phy: Add a driver for dm816x USB PHY

Device tree binding documentation for am816x USB PHY

=========================

Required properties:

- compatible : should be "ti,dm816x-usb-phy"

- reg : offset and length of the PHY register set.

- reg-names : name for the phy registers

- clocks : phandle to the clock

- clock-names : name of the clock

- syscon: phandle for the syscon node to access misc registers

- #phy-cells : from the generic PHY bindings, must be 1

- syscon: phandle for the syscon node to access misc registers

Example:

usb_phy0: usb-phy@20 {

	compatible = "ti,dm8168-usb-phy";

	reg = <0x20 0x8>;

	reg-names = "phy";

	clocks = <&main_fapll 6>;

	clock-names = "refclk";

	#phy-cells = <0>;

	syscon = <&scm_conf>;

};

	depends on OF

	select GENERIC_PHY

config PHY_DM816X_USB

	tristate "TI dm816x USB PHY driver"

	depends on ARCH_OMAP2PLUS

	select GENERIC_PHY

	help

	  Enable this for dm816x USB to work.

config PHY_EXYNOS_MIPI_VIDEO

	tristate "S5P/EXYNOS SoC series MIPI CSI-2/DSI PHY driver"

	depends on HAS_IOMEM

obj-$(CONFIG_GENERIC_PHY)		+= phy-core.o

obj-$(CONFIG_PHY_BERLIN_USB)		+= phy-berlin-usb.o

obj-$(CONFIG_PHY_BERLIN_SATA)		+= phy-berlin-sata.o

obj-$(CONFIG_PHY_DM816X_USB)		+= phy-dm816x-usb.o

obj-$(CONFIG_ARMADA375_USBCLUSTER_PHY)	+= phy-armada375-usb2.o

obj-$(CONFIG_BCM_KONA_USB2_PHY)		+= phy-bcm-kona-usb2.o

obj-$(CONFIG_PHY_EXYNOS_DP_VIDEO)	+= phy-exynos-dp-video.o

/*

 * 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 version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

 * GNU General Public License for more details.

 */

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>

#include <linux/slab.h>

#include <linux/of.h>

#include <linux/io.h>

#include <linux/usb/phy_companion.h>

#include <linux/clk.h>

#include <linux/err.h>

#include <linux/pm_runtime.h>

#include <linux/delay.h>

#include <linux/phy/phy.h>

#include <linux/of_platform.h>

#include <linux/mfd/syscon.h>

/*

 * TRM has two sets of USB_CTRL registers.. The correct register bits

 * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the

 * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at

 * least dm816x rev c ignores writes to USB_CTRL register, but the TI

 * kernel is writing to those so it's possible that later revisions

 * have worknig USB_CTRL register.

 *

 * Also note that At least USB_CTRL register seems to be dm816x specific

 * according to the TRM. It's possible that USBPHY_CTRL is more generic,

 * but that would have to be checked against the SR70LX documentation

 * which does not seem to be publicly available.

 *

 * Finally, the phy on dm814x and am335x is different from dm816x.

 */

#define DM816X_USB_CTRL_PHYCLKSRC	BIT(8)	/* 1 = PLL ref clock */

#define DM816X_USB_CTRL_PHYSLEEP1	BIT(1)	/* Enable the first phy */

#define DM816X_USB_CTRL_PHYSLEEP0	BIT(0)	/* Enable the second phy */

#define DM816X_USBPHY_CTRL_TXRISETUNE	1

#define DM816X_USBPHY_CTRL_TXVREFTUNE	0xc

#define DM816X_USBPHY_CTRL_TXPREEMTUNE	0x2

struct dm816x_usb_phy {

	struct regmap *syscon;

	struct device *dev;

	unsigned int instance;

	struct clk *refclk;

	struct usb_phy phy;

	unsigned int usb_ctrl;		/* Shared between phy0 and phy1 */

	unsigned int usbphy_ctrl;

};

static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)

{

	otg->host = host;

	if (!host)

		otg->state = OTG_STATE_UNDEFINED;

	return 0;

}

static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,

					 struct usb_gadget *gadget)

{

	otg->gadget = gadget;

	if (!gadget)

		otg->state = OTG_STATE_UNDEFINED;

	return 0;

}

static int dm816x_usb_phy_init(struct phy *x)

{

	struct dm816x_usb_phy *phy = phy_get_drvdata(x);

	unsigned int val;

	int error;

	if (clk_get_rate(phy->refclk) != 24000000)

		dev_warn(phy->dev, "nonstandard phy refclk\n");

	/* Set PLL ref clock and put phys to sleep */

	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,

				   DM816X_USB_CTRL_PHYCLKSRC |

				   DM816X_USB_CTRL_PHYSLEEP1 |

				   DM816X_USB_CTRL_PHYSLEEP0,

				   0);

	regmap_read(phy->syscon, phy->usb_ctrl, &val);

	if ((val & 3) != 0)

		dev_info(phy->dev,

			 "Working dm816x USB_CTRL! (0x%08x)\n",

			 val);

	/*

	 * TI kernel sets these values for "symmetrical eye diagram and

	 * better signal quality" so let's assume somebody checked the

	 * values with a scope and set them here too.

