1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * ISP1704 USB Charger Detection driver
4  *
5  * Copyright (C) 2010 Nokia Corporation
6  * Copyright (C) 2012 - 2013 Pali Rohár <pali@kernel.org>
7  */
8 
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/err.h>
12 #include <linux/init.h>
13 #include <linux/types.h>
14 #include <linux/device.h>
15 #include <linux/sysfs.h>
16 #include <linux/platform_device.h>
17 #include <linux/power_supply.h>
18 #include <linux/delay.h>
19 #include <linux/of.h>
20 
21 #include <linux/gpio/consumer.h>
22 #include <linux/usb/otg.h>
23 #include <linux/usb/ulpi.h>
24 #include <linux/usb/ch9.h>
25 #include <linux/usb/gadget.h>
26 
27 /* Vendor specific Power Control register */
28 #define ISP1704_PWR_CTRL		0x3d
29 #define ISP1704_PWR_CTRL_SWCTRL		(1 << 0)
30 #define ISP1704_PWR_CTRL_DET_COMP	(1 << 1)
31 #define ISP1704_PWR_CTRL_BVALID_RISE	(1 << 2)
32 #define ISP1704_PWR_CTRL_BVALID_FALL	(1 << 3)
33 #define ISP1704_PWR_CTRL_DP_WKPU_EN	(1 << 4)
34 #define ISP1704_PWR_CTRL_VDAT_DET	(1 << 5)
35 #define ISP1704_PWR_CTRL_DPVSRC_EN	(1 << 6)
36 #define ISP1704_PWR_CTRL_HWDETECT	(1 << 7)
37 
38 #define NXP_VENDOR_ID			0x04cc
39 
40 static u16 isp170x_id[] = {
41 	0x1704,
42 	0x1707,
43 };
44 
45 struct isp1704_charger {
46 	struct device			*dev;
47 	struct power_supply		*psy;
48 	struct power_supply_desc	psy_desc;
49 	struct gpio_desc		*enable_gpio;
50 	struct usb_phy			*phy;
51 	struct notifier_block		nb;
52 	struct work_struct		work;
53 
54 	/* properties */
55 	char			model[8];
56 	unsigned		present:1;
57 	unsigned		online:1;
58 	unsigned		current_max;
59 };
60 
61 static inline int isp1704_read(struct isp1704_charger *isp, u32 reg)
62 {
63 	return usb_phy_io_read(isp->phy, reg);
64 }
65 
66 static inline int isp1704_write(struct isp1704_charger *isp, u32 reg, u32 val)
67 {
68 	return usb_phy_io_write(isp->phy, val, reg);
69 }
70 
71 static void isp1704_charger_set_power(struct isp1704_charger *isp, bool on)
72 {
73 	gpiod_set_value(isp->enable_gpio, on);
74 }
75 
76 /*
77  * Determine is the charging port DCP (dedicated charger) or CDP (Host/HUB
78  * chargers).
79  *
80  * REVISIT: The method is defined in Battery Charging Specification and is
81  * applicable to any ULPI transceiver. Nothing isp170x specific here.
82  */
83 static inline int isp1704_charger_type(struct isp1704_charger *isp)
84 {
85 	u8 reg;
86 	u8 func_ctrl;
87 	u8 otg_ctrl;
88 	int type = POWER_SUPPLY_TYPE_USB_DCP;
89 
90 	func_ctrl = isp1704_read(isp, ULPI_FUNC_CTRL);
91 	otg_ctrl = isp1704_read(isp, ULPI_OTG_CTRL);
92 
93 	/* disable pulldowns */
94 	reg = ULPI_OTG_CTRL_DM_PULLDOWN | ULPI_OTG_CTRL_DP_PULLDOWN;
95 	isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), reg);
96 
97 	/* full speed */
98 	isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
99 			ULPI_FUNC_CTRL_XCVRSEL_MASK);
100 	isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL),
101 			ULPI_FUNC_CTRL_FULL_SPEED);
102 
103 	/* Enable strong pull-up on DP (1.5K) and reset */
104 	reg = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
105 	isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), reg);
106 	usleep_range(1000, 2000);
107 
108 	reg = isp1704_read(isp, ULPI_DEBUG);
109 	if ((reg & 3) != 3)
110 		type = POWER_SUPPLY_TYPE_USB_CDP;
111 
112 	/* recover original state */
113 	isp1704_write(isp, ULPI_FUNC_CTRL, func_ctrl);
114 	isp1704_write(isp, ULPI_OTG_CTRL, otg_ctrl);
115 
116 	return type;
117 }
118 
119 /*
120  * ISP1704 detects PS/2 adapters as charger. To make sure the detected charger
121  * is actually a dedicated charger, the following steps need to be taken.
