1 /*
2  *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
3  *  Driver for chargers which report their online status through a GPIO pin
4  *
5  *  This program is free software; you can redistribute it and/or modify it
6  *  under  the terms of the GNU General  Public License as published by the
7  *  Free Software Foundation;  either version 2 of the License, or (at your
8  *  option) any later version.
9  *
10  *  You should have received a copy of the GNU General Public License along
11  *  with this program; if not, write to the Free Software Foundation, Inc.,
12  *  675 Mass Ave, Cambridge, MA 02139, USA.
13  *
14  */
15 
16 #include <linux/device.h>
17 #include <linux/gpio.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/platform_device.h>
23 #include <linux/power_supply.h>
24 #include <linux/slab.h>
25 #include <linux/of.h>
26 #include <linux/of_gpio.h>
27 
28 #include <linux/power/gpio-charger.h>
29 
30 struct gpio_charger {
31 	const struct gpio_charger_platform_data *pdata;
32 	unsigned int irq;
33 	bool wakeup_enabled;
34 
35 	struct power_supply *charger;
36 	struct power_supply_desc charger_desc;
37 };
38 
39 static irqreturn_t gpio_charger_irq(int irq, void *devid)
40 {
41 	struct power_supply *charger = devid;
42 
43 	power_supply_changed(charger);
44 
45 	return IRQ_HANDLED;
46 }
47 
48 static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
49 {
50 	return power_supply_get_drvdata(psy);
51 }
52 
53 static int gpio_charger_get_property(struct power_supply *psy,
54 		enum power_supply_property psp, union power_supply_propval *val)
55 {
56 	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
57 	const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
58 
59 	switch (psp) {
60 	case POWER_SUPPLY_PROP_ONLINE:
61 		val->intval = !!gpio_get_value_cansleep(pdata->gpio);
62 		val->intval ^= pdata->gpio_active_low;
63 		break;
64 	default:
65 		return -EINVAL;
66 	}
67 
68 	return 0;
69 }
70 
71 static enum power_supply_property gpio_charger_properties[] = {
72 	POWER_SUPPLY_PROP_ONLINE,
73 };
74 
75 static
76 struct gpio_charger_platform_data *gpio_charger_parse_dt(struct device *dev)
77 {
78 	struct device_node *np = dev->of_node;
79 	struct gpio_charger_platform_data *pdata;
80 	const char *chargetype;
81 	enum of_gpio_flags flags;
82 	int ret;
83 
84 	if (!np)
85 		return ERR_PTR(-ENOENT);
86 
87 	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
88 	if (!pdata)
89 		return ERR_PTR(-ENOMEM);
90 
91 	pdata->name = np->name;
92 
93 	pdata->gpio = of_get_gpio_flags(np, 0, &flags);
94 	if (pdata->gpio < 0) {
95 		if (pdata->gpio != -EPROBE_DEFER)
96 			dev_err(dev, "could not get charger gpio\n");
97 		return ERR_PTR(pdata->gpio);
98 	}
99 
100 	pdata->gpio_active_low = !!(flags & OF_GPIO_ACTIVE_LOW);
101 
102 	pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
103 	ret = of_property_read_string(np, "charger-type", &chargetype);
104 	if (ret >= 0) {
105 		if (!strncmp("unknown", chargetype, 7))
106 			pdata->type = POWER_SUPPLY_TYPE_UNKNOWN;
107 		else if (!strncmp("battery", chargetype, 7))
108 			pdata->type = POWER_SUPPLY_TYPE_BATTERY;
109 		else if (!strncmp("ups", chargetype, 3))
110 			pdata->type = POWER_SUPPLY_TYPE_UPS;
111 		else if (!strncmp("mains", chargetype, 5))
112 			pdata->type = POWER_SUPPLY_TYPE_MAINS;
113 		else if (!strncmp("usb-sdp", chargetype, 7))
114 			pdata->type = POWER_SUPPLY_TYPE_USB;
115 		else if (!strncmp("usb-dcp", chargetype, 7))
116 			pdata->type = POWER_SUPPLY_TYPE_USB_DCP;
117 		else if (!strncmp("usb-cdp", chargetype, 7))
118 			pdata->type = POWER_SUPPLY_TYPE_USB_CDP;
119 		else if (!strncmp("usb-aca", chargetype, 7))
120 			pdata->type = POWER_SUPPLY_TYPE_USB_ACA;
121 		else
122 			dev_warn(dev, "unknown charger type %s\n", chargetype);
123 	}
124 
125 	return pdata;
126 }
127 
128 static int gpio_charger_probe(struct platform_device *pdev)
129 {
130 	const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
131 	struct power_supply_config psy_cfg = {};
132 	struct gpio_charger *gpio_charger;
133 	struct power_supply_desc *charger_desc;
134 	int ret;
135 	int irq;
136 
137 	if (!pdata) {
138 		pdata = gpio_charger_parse_dt(&pdev->dev);
