1 /*
2  * Extcon charger detection driver for Intel Cherrytrail Whiskey Cove PMIC
3  * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
4  *
5  * Based on various non upstream patches to support the CHT Whiskey Cove PMIC:
6  * Copyright (C) 2013-2015 Intel Corporation. All rights reserved.
7  *
8  * This program is free software; you can redistribute it and/or modify it
9  * under the terms and conditions of the GNU General Public License,
10  * version 2, as published by the Free Software Foundation.
11  *
12  * This program is distributed in the hope it will be useful, but WITHOUT
13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
15  * more details.
16  */
17 
18 #include <linux/extcon-provider.h>
19 #include <linux/interrupt.h>
20 #include <linux/kernel.h>
21 #include <linux/mfd/intel_soc_pmic.h>
22 #include <linux/module.h>
23 #include <linux/platform_device.h>
24 #include <linux/regmap.h>
25 #include <linux/slab.h>
26 
27 #define CHT_WC_PHYCTRL			0x5e07
28 
29 #define CHT_WC_CHGRCTRL0		0x5e16
30 #define CHT_WC_CHGRCTRL0_CHGRRESET	BIT(0)
31 #define CHT_WC_CHGRCTRL0_EMRGCHREN	BIT(1)
32 #define CHT_WC_CHGRCTRL0_EXTCHRDIS	BIT(2)
33 #define CHT_WC_CHGRCTRL0_SWCONTROL	BIT(3)
34 #define CHT_WC_CHGRCTRL0_TTLCK_MASK	BIT(4)
35 #define CHT_WC_CHGRCTRL0_CCSM_OFF_MASK	BIT(5)
36 #define CHT_WC_CHGRCTRL0_DBPOFF_MASK	BIT(6)
37 #define CHT_WC_CHGRCTRL0_WDT_NOKICK	BIT(7)
38 
39 #define CHT_WC_CHGRCTRL1		0x5e17
40 
41 #define CHT_WC_USBSRC			0x5e29
42 #define CHT_WC_USBSRC_STS_MASK		GENMASK(1, 0)
43 #define CHT_WC_USBSRC_STS_SUCCESS	2
44 #define CHT_WC_USBSRC_STS_FAIL		3
45 #define CHT_WC_USBSRC_TYPE_SHIFT	2
46 #define CHT_WC_USBSRC_TYPE_MASK		GENMASK(5, 2)
47 #define CHT_WC_USBSRC_TYPE_NONE		0
48 #define CHT_WC_USBSRC_TYPE_SDP		1
49 #define CHT_WC_USBSRC_TYPE_DCP		2
50 #define CHT_WC_USBSRC_TYPE_CDP		3
51 #define CHT_WC_USBSRC_TYPE_ACA		4
52 #define CHT_WC_USBSRC_TYPE_SE1		5
53 #define CHT_WC_USBSRC_TYPE_MHL		6
54 #define CHT_WC_USBSRC_TYPE_FLOAT_DP_DN	7
55 #define CHT_WC_USBSRC_TYPE_OTHER	8
56 #define CHT_WC_USBSRC_TYPE_DCP_EXTPHY	9
57 
58 #define CHT_WC_PWRSRC_IRQ		0x6e03
59 #define CHT_WC_PWRSRC_IRQ_MASK		0x6e0f
60 #define CHT_WC_PWRSRC_STS		0x6e1e
61 #define CHT_WC_PWRSRC_VBUS		BIT(0)
62 #define CHT_WC_PWRSRC_DC		BIT(1)
63 #define CHT_WC_PWRSRC_BAT		BIT(2)
64 #define CHT_WC_PWRSRC_ID_GND		BIT(3)
65 #define CHT_WC_PWRSRC_ID_FLOAT		BIT(4)
66 
67 #define CHT_WC_VBUS_GPIO_CTLO		0x6e2d
68 #define CHT_WC_VBUS_GPIO_CTLO_OUTPUT	BIT(0)
69 #define CHT_WC_VBUS_GPIO_CTLO_DRV_OD	BIT(4)
70 #define CHT_WC_VBUS_GPIO_CTLO_DIR_OUT	BIT(5)
71 
72 enum cht_wc_usb_id {
73 	USB_ID_OTG,
74 	USB_ID_GND,
75 	USB_ID_FLOAT,
76 	USB_RID_A,
77 	USB_RID_B,
78 	USB_RID_C,
79 };
80 
81 enum cht_wc_mux_select {
82 	MUX_SEL_PMIC = 0,
83 	MUX_SEL_SOC,
84 };
85 
86 static const unsigned int cht_wc_extcon_cables[] = {
87 	EXTCON_USB,
88 	EXTCON_USB_HOST,
89 	EXTCON_CHG_USB_SDP,
90 	EXTCON_CHG_USB_CDP,
91 	EXTCON_CHG_USB_DCP,
92 	EXTCON_CHG_USB_ACA,
93 	EXTCON_NONE,
94 };
95 
96 struct cht_wc_extcon_data {
97 	struct device *dev;
98 	struct regmap *regmap;
99 	struct extcon_dev *edev;
100 	unsigned int previous_cable;
101 	bool usb_host;
102 };
103 
104 static int cht_wc_extcon_get_id(struct cht_wc_extcon_data *ext, int pwrsrc_sts)
105 {
106 	if (pwrsrc_sts & CHT_WC_PWRSRC_ID_GND)
107 		return USB_ID_GND;
108 	if (pwrsrc_sts & CHT_WC_PWRSRC_ID_FLOAT)
109 		return USB_ID_FLOAT;
110 
111 	/*
112 	 * Once we have iio support for the gpadc we should read the USBID
113 	 * gpadc channel here and determine ACA role based on that.
