1/*
2 * This program is free software; you can redistribute it and/or
3 * modify it under the terms of the GNU General Public License as
4 * published by the Free Software Foundation version 2.
5 *
6 * This program is distributed "as is" WITHOUT ANY WARRANTY of any
7 * kind, whether express or implied; without even the implied warranty
8 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 * GNU General Public License for more details.
10 */
11
12#include <linux/module.h>
13#include <linux/platform_device.h>
14#include <linux/regmap.h>
15
16#include <linux/slab.h>
17#include <linux/of.h>
18#include <linux/io.h>
19#include <linux/usb/phy_companion.h>
20#include <linux/clk.h>
21#include <linux/err.h>
22#include <linux/pm_runtime.h>
23#include <linux/delay.h>
24#include <linux/phy/phy.h>
25#include <linux/of_platform.h>
26
27#include <linux/mfd/syscon.h>
28
29/*
30 * TRM has two sets of USB_CTRL registers.. The correct register bits
31 * are in TRM section 24.9.8.2 USB_CTRL Register. The TRM documents the
32 * phy as being SR70LX Synopsys USB 2.0 OTG nanoPHY. It also seems at
33 * least dm816x rev c ignores writes to USB_CTRL register, but the TI
34 * kernel is writing to those so it's possible that later revisions
35 * have worknig USB_CTRL register.
36 *
37 * Also note that At least USB_CTRL register seems to be dm816x specific
38 * according to the TRM. It's possible that USBPHY_CTRL is more generic,
39 * but that would have to be checked against the SR70LX documentation
40 * which does not seem to be publicly available.
41 *
42 * Finally, the phy on dm814x and am335x is different from dm816x.
43 */
44#define DM816X_USB_CTRL_PHYCLKSRC	BIT(8)	/* 1 = PLL ref clock */
45#define DM816X_USB_CTRL_PHYSLEEP1	BIT(1)	/* Enable the first phy */
46#define DM816X_USB_CTRL_PHYSLEEP0	BIT(0)	/* Enable the second phy */
47
48#define DM816X_USBPHY_CTRL_TXRISETUNE	1
49#define DM816X_USBPHY_CTRL_TXVREFTUNE	0xc
50#define DM816X_USBPHY_CTRL_TXPREEMTUNE	0x2
51
52struct dm816x_usb_phy {
53	struct regmap *syscon;
54	struct device *dev;
55	unsigned int instance;
56	struct clk *refclk;
57	struct usb_phy phy;
58	unsigned int usb_ctrl;		/* Shared between phy0 and phy1 */
59	unsigned int usbphy_ctrl;
60};
61
62static int dm816x_usb_phy_set_host(struct usb_otg *otg, struct usb_bus *host)
63{
64	otg->host = host;
65	if (!host)
66		otg->state = OTG_STATE_UNDEFINED;
67
68	return 0;
69}
70
71static int dm816x_usb_phy_set_peripheral(struct usb_otg *otg,
72					 struct usb_gadget *gadget)
73{
74	otg->gadget = gadget;
75	if (!gadget)
76		otg->state = OTG_STATE_UNDEFINED;
77
78	return 0;
79}
80
81static int dm816x_usb_phy_init(struct phy *x)
82{
83	struct dm816x_usb_phy *phy = phy_get_drvdata(x);
84	unsigned int val;
85
86	if (clk_get_rate(phy->refclk) != 24000000)
87		dev_warn(phy->dev, "nonstandard phy refclk\n");
88
89	/* Set PLL ref clock and put phys to sleep */
90	regmap_update_bits(phy->syscon, phy->usb_ctrl,
91			   DM816X_USB_CTRL_PHYCLKSRC |
92			   DM816X_USB_CTRL_PHYSLEEP1 |
93			   DM816X_USB_CTRL_PHYSLEEP0,
94			   0);
95	regmap_read(phy->syscon, phy->usb_ctrl, &val);
96	if ((val & 3) != 0)
97		dev_info(phy->dev,
98			 "Working dm816x USB_CTRL! (0x%08x)\n",
99			 val);
100
101	/*
102	 * TI kernel sets these values for "symmetrical eye diagram and
103	 * better signal quality" so let's assume somebody checked the
104	 * values with a scope and set them here too.
105	 */
106	regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
107	val |= DM816X_USBPHY_CTRL_TXRISETUNE |
108		DM816X_USBPHY_CTRL_TXVREFTUNE |
109		DM816X_USBPHY_CTRL_TXPREEMTUNE;
110	regmap_write(phy->syscon, phy->usbphy_ctrl, val);
111
112	return 0;
113}
114
115static const struct phy_ops ops = {
116	.init		= dm816x_usb_phy_init,
117	.owner		= THIS_MODULE,
118};
119
120static int __maybe_unused dm816x_usb_phy_runtime_suspend(struct device *dev)
121{
122	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
123	unsigned int mask, val;
124	int error = 0;
125
126	mask = BIT(phy->instance);
127	val = ~BIT(phy->instance);
128	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
129				   mask, val);
130	if (error)
131		dev_err(phy->dev, "phy%i failed to power off\n",
132			phy->instance);
133	clk_disable(phy->refclk);
134
135	return 0;
136}
137
138static int __maybe_unused dm816x_usb_phy_runtime_resume(struct device *dev)
139{
140	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
141	unsigned int mask, val;
142	int error;
143
144	error = clk_enable(phy->refclk);
145	if (error)
146		return error;
147
148	/*
149	 * Note that at least dm816x rev c does not seem to do
150	 * anything with the USB_CTRL register. But let's follow
151	 * what the TI tree is doing in case later revisions use
152	 * USB_CTRL.
