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
26#include <linux/power/gpio-charger.h>
27
28struct gpio_charger {
29	const struct gpio_charger_platform_data *pdata;
30	unsigned int irq;
31	bool wakeup_enabled;
32
33	struct power_supply charger;
34};
35
36static irqreturn_t gpio_charger_irq(int irq, void *devid)
37{
38	struct power_supply *charger = devid;
39
40	power_supply_changed(charger);
41
42	return IRQ_HANDLED;
43}
44
45static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
46{
47	return container_of(psy, struct gpio_charger, charger);
48}
49
50static int gpio_charger_get_property(struct power_supply *psy,
51		enum power_supply_property psp, union power_supply_propval *val)
52{
53	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
54	const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
55
56	switch (psp) {
57	case POWER_SUPPLY_PROP_ONLINE:
58		val->intval = !!gpio_get_value_cansleep(pdata->gpio);
59		val->intval ^= pdata->gpio_active_low;
60		break;
61	default:
62		return -EINVAL;
63	}
64
65	return 0;
66}
67
68static enum power_supply_property gpio_charger_properties[] = {
69	POWER_SUPPLY_PROP_ONLINE,
70};
71
72static int gpio_charger_probe(struct platform_device *pdev)
73{
74	const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
75	struct gpio_charger *gpio_charger;
76	struct power_supply *charger;
77	int ret;
78	int irq;
79
80	if (!pdata) {
81		dev_err(&pdev->dev, "No platform data\n");
82		return -EINVAL;
83	}
84
85	if (!gpio_is_valid(pdata->gpio)) {
86		dev_err(&pdev->dev, "Invalid gpio pin\n");
87		return -EINVAL;
88	}
89
90	gpio_charger = devm_kzalloc(&pdev->dev, sizeof(*gpio_charger),
91					GFP_KERNEL);
92	if (!gpio_charger) {
93		dev_err(&pdev->dev, "Failed to alloc driver structure\n");
94		return -ENOMEM;
95	}
96
97	charger = &gpio_charger->charger;
98
99	charger->name = pdata->name ? pdata->name : "gpio-charger";
100	charger->type = pdata->type;
101	charger->properties = gpio_charger_properties;
102	charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
103	charger->get_property = gpio_charger_get_property;
104	charger->supplied_to = pdata->supplied_to;
105	charger->num_supplicants = pdata->num_supplicants;
106
107	ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
108	if (ret) {
109		dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
110		goto err_free;
111	}
112	ret = gpio_direction_input(pdata->gpio);
113	if (ret) {
114		dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
115		goto err_gpio_free;
116	}
117
118	gpio_charger->pdata = pdata;
119
120	ret = power_supply_register(&pdev->dev, charger);
121	if (ret < 0) {
122		dev_err(&pdev->dev, "Failed to register power supply: %d\n",
123			ret);
124		goto err_gpio_free;
125	}
126
127	irq = gpio_to_irq(pdata->gpio);
128	if (irq > 0) {
129		ret = request_any_context_irq(irq, gpio_charger_irq,
130				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
131				dev_name(&pdev->dev), charger);
132		if (ret < 0)
133			dev_warn(&pdev->dev, "Failed to request irq: %d\n", ret);
134		else
135			gpio_charger->irq = irq;
136	}
137
138	platform_set_drvdata(pdev, gpio_charger);
139
140	device_init_wakeup(&pdev->dev, 1);
141
142	return 0;
143
144err_gpio_free:
145	gpio_free(pdata->gpio);
146err_free:
147	return ret;
148}
149
150static int gpio_charger_remove(struct platform_device *pdev)
151{
152	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
153
154	if (gpio_charger->irq)
155		free_irq(gpio_charger->irq, &gpio_charger->charger);
156
157	power_supply_unregister(&gpio_charger->charger);
158
159	gpio_free(gpio_charger->pdata->gpio);
160
161	return 0;
162}
163
164#ifdef CONFIG_PM_SLEEP
165static int gpio_charger_suspend(struct device *dev)
166{
167	struct gpio_charger *gpio_charger = dev_get_drvdata(dev);
168
169	if (device_may_wakeup(dev))
170		gpio_charger->wakeup_enabled =
171			enable_irq_wake(gpio_charger->irq);
172
173	return 0;
174}
175
176static int gpio_charger_resume(struct device *dev)
177{
178	struct platform_device *pdev = to_platform_device(dev);
179	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
180
181	if (gpio_charger->wakeup_enabled)
182		disable_irq_wake(gpio_charger->irq);
183	power_supply_changed(&gpio_charger->charger);
184
185	return 0;
186}
187#endif
188
189static SIMPLE_DEV_PM_OPS(gpio_charger_pm_ops,
190		gpio_charger_suspend, gpio_charger_resume);
191
192static struct platform_driver gpio_charger_driver = {
193	.probe = gpio_charger_probe,
194	.remove = gpio_charger_remove,
195	.driver = {
196		.name = "gpio-charger",
197		.owner = THIS_MODULE,
198		.pm = &gpio_charger_pm_ops,
199	},
200};
201
202module_platform_driver(gpio_charger_driver);
203
204MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
205MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
206MODULE_LICENSE("GPL");
207MODULE_ALIAS("platform:gpio-charger");
208