114 	 */
115 	return USB_ID_FLOAT;
116 }
117 
118 static int cht_wc_extcon_get_charger(struct cht_wc_extcon_data *ext,
119 				     bool ignore_errors)
120 {
121 	int ret, usbsrc, status;
122 	unsigned long timeout;
123 
124 	/* Charger detection can take upto 600ms, wait 800ms max. */
125 	timeout = jiffies + msecs_to_jiffies(800);
126 	do {
127 		ret = regmap_read(ext->regmap, CHT_WC_USBSRC, &usbsrc);
128 		if (ret) {
129 			dev_err(ext->dev, "Error reading usbsrc: %d\n", ret);
130 			return ret;
131 		}
132 
133 		status = usbsrc & CHT_WC_USBSRC_STS_MASK;
134 		if (status == CHT_WC_USBSRC_STS_SUCCESS ||
135 		    status == CHT_WC_USBSRC_STS_FAIL)
136 			break;
137 
138 		msleep(50); /* Wait a bit before retrying */
139 	} while (time_before(jiffies, timeout));
140 
141 	if (status != CHT_WC_USBSRC_STS_SUCCESS) {
142 		if (ignore_errors)
143 			return EXTCON_CHG_USB_SDP; /* Save fallback */
144 
145 		if (status == CHT_WC_USBSRC_STS_FAIL)
146 			dev_warn(ext->dev, "Could not detect charger type\n");
147 		else
148 			dev_warn(ext->dev, "Timeout detecting charger type\n");
149 		return EXTCON_CHG_USB_SDP; /* Save fallback */
150 	}
151 
152 	usbsrc = (usbsrc & CHT_WC_USBSRC_TYPE_MASK) >> CHT_WC_USBSRC_TYPE_SHIFT;
153 	switch (usbsrc) {
154 	default:
155 		dev_warn(ext->dev,
156 			"Unhandled charger type %d, defaulting to SDP\n",
157 			 ret);
158 		/* Fall through, treat as SDP */
159 	case CHT_WC_USBSRC_TYPE_SDP:
160 	case CHT_WC_USBSRC_TYPE_FLOAT_DP_DN:
161 	case CHT_WC_USBSRC_TYPE_OTHER:
162 		return EXTCON_CHG_USB_SDP;
163 	case CHT_WC_USBSRC_TYPE_CDP:
164 		return EXTCON_CHG_USB_CDP;
165 	case CHT_WC_USBSRC_TYPE_DCP:
166 	case CHT_WC_USBSRC_TYPE_DCP_EXTPHY:
167 	case CHT_WC_USBSRC_TYPE_MHL: /* MHL2+ delivers upto 2A, treat as DCP */
168 		return EXTCON_CHG_USB_DCP;
169 	case CHT_WC_USBSRC_TYPE_ACA:
170 		return EXTCON_CHG_USB_ACA;
171 	}
172 }
173 
174 static void cht_wc_extcon_set_phymux(struct cht_wc_extcon_data *ext, u8 state)
175 {
176 	int ret;
177 
178 	ret = regmap_write(ext->regmap, CHT_WC_PHYCTRL, state);
179 	if (ret)
180 		dev_err(ext->dev, "Error writing phyctrl: %d\n", ret);
181 }
182 
183 static void cht_wc_extcon_set_5v_boost(struct cht_wc_extcon_data *ext,
184 				       bool enable)
185 {
186 	int ret, val;
187 
188 	/*
189 	 * The 5V boost converter is enabled through a gpio on the PMIC, since
190 	 * there currently is no gpio driver we access the gpio reg directly.
