RE: [RFC PATCH 2/2] usb: phy: Add platform driver support for ULPI PHYs

[Subbaraya Sundeep Bhatta]

Hi Peter,

> -----Original Message-----
> From: Peter Chen [mailto:peter.chen@xxxxxxxxxxxxx]
> Sent: Thursday, September 24, 2015 2:37 PM
> To: Subbaraya Sundeep Bhatta
> Cc: balbi@xxxxxx; devicetree@xxxxxxxxxxxxxxx; kishon@xxxxxx;
> gregkh@xxxxxxxxxxxxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Punnaiah Choudary Kalluri; Subbaraya Sundeep Bhatta
> Subject: Re: [RFC PATCH 2/2] usb: phy: Add platform driver support for ULPI
> PHYs
> 
> On Wed, Sep 23, 2015 at 06:24:33PM +0530, Subbaraya Sundeep Bhatta
> wrote:
> > Based on board design USB controller needs explicit software access to
> > ULPI PHY for controlling VBUS. This patch adds platform driver support
> > for generic ULPI PHYs and provides a USB2 PHY device to controllers.
> >
> > Signed-off-by: Subbaraya Sundeep Bhatta <sbhatta@xxxxxxxxxx>
> > ---
> >  drivers/usb/phy/Kconfig             |   12 +++
> >  drivers/usb/phy/Makefile            |    1 +
> >  drivers/usb/phy/phy-platform-ulpi.c |  143
> > +++++++++++++++++++++++++++++++++++
> >  3 files changed, 156 insertions(+), 0 deletions(-)  create mode
> > 100644 drivers/usb/phy/phy-platform-ulpi.c
> >
> > diff --git a/drivers/usb/phy/Kconfig b/drivers/usb/phy/Kconfig index
> > 7d3beee..2956ad4 100644
> > --- a/drivers/usb/phy/Kconfig
> > +++ b/drivers/usb/phy/Kconfig
> > @@ -201,6 +201,18 @@ config USB_RCAR_PHY
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called phy-rcar-usb.
> >
> > +config USB_PLATFORM_ULPI_PHY
> > +	tristate "Platform driver support for ULPI PHYs"
> > +	depends on ARCH_ZYNQ || COMPILE_TEST
> 
> If you want this as a common driver, drop platform dependency please.

Ok I will remove depends on.
> 
> > +	select USB_PHY
> > +	select USB_ULPI_VIEWPORT
> > +	help
> > +	  Say Y here to add support for the Platform driver for ULPI PHYs.
> > +	  This adds platform driver support for all generic ULPI PHYs and is
> > +	  typically used if usb controller driver needs explicit access to PHY.
> > +
> > +	  To compile this driver as a module, choose M here.
> > +
> >  config USB_ULPI
> >  	bool "Generic ULPI Transceiver Driver"
> >  	depends on ARM || ARM64
> > diff --git a/drivers/usb/phy/Makefile b/drivers/usb/phy/Makefile index
> > 19c0dcc..8431b6b 100644
> > --- a/drivers/usb/phy/Makefile
> > +++ b/drivers/usb/phy/Makefile
> > @@ -24,6 +24,7 @@ obj-$(CONFIG_USB_QCOM_8X16_PHY)	+= phy-
> qcom-8x16-usb.o
> >  obj-$(CONFIG_USB_MV_OTG)		+= phy-mv-usb.o
> >  obj-$(CONFIG_USB_MXS_PHY)		+= phy-mxs-usb.o
> >  obj-$(CONFIG_USB_RCAR_PHY)		+= phy-rcar-usb.o
> > +obj-$(CONFIG_USB_PLATFORM_ULPI_PHY)	+= phy-platform-ulpi.o
> >  obj-$(CONFIG_USB_ULPI)			+= phy-ulpi.o
> >  obj-$(CONFIG_USB_ULPI_VIEWPORT)		+= phy-ulpi-viewport.o
> >  obj-$(CONFIG_KEYSTONE_USB_PHY)		+= phy-keystone.o
> > diff --git a/drivers/usb/phy/phy-platform-ulpi.c
> > b/drivers/usb/phy/phy-platform-ulpi.c
> > new file mode 100644
> > index 0000000..fb89363
> > --- /dev/null
> > +++ b/drivers/usb/phy/phy-platform-ulpi.c
> > @@ -0,0 +1,143 @@
> > +/*
> > + * Platform driver for generic ULPI PHYs.
> > + *
> > + * Copyright (C) 2015 Xilinx, Inc.
> > + *
> > + * Author: Subbaraya Sundeep <sbhatta@xxxxxxxxxx>
> > + *
> > + * This program is free software; you can redistribute it
> > + * and/or modify it under the terms of the GNU General Public
> > + * License as published by the Free Software Foundation;
> > + * either version 2 of the License, or (at your option) any
> > + * later version.
> > + */
> > +
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/usb/ulpi.h>
> > +#include <linux/usb/phy.h>
> > +
> > +/**
> > + * struct ulpi_phy - The ULPI PHY
> > + * @usb_phy: pointer to usb phy
> > + * @regs: base address of USB controller to which PHY is connected
> > + * @vp_offset: ulpi viewport register offset of USB controller
> > + * @flags: initial required settings of PHY  */
> > +
> > +struct ulpi_phy {
> > +	struct usb_phy	*usb_phy;
> > +	void __iomem *regs;
> > +	unsigned int vp_offset;
> > +	unsigned int flags;
> > +};
> > +
> > +/**
> > + * usbphy_set_vbus - Sets VBUS by writing to PHY.
> > + * @phy: pointer to PHY
> > + * @on: 1 - turn on VBUS
> > + *	0 - turn off VBUS
> > + * Return: 0 for success and error value on failure  */ static int
> > +usbphy_set_vbus(struct usb_phy *phy, int on) {
> > +	unsigned int flags = usb_phy_io_read(phy, ULPI_OTG_CTRL);
> > +
> > +	flags &= ~(ULPI_OTG_CTRL_DRVVBUS |
> ULPI_OTG_CTRL_DRVVBUS_EXT);
> > +
> > +	if (on) {
> > +		if (phy->flags & ULPI_OTG_DRVVBUS)
> > +			flags |= ULPI_OTG_CTRL_DRVVBUS;
> > +
> > +		if (phy->flags & ULPI_OTG_DRVVBUS_EXT)
> > +			flags |= ULPI_OTG_CTRL_DRVVBUS_EXT;
> > +	}
> > +
> > +	return usb_phy_io_write(phy, flags, ULPI_OTG_CTRL); }
> > +
> > +/**
> > + * ulpi_phy_probe - The device probe function for driver initialization.
> > + * @pdev: pointer to the platform device structure.
> > + *
> > + * Return: 0 for success and error value on failure  */ static int
> > +ulpi_phy_probe(struct platform_device *pdev) {
> > +	struct device_node *np = pdev->dev.of_node;
> > +	struct resource *res;
> > +	struct ulpi_phy *uphy;
> > +	bool flag;
> > +	int ret;
> > +
> > +	uphy = devm_kzalloc(&pdev->dev, sizeof(*uphy), GFP_KERNEL);
> > +	if (!uphy)
> > +		return -ENOMEM;
> > +
> > +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	uphy->regs = devm_ioremap(&pdev->dev, res->start,
> resource_size(res));
> > +	if (IS_ERR(uphy->regs))
> > +		return PTR_ERR(uphy->regs);
> > +
> > +	ret = of_property_read_u32(np, "view-port", &uphy->vp_offset);
> > +	if (IS_ERR(uphy->regs)) {
> > +		dev_err(&pdev->dev, "view-port register not specified\n");
> > +		return PTR_ERR(uphy->regs);
> > +	}
> > +
> > +	flag = of_property_read_bool(np, "drv-vbus");
> > +	if (flag)
> > +		uphy->flags |= ULPI_OTG_DRVVBUS |
> ULPI_OTG_DRVVBUS_EXT;
> > +
> > +	uphy->usb_phy = otg_ulpi_create(&ulpi_viewport_access_ops,
> > +uphy->flags);
> > +
> > +	uphy->usb_phy->set_vbus	= usbphy_set_vbus;
> 
> When you will call it?