	 */

	regmap_read(phy->syscon, phy->usbphy_ctrl, &val);

	val |= DM816X_USBPHY_CTRL_TXRISETUNE |

		DM816X_USBPHY_CTRL_TXVREFTUNE |

		DM816X_USBPHY_CTRL_TXPREEMTUNE;

	regmap_write(phy->syscon, phy->usbphy_ctrl, val);

	return 0;

}

static struct phy_ops ops = {

	.init		= dm816x_usb_phy_init,

	.owner		= THIS_MODULE,

};

static int dm816x_usb_phy_runtime_suspend(struct device *dev)

{

	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);

	unsigned int mask, val;

	int error = 0;

	mask = BIT(phy->instance);

	val = ~BIT(phy->instance);

	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,

				   mask, val);

	if (error)

		dev_err(phy->dev, "phy%i failed to power off\n",

			phy->instance);

	clk_disable(phy->refclk);

	return 0;

}

static int dm816x_usb_phy_runtime_resume(struct device *dev)

{

	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);

	unsigned int mask, val;

	int error;

	error = clk_enable(phy->refclk);

	if (error)

		return error;

	/*

	 * Note that at least dm816x rev c does not seem to do

	 * anything with the USB_CTRL register. But let's follow

	 * what the TI tree is doing in case later revisions use

	 * USB_CTRL.

	 */

	mask = BIT(phy->instance);

	val = BIT(phy->instance);

	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,

				   mask, val);

	if (error) {

		dev_err(phy->dev, "phy%i failed to power on\n",

			phy->instance);

		clk_disable(phy->refclk);

		return error;

	}

	return 0;

}

static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,

			    dm816x_usb_phy_runtime_suspend,

			    dm816x_usb_phy_runtime_resume,

			    NULL);

#ifdef CONFIG_OF

static const struct of_device_id dm816x_usb_phy_id_table[] = {

	{

		.compatible = "ti,dm8168-usb-phy",

	},

	{},

};

MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);

#endif

static int dm816x_usb_phy_probe(struct platform_device *pdev)

{

	struct dm816x_usb_phy *phy;

	struct resource *res;

	struct phy *generic_phy;

	struct phy_provider *phy_provider;

	struct usb_otg *otg;

	const struct of_device_id *of_id;

	const struct usb_phy_data *phy_data;

	int error;

	of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),

				&pdev->dev);

	if (!of_id)

		return -EINVAL;

	phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);

	if (!phy)

		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENOENT;

	phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,

						      "syscon");

	if (IS_ERR(phy->syscon))

		return PTR_ERR(phy->syscon);

	/*

	 * According to sprs614e.pdf, the first usb_ctrl is shared and

	 * the second instance for usb_ctrl is reserved.. Also the

	 * register bits are different from earlier TRMs.

	 */

	phy->usb_ctrl = 0x20;

	phy->usbphy_ctrl = (res->start & 0xff) + 4;

	if (phy->usbphy_ctrl == 0x2c)

		phy->instance = 1;

	phy_data = of_id->data;

	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);

	if (!otg)

		return -ENOMEM;

	phy->dev = &pdev->dev;

	phy->phy.dev = phy->dev;

	phy->phy.label = "dm8168_usb_phy";

	phy->phy.otg = otg;

	phy->phy.type = USB_PHY_TYPE_USB2;

	otg->set_host = dm816x_usb_phy_set_host;

	otg->set_peripheral = dm816x_usb_phy_set_peripheral;

	otg->usb_phy = &phy->phy;

	platform_set_drvdata(pdev, phy);

	phy->refclk = devm_clk_get(phy->dev, "refclk");

	if (IS_ERR(phy->refclk))

		return PTR_ERR(phy->refclk);

	error = clk_prepare(phy->refclk);

	if (error)

		return error;

	pm_runtime_enable(phy->dev);

	generic_phy = devm_phy_create(phy->dev, NULL, &ops);

	if (IS_ERR(generic_phy))

		return PTR_ERR(generic_phy);

	phy_set_drvdata(generic_phy, phy);

	phy_provider = devm_of_phy_provider_register(phy->dev,

						     of_phy_simple_xlate);

	if (IS_ERR(phy_provider))

		return PTR_ERR(phy_provider);

	usb_add_phy_dev(&phy->phy);

	return 0;

}

static int dm816x_usb_phy_remove(struct platform_device *pdev)

{

	struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);

	usb_remove_phy(&phy->phy);

	pm_runtime_disable(phy->dev);

	clk_unprepare(phy->refclk);

	return 0;

}

static struct platform_driver dm816x_usb_phy_driver = {

	.probe		= dm816x_usb_phy_probe,

	.remove		= dm816x_usb_phy_remove,

	.driver		= {

		.name	= "dm816x-usb-phy",

		.pm	= &dm816x_usb_phy_pm_ops,

		.of_match_table = of_match_ptr(dm816x_usb_phy_id_table),

	},

};

module_platform_driver(dm816x_usb_phy_driver);

MODULE_ALIAS("platform:dm816x_usb");

MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");

MODULE_DESCRIPTION("dm816x usb phy driver");

MODULE_LICENSE("GPL v2");