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#include <linux/of_platform.h>
17
18#include <linux/mfd/syscon.h>
19
20/*
21 * TRM has two sets of USB_CTRL registers.. The correct register bits
22 * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the
23 * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at
24 * least dm816x rev c ignores writes to USB_CTRL register, but the TI
25 * kernel is writing to those so it's possible that later revisions
26 * have worknig USB_CTRL register.
27 *
28 * Also note that At least USB_CTRL register seems to be dm816x specific
29 * according to the TRM. It's possible that USBPHY_CTRL is more generic,
30 * but that would have to be checked against the SR70LX documentation
31 * which does not seem to be publicly available.
32 *
33 * Finally, the phy on dm814x and am335x is different from dm816x.
34 */
35#define DM816X_USB_CTRL_PHYCLKSRC	BIT(8)	/* 1 = PLL ref clock */
36#define DM816X_USB_CTRL_PHYSLEEP1	BIT(1)	/* Enable the first phy */
37#define DM816X_USB_CTRL_PHYSLEEP0	BIT(0)	/* Enable the second phy */
38
39#define DM816X_USBPHY_CTRL_TXRISETUNE	1
40#define DM816X_USBPHY_CTRL_TXVREFTUNE	0xc
41#define DM816X_USBPHY_CTRL_TXPREEMTUNE	0x2
42
43struct dm816x_usb_phy {
44	struct regmap *syscon;
45	struct device *dev;
46	unsigned int instance;
47	struct clk *refclk;
48	struct usb_phy phy;
49	unsigned int usb_ctrl;		/* Shared between phy0 and phy1 */
50	unsigned int usbphy_ctrl;
51};
52
53static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
54{
55	otg->host = host;
56	if (!host)
57		otg->state = OTG_STATE_UNDEFINED;
58
59	return 0;
60}
61
62static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,
63					 struct usb_gadget *gadget)
64{
65	otg->gadget = gadget;
66	if (!gadget)
67		otg->state = OTG_STATE_UNDEFINED;
68
69	return 0;
70}
71
72static int dm816x_usb_phy_init(struct phy *x)
73{
74	struct dm816x_usb_phy *phy = phy_get_drvdata(x);
75	unsigned int val;
76
77	if (clk_get_rate(phy->refclk) != 24000000)
78		dev_warn(phy->dev, "nonstandard phy refclk\n");
79
80	/* Set PLL ref clock and put phys to sleep */
81	regmap_update_bits(phy->syscon, phy->usb_ctrl,
82			   DM816X_USB_CTRL_PHYCLKSRC |
83			   DM816X_USB_CTRL_PHYSLEEP1 |
84			   DM816X_USB_CTRL_PHYSLEEP0,
85			   0);
86	regmap_read(phy->syscon, phy->usb_ctrl, &val);
87	if ((val & 3) != 0)
88		dev_info(phy->dev,
89			 "Working dm816x USB_CTRL! (0x%08x)\n",
90			 val);
91
92	/*
93	 * TI kernel sets these values for "symmetrical eye diagram and
94	 * better signal quality" so let's assume somebody checked the
95	 * values with a scope and set them here too.
96	 */
97	regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
98	val |= DM816X_USBPHY_CTRL_TXRISETUNE |
99		DM816X_USBPHY_CTRL_TXVREFTUNE |
100		DM816X_USBPHY_CTRL_TXPREEMTUNE;
101	regmap_write(phy->syscon, phy->usbphy_ctrl, val);
102
103	return 0;
104}
105
106static const struct phy_ops ops = {
107	.init		= dm816x_usb_phy_init,
108	.owner		= THIS_MODULE,
109};
110
111static int __maybe_unused dm816x_usb_phy_runtime_suspend(struct device *dev)
112{
113	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
114	unsigned int mask, val;
115	int error = 0;
116
117	mask = BIT(phy->instance);
118	val = ~BIT(phy->instance);
119	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
120				   mask, val);
121	if (error)
122		dev_err(phy->dev, "phy%i failed to power off\n",
123			phy->instance);
124	clk_disable(phy->refclk);
125
126	return 0;
127}
128
129static int __maybe_unused dm816x_usb_phy_runtime_resume(struct device *dev)
130{
131	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
132	unsigned int mask, val;
133	int error;
134
135	error = clk_enable(phy->refclk);
136	if (error)
137		return error;
138
139	/*
140	 * Note that at least dm816x rev c does not seem to do
141	 * anything with the USB_CTRL register. But let's follow
142	 * what the TI tree is doing in case later revisions use
143	 * USB_CTRL.
