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