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	int error;
86
87	if (clk_get_rate(phy->refclk) != 24000000)
88		dev_warn(phy->dev, "nonstandard phy refclk\n");
89
90	/* Set PLL ref clock and put phys to sleep */
91	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
92				   DM816X_USB_CTRL_PHYCLKSRC |
93				   DM816X_USB_CTRL_PHYSLEEP1 |
94				   DM816X_USB_CTRL_PHYSLEEP0,
95				   0);
96	regmap_read(phy->syscon, phy->usb_ctrl, &val);
97	if ((val & 3) != 0)
98		dev_info(phy->dev,
99			 "Working dm816x USB_CTRL! (0x%08x)\n",
100			 val);
101
102	/*
103	 * TI kernel sets these values for "symmetrical eye diagram and
104	 * better signal quality" so let's assume somebody checked the
105	 * values with a scope and set them here too.
106	 */
107	regmap_read(phy->syscon, phy->usbphy_ctrl, &val);
108	val |= DM816X_USBPHY_CTRL_TXRISETUNE |
109		DM816X_USBPHY_CTRL_TXVREFTUNE |
110		DM816X_USBPHY_CTRL_TXPREEMTUNE;
111	regmap_write(phy->syscon, phy->usbphy_ctrl, val);
112
113	return 0;
114}
115
116static struct phy_ops ops = {
117	.init		= dm816x_usb_phy_init,
118	.owner		= THIS_MODULE,
119};
120
121static int dm816x_usb_phy_runtime_suspend(struct device *dev)
122{
123	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
124	unsigned int mask, val;
125	int error = 0;
126
127	mask = BIT(phy->instance);
128	val = ~BIT(phy->instance);
129	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
130				   mask, val);
131	if (error)
132		dev_err(phy->dev, "phy%i failed to power off\n",
133			phy->instance);
134	clk_disable(phy->refclk);
135
136	return 0;
137}
138
139static int dm816x_usb_phy_runtime_resume(struct device *dev)
140{
141	struct dm816x_usb_phy *phy = dev_get_drvdata(dev);
142	unsigned int mask, val;
143	int error;
144
145	error = clk_enable(phy->refclk);
146	if (error)
147		return error;
148
149	/*
150	 * Note that at least dm816x rev c does not seem to do
151	 * anything with the USB_CTRL register. But let's follow
152	 * what the TI tree is doing in case later revisions use
153	 * USB_CTRL.
154	 */
155	mask = BIT(phy->instance);
156	val = BIT(phy->instance);
157	error = regmap_update_bits(phy->syscon, phy->usb_ctrl,
158				   mask, val);
159	if (error) {
160		dev_err(phy->dev, "phy%i failed to power on\n",
161			phy->instance);
162		clk_disable(phy->refclk);
163		return error;
164	}
165
166	return 0;
167}
168
169static UNIVERSAL_DEV_PM_OPS(dm816x_usb_phy_pm_ops,
170			    dm816x_usb_phy_runtime_suspend,
171			    dm816x_usb_phy_runtime_resume,
172			    NULL);
173
174#ifdef CONFIG_OF
175static const struct of_device_id dm816x_usb_phy_id_table[] = {
176	{
177		.compatible = "ti,dm8168-usb-phy",
178	},
179	{},
180};
181MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
182#endif
183
184static int dm816x_usb_phy_probe(struct platform_device *pdev)
185{
186	struct dm816x_usb_phy *phy;
187	struct resource *res;
188	struct phy *generic_phy;
189	struct phy_provider *phy_provider;
190	struct usb_otg *otg;
191	const struct of_device_id *of_id;
192	const struct usb_phy_data *phy_data;
193	int error;
194
195	of_id = of_match_device(of_match_ptr(dm816x_usb_phy_id_table),
196				&pdev->dev);
197	if (!of_id)
198		return -EINVAL;
199
200	phy = devm_kzalloc(&pdev->dev, sizeof(*phy), GFP_KERNEL);
201	if (!phy)
202		return -ENOMEM;
203
204	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
205	if (!res)
206		return -ENOENT;
207
208	phy->syscon = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
209						      "syscon");
210	if (IS_ERR(phy->syscon))
211		return PTR_ERR(phy->syscon);
212
213	/*
214	 * According to sprs614e.pdf, the first usb_ctrl is shared and
215	 * the second instance for usb_ctrl is reserved.. Also the
216	 * register bits are different from earlier TRMs.
217	 */
218	phy->usb_ctrl = 0x20;
219	phy->usbphy_ctrl = (res->start & 0xff) + 4;
220	if (phy->usbphy_ctrl == 0x2c)
221		phy->instance = 1;
222
223	phy_data = of_id->data;
224
225	otg = devm_kzalloc(&pdev->dev, sizeof(*otg), GFP_KERNEL);
226	if (!otg)
227		return -ENOMEM;
228
229	phy->dev = &pdev->dev;
230	phy->phy.dev = phy->dev;
231	phy->phy.label = "dm8168_usb_phy";
232	phy->phy.otg = otg;
233	phy->phy.type = USB_PHY_TYPE_USB2;
234	otg->set_host = dm816x_usb_phy_set_host;
235	otg->set_peripheral = dm816x_usb_phy_set_peripheral;
236	otg->usb_phy = &phy->phy;
237
238	platform_set_drvdata(pdev, phy);
239
240	phy->refclk = devm_clk_get(phy->dev, "refclk");
241	if (IS_ERR(phy->refclk))
242		return PTR_ERR(phy->refclk);
243	error = clk_prepare(phy->refclk);
244	if (error)
245		return error;
246
247	pm_runtime_enable(phy->dev);
248	generic_phy = devm_phy_create(phy->dev, NULL, &ops);
249	if (IS_ERR(generic_phy))
250		return PTR_ERR(generic_phy);
251
252	phy_set_drvdata(generic_phy, phy);
253
254	phy_provider = devm_of_phy_provider_register(phy->dev,
255						     of_phy_simple_xlate);
256	if (IS_ERR(phy_provider))
257		return PTR_ERR(phy_provider);
258
259	usb_add_phy_dev(&phy->phy);
260
261	return 0;
262}
263
264static int dm816x_usb_phy_remove(struct platform_device *pdev)
265{
266	struct dm816x_usb_phy *phy = platform_get_drvdata(pdev);
267
268	usb_remove_phy(&phy->phy);
269	pm_runtime_disable(phy->dev);
270	clk_unprepare(phy->refclk);
271
272	return 0;
273}
274
275static struct platform_driver dm816x_usb_phy_driver = {
276	.probe		= dm816x_usb_phy_probe,
277	.remove		= dm816x_usb_phy_remove,
278	.driver		= {
279		.name	= "dm816x-usb-phy",
280		.pm	= &dm816x_usb_phy_pm_ops,
281		.of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
282	},
283};
284
285module_platform_driver(dm816x_usb_phy_driver);
286
287MODULE_ALIAS("platform:dm816x_usb");
288MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
289MODULE_DESCRIPTION("dm816x usb phy driver");
290MODULE_LICENSE("GPL v2");
291