1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * extcon_gpio.c - Single-state GPIO extcon driver based on extcon class |
4 | * |
5 | * Copyright (C) 2008 Google, Inc. |
6 | * Author: Mike Lockwood <lockwood@android.com> |
7 | * |
8 | * Modified by MyungJoo Ham <myungjoo.ham@samsung.com> to support extcon |
9 | * (originally switch class is supported) |
10 | */ |
11 | |
12 | #include <linux/devm-helpers.h> |
13 | #include <linux/extcon-provider.h> |
14 | #include <linux/gpio/consumer.h> |
15 | #include <linux/init.h> |
16 | #include <linux/interrupt.h> |
17 | #include <linux/kernel.h> |
18 | #include <linux/module.h> |
19 | #include <linux/platform_device.h> |
20 | #include <linux/slab.h> |
21 | #include <linux/workqueue.h> |
22 | |
23 | /** |
24 | * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container. |
25 | * @edev: Extcon device. |
26 | * @work: Work fired by the interrupt. |
27 | * @debounce_jiffies: Number of jiffies to wait for the GPIO to stabilize, from the debounce |
28 | * value. |
29 | * @gpiod: GPIO descriptor for this external connector. |
30 | * @extcon_id: The unique id of specific external connector. |
31 | * @debounce: Debounce time for GPIO IRQ in ms. |
32 | * @check_on_resume: Boolean describing whether to check the state of gpio |
33 | * while resuming from sleep. |
34 | */ |
35 | struct gpio_extcon_data { |
36 | struct extcon_dev *edev; |
37 | struct delayed_work work; |
38 | unsigned long debounce_jiffies; |
39 | struct gpio_desc *gpiod; |
40 | unsigned int extcon_id; |
41 | unsigned long debounce; |
42 | bool check_on_resume; |
43 | }; |
44 | |
45 | static void gpio_extcon_work(struct work_struct *work) |
46 | { |
47 | int state; |
48 | struct gpio_extcon_data *data = |
49 | container_of(to_delayed_work(work), struct gpio_extcon_data, |
50 | work); |
51 | |
52 | state = gpiod_get_value_cansleep(desc: data->gpiod); |
53 | extcon_set_state_sync(edev: data->edev, id: data->extcon_id, state); |
54 | } |
55 | |
56 | static irqreturn_t gpio_irq_handler(int irq, void *dev_id) |
57 | { |
58 | struct gpio_extcon_data *data = dev_id; |
59 | |
60 | queue_delayed_work(wq: system_power_efficient_wq, dwork: &data->work, |
61 | delay: data->debounce_jiffies); |
62 | return IRQ_HANDLED; |
63 | } |
64 | |
65 | static int gpio_extcon_probe(struct platform_device *pdev) |
66 | { |
67 | struct gpio_extcon_data *data; |
68 | struct device *dev = &pdev->dev; |
69 | unsigned long irq_flags; |
70 | int irq; |
71 | int ret; |
72 | |
73 | data = devm_kzalloc(dev, size: sizeof(struct gpio_extcon_data), GFP_KERNEL); |
74 | if (!data) |
75 | return -ENOMEM; |
76 | |
77 | /* |
78 | * FIXME: extcon_id represents the unique identifier of external |
79 | * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id |
80 | * is necessary to register the extcon device. But, it's not yet |
81 | * developed to get the extcon id from device-tree or others. |
82 | * On later, it have to be solved. |
83 | */ |
84 | if (data->extcon_id > EXTCON_NONE) |
85 | return -EINVAL; |
86 | |
87 | data->gpiod = devm_gpiod_get(dev, con_id: "extcon" , flags: GPIOD_IN); |
88 | if (IS_ERR(ptr: data->gpiod)) |
89 | return PTR_ERR(ptr: data->gpiod); |
90 | irq = gpiod_to_irq(desc: data->gpiod); |
91 | if (irq <= 0) |
92 | return irq; |
93 | |
94 | /* |
95 | * It is unlikely that this is an acknowledged interrupt that goes |
96 | * away after handling, what we are looking for are falling edges |
97 | * if the signal is active low, and rising edges if the signal is |
98 | * active high. |
99 | */ |
100 | if (gpiod_is_active_low(desc: data->gpiod)) |
101 | irq_flags = IRQF_TRIGGER_FALLING; |
102 | else |
103 | irq_flags = IRQF_TRIGGER_RISING; |
104 | |
105 | /* Allocate the memory of extcon devie and register extcon device */ |
106 | data->edev = devm_extcon_dev_allocate(dev, cable: &data->extcon_id); |
107 | if (IS_ERR(ptr: data->edev)) { |
108 | dev_err(dev, "failed to allocate extcon device\n" ); |
109 | return -ENOMEM; |
110 | } |
111 | |
112 | ret = devm_extcon_dev_register(dev, edev: data->edev); |
113 | if (ret < 0) |
114 | return ret; |
115 | |
116 | ret = devm_delayed_work_autocancel(dev, w: &data->work, worker: gpio_extcon_work); |
117 | if (ret) |
118 | return ret; |
119 | |
120 | /* |
121 | * Request the interrupt of gpio to detect whether external connector |
122 | * is attached or detached. |
123 | */ |
124 | ret = devm_request_any_context_irq(dev, irq, |
125 | handler: gpio_irq_handler, irqflags: irq_flags, |
126 | devname: pdev->name, dev_id: data); |
127 | if (ret < 0) |
128 | return ret; |
129 | |
130 | platform_set_drvdata(pdev, data); |
131 | /* Perform initial detection */ |
132 | gpio_extcon_work(work: &data->work.work); |
133 | |
134 | return 0; |
135 | } |
136 | |
137 | #ifdef CONFIG_PM_SLEEP |
138 | static int gpio_extcon_resume(struct device *dev) |
139 | { |
140 | struct gpio_extcon_data *data; |
141 | |
142 | data = dev_get_drvdata(dev); |
143 | if (data->check_on_resume) |
144 | queue_delayed_work(wq: system_power_efficient_wq, |
145 | dwork: &data->work, delay: data->debounce_jiffies); |
146 | |
147 | return 0; |
148 | } |
149 | #endif |
150 | |
151 | static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); |
152 | |
153 | static struct platform_driver gpio_extcon_driver = { |
154 | .probe = gpio_extcon_probe, |
155 | .driver = { |
156 | .name = "extcon-gpio" , |
157 | .pm = &gpio_extcon_pm_ops, |
158 | }, |
159 | }; |
160 | |
161 | module_platform_driver(gpio_extcon_driver); |
162 | |
163 | MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>" ); |
164 | MODULE_DESCRIPTION("GPIO extcon driver" ); |
165 | MODULE_LICENSE("GPL" ); |
166 | |