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

[Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>]

Hi,

> From: Kishon Vijay Abraham I
> Sent: Tuesday, April 05, 2016 7:54 PM
> 
> 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@renesas.com>
> > Acked-by: Rob Herring <robh@kernel.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.

Thank you for the review!

I'm afraid, I should have added your address as CC when I sent RFC patch set.
Anyway, Rob had a comment about "phy-supply":
http://thread.gmane.org/gmane.linux.kernel.renesas-soc/366/focus=406

I agreed with Rob because the document mentioned the followings:

Optional Properties:
phy-supply:	Phandle to a regulator that provides power to the PHY. This
		regulator will be managed during the PHY power on/off sequence.

https://git.kernel.org/cgit/linux/kernel/git/kishon/linux-phy.git/tree/Documentation/devicetree/bindings/phy/phy-bindings.txt?h=next#n13

And then, I changed the "phy-supply" to "vbus-supply" and this driver managed the "vbus-supply".
Or, do I misunderstand the document?

Best regards,
Yoshihiro Shimoda

> 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);
> >