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

[Peter Chen <peter.chen@freescale.com>]

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@xilinx.com>
> ---
>  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.

> +	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@xilinx.com>
> + *
> + * 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?

> +
> +	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

> +
> +	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