122  */
123 static inline int isp1704_charger_verify(struct isp1704_charger *isp)
124 {
125 	int	ret = 0;
126 	u8	r;
127 
128 	/* Reset the transceiver */
129 	r = isp1704_read(isp, ULPI_FUNC_CTRL);
130 	r |= ULPI_FUNC_CTRL_RESET;
131 	isp1704_write(isp, ULPI_FUNC_CTRL, r);
132 	usleep_range(1000, 2000);
133 
134 	/* Set normal mode */
135 	r &= ~(ULPI_FUNC_CTRL_RESET | ULPI_FUNC_CTRL_OPMODE_MASK);
136 	isp1704_write(isp, ULPI_FUNC_CTRL, r);
137 
138 	/* Clear the DP and DM pull-down bits */
139 	r = ULPI_OTG_CTRL_DP_PULLDOWN | ULPI_OTG_CTRL_DM_PULLDOWN;
140 	isp1704_write(isp, ULPI_CLR(ULPI_OTG_CTRL), r);
141 
142 	/* Enable strong pull-up on DP (1.5K) and reset */
143 	r = ULPI_FUNC_CTRL_TERMSELECT | ULPI_FUNC_CTRL_RESET;
144 	isp1704_write(isp, ULPI_SET(ULPI_FUNC_CTRL), r);
145 	usleep_range(1000, 2000);
146 
147 	/* Read the line state */
148 	if (!isp1704_read(isp, ULPI_DEBUG)) {
149 		/* Disable strong pull-up on DP (1.5K) */
150 		isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
151 				ULPI_FUNC_CTRL_TERMSELECT);
152 		return 1;
153 	}
154 
155 	/* Is it a charger or PS/2 connection */
156 
157 	/* Enable weak pull-up resistor on DP */
158 	isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
159 			ISP1704_PWR_CTRL_DP_WKPU_EN);
160 
161 	/* Disable strong pull-up on DP (1.5K) */
162 	isp1704_write(isp, ULPI_CLR(ULPI_FUNC_CTRL),
163 			ULPI_FUNC_CTRL_TERMSELECT);
164 
165 	/* Enable weak pull-down resistor on DM */
166 	isp1704_write(isp, ULPI_SET(ULPI_OTG_CTRL),
167 			ULPI_OTG_CTRL_DM_PULLDOWN);
168 
169 	/* It's a charger if the line states are clear */
170 	if (!(isp1704_read(isp, ULPI_DEBUG)))
171 		ret = 1;
172 
173 	/* Disable weak pull-up resistor on DP */
174 	isp1704_write(isp, ULPI_CLR(ISP1704_PWR_CTRL),
175 			ISP1704_PWR_CTRL_DP_WKPU_EN);
176 
177 	return ret;
178 }
179 
180 static inline int isp1704_charger_detect(struct isp1704_charger *isp)
181 {
182 	unsigned long	timeout;
183 	u8		pwr_ctrl;
184 	int		ret = 0;
185 
186 	pwr_ctrl = isp1704_read(isp, ISP1704_PWR_CTRL);
187 
188 	/* set SW control bit in PWR_CTRL register */
189 	isp1704_write(isp, ISP1704_PWR_CTRL,
190 			ISP1704_PWR_CTRL_SWCTRL);
191 
192 	/* enable manual charger detection */
193 	isp1704_write(isp, ULPI_SET(ISP1704_PWR_CTRL),
194 			ISP1704_PWR_CTRL_SWCTRL
195 			| ISP1704_PWR_CTRL_DPVSRC_EN);
196 	usleep_range(1000, 2000);
