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
52 struct 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
dm816x_usb_phy_set_host(struct usb_otg * otg,struct usb_bus * host)62 static 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
dm816x_usb_phy_set_peripheral(struct usb_otg * otg,struct usb_gadget * gadget)71 static 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
dm816x_usb_phy_init(struct phy * x)81 static 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
115 static const struct phy_ops ops = {
116 .init = dm816x_usb_phy_init,
117 .owner = THIS_MODULE,
118 };
119
dm816x_usb_phy_runtime_suspend(struct device * dev)120 static 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
dm816x_usb_phy_runtime_resume(struct device * dev)138 static 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
168 static 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
174 static const struct of_device_id dm816x_usb_phy_id_table[] = {
175 {
176 .compatible = "ti,dm8168-usb-phy",
177 },
178 {},
179 };
180 MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
181 #endif
182
dm816x_usb_phy_probe(struct platform_device * pdev)183 static 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 return PTR_ERR(generic_phy);
247
248 phy_set_drvdata(generic_phy, phy);
249
250 phy_provider = devm_of_phy_provider_register(phy->dev,
251 of_phy_simple_xlate);
252 if (IS_ERR(phy_provider))
253 return PTR_ERR(phy_provider);
254
255 usb_add_phy_dev(&phy->phy);
256
257 return 0;
258 }
259
dm816x_usb_phy_remove(struct platform_device * pdev)260 static int 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 return 0;
269 }
270
271 static struct platform_driver dm816x_usb_phy_driver = {
272 .probe = dm816x_usb_phy_probe,
273 .remove = dm816x_usb_phy_remove,
274 .driver = {
275 .name = "dm816x-usb-phy",
276 .pm = &dm816x_usb_phy_pm_ops,
277 .of_match_table = of_match_ptr(dm816x_usb_phy_id_table),
278 },
279 };
280
281 module_platform_driver(dm816x_usb_phy_driver);
282
283 MODULE_ALIAS("platform:dm816x_usb");
284 MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
285 MODULE_DESCRIPTION("dm816x usb phy driver");
286 MODULE_LICENSE("GPL v2");
287
