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
40static u16 isp170x_id[] = {
41	0x1704,
42	0x1707,
43};
44
45struct 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
61static inline int isp1704_read(struct isp1704_charger *isp, u32 reg)
62{
63	return usb_phy_io_read(isp->phy, reg);
64}
65
66static 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
71static 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 */
83static 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 */
123static 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
180static 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
214static 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
223static 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);
289out:
290	mutex_unlock(&lock);
291}
292
293static 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
304static 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
332static 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
340static 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
380static 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;
470fail2:
471	power_supply_unregister(isp->psy);
472fail1:
473	isp1704_charger_set_power(isp, 0);
474fail0:
475	dev_err(&pdev->dev, "failed to register isp1704 with error %d\n", ret);
476
477	return ret;
478}
479
480static 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
492static const struct of_device_id omap_isp1704_of_match[] = {
493	{ .compatible = "nxp,isp1704", },
494	{ .compatible = "nxp,isp1707", },
495	{},
496};
497MODULE_DEVICE_TABLE(of, omap_isp1704_of_match);
498#endif
499
500static 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
509module_platform_driver(isp1704_charger_driver);
510
511MODULE_ALIAS("platform:isp1704_charger");
512MODULE_AUTHOR("Nokia Corporation");
513MODULE_DESCRIPTION("ISP170x USB Charger driver");
514MODULE_LICENSE("GPL");
515