1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * extcon driver for Basin Cove PMIC
4  *
5  * Copyright (c) 2019, Intel Corporation.
6  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
7  */
8 
9 #include <linux/extcon-provider.h>
10 #include <linux/interrupt.h>
11 #include <linux/mfd/intel_soc_pmic.h>
12 #include <linux/mfd/intel_soc_pmic_mrfld.h>
13 #include <linux/mod_devicetable.h>
14 #include <linux/module.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17 
18 #include "extcon-intel.h"
19 
20 #define BCOVE_USBIDCTRL			0x19
21 #define BCOVE_USBIDCTRL_ID		BIT(0)
22 #define BCOVE_USBIDCTRL_ACA		BIT(1)
23 #define BCOVE_USBIDCTRL_ALL	(BCOVE_USBIDCTRL_ID | BCOVE_USBIDCTRL_ACA)
24 
25 #define BCOVE_USBIDSTS			0x1a
26 #define BCOVE_USBIDSTS_GND		BIT(0)
27 #define BCOVE_USBIDSTS_RARBRC_MASK	GENMASK(2, 1)
28 #define BCOVE_USBIDSTS_RARBRC_SHIFT	1
29 #define BCOVE_USBIDSTS_NO_ACA		0
30 #define BCOVE_USBIDSTS_R_ID_A		1
31 #define BCOVE_USBIDSTS_R_ID_B		2
32 #define BCOVE_USBIDSTS_R_ID_C		3
33 #define BCOVE_USBIDSTS_FLOAT		BIT(3)
34 #define BCOVE_USBIDSTS_SHORT		BIT(4)
35 
36 #define BCOVE_CHGRIRQ_ALL	(BCOVE_CHGRIRQ_VBUSDET | BCOVE_CHGRIRQ_DCDET | \
37 				 BCOVE_CHGRIRQ_BATTDET | BCOVE_CHGRIRQ_USBIDDET)
38 
39 #define BCOVE_CHGRCTRL0			0x4b
40 #define BCOVE_CHGRCTRL0_CHGRRESET	BIT(0)
41 #define BCOVE_CHGRCTRL0_EMRGCHREN	BIT(1)
42 #define BCOVE_CHGRCTRL0_EXTCHRDIS	BIT(2)
43 #define BCOVE_CHGRCTRL0_SWCONTROL	BIT(3)
44 #define BCOVE_CHGRCTRL0_TTLCK		BIT(4)
45 #define BCOVE_CHGRCTRL0_BIT_5		BIT(5)
46 #define BCOVE_CHGRCTRL0_BIT_6		BIT(6)
47 #define BCOVE_CHGRCTRL0_CHR_WDT_NOKICK	BIT(7)
48 
49 struct mrfld_extcon_data {
50 	struct device *dev;
51 	struct regmap *regmap;
52 	struct extcon_dev *edev;
53 	unsigned int status;
54 	unsigned int id;
55 };
56 
57 static const unsigned int mrfld_extcon_cable[] = {
58 	EXTCON_USB,
59 	EXTCON_USB_HOST,
60 	EXTCON_CHG_USB_SDP,
61 	EXTCON_CHG_USB_CDP,
62 	EXTCON_CHG_USB_DCP,
63 	EXTCON_CHG_USB_ACA,
64 	EXTCON_NONE,
65 };
66 
67 static int mrfld_extcon_clear(struct mrfld_extcon_data *data, unsigned int reg,
68 			      unsigned int mask)
69 {
70 	return regmap_update_bits(data->regmap, reg, mask, 0x00);
71 }
72 
73 static int mrfld_extcon_set(struct mrfld_extcon_data *data, unsigned int reg,
74 			    unsigned int mask)
75 {
76 	return regmap_update_bits(data->regmap, reg, mask, 0xff);