153	 */
154	mask = BIT(phy->instance);
155	val = BIT(phy->instance);
156	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
157				   mask, val);
158	if (error) {
159		dev_err(phy->dev, "phy%i failed to power on\n",
160			phy->instance);
161		clk_disable(phy->refclk);
162		return error;
163	}
164
165	return 0;
166}
167
168static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
169			    dm816x_usb_phy_runtime_suspend,
170			    dm816x_usb_phy_runtime_resume,
171			    NULL);
172
173#ifdef CONFIG_OF
174static const struct of_device_id dm816x_usb_phy_id_table[] = {
175	{
176		.compatible = "ti,dm8168-usb-phy",
177	},
178	{},
179};
180MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
181#endif
182
183static int dm816x_usb_phy_probe(struct platform_device *pdev)
184{
185	struct dm816x_usb_phy *phy;
186	struct resource *res;
187	struct phy *generic_phy;
188	struct phy_provider *phy_provider;
189	struct usb_otg *otg;
190	const struct of_device_id *of_id;
191	int error;
192
193	of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),
194				&pdev->dev);
195	if (!of_id)
196		return -EINVAL;
197
198	phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
199	if (!phy)
200		return -ENOMEM;
201
202	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
203	if (!res)
204		return -ENOENT;
205
206	phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
207						      "syscon");
208	if (IS_ERR(phy->syscon))
209		return PTR_ERR(phy->syscon);
210
211	/*
212	 * According to sprs614e.pdf, the first usb_ctrl is shared and
213	 * the second instance for usb_ctrl is reserved.. Also the
214	 * register bits are different from earlier TRMs.
215	 */
216	phy->usb_ctrl = 0x20;
217	phy->usbphy_ctrl = (res->start & 0xff) + 4;
218	if (phy->usbphy_ctrl == 0x2c)
219		phy->instance = 1;
220
221	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
222	if (!otg)
223		return -ENOMEM;
224
225	phy->dev = &pdev->dev;
226	phy->phy.dev = phy->dev;
227	phy->phy.label = "dm8168_usb_phy";
228	phy->phy.otg = otg;
229	phy->phy.type = USB_PHY_TYPE_USB2;
230	otg->set_host = dm816x_usb_phy_set_host;
231	otg->set_peripheral = dm816x_usb_phy_set_peripheral;
232	otg->usb_phy = &phy->phy;
233
234	platform_set_drvdata(pdev, phy);
235
236	phy->refclk = devm_clk_get(phy->dev, "refclk");
237	if (IS_ERR(phy->refclk))
238		return PTR_ERR(phy->refclk);
239	error = clk_prepare(phy->refclk);
240	if (error)
241		return error;
242
243	pm_runtime_enable(phy->dev);
244	generic_phy = devm_phy_create(phy->dev, NULL, &ops);
245	if (IS_ERR(generic_phy)) {
246		error = PTR_ERR(generic_phy);
247		goto clk_unprepare;
248	}
249
250	phy_set_drvdata(generic_phy, phy);
251
252	phy_provider = devm_of_phy_provider_register(phy->dev,
253						     of_phy_simple_xlate);
254	if (IS_ERR(phy_provider)) {
255		error = PTR_ERR(phy_provider);
256		goto clk_unprepare;
257	}
258
259	usb_add_phy_dev(&phy->phy);
260
261	return 0;
262
263clk_unprepare:
264	pm_runtime_disable(phy->dev);
265	clk_unprepare(phy->refclk);
266	return error;
267}
268
269static int dm816x_usb_phy_remove(struct platform_device *pdev)
270{
271	struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
272
273	usb_remove_phy(&phy->phy);
274	pm_runtime_disable(phy->dev);
275	clk_unprepare(phy->refclk);
276
277	return 0;
278}
279
280static struct platform_driver dm816x_usb_phy_driver = {
281	.probe		= dm816x_usb_phy_probe,
282	.remove		= dm816x_usb_phy_remove,
283	.driver		= {
284		.name	= "dm816x-usb-phy",
285		.pm	= &dm816x_usb_phy_pm_ops,
286		.of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
287	},
288};
289
290module_platform_driver(dm816x_usb_phy_driver);
291
292MODULE_ALIAS("platform:dm816x_usb");
293MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
294MODULE_DESCRIPTION("dm816x usb phy driver");
295MODULE_LICENSE("GPL v2");
296