			goto error;
>  	}
> 
> -	return PTR_ERR_OR_ZERO(provider);
> +	return 0;
> +
> +error:
> +	pm_runtime_disable(dev);
> +
> +	return ret;
>  }
> 
>  static int rcar_gen3_phy_usb2_remove(struct platform_device *pdev)
> @@ -472,6 +487,8 @@ static int rcar_gen3_phy_usb2_remove(struct platform_device *pdev)
>  	if (channel->has_otg)
>  		device_remove_file(&pdev->dev, &dev_attr_role);
> 
> +	pm_runtime_disable(&pdev->dev);
> +
>  	return 0;
>  };
> 
> --
> 1.9.1