197 
198 	timeout = jiffies + msecs_to_jiffies(300);
199 	do {
200 		/* Check if there is a charger */
201 		if (isp1704_read(isp, ISP1704_PWR_CTRL)
202 				& ISP1704_PWR_CTRL_VDAT_DET) {
203 			ret = isp1704_charger_verify(isp);
204 			break;
205 		}
206 	} while (!time_after(jiffies, timeout) && isp->online);
207 
208 	/* recover original state */
209 	isp1704_write(isp, ISP1704_PWR_CTRL, pwr_ctrl);
210 
211 	return ret;
212 }
213 
214 static inline int isp1704_charger_detect_dcp(struct isp1704_charger *isp)
215 {
216 	if (isp1704_charger_detect(isp) &&
217 			isp1704_charger_type(isp) == POWER_SUPPLY_TYPE_USB_DCP)
218 		return true;
219 	else
220 		return false;
221 }
222 
223 static void isp1704_charger_work(struct work_struct *data)
224 {
225 	struct isp1704_charger	*isp =
226 		container_of(data, struct isp1704_charger, work);
227 	static DEFINE_MUTEX(lock);
228 
229 	mutex_lock(&lock);
230 
231 	switch (isp->phy->last_event) {
232 	case USB_EVENT_VBUS:
233 		/* do not call wall charger detection more times */
234 		if (!isp->present) {
235 			isp->online = true;
236 			isp->present = 1;
237 			isp1704_charger_set_power(isp, 1);
238 
239 			/* detect wall charger */
240 			if (isp1704_charger_detect_dcp(isp)) {
241 				isp->psy_desc.type = POWER_SUPPLY_TYPE_USB_DCP;
242 				isp->current_max = 1800;
243 			} else {
244 				isp->psy_desc.type = POWER_SUPPLY_TYPE_USB;
245 				isp->current_max = 500;
246 			}
247 
248 			/* enable data pullups */
249 			if (isp->phy->otg->gadget)
250 				usb_gadget_connect(isp->phy->otg->gadget);
251 		}
252 
253 		if (isp->psy_desc.type != POWER_SUPPLY_TYPE_USB_DCP) {
254 			/*
255 			 * Only 500mA here or high speed chirp
256 			 * handshaking may break
257 			 */
258 			if (isp->current_max > 500)
259 				isp->current_max = 500;
260 
261 			if (isp->current_max > 100)
262 				isp->psy_desc.type = POWER_SUPPLY_TYPE_USB_CDP;
263 		}
264 		break;
265 	case USB_EVENT_NONE:
266 		isp->online = false;
267 		isp->present = 0;
268 		isp->current_max = 0;
269 		isp->psy_desc.type = POWER_SUPPLY_TYPE_USB;
270 
271 		/*
272 		 * Disable data pullups. We need to prevent the controller from
273 		 * enumerating.
274 		 *
275 		 * FIXME: This is here to allow charger detection with Host/HUB
276 		 * chargers. The pullups may be enabled elsewhere, so this can
277 		 * not be the final solution.