191 	 */
192 	val = CHT_WC_VBUS_GPIO_CTLO_DRV_OD | CHT_WC_VBUS_GPIO_CTLO_DIR_OUT;
193 	if (enable)
194 		val |= CHT_WC_VBUS_GPIO_CTLO_OUTPUT;
195 
196 	ret = regmap_write(ext->regmap, CHT_WC_VBUS_GPIO_CTLO, val);
197 	if (ret)
198 		dev_err(ext->dev, "Error writing Vbus GPIO CTLO: %d\n", ret);
199 }
200 
201 /* Small helper to sync EXTCON_CHG_USB_SDP and EXTCON_USB state */
202 static void cht_wc_extcon_set_state(struct cht_wc_extcon_data *ext,
203 				    unsigned int cable, bool state)
204 {
205 	extcon_set_state_sync(ext->edev, cable, state);
206 	if (cable == EXTCON_CHG_USB_SDP)
207 		extcon_set_state_sync(ext->edev, EXTCON_USB, state);
208 }
209 
210 static void cht_wc_extcon_pwrsrc_event(struct cht_wc_extcon_data *ext)
211 {
212 	int ret, pwrsrc_sts, id;
213 	unsigned int cable = EXTCON_NONE;
214 	/* Ignore errors in host mode, as the 5v boost converter is on then */
215 	bool ignore_get_charger_errors = ext->usb_host;
216 
217 	ret = regmap_read(ext->regmap, CHT_WC_PWRSRC_STS, &pwrsrc_sts);
218 	if (ret) {
219 		dev_err(ext->dev, "Error reading pwrsrc status: %d\n", ret);
220 		return;
221 	}
222 
223 	id = cht_wc_extcon_get_id(ext, pwrsrc_sts);
224 	if (id == USB_ID_GND) {
225 		/* The 5v boost causes a false VBUS / SDP detect, skip */
226 		goto charger_det_done;
227 	}
228 
229 	/* Plugged into a host/charger or not connected? */
230 	if (!(pwrsrc_sts & CHT_WC_PWRSRC_VBUS)) {
231 		/* Route D+ and D- to PMIC for future charger detection */
232 		cht_wc_extcon_set_phymux(ext, MUX_SEL_PMIC);
233 		goto set_state;
234 	}
235 
236 	ret = cht_wc_extcon_get_charger(ext, ignore_get_charger_errors);
237 	if (ret >= 0)
238 		cable = ret;
239 
240 charger_det_done:
241 	/* Route D+ and D- to SoC for the host or gadget controller */
242 	cht_wc_extcon_set_phymux(ext, MUX_SEL_SOC);
243 
244 set_state:
245 	if (cable != ext->previous_cable) {
246 		cht_wc_extcon_set_state(ext, cable, true);
247 		cht_wc_extcon_set_state(ext, ext->previous_cable, false);
248 		ext->previous_cable = cable;
249 	}
250 
251 	ext->usb_host = ((id == USB_ID_GND) || (id == USB_RID_A));
252 	extcon_set_state_sync(ext->edev, EXTCON_USB_HOST, ext->usb_host);
253 }
254 
255 static irqreturn_t cht_wc_extcon_isr(int irq, void *data)
256 {
257 	struct cht_wc_extcon_data *ext = data;
258 	int ret, irqs;
259 
260 	ret = regmap_read(ext->regmap, CHT_WC_PWRSRC_IRQ, &irqs);
261 	if (ret) {
262 		dev_err(ext->dev, "Error reading irqs: %d\n", ret);
263 		return IRQ_NONE;
264 	}
265 
266 	cht_wc_extcon_pwrsrc_event(ext);
267 
268 	ret = regmap_write(ext->regmap, CHT_WC_PWRSRC_IRQ, irqs);
269 	if (ret) {
270 		dev_err(ext->dev, "Error writing irqs: %d\n", ret);
271 		return IRQ_NONE;
272 	}
273 
274 	return IRQ_HANDLED;
275 }
276 
277 static int cht_wc_extcon_sw_control(struct cht_wc_extcon_data *ext, bool enable)
278 {
279 	int ret, mask, val;
280 
281 	mask = CHT_WC_CHGRCTRL0_SWCONTROL | CHT_WC_CHGRCTRL0_CCSM_OFF_MASK;
282 	val = enable ? mask : 0;
283 	ret = regmap_update_bits(ext->regmap, CHT_WC_CHGRCTRL0, mask, val);
284 	if (ret)
285 		dev_err(ext->dev, "Error setting sw control: %d\n", ret);
286 
287 	return ret;
288 }
289 
290 static int cht_wc_extcon_probe(struct platform_device *pdev)
291 {
292 	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);
293 	struct cht_wc_extcon_data *ext;
294 	int irq, ret;
295 
296 	irq = platform_get_irq(pdev, 0);