144	 */
145	mask = BIT(phy->instance);
146	val = BIT(phy->instance);
147	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
148				   mask, val);
149	if (error) {
150		dev_err(phy->dev, "phy%i failed to power on\n",
151			phy->instance);
152		clk_disable(phy->refclk);
153		return error;
154	}
155
156	return 0;
157}
158
159static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
160			    dm816x_usb_phy_runtime_suspend,
161			    dm816x_usb_phy_runtime_resume,
162			    NULL);
163
164#ifdef CONFIG_OF
165static const struct of_device_id dm816x_usb_phy_id_table[] = {
166	{
167		.compatible = "ti,dm8168-usb-phy",
168	},
169	{},
170};
171MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
172#endif
173
174static int dm816x_usb_phy_probe(struct platform_device *pdev)
175{
176	struct dm816x_usb_phy *phy;
177	struct resource *res;
178	struct phy *generic_phy;
179	struct phy_provider *phy_provider;
180	struct usb_otg *otg;
181	const struct of_device_id *of_id;
182	int error;
183
184	of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),
185				&pdev->dev);
186	if (!of_id)
187		return -EINVAL;
188
189	phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
190	if (!phy)
191		return -ENOMEM;
192
193	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
194	if (!res)
195		return -ENOENT;
196
197	phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
198						      "syscon");
199	if (IS_ERR(phy->syscon))
200		return PTR_ERR(phy->syscon);
201
202	/*
203	 * According to sprs614e.pdf, the first usb_ctrl is shared and
204	 * the second instance for usb_ctrl is reserved.. Also the
205	 * register bits are different from earlier TRMs.
206	 */
207	phy->usb_ctrl = 0x20;
208	phy->usbphy_ctrl = (res->start & 0xff) + 4;
209	if (phy->usbphy_ctrl == 0x2c)
210		phy->instance = 1;
211
212	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
213	if (!otg)
214		return -ENOMEM;
215
216	phy->dev = &pdev->dev;
217	phy->phy.dev = phy->dev;
218	phy->phy.label = "dm8168_usb_phy";
219	phy->phy.otg = otg;
220	phy->phy.type = USB_PHY_TYPE_USB2;
221	otg->set_host = dm816x_usb_phy_set_host;
222	otg->set_peripheral = dm816x_usb_phy_set_peripheral;
223	otg->usb_phy = &phy->phy;
224
225	platform_set_drvdata(pdev, phy);
226
227	phy->refclk = devm_clk_get(phy->dev, "refclk");
228	if (IS_ERR(phy->refclk))
229		return PTR_ERR(phy->refclk);
230	error = clk_prepare(phy->refclk);
231	if (error)
232		return error;
233
234	pm_runtime_enable(phy->dev);
235	generic_phy = devm_phy_create(phy->dev, NULL, &ops);
236	if (IS_ERR(generic_phy)) {
237		error = PTR_ERR(generic_phy);
238		goto clk_unprepare;
239	}
240
241	phy_set_drvdata(generic_phy, phy);
242
243	phy_provider = devm_of_phy_provider_register(phy->dev,
244						     of_phy_simple_xlate);
245	if (IS_ERR(phy_provider)) {
246		error = PTR_ERR(phy_provider);
247		goto clk_unprepare;
248	}
249
250	usb_add_phy_dev(&phy->phy);
251
252	return 0;
253
254clk_unprepare:
255	pm_runtime_disable(phy->dev);
256	clk_unprepare(phy->refclk);
257	return error;
258}
259
260static void dm816x_usb_phy_remove(struct platform_device *pdev)
261{
262	struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
263
264	usb_remove_phy(&phy->phy);
265	pm_runtime_disable(phy->dev);
266	clk_unprepare(phy->refclk);
267}
268
269static struct platform_driver dm816x_usb_phy_driver = {
270	.probe		= dm816x_usb_phy_probe,
271	.remove_new	= dm816x_usb_phy_remove,
272	.driver		= {
273		.name	= "dm816x-usb-phy",
274		.pm	= &dm816x_usb_phy_pm_ops,
275		.of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
276	},
277};
278
279module_platform_driver(dm816x_usb_phy_driver);
280
281MODULE_ALIAS("platform:dm816x_usb");
282MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
283MODULE_DESCRIPTION("dm816x usb phy driver");
284MODULE_LICENSE("GPL v2");
285