linux-kernel - Re: [PATCH 2/3] phy: rcar-gen3-usb2: Add vbus-supply to handle VBUS on/off

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Date:	Tue, 5 Apr 2016 16:23:35 +0530
From:	Kishon Vijay Abraham I <kishon@...com>
To:	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
	<robh+dt@...nel.org>, <pawel.moll@....com>, <mark.rutland@....com>,
	<ijc+devicetree@...lion.org.uk>, <galak@...eaurora.org>
CC:	<linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
	<linux-renesas-soc@...r.kernel.org>
Subject: Re: [PATCH 2/3] phy: rcar-gen3-usb2: Add vbus-supply to handle VBUS
 on/off

Hi,

On Thursday 03 March 2016 03:39 PM, Yoshihiro Shimoda wrote:
> To handle the VBUS on/off by a regulator driver, this patch adds
> regulator APIs calling in the driver and description about vbus-supply
> in the rcar-gen3-phy-usb2.txt.
> 
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> Acked-by: Rob Herring <robh@...nel.org>
> ---
>  .../devicetree/bindings/phy/rcar-gen3-phy-usb2.txt |  2 ++
>  drivers/phy/phy-rcar-gen3-usb2.c                   | 28 ++++++++++++++++++++++
>  2 files changed, 30 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
> index 86826ca..7243b3b 100644
> --- a/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
> +++ b/Documentation/devicetree/bindings/phy/rcar-gen3-phy-usb2.txt
> @@ -21,6 +21,8 @@ To use a USB channel where USB 2.0 Host and HSUSB (USB 2.0 Peripheral) are
>  combined, the device tree node should set interrupt properties to use the
>  channel as USB OTG:
>  - interrupts: interrupt specifier for the PHY.
> +- vbus-supply: Phandle to a regulator that provides power to the VBUS. This
> +	       regulator will be managed during the PHY power on/off sequence.

Why not use phy-supply from the generic PHY binding? It can then be managed by
the phy core during power_on/power_off.

Thanks
Kishon

>  
>  Example (R-Car H3):
>  
> diff --git a/drivers/phy/phy-rcar-gen3-usb2.c b/drivers/phy/phy-rcar-gen3-usb2.c
> index 3c647cd..7b14244 100644
> --- a/drivers/phy/phy-rcar-gen3-usb2.c
> +++ b/drivers/phy/phy-rcar-gen3-usb2.c
> @@ -19,6 +19,7 @@
>  #include <linux/of_address.h>
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
> +#include <linux/regulator/consumer.h>
>  
>  /******* USB2.0 Host registers (original offset is +0x200) *******/
>  #define USB2_INT_ENABLE		0x000
> @@ -77,6 +78,7 @@
>  struct rcar_gen3_chan {
>  	void __iomem *base;
>  	struct phy *phy;
> +	struct regulator *vbus;
>  	bool has_otg;
>  };
>  
> @@ -210,6 +212,13 @@ static int rcar_gen3_phy_usb2_power_on(struct phy *p)
>  	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
>  	void __iomem *usb2_base = channel->base;
>  	u32 val;
> +	int ret;
> +
> +	if (channel->vbus) {
> +		ret = regulator_enable(channel->vbus);
> +		if (ret)
> +			return ret;
> +	}
>  
>  	val = readl(usb2_base + USB2_USBCTR);
>  	val |= USB2_USBCTR_PLL_RST;
> @@ -220,10 +229,22 @@ static int rcar_gen3_phy_usb2_power_on(struct phy *p)
>  	return 0;
>  }
>  
> +static int rcar_gen3_phy_usb2_power_off(struct phy *p)
> +{
> +	struct rcar_gen3_chan *channel = phy_get_drvdata(p);
> +	int ret = 0;
> +
> +	if (channel->vbus)
> +		ret = regulator_disable(channel->vbus);
> +
> +	return ret;
> +}
> +
>  static struct phy_ops rcar_gen3_phy_usb2_ops = {
>  	.init		= rcar_gen3_phy_usb2_init,
>  	.exit		= rcar_gen3_phy_usb2_exit,
>  	.power_on	= rcar_gen3_phy_usb2_power_on,
> +	.power_off	= rcar_gen3_phy_usb2_power_off,
>  	.owner		= THIS_MODULE,
>  };
>  
> @@ -290,6 +311,13 @@ static int rcar_gen3_phy_usb2_probe(struct platform_device *pdev)
>  		return PTR_ERR(channel->phy);
>  	}
>  
> +	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);
> +		channel->vbus = NULL;
> +	}
> +
>  	phy_set_drvdata(channel->phy, channel);
>  
>  	provider = devm_of_phy_provider_register(dev, of_phy_simple_xlate);
>