297 	if (irq < 0)
298 		return irq;
299 
300 	ext = devm_kzalloc(&pdev->dev, sizeof(*ext), GFP_KERNEL);
301 	if (!ext)
302 		return -ENOMEM;
303 
304 	ext->dev = &pdev->dev;
305 	ext->regmap = pmic->regmap;
306 	ext->previous_cable = EXTCON_NONE;
307 
308 	/* Initialize extcon device */
309 	ext->edev = devm_extcon_dev_allocate(ext->dev, cht_wc_extcon_cables);
310 	if (IS_ERR(ext->edev))
311 		return PTR_ERR(ext->edev);
312 
313 	/*
314 	 * When a host-cable is detected the BIOS enables an external 5v boost
315 	 * converter to power connected devices there are 2 problems with this:
316 	 * 1) This gets seen by the external battery charger as a valid Vbus
317 	 *    supply and it then tries to feed Vsys from this creating a
318 	 *    feedback loop which causes aprox. 300 mA extra battery drain
319 	 *    (and unless we drive the external-charger-disable pin high it
320 	 *    also tries to charge the battery causing even more feedback).
321 	 * 2) This gets seen by the pwrsrc block as a SDP USB Vbus supply
322 	 * Since the external battery charger has its own 5v boost converter
323 	 * which does not have these issues, we simply turn the separate
324 	 * external 5v boost converter off and leave it off entirely.
325 	 */
326 	cht_wc_extcon_set_5v_boost(ext, false);
327 
328 	/* Enable sw control */
329 	ret = cht_wc_extcon_sw_control(ext, true);
330 	if (ret)
331 		return ret;
332 
333 	/* Register extcon device */
334 	ret = devm_extcon_dev_register(ext->dev, ext->edev);
335 	if (ret) {
336 		dev_err(ext->dev, "Error registering extcon device: %d\n", ret);
337 		goto disable_sw_control;
338 	}
339 
340 	/* Route D+ and D- to PMIC for initial charger detection */
341 	cht_wc_extcon_set_phymux(ext, MUX_SEL_PMIC);
342 
343 	/* Get initial state */
344 	cht_wc_extcon_pwrsrc_event(ext);
345 
346 	ret = devm_request_threaded_irq(ext->dev, irq, NULL, cht_wc_extcon_isr,
347 					IRQF_ONESHOT, pdev->name, ext);
348 	if (ret) {
349 		dev_err(ext->dev, "Error requesting interrupt: %d\n", ret);
350 		goto disable_sw_control;
351 	}
352 
353 	/* Unmask irqs */
354 	ret = regmap_write(ext->regmap, CHT_WC_PWRSRC_IRQ_MASK,
355 			   (int)~(CHT_WC_PWRSRC_VBUS | CHT_WC_PWRSRC_ID_GND |
356 				  CHT_WC_PWRSRC_ID_FLOAT));
357 	if (ret) {
358 		dev_err(ext->dev, "Error writing irq-mask: %d\n", ret);
359 		goto disable_sw_control;
360 	}
361 
362 	platform_set_drvdata(pdev, ext);
363 
364 	return 0;
365 
366 disable_sw_control:
367 	cht_wc_extcon_sw_control(ext, false);
368 	return ret;
369 }
370 
371 static int cht_wc_extcon_remove(struct platform_device *pdev)
372 {
373 	struct cht_wc_extcon_data *ext = platform_get_drvdata(pdev);
374 
375 	cht_wc_extcon_sw_control(ext, false);
376 
377 	return 0;
378 }
379 
380 static const struct platform_device_id cht_wc_extcon_table[] = {
381 	{ .name = "cht_wcove_pwrsrc" },
382 	{},
383 };
384 MODULE_DEVICE_TABLE(platform, cht_wc_extcon_table);
385 
386 static struct platform_driver cht_wc_extcon_driver = {
387 	.probe = cht_wc_extcon_probe,
388 	.remove = cht_wc_extcon_remove,
389 	.id_table = cht_wc_extcon_table,
390 	.driver = {
391 		.name = "cht_wcove_pwrsrc",
392 	},
393 };
394 module_platform_driver(cht_wc_extcon_driver);
395 
396 MODULE_DESCRIPTION("Intel Cherrytrail Whiskey Cove PMIC extcon driver");
397 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
398 MODULE_LICENSE("GPL v2");
399