1// SPDX-License-Identifier: GPL-2.0-only
2
3#include <linux/module.h>
4#include <linux/platform_device.h>
5#include <linux/regmap.h>
6
7#include <linux/slab.h>
8#include <linux/of.h>
9#include <linux/io.h>
10#include <linux/usb/phy_companion.h>
11#include <linux/clk.h>
12#include <linux/err.h>
13#include <linux/pm_runtime.h>
14#include <linux/delay.h>
15#include <linux/phy/phy.h>
16
17#include <linux/mfd/syscon.h>
18
19/*
20 * TRM has two sets of USB_CTRL registers.. The correct register bits
21 * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the
22 * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at
23 * least dm816x rev c ignores writes to USB_CTRL register, but the TI
24 * kernel is writing to those so it's possible that later revisions
25 * have worknig USB_CTRL register.
26 *
27 * Also note that At least USB_CTRL register seems to be dm816x specific
28 * according to the TRM. It's possible that USBPHY_CTRL is more generic,
29 * but that would have to be checked against the SR70LX documentation
30 * which does not seem to be publicly available.
31 *
32 * Finally, the phy on dm814x and am335x is different from dm816x.
33 */
34#define DM816X_USB_CTRL_PHYCLKSRC	BIT(8)	/* 1 = PLL ref clock */
35#define DM816X_USB_CTRL_PHYSLEEP1	BIT(1)	/* Enable the first phy */
36#define DM816X_USB_CTRL_PHYSLEEP0	BIT(0)	/* Enable the second phy */
37
38#define DM816X_USBPHY_CTRL_TXRISETUNE	1
39#define DM816X_USBPHY_CTRL_TXVREFTUNE	0xc
40#define DM816X_USBPHY_CTRL_TXPREEMTUNE	0x2
41
42struct dm816x_usb_phy {
43	struct regmap *syscon;
44	struct device *dev;
45	unsigned int instance;
46	struct clk *refclk;
47	struct usb_phy phy;
48	unsigned int usb_ctrl;		/* Shared between phy0 and phy1 */
49	unsigned int usbphy_ctrl;
50};
51
52static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
53{
54	otg->host = host;
55	if (!host)
56		otg->state = OTG_STATE_UNDEFINED;
57
58	return 0;
59}
60
61static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,
62					 struct usb_gadget *gadget)
63{
64	otg->gadget = gadget;
65	if (!gadget)
66		otg->state = OTG_STATE_UNDEFINED;
67
68	return 0;
69}
70
71static int dm816x_usb_phy_init(struct phy *x)
72{
73	struct dm816x_usb_phy *phy = phy_get_drvdata(x);
74	unsigned int val;
75
76	if (clk_get_rate(phy->refclk) != 24000000)
77		dev_warn(phy->dev, "nonstandard phy refclk\n");
78
79	/* Set PLL ref clock and put phys to sleep */
80	regmap_update_bits(phy->syscon, phy->usb_ctrl,
81			   DM816X_USB_CTRL_PHYCLKSRC |
82			   DM816X_USB_CTRL_PHYSLEEP1 |
83			   DM816X_USB_CTRL_PHYSLEEP0,
84			   0);
85	regmap_read(phy->syscon, phy->usb_ctrl, &val);
86	if ((val & 3) != 0)
87		dev_info(phy->dev,
88			 "Working dm816x USB_CTRL! (0x%08x)\n",
89			 val);
90
91	/*
92	 * TI kernel sets these values for "symmetrical eye diagram and
93	 * better signal quality" so let's assume somebody checked the
94	 * values with a scope and set them here too.
95	 */
96	regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
97	val |= DM816X_USBPHY_CTRL_TXRISETUNE |
98		DM816X_USBPHY_CTRL_TXVREFTUNE |
99		DM816X_USBPHY_CTRL_TXPREEMTUNE;
100	regmap_write(phy->syscon, phy->usbphy_ctrl, val);
101
102	return 0;
103}
104
105static const struct phy_ops ops = {
106	.init		= dm816x_usb_phy_init,
107	.owner		= THIS_MODULE,
108};
109
110static int __maybe_unused dm816x_usb_phy_runtime_suspend(struct device *dev)
111{
112	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
113	unsigned int mask, val;
114	int error = 0;
115
116	mask = BIT(phy->instance);
117	val = ~BIT(phy->instance);
118	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
119				   mask, val);
120	if (error)
121		dev_err(phy->dev, "phy%i failed to power off\n",
122			phy->instance);
123	clk_disable(phy->refclk);
124
125	return 0;
126}
127
128static int __maybe_unused dm816x_usb_phy_runtime_resume(struct device *dev)
129{
130	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
131	unsigned int mask, val;
132	int error;
133
134	error = clk_enable(phy->refclk);
135	if (error)
136		return error;
137
138	/*
139	 * Note that at least dm816x rev c does not seem to do
140	 * anything with the USB_CTRL register. But let's follow
141	 * what the TI tree is doing in case later revisions use
142	 * USB_CTRL.