278 		 */
279 		if (isp->phy->otg->gadget)
280 			usb_gadget_disconnect(isp->phy->otg->gadget);
281 
282 		isp1704_charger_set_power(isp, 0);
283 		break;
284 	default:
285 		goto out;
286 	}
287 
288 	power_supply_changed(isp->psy);
289 out:
290 	mutex_unlock(&lock);
291 }
292 
293 static int isp1704_notifier_call(struct notifier_block *nb,
294 		unsigned long val, void *v)
295 {
296 	struct isp1704_charger *isp =
297 		container_of(nb, struct isp1704_charger, nb);
298 
299 	schedule_work(&isp->work);
300 
301 	return NOTIFY_OK;
302 }
303 
304 static int isp1704_charger_get_property(struct power_supply *psy,
305 				enum power_supply_property psp,
306 				union power_supply_propval *val)
307 {
308 	struct isp1704_charger *isp = power_supply_get_drvdata(psy);
309 
310 	switch (psp) {
311 	case POWER_SUPPLY_PROP_PRESENT:
312 		val->intval = isp->present;
313 		break;
314 	case POWER_SUPPLY_PROP_ONLINE:
315 		val->intval = isp->online;
316 		break;
317 	case POWER_SUPPLY_PROP_CURRENT_MAX:
318 		val->intval = isp->current_max;
319 		break;
320 	case POWER_SUPPLY_PROP_MODEL_NAME:
321 		val->strval = isp->model;
322 		break;
323 	case POWER_SUPPLY_PROP_MANUFACTURER:
324 		val->strval = "NXP";
325 		break;
326 	default:
327 		return -EINVAL;
328 	}
329 	return 0;
330 }
331 
332 static enum power_supply_property power_props[] = {
333 	POWER_SUPPLY_PROP_PRESENT,
334 	POWER_SUPPLY_PROP_ONLINE,
335 	POWER_SUPPLY_PROP_CURRENT_MAX,
336 	POWER_SUPPLY_PROP_MODEL_NAME,
337 	POWER_SUPPLY_PROP_MANUFACTURER,
338 };
339 
340 static inline int isp1704_test_ulpi(struct isp1704_charger *isp)
341 {
342 	int vendor;
343 	int product;
344 	int i;
345 	int ret;
346 
347 	/* Test ULPI interface */
348 	ret = isp1704_write(isp, ULPI_SCRATCH, 0xaa);
349 	if (ret < 0)
350 		return ret;
351 
352 	ret = isp1704_read(isp, ULPI_SCRATCH);
353 	if (ret < 0)
354 		return ret;
355 
356 	if (ret != 0xaa)
357 		return -ENODEV;
358 
359 	/* Verify the product and vendor id matches */
360 	vendor = isp1704_read(isp, ULPI_VENDOR_ID_LOW);
361 	vendor |= isp1704_read(isp, ULPI_VENDOR_ID_HIGH) << 8;
362 	if (vendor != NXP_VENDOR_ID)
363 		return -ENODEV;
364 
365 	product = isp1704_read(isp, ULPI_PRODUCT_ID_LOW);
366 	product |= isp1704_read(isp, ULPI_PRODUCT_ID_HIGH) << 8;
367 
368 	for (i = 0; i < ARRAY_SIZE(isp170x_id); i++) {
369 		if (product == isp170x_id[i]) {
370 			sprintf(isp->model, "isp%x", product);
371 			return product;
372 		}
373 	}
374 
375 	dev_err(isp->dev, "product id %x not matching known ids", product);
376 
377 	return -ENODEV;
378 }
379 
380 static int isp1704_charger_probe(struct platform_device *pdev)
381 {
382 	struct isp1704_charger	*isp;
383 	int			ret = -ENODEV;
384 	struct power_supply_config psy_cfg = {};
385 
386 	isp = devm_kzalloc(&pdev->dev, sizeof(*isp), GFP_KERNEL);
387 	if (!isp)
388 		return -ENOMEM;
389 
390 	isp->enable_gpio = devm_gpiod_get(&pdev->dev, "nxp,enable",
391 					  GPIOD_OUT_HIGH);
392 	if (IS_ERR(isp->enable_gpio)) {
393 		ret = PTR_ERR(isp->enable_gpio);
394 		dev_err(&pdev->dev, "Could not get reset gpio: %d\n", ret);
395 		return ret;
396 	}
397 
398 	if (pdev->dev.of_node)
399 		isp->phy = devm_usb_get_phy_by_phandle(&pdev->dev, "usb-phy", 0);
400 	else
401 		isp->phy = devm_usb_get_phy(&pdev->dev, USB_PHY_TYPE_USB2);
402 
403 	if (IS_ERR(isp->phy)) {
404 		ret = PTR_ERR(isp->phy);
405 		dev_err(&pdev->dev, "usb_get_phy failed\n");
406 		goto fail0;
407 	}
408 
409 	isp->dev = &pdev->dev;
410 	platform_set_drvdata(pdev, isp);
411 
412 	isp1704_charger_set_power(isp, 1);
413 
414 	ret = isp1704_test_ulpi(isp);
415 	if (ret < 0) {
416 		dev_err(&pdev->dev, "isp1704_test_ulpi failed\n");
417 		goto fail1;
418 	}
419 
420 	isp->psy_desc.name		= "isp1704";
421 	isp->psy_desc.type		= POWER_SUPPLY_TYPE_USB;
422 	isp->psy_desc.properties	= power_props;
423 	isp->psy_desc.num_properties	= ARRAY_SIZE(power_props);
424 	isp->psy_desc.get_property	= isp1704_charger_get_property;
425 
426 	psy_cfg.drv_data		= isp;
427 
428 	isp->psy = power_supply_register(isp->dev, &isp->psy_desc, &psy_cfg);
429 	if (IS_ERR(isp->psy)) {
430 		ret = PTR_ERR(isp->psy);
431 		dev_err(&pdev->dev, "power_supply_register failed\n");
432 		goto fail1;
433 	}
434 
435 	/*
436 	 * REVISIT: using work in order to allow the usb notifications to be
437 	 * made atomically in the future.
