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1 | /* |
2 | * drivers/extcon/extcon_gpio.c |
3 | * |
4 | * Single-state GPIO extcon driver based on extcon class |
5 | * |
6 | * Copyright (C) 2008 Google, Inc. |
7 | * Author: Mike Lockwood <lockwood@android.com> |
8 | * |
9 | * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon |
10 | * (originally switch class is supported) |
11 | * |
12 | * This software is licensed under the terms of the GNU General Public |
13 | * License version 2, as published by the Free Software Foundation, and |
14 | * may be copied, distributed, and modified under those terms. |
15 | * |
16 | * This program is distributed in the hope that it will be useful, |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
19 | * GNU General Public License for more details. |
20 | * |
21 | */ |
22 | |
23 | #include <linux/extcon.h> |
24 | #include <linux/extcon/extcon-gpio.h> |
25 | #include <linux/gpio.h> |
26 | #include <linux/init.h> |
27 | #include <linux/interrupt.h> |
28 | #include <linux/kernel.h> |
29 | #include <linux/module.h> |
30 | #include <linux/platform_device.h> |
31 | #include <linux/slab.h> |
32 | #include <linux/workqueue.h> |
33 | |
34 | struct gpio_extcon_data { |
35 | struct extcon_dev *edev; |
36 | unsigned gpio; |
37 | bool gpio_active_low; |
38 | const char *state_on; |
39 | const char *state_off; |
40 | int irq; |
41 | struct delayed_work work; |
42 | unsigned long debounce_jiffies; |
43 | bool check_on_resume; |
44 | }; |
45 | |
46 | static void gpio_extcon_work(struct work_struct *work) |
47 | { |
48 | int state; |
49 | struct gpio_extcon_data *data = |
50 | container_of(to_delayed_work(work), struct gpio_extcon_data, |
51 | work); |
52 | |
53 | state = gpio_get_value(data->gpio); |
54 | if (data->gpio_active_low) |
55 | state = !state; |
56 | extcon_set_state(data->edev, state); |
57 | } |
58 | |
59 | static irqreturn_t gpio_irq_handler(int irq, void *dev_id) |
60 | { |
61 | struct gpio_extcon_data *extcon_data = dev_id; |
62 | |
63 | queue_delayed_work(system_power_efficient_wq, &extcon_data->work, |
64 | extcon_data->debounce_jiffies); |
65 | return IRQ_HANDLED; |
66 | } |
67 | |
68 | static ssize_t extcon_gpio_print_state(struct extcon_dev *edev, char *buf) |
69 | { |
70 | struct device *dev = edev->dev.parent; |
71 | struct gpio_extcon_data *extcon_data = dev_get_drvdata(dev); |
72 | const char *state; |
73 | |
74 | if (extcon_get_state(edev)) |
75 | state = extcon_data->state_on; |
76 | else |
77 | state = extcon_data->state_off; |
78 | |
79 | if (state) |
80 | return sprintf(buf, "%s\n", state); |
81 | return -EINVAL; |
82 | } |
83 | |
84 | static int gpio_extcon_probe(struct platform_device *pdev) |
85 | { |
86 | struct gpio_extcon_platform_data *pdata = dev_get_platdata(&pdev->dev); |
87 | struct gpio_extcon_data *extcon_data; |
88 | int ret; |
89 | |
90 | if (!pdata) |
91 | return -EBUSY; |
92 | if (!pdata->irq_flags) { |
93 | dev_err(&pdev->dev, "IRQ flag is not specified.\n"); |
94 | return -EINVAL; |
95 | } |
96 | |
97 | extcon_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_extcon_data), |
98 | GFP_KERNEL); |
99 | if (!extcon_data) |
100 | return -ENOMEM; |
101 | |
102 | extcon_data->edev = devm_extcon_dev_allocate(&pdev->dev, NULL); |
103 | if (IS_ERR(extcon_data->edev)) { |
104 | dev_err(&pdev->dev, "failed to allocate extcon device\n"); |
105 | return -ENOMEM; |
106 | } |
107 | extcon_data->edev->name = pdata->name; |
108 | |
109 | extcon_data->gpio = pdata->gpio; |
110 | extcon_data->gpio_active_low = pdata->gpio_active_low; |
111 | extcon_data->state_on = pdata->state_on; |
112 | extcon_data->state_off = pdata->state_off; |
113 | extcon_data->check_on_resume = pdata->check_on_resume; |
114 | if (pdata->state_on && pdata->state_off) |
115 | extcon_data->edev->print_state = extcon_gpio_print_state; |
116 | |
117 | ret = devm_gpio_request_one(&pdev->dev, extcon_data->gpio, GPIOF_DIR_IN, |
118 | pdev->name); |
119 | if (ret < 0) |
120 | return ret; |
121 | |
122 | if (pdata->debounce) { |
123 | ret = gpio_set_debounce(extcon_data->gpio, |
124 | pdata->debounce * 1000); |
125 | if (ret < 0) |
126 | extcon_data->debounce_jiffies = |
127 | msecs_to_jiffies(pdata->debounce); |
128 | } |
129 | |
130 | ret = devm_extcon_dev_register(&pdev->dev, extcon_data->edev); |
131 | if (ret < 0) |
132 | return ret; |
133 | |
134 | INIT_DELAYED_WORK(&extcon_data->work, gpio_extcon_work); |
135 | |
136 | extcon_data->irq = gpio_to_irq(extcon_data->gpio); |
137 | if (extcon_data->irq < 0) |
138 | return extcon_data->irq; |
139 | |
140 | ret = request_any_context_irq(extcon_data->irq, gpio_irq_handler, |
141 | pdata->irq_flags, pdev->name, |
142 | extcon_data); |
143 | if (ret < 0) |
144 | return ret; |
145 | |
146 | platform_set_drvdata(pdev, extcon_data); |
147 | /* Perform initial detection */ |
148 | gpio_extcon_work(&extcon_data->work.work); |
149 | |
150 | return 0; |
151 | } |
152 | |
153 | static int gpio_extcon_remove(struct platform_device *pdev) |
154 | { |
155 | struct gpio_extcon_data *extcon_data = platform_get_drvdata(pdev); |
156 | |
157 | cancel_delayed_work_sync(&extcon_data->work); |
158 | free_irq(extcon_data->irq, extcon_data); |
159 | |
160 | return 0; |
161 | } |
162 | |
163 | #ifdef CONFIG_PM_SLEEP |
164 | static int gpio_extcon_resume(struct device *dev) |
165 | { |
166 | struct gpio_extcon_data *extcon_data; |
167 | |
168 | extcon_data = dev_get_drvdata(dev); |
169 | if (extcon_data->check_on_resume) |
170 | queue_delayed_work(system_power_efficient_wq, |
171 | &extcon_data->work, extcon_data->debounce_jiffies); |
172 | |
173 | return 0; |
174 | } |
175 | #endif |
176 | |
177 | static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); |
178 | |
179 | static struct platform_driver gpio_extcon_driver = { |
180 | .probe = gpio_extcon_probe, |
181 | .remove = gpio_extcon_remove, |
182 | .driver = { |
183 | .name = "extcon-gpio", |
184 | .owner = THIS_MODULE, |
185 | .pm = &gpio_extcon_pm_ops, |
186 | }, |
187 | }; |
188 | |
189 | module_platform_driver(gpio_extcon_driver); |
190 | |
191 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); |
192 | MODULE_DESCRIPTION("GPIO extcon driver"); |
193 | MODULE_LICENSE("GPL"); |
194 |
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