143	 */
144	mask = BIT(phy->instance);
145	val = BIT(phy->instance);
146	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
147				   mask, val);
148	if (error) {
149		dev_err(phy->dev, "phy%i failed to power on\n",
150			phy->instance);
151		clk_disable(phy->refclk);
152		return error;
153	}
154
155	return 0;
156}
157
158static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
159			    dm816x_usb_phy_runtime_suspend,
160			    dm816x_usb_phy_runtime_resume,
161			    NULL);
162
163static const struct of_device_id dm816x_usb_phy_id_table[] = {
164	{
165		.compatible = "ti,dm8168-usb-phy",
166	},
167	{},
168};
169MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
170
171static int dm816x_usb_phy_probe(struct platform_device *pdev)
172{
173	struct dm816x_usb_phy *phy;
174	struct resource *res;
175	struct phy *generic_phy;
176	struct phy_provider *phy_provider;
177	struct usb_otg *otg;
178	int error;
179
180	phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
181	if (!phy)
182		return -ENOMEM;
183
184	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
185	if (!res)
186		return -ENOENT;
187
188	phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
189						      "syscon");
190	if (IS_ERR(phy->syscon))
191		return PTR_ERR(phy->syscon);
192
193	/*
194	 * According to sprs614e.pdf, the first usb_ctrl is shared and
195	 * the second instance for usb_ctrl is reserved.. Also the
196	 * register bits are different from earlier TRMs.
197	 */
198	phy->usb_ctrl = 0x20;
199	phy->usbphy_ctrl = (res->start & 0xff) + 4;
200	if (phy->usbphy_ctrl == 0x2c)
201		phy->instance = 1;
202
203	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
204	if (!otg)
205		return -ENOMEM;
206
207	phy->dev = &pdev->dev;
208	phy->phy.dev = phy->dev;
209	phy->phy.label = "dm8168_usb_phy";
210	phy->phy.otg = otg;
211	phy->phy.type = USB_PHY_TYPE_USB2;
212	otg->set_host = dm816x_usb_phy_set_host;
213	otg->set_peripheral = dm816x_usb_phy_set_peripheral;
214	otg->usb_phy = &phy->phy;
215
216	platform_set_drvdata(pdev, phy);
217
218	phy->refclk = devm_clk_get(phy->dev, "refclk");
219	if (IS_ERR(phy->refclk))
220		return PTR_ERR(phy->refclk);
221	error = clk_prepare(phy->refclk);
222	if (error)
223		return error;
224
225	pm_runtime_enable(phy->dev);
226	generic_phy = devm_phy_create(phy->dev, NULL, &ops);
227	if (IS_ERR(generic_phy)) {
228		error = PTR_ERR(generic_phy);
229		goto clk_unprepare;
230	}
231
232	phy_set_drvdata(generic_phy, phy);
233
234	phy_provider = devm_of_phy_provider_register(phy->dev,
235						     of_phy_simple_xlate);
236	if (IS_ERR(phy_provider)) {
237		error = PTR_ERR(phy_provider);
238		goto clk_unprepare;
239	}
240
241	usb_add_phy_dev(&phy->phy);
242
243	return 0;
244
245clk_unprepare:
246	pm_runtime_disable(phy->dev);
247	clk_unprepare(phy->refclk);
248	return error;
249}
250
251static void dm816x_usb_phy_remove(struct platform_device *pdev)
252{
253	struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
254
255	usb_remove_phy(&phy->phy);
256	pm_runtime_disable(phy->dev);
257	clk_unprepare(phy->refclk);
258}
259
260static struct platform_driver dm816x_usb_phy_driver = {
261	.probe		= dm816x_usb_phy_probe,
262	.remove_new	= dm816x_usb_phy_remove,
263	.driver		= {
264		.name	= "dm816x-usb-phy",
265		.pm	= &dm816x_usb_phy_pm_ops,
266		.of_match_table = dm816x_usb_phy_id_table,
267	},
268};
269
270module_platform_driver(dm816x_usb_phy_driver);
271
272MODULE_ALIAS("platform:dm816x_usb");
273MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
274MODULE_DESCRIPTION("dm816x usb phy driver");
275MODULE_LICENSE("GPL v2");
276