438 	 */
439 	INIT_WORK(&isp->work, isp1704_charger_work);
440 
441 	isp->nb.notifier_call = isp1704_notifier_call;
442 
443 	ret = usb_register_notifier(isp->phy, &isp->nb);
444 	if (ret) {
445 		dev_err(&pdev->dev, "usb_register_notifier failed\n");
446 		goto fail2;
447 	}
448 
449 	dev_info(isp->dev, "registered with product id %s\n", isp->model);
450 
451 	/*
452 	 * Taking over the D+ pullup.
453 	 *
454 	 * FIXME: The device will be disconnected if it was already
455 	 * enumerated. The charger driver should be always loaded before any
456 	 * gadget is loaded.
457 	 */
458 	if (isp->phy->otg->gadget)
459 		usb_gadget_disconnect(isp->phy->otg->gadget);
460 
461 	if (isp->phy->last_event == USB_EVENT_NONE)
462 		isp1704_charger_set_power(isp, 0);
463 
464 	/* Detect charger if VBUS is valid (the cable was already plugged). */
465 	if (isp->phy->last_event == USB_EVENT_VBUS &&
466 			!isp->phy->otg->default_a)
467 		schedule_work(&isp->work);
468 
469 	return 0;
470 fail2:
471 	power_supply_unregister(isp->psy);
472 fail1:
473 	isp1704_charger_set_power(isp, 0);
474 fail0:
475 	dev_err(&pdev->dev, "failed to register isp1704 with error %d\n", ret);
476 
477 	return ret;
478 }
479 
480 static int isp1704_charger_remove(struct platform_device *pdev)
481 {
482 	struct isp1704_charger *isp = platform_get_drvdata(pdev);
483 
484 	usb_unregister_notifier(isp->phy, &isp->nb);
485 	power_supply_unregister(isp->psy);
486 	isp1704_charger_set_power(isp, 0);
487 
488 	return 0;
489 }
490 
491 #ifdef CONFIG_OF
492 static const struct of_device_id omap_isp1704_of_match[] = {
493 	{ .compatible = "nxp,isp1704", },
494 	{ .compatible = "nxp,isp1707", },
495 	{},
496 };
497 MODULE_DEVICE_TABLE(of, omap_isp1704_of_match);
498 #endif
499 
500 static struct platform_driver isp1704_charger_driver = {
501 	.driver = {
502 		.name = "isp1704_charger",
503 		.of_match_table = of_match_ptr(omap_isp1704_of_match),
504 	},
505 	.probe = isp1704_charger_probe,
506 	.remove = isp1704_charger_remove,
507 };
508 
509 module_platform_driver(isp1704_charger_driver);
510 
511 MODULE_ALIAS("platform:isp1704_charger");
512 MODULE_AUTHOR("Nokia Corporation");
513 MODULE_DESCRIPTION("ISP170x USB Charger driver");
514 MODULE_LICENSE("GPL");
515