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
43 struct 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
dm816x_usb_phy_set_host(struct usb_otg * otg,struct usb_bus * host)53 static 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
dm816x_usb_phy_set_peripheral(struct usb_otg * otg,struct usb_gadget * gadget)62 static 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
dm816x_usb_phy_init(struct phy * x)72 static 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
106 static const struct phy_ops ops = {
107 .init = dm816x_usb_phy_init,
108 .owner = THIS_MODULE,
109 };
110
dm816x_usb_phy_runtime_suspend(struct device * dev)111 static 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
dm816x_usb_phy_runtime_resume(struct device * dev)129 static 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
159 static 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
165 static const struct of_device_id dm816x_usb_phy_id_table[] = {
166 {
167 .compatible = "ti,dm8168-usb-phy",
168 },
169 {},
170 };
171 MODULE_DEVICE_TABLE(of, dm816x_usb_phy_id_table);
172 #endif
173
dm816x_usb_phy_probe(struct platform_device * pdev)174 static 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
254 clk_unprepare:
255 pm_runtime_disable(phy->dev);
256 clk_unprepare(phy->refclk);
257 return error;
258 }
259
dm816x_usb_phy_remove(struct platform_device * pdev)260 static 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
269 static 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
279 module_platform_driver(dm816x_usb_phy_driver);
280
281 MODULE_ALIAS("platform:dm816x_usb");
282 MODULE_AUTHOR("Tony Lindgren <tony@atomide.com>");
283 MODULE_DESCRIPTION("dm816x usb phy driver");
284 MODULE_LICENSE("GPL v2");
285