139 		if (IS_ERR(pdata)) {
140 			ret = PTR_ERR(pdata);
141 			if (ret != -EPROBE_DEFER)
142 				dev_err(&pdev->dev, "No platform data\n");
143 			return ret;
144 		}
145 	}
146 
147 	if (!gpio_is_valid(pdata->gpio)) {
148 		dev_err(&pdev->dev, "Invalid gpio pin\n");
149 		return -EINVAL;
150 	}
151 
152 	gpio_charger = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger),
153 					GFP_KERNEL);
154 	if (!gpio_charger) {
155 		dev_err(&pdev->dev, "Failed to alloc driver structure\n");
156 		return -ENOMEM;
157 	}
158 
159 	charger_desc = &gpio_charger->charger_desc;
160 
161 	charger_desc->name = pdata->name ? pdata->name : "gpio-charger";
162 	charger_desc->type = pdata->type;
163 	charger_desc->properties = gpio_charger_properties;
164 	charger_desc->num_properties = ARRAY_SIZE(gpio_charger_properties);
165 	charger_desc->get_property = gpio_charger_get_property;
166 
167 	psy_cfg.supplied_to = pdata->supplied_to;
168 	psy_cfg.num_supplicants = pdata->num_supplicants;
169 	psy_cfg.of_node = pdev->dev.of_node;
170 	psy_cfg.drv_data = gpio_charger;
171 
172 	ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
173 	if (ret) {
174 		dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
175 		goto err_free;
176 	}
177 	ret = gpio_direction_input(pdata->gpio);
178 	if (ret) {
179 		dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
180 		goto err_gpio_free;
181 	}
182 
183 	gpio_charger->pdata = pdata;
184 
185 	gpio_charger->charger = power_supply_register(&pdev->dev,
186 						      charger_desc, &psy_cfg);
187 	if (IS_ERR(gpio_charger->charger)) {
188 		ret = PTR_ERR(gpio_charger->charger);
189 		dev_err(&pdev->dev, "Failed to register power supply: %d\n",
190 			ret);
191 		goto err_gpio_free;
192 	}
193 
194 	irq = gpio_to_irq(pdata->gpio);
195 	if (irq > 0) {
196 		ret = request_any_context_irq(irq, gpio_charger_irq,
197 				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
198 				dev_name(&pdev->dev), gpio_charger->charger);
199 		if (ret < 0)
200 			dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
201 		else
202 			gpio_charger->irq = irq;
203 	}
204 
205 	platform_set_drvdata(pdev, gpio_charger);
206 
207 	device_init_wakeup(&pdev->dev, 1);
208 
209 	return 0;
210 
211 err_gpio_free:
212 	gpio_free(pdata->gpio);
213 err_free:
214 	return ret;
215 }
216 
217 static int gpio_charger_remove(struct platform_device *pdev)
218 {
219 	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
220 
221 	if (gpio_charger->irq)
222 		free_irq(gpio_charger->irq, gpio_charger->charger);
223 
224 	power_supply_unregister(gpio_charger->charger);
225 
226 	gpio_free(gpio_charger->pdata->gpio);
227 
228 	return 0;
229 }
230 
231 #ifdef CONFIG_PM_SLEEP
232 static int gpio_charger_suspend(struct device *dev)
233 {
234 	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
235 
236 	if (device_may_wakeup(dev))
237 		gpio_charger->wakeup_enabled =
238 			!enable_irq_wake(gpio_charger->irq);
239 
240 	return 0;
241 }
242 
243 static int gpio_charger_resume(struct device *dev)
244 {
245 	struct platform_device *pdev = to_platform_device(dev);
246 	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
247 
248 	if (device_may_wakeup(dev) && gpio_charger->wakeup_enabled)
249 		disable_irq_wake(gpio_charger->irq);
250 	power_supply_changed(gpio_charger->charger);
251 
252 	return 0;
253 }
254 #endif
255 
256 static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
257 		gpio_charger_suspend, gpio_charger_resume);
258 
259 static const struct of_device_id gpio_charger_match[] = {
260 	{ .compatible = "gpio-charger" },
261 	{ }
262 };
263 MODULE_DEVICE_TABLE(of, gpio_charger_match);
264 
265 static struct platform_driver gpio_charger_driver = {
266 	.probe = gpio_charger_probe,
267 	.remove = gpio_charger_remove,
268 	.driver = {
269 		.name = "gpio-charger",
270 		.pm = &gpio_charger_pm_ops,
271 		.of_match_table = gpio_charger_match,
272 	},
273 };
274 
275 module_platform_driver(gpio_charger_driver);
276 
277 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
278 MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
279 MODULE_LICENSE("GPL");
280 MODULE_ALIAS("platform:gpio-charger");
281