77 }
78 
79 static int mrfld_extcon_sw_control(struct mrfld_extcon_data *data, bool enable)
80 {
81 	unsigned int mask = BCOVE_CHGRCTRL0_SWCONTROL;
82 	struct device *dev = data->dev;
83 	int ret;
84 
85 	if (enable)
86 		ret = mrfld_extcon_set(data, BCOVE_CHGRCTRL0, mask);
87 	else
88 		ret = mrfld_extcon_clear(data, BCOVE_CHGRCTRL0, mask);
89 	if (ret)
90 		dev_err(dev, "can't set SW control: %d\n", ret);
91 	return ret;
92 }
93 
94 static int mrfld_extcon_get_id(struct mrfld_extcon_data *data)
95 {
96 	struct regmap *regmap = data->regmap;
97 	unsigned int id;
98 	bool ground;
99 	int ret;
100 
101 	ret = regmap_read(regmap, BCOVE_USBIDSTS, &id);
102 	if (ret)
103 		return ret;
104 
105 	if (id & BCOVE_USBIDSTS_FLOAT)
106 		return INTEL_USB_ID_FLOAT;
107 
108 	switch ((id & BCOVE_USBIDSTS_RARBRC_MASK) >> BCOVE_USBIDSTS_RARBRC_SHIFT) {
109 	case BCOVE_USBIDSTS_R_ID_A:
110 		return INTEL_USB_RID_A;
111 	case BCOVE_USBIDSTS_R_ID_B:
112 		return INTEL_USB_RID_B;
113 	case BCOVE_USBIDSTS_R_ID_C:
114 		return INTEL_USB_RID_C;
115 	}
116 
117 	/*
118 	 * PMIC A0 reports USBIDSTS_GND = 1 for ID_GND,
119 	 * but PMIC B0 reports USBIDSTS_GND = 0 for ID_GND.
120 	 * Thus we must check this bit at last.
121 	 */
122 	ground = id & BCOVE_USBIDSTS_GND;
123 	switch ('A' + BCOVE_MAJOR(data->id)) {
124 	case 'A':
125 		return ground ? INTEL_USB_ID_GND : INTEL_USB_ID_FLOAT;
126 	case 'B':
127 		return ground ? INTEL_USB_ID_FLOAT : INTEL_USB_ID_GND;
128 	}
129 
130 	/* Unknown or unsupported type */
131 	return INTEL_USB_ID_FLOAT;
132 }
133 
134 static int mrfld_extcon_role_detect(struct mrfld_extcon_data *data)
135 {
136 	unsigned int id;
137 	bool usb_host;
138 	int ret;
139 
140 	ret = mrfld_extcon_get_id(data);
141 	if (ret < 0)
142 		return ret;
143 
144 	id = ret;
145 
146 	usb_host = (id == INTEL_USB_ID_GND) || (id == INTEL_USB_RID_A);
147 	extcon_set_state_sync(data->edev, EXTCON_USB_HOST, usb_host);
148 
149 	return 0;
150 }
151 
152 static int mrfld_extcon_cable_detect(struct mrfld_extcon_data *data)
153 {
154 	struct regmap *regmap = data->regmap;
155 	unsigned int status, change;
156 	int ret;
157 
158 	/*
159 	 * It seems SCU firmware clears the content of BCOVE_CHGRIRQ1
160 	 * and makes it useless for OS. Instead we compare a previously
161 	 * stored status to the current one, provided by BCOVE_SCHGRIRQ1.
