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 * @irq: Interrupt line for the external connector. 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 * @irq_flags: IRQ Flags (e.g., IRQF_TRIGGER_LOW). 33 * @check_on_resume: Boolean describing whether to check the state of gpio 34 * while resuming from sleep. 35 */ 36 struct gpio_extcon_data { 37 struct extcon_dev *edev; 38 int irq; 39 struct delayed_work work; 40 unsigned long debounce_jiffies; 41 struct gpio_desc *gpiod; 42 unsigned int extcon_id; 43 unsigned long debounce; 44 unsigned long irq_flags; 45 bool check_on_resume; 46 }; 47 48 static void gpio_extcon_work(struct work_struct *work) 49 { 50 int state; 51 struct gpio_extcon_data *data = 52 container_of(to_delayed_work(work), struct gpio_extcon_data, 53 work); 54 55 state = gpiod_get_value_cansleep(data->gpiod); 56 extcon_set_state_sync(data->edev, data->extcon_id, state); 57 } 58 59 static irqreturn_t gpio_irq_handler(int irq, void *dev_id) 60 { 61 struct gpio_extcon_data *data = dev_id; 62 63 queue_delayed_work(system_power_efficient_wq, &data->work, 64 data->debounce_jiffies); 65 return IRQ_HANDLED; 66 } 67 68 static int gpio_extcon_probe(struct platform_device *pdev) 69 { 70 struct gpio_extcon_data *data; 71 struct device *dev = &pdev->dev; 72 int ret; 73 74 data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL); 75 if (!data) 76 return -ENOMEM; 77 78 /* 79 * FIXME: extcon_id represents the unique identifier of external 80 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id 81 * is necessary to register the extcon device. But, it's not yet 82 * developed to get the extcon id from device-tree or others. 83 * On later, it have to be solved. 84 */ 85 if (!data->irq_flags || data->extcon_id > EXTCON_NONE) 86 return -EINVAL; 87 88 data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN); 89 if (IS_ERR(data->gpiod)) 90 return PTR_ERR(data->gpiod); 91 data->irq = gpiod_to_irq(data->gpiod); 92 if (data->irq <= 0) 93 return data->irq; 94 95 /* Allocate the memory of extcon devie and register extcon device */ 96 data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id); 97 if (IS_ERR(data->edev)) { 98 dev_err(dev, "failed to allocate extcon device\n"); 99 return -ENOMEM; 100 } 101 102 ret = devm_extcon_dev_register(dev, data->edev); 103 if (ret < 0) 104 return ret; 105 106 INIT_DELAYED_WORK(&data->work, gpio_extcon_work); 107 108 /* 109 * Request the interrupt of gpio to detect whether external connector 110 * is attached or detached. 111 */ 112 ret = devm_request_any_context_irq(dev, data->irq, 113 gpio_irq_handler, data->irq_flags, 114 pdev->name, data); 115 if (ret < 0) 116 return ret; 117 118 platform_set_drvdata(pdev, data); 119 /* Perform initial detection */ 120 gpio_extcon_work(&data->work.work); 121 122 return 0; 123 } 124 125 static int gpio_extcon_remove(struct platform_device *pdev) 126 { 127 struct gpio_extcon_data *data = platform_get_drvdata(pdev); 128 129 cancel_delayed_work_sync(&data->work); 130 131 return 0; 132 } 133 134 #ifdef CONFIG_PM_SLEEP 135 static int gpio_extcon_resume(struct device *dev) 136 { 137 struct gpio_extcon_data *data; 138 139 data = dev_get_drvdata(dev); 140 if (data->check_on_resume) 141 queue_delayed_work(system_power_efficient_wq, 142 &data->work, data->debounce_jiffies); 143 144 return 0; 145 } 146 #endif 147 148 static SIMPLE_DEV_PM_OPS(gpio_extcon_pm_ops, NULL, gpio_extcon_resume); 149 150 static struct platform_driver gpio_extcon_driver = { 151 .probe = gpio_extcon_probe, 152 .remove = gpio_extcon_remove, 153 .driver = { 154 .name = "extcon-gpio", 155 .pm = &gpio_extcon_pm_ops, 156 }, 157 }; 158 159 module_platform_driver(gpio_extcon_driver); 160 161 MODULE_AUTHOR("Mike Lockwood <lockwood@android.com>"); 162 MODULE_DESCRIPTION("GPIO extcon driver"); 163 MODULE_LICENSE("GPL"); 164