I am calling it in host.c and otg_fsm.c of Chipidea driver wherever
regulator_enable/disable is called to control VBUS like below: 

if (ci->platdata->flags & CI_HDRC_PHY_VBUS_CONTROL) {
                if (enable)
                        ci->usb_phy->set_vbus(ci->usb_phy, 1);
                else
                        ci->usb_phy->set_vbus(ci->usb_phy, 0);
}

After these changes host mode and otg modes works fine
for my case.

> 
> > +
> > +	uphy->usb_phy->dev = &pdev->dev;
> > +
> > +	uphy->usb_phy->io_priv = uphy->regs + uphy->vp_offset;
> > +
> > +	ret = usb_add_phy_dev(uphy->usb_phy);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * ulpi_phy_remove - Releases the resources allocated during the
> initialization.
> > + * @pdev: pointer to the platform device structure.
> > + *
> > + * Return: 0 always
> > + */
> > +static int ulpi_phy_remove(struct platform_device *pdev) {
> > +	struct ulpi_phy *uphy = platform_get_drvdata(pdev);
> 
> You have not set uphy as device drvdata at probe

Yes I missed it. Thanks for pointing.

Sundeep
> 
> > +
> > +	usb_remove_phy(uphy->usb_phy);
> > +
> > +	return 0;
> > +}
> > +
> > +/* Match table for of_platform binding */ static const struct
> > +of_device_id ulpi_phy_table[] = {
> > +	{ .compatible = "ulpi-phy" },
> > +	{ /* end of list */},
> > +};
> > +MODULE_DEVICE_TABLE(of, ulpi_phy_table);
> > +
> > +static struct platform_driver ulpi_phy_driver = {
> > +	.probe		= ulpi_phy_probe,
> > +	.remove		= ulpi_phy_remove,
> > +	.driver		= {
> > +		.name	= "ulpi-platform-phy",
> > +		.of_match_table = of_match_ptr(ulpi_phy_table),
> > +	},
> > +};
> > +module_platform_driver(ulpi_phy_driver);
> > +
> > +MODULE_DESCRIPTION("ULPI PHY platform driver");
> > +MODULE_AUTHOR("Xilinx, Inc"); MODULE_LICENSE("GPL v2");
> > --
> > 1.7.1
> >
> 
> --
> 
> Best Regards,
> Peter Chen
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