162 	 */
163 	ret = regmap_read(regmap, BCOVE_SCHGRIRQ1, &status);
164 	if (ret)
165 		return ret;
166 
167 	change = status ^ data->status;
168 	if (!change)
169 		return -ENODATA;
170 
171 	if (change & BCOVE_CHGRIRQ_USBIDDET) {
172 		ret = mrfld_extcon_role_detect(data);
173 		if (ret)
174 			return ret;
175 	}
176 
177 	data->status = status;
178 
179 	return 0;
180 }
181 
182 static irqreturn_t mrfld_extcon_interrupt(int irq, void *dev_id)
183 {
184 	struct mrfld_extcon_data *data = dev_id;
185 	int ret;
186 
187 	ret = mrfld_extcon_cable_detect(data);
188 
189 	mrfld_extcon_clear(data, BCOVE_MIRQLVL1, BCOVE_LVL1_CHGR);
190 
191 	return ret ? IRQ_NONE: IRQ_HANDLED;
192 }
193 
194 static int mrfld_extcon_probe(struct platform_device *pdev)
195 {
196 	struct device *dev = &pdev->dev;
197 	struct intel_soc_pmic *pmic = dev_get_drvdata(dev->parent);
198 	struct regmap *regmap = pmic->regmap;
199 	struct mrfld_extcon_data *data;
200 	unsigned int status;
201 	unsigned int id;
202 	int irq, ret;
203 
204 	irq = platform_get_irq(pdev, 0);
205 	if (irq < 0)
206 		return irq;
207 
208 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
209 	if (!data)
210 		return -ENOMEM;
211 
212 	data->dev = dev;
213 	data->regmap = regmap;
214 
215 	data->edev = devm_extcon_dev_allocate(dev, mrfld_extcon_cable);
216 	if (IS_ERR(data->edev))
217 		return -ENOMEM;
218 
219 	ret = devm_extcon_dev_register(dev, data->edev);
220 	if (ret < 0) {
221 		dev_err(dev, "can't register extcon device: %d\n", ret);
222 		return ret;
223 	}
224 
225 	ret = devm_request_threaded_irq(dev, irq, NULL, mrfld_extcon_interrupt,
226 					IRQF_ONESHOT | IRQF_SHARED, pdev->name,
227 					data);
228 	if (ret) {
229 		dev_err(dev, "can't register IRQ handler: %d\n", ret);
230 		return ret;
231 	}
232 
233 	ret = regmap_read(regmap, BCOVE_ID, &id);
234 	if (ret) {
235 		dev_err(dev, "can't read PMIC ID: %d\n", ret);
236 		return ret;
237 	}
238 
239 	data->id = id;
240 
241 	ret = mrfld_extcon_sw_control(data, true);
242 	if (ret)
243 		return ret;
244 
245 	/* Get initial state */
246 	mrfld_extcon_role_detect(data);
247 
248 	/*
249 	 * Cached status value is used for cable detection, see comments
250 	 * in mrfld_extcon_cable_detect(), we need to sync cached value
251 	 * with a real state of the hardware.
252 	 */
253 	regmap_read(regmap, BCOVE_SCHGRIRQ1, &status);
254 	data->status = status;
255 
256 	mrfld_extcon_clear(data, BCOVE_MIRQLVL1, BCOVE_LVL1_CHGR);
257 	mrfld_extcon_clear(data, BCOVE_MCHGRIRQ1, BCOVE_CHGRIRQ_ALL);
258 
259 	mrfld_extcon_set(data, BCOVE_USBIDCTRL, BCOVE_USBIDCTRL_ALL);
260 
261 	platform_set_drvdata(pdev, data);
262 
263 	return 0;
264 }
265 
266 static int mrfld_extcon_remove(struct platform_device *pdev)
267 {
268 	struct mrfld_extcon_data *data = platform_get_drvdata(pdev);
269 
270 	mrfld_extcon_sw_control(data, false);
271 
272 	return 0;
273 }
274 
275 static const struct platform_device_id mrfld_extcon_id_table[] = {
276 	{ .name = "mrfld_bcove_pwrsrc" },
277 	{}
278 };
279 MODULE_DEVICE_TABLE(platform, mrfld_extcon_id_table);
280 
281 static struct platform_driver mrfld_extcon_driver = {
282 	.driver = {
283 		.name	= "mrfld_bcove_pwrsrc",
284 	},
285 	.probe		= mrfld_extcon_probe,
286 	.remove		= mrfld_extcon_remove,
287 	.id_table	= mrfld_extcon_id_table,
288 };
289 module_platform_driver(mrfld_extcon_driver);
290 
291 MODULE_AUTHOR("Andy Shevchenko <andriy.shevchenko@linux.intel.com>");
292 MODULE_DESCRIPTION("extcon driver for Intel Merrifield Basin Cove PMIC");
293 MODULE_LICENSE("GPL v2");
294