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/extcon-provider.h> 13 #include <linux/gpio/consumer.h> 14 #include <linux/init.h> 15 #include <linux/interrupt.h> 16 #include <linux/kernel.h> 17 #include <linux/module.h> 18 #include <linux/platform_device.h> 19 #include <linux/slab.h> 20 #include <linux/workqueue.h> 21 22 /** 23 * struct gpio_extcon_data - A simple GPIO-controlled extcon device state container. 24 * @edev: Extcon device. 25 * @work: Work fired by the interrupt. 26 * @debounce_jiffies: Number of jiffies to wait for the GPIO to stabilize, from the debounce 27 * value. 28 * @gpiod: GPIO descriptor for this external connector. 29 * @extcon_id: The unique id of specific external connector. 30 * @debounce: Debounce time for GPIO IRQ in ms. 31 * @check_on_resume: Boolean describing whether to check the state of gpio 32 * while resuming from sleep. 33 */ 34 struct gpio_extcon_data { 35 struct extcon_dev *edev; 36 struct delayed_work work; 37 unsigned long debounce_jiffies; 38 struct gpio_desc *gpiod; 39 unsigned int extcon_id; 40 unsigned long debounce; 41 bool check_on_resume; 42 }; 43 44 static void gpio_extcon_work(struct work_struct *work) 45 { 46 int state; 47 struct gpio_extcon_data *data = 48 container_of(to_delayed_work(work), struct gpio_extcon_data, 49 work); 50 51 state = gpiod_get_value_cansleep(data->gpiod); 52 extcon_set_state_sync(data->edev, data->extcon_id, state); 53 } 54 55 static irqreturn_t gpio_irq_handler(int irq, void *dev_id) 56 { 57 struct gpio_extcon_data *data = dev_id; 58 59 queue_delayed_work(system_power_efficient_wq, &data->work, 60 data->debounce_jiffies); 61 return IRQ_HANDLED; 62 } 63 64 static int gpio_extcon_probe(struct platform_device *pdev) 65 { 66 struct gpio_extcon_data *data; 67 struct device *dev = &pdev->dev; 68 unsigned long irq_flags; 69 int irq; 70 int ret; 71 72 data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL); 73 if (!data) 74 return -ENOMEM; 75 76 /* 77 * FIXME: extcon_id represents the unique identifier of external 78 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id 79 * is necessary to register the extcon device. But, it's not yet 80 * developed to get the extcon id from device-tree or others. 81 * On later, it have to be solved. 82 */ 83 if (data->extcon_id > EXTCON_NONE) 84 return -EINVAL; 85 86 data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN); 87 if (IS_ERR(data->gpiod)) 88 return PTR_ERR(data->gpiod); 89 irq = gpiod_to_irq(data->gpiod); 90 if (irq <= 0) 91 return irq; 92 93 /* 94 * It is unlikely that this is an acknowledged interrupt that goes 95 * away after handling, what we are looking for are falling edges 96 * if the signal is active low, and rising edges if the signal is 97 * active high. 98 */ 99 if (gpiod_is_active_low(data->gpiod)) 100 irq_flags = IRQF_TRIGGER_FALLING; 101 else 102 irq_flags = IRQF_TRIGGER_RISING; 103 104 /* Allocate the memory of extcon devie and register extcon device */ 105 data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id); 106 if (IS_ERR(data->edev)) { 107 dev_err(dev, "failed to allocate extcon device\n"); 108 return -ENOMEM; 109 } 110 111 ret = devm_extcon_dev_register(dev, data->edev); 112 if (ret < 0) 113 return ret; 114 115 INIT_DELAYED_WORK(&data->work, gpio_extcon_work); 116 117 /* 118 * Request the interrupt of gpio to detect whether external connector 119 * is attached or detached. 120 */ 121 ret = devm_request_any_context_irq(dev, irq, 122 gpio_irq_handler, irq_flags, 123 pdev->name, data); 124 if (ret < 0) 125 return ret; 126 127 platform_set_drvdata(pdev, data); 128 /* Perform initial detection */ 129 gpio_extcon_work(&data->work.work); 130 131 return 0; 132 } 133 134 static int gpio_extcon_remove(struct platform_device *pdev) 135 { 136 struct gpio_extcon_data *data = platform_get_drvdata(pdev); 137 138 cancel_delayed_work_sync(&data->work); 139 140 return 0; 141 } 142 143 #ifdef CONFIG_PM_SLEEP 144 static int gpio_extcon_resume(struct device *dev) 145 { 146 struct gpio_extcon_data *data; 147 148 data = dev_get_drvdata(dev); 149 if (data->check_on_resume) 150 queue_delayed_work(system_power_efficient_wq, 151 &data->work, data->debounce_jiffies); 152 153 return 0; 154 } 155 #endif 156 157 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); 158 159 static struct platform_driver gpio_extcon_driver = { 160 .probe = gpio_extcon_probe, 161 .remove = gpio_extcon_remove, 162 .driver = { 163 .name = "extcon-gpio", 164 .pm = &gpio_extcon_pm_ops, 165 }, 166 }; 167 168 module_platform_driver(gpio_extcon_driver); 169 170 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 171 MODULE_DESCRIPTION("GPIO extcon driver"); 172 MODULE_LICENSE("GPL"); 173