设备树节点可以查看一下设备树中其他节点是如何写的100ask_imx6ull-14x14.dts先简单的写一个sr501设备节点sr501{ compatible 100ask,sr501; gpios gpio4 19 GPIO_ACTIVE_HIGH; };关于如何设置gpio属性可以通过grep来查找grep gpio4 * -nrw | grep imx6ull基础框架#include linux/module.h #include linux/poll.h #include linux/fs.h #include linux/errno.h #include linux/miscdevice.h #include linux/kernel.h #include linux/major.h #include linux/mutex.h #include linux/proc_fs.h #include linux/seq_file.h #include linux/stat.h #include linux/init.h #include linux/device.h #include linux/tty.h #include linux/kmod.h #include linux/gfp.h #include linux/gpio/consumer.h #include linux/platform_device.h #include linux/of_gpio.h #include linux/of_irq.h #include linux/interrupt.h #include linux/irq.h #include linux/slab.h #include linux/fcntl.h #include linux/timer.h #include linux/workqueue.h #include asm/current.h static ssize_t sr501_drv_read(struct file *file, char __user *buf, size_t size, loff_t *offset) { return 0; } static unsighed int sr501_drv_poll (struct file *fp, poll_table * wait) { return 0; } static struct file_operation sr501_drv { .owner THIS_MODULE, .read sr501_drv_read, .poll sr501_drv_poll, }; static irqreturn_t sr501_isr(int irq, void *dev_id) { return IRQ_WAKE_THREAD; } static int sr501_probe(struct platform_device *pdev) { printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); return 0; } static int sr501_remove(struct platform_device *pdev) { printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); return 0; } static const struct of_device_id ask100_sr501[] { { .compatible 100ask,sr501 }, {}, } static struct platform_driver sr501_driver { .probe sr501_probe, .remove sr501_remove, .driver { .name 100ask_sr501, .of_match_table ask100_sr501, } } static int __init sr501_init(void) { int err; printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); err platform_driver_register(sr501s_driver); return err; } static void __eixt sr501_exit(void) { printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); platform_driver_unregister(sr501s_driver); } module_init(sr501_init); module_exit(sr501_exit); MODULE_LICENSE(GPL);上机实验编译设备树export ARCHarm export CROSS_COMPILEarm-buildroot-linux-gnueabihf- export PATH$PATH:/home/book/100ask_imx6ull-sdk/ToolChain/arm-buildroot-linux-gnueabihf_sdk-buildroot/bin make dtbs编译.c文件并将两个文件传到开发板上去并且安装驱动通过dmesg来查看简易代码#include linux/module.h #include linux/poll.h #include linux/fs.h #include linux/errno.h #include linux/miscdevice.h #include linux/kernel.h #include linux/major.h #include linux/mutex.h #include linux/proc_fs.h #include linux/seq_file.h #include linux/stat.h #include linux/init.h #include linux/device.h #include linux/tty.h #include linux/kmod.h #include linux/gfp.h #include linux/gpio/consumer.h #include linux/platform_device.h #include linux/of_gpio.h #include linux/of_irq.h #include linux/interrupt.h #include linux/irq.h #include linux/slab.h #include linux/fcntl.h #include linux/timer.h #include linux/workqueue.h #include asm/current.h static int major; static struct class *sr501_class; static wait_queue_head_t sr501_wq; static struct gpio_desc *sr501_gpio; static int irq; static int sr501_data 0; static ssize_t sr501_drv_read(struct file *file, char __user *buf, size_t size, loff_t *offset) { printk(%s %s %d\n, __FILE__, __FUNCTION__, __LINE__); int len (size) 4? size : 4; wait_event_interruptible(sr501_wq, sr501_data); copy_to_user(buf, sr501_data, len); sr501_data 0; return len; } static unsigned int sr501_drv_poll (struct file *fp, poll_table * wait) { return 0; } // file_operations结构体 static struct file_operations sr501_fops { .owner THIS_MODULE, .read sr501_drv_read, .poll sr501_drv_poll, }; //中断处理函数 static irqreturn_t sr501_isr(int irq, void *dev_id) { printk(%s %s %d\n, __FILE__, __FUNCTION__, __LINE__); int val gpiod_get_value(sr501_gpio); sr501_data 0x80 | val; wake_up(sr501_wq); return IRQ_HANDLED; } /* 1. 从platform_device获得GPIO * 2. gpioirq * 3. request_irq */ static int sr501_probe(struct platform_device *pdev) { //gpio sr501_gpio gpiod_get(pdev-dev, NULL, 0); gpiod_direction_input(sr501_gpio); irq gpiod_to_irq(sr501_gpio); request_irq(irq, sr501_isr, IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING, sr501, NULL); device_create(sr501_class, NULL, MKDEV(major, 0), NULL, /dev/sr501); return 0; } //remove释放获得的资源 static int sr501_remove(struct platform_device *pdev) { device_destroy(sr501_class, MKDEV(major, 0)); free_irq(irq, NULL); gpiod_put(sr501_gpio); return 0; } //match tabel static const struct of_device_id ask100_sr501[] { {.compatible 100ask,sr501}, { }, }; // platform_driver结构体 static struct platform_driver sr501s_driver { .probe sr501_probe, .remove sr501_remove, .driver { .name 100ask_sr501, .of_match_table ask100_sr501, }, }; //init中注册file_operation、platform_driver,初始化等待队列用于中断 static int __init sr501_init(void) { int err; printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); //注册file_operation结构体 major register_chrdev(0, sr501, sr501_fops); sr501_class class_create(THIS_MODULE, sr501_class); if(IS_ERR(sr501_class)) { printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); unregister_chrdev(major, sr501); return PTR_ERR(sr501_class); } //初始化等待队列(用于中断) init_waitqueue_head(sr501_wq); err platform_driver_register(sr501s_driver); return err; } //释放获得的资源 static void __exit sr501_exit(void) { printk(%s %s line %d\n, __FILE__, __FUNCTION__, __LINE__); platform_driver_unregister(sr501s_driver); class_destroy(sr501_class); unregister_chrdev(major, sr501); } module_init(sr501_init); module_exit(sr501_exit); MODULE_LICENSE(GPL);