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| #include <linux/module.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>
struct gpio_key{ int gpio; struct gpio_desc *gpiod; int flag; int irq; } ; static struct gpio_key *gpio_keys_100ask; static int major = 0; static struct class *gpio_key_class;
#define BUF_LEN 128 static int g_keys[BUF_LEN]; static int r, w; #define NEXT_POS(x) ((x+1) % BUF_LEN) static int is_key_buf_empty(void){ return (r == w); } static int is_key_buf_full(void){ return (r == NEXT_POS(w)); } static void put_key(int key){ if (!is_key_buf_full()){ g_keys[w] = key; w = NEXT_POS(w); } } static int get_key(void){ int key = 0; if (!is_key_buf_empty()){ key = g_keys[r]; r = NEXT_POS(r); } return key; }
static DECLARE_WAIT_QUEUE_HEAD(gpio_key_wait);
static ssize_t gpio_key_drv_read (struct file *file, char __user *buf, size_t size, loff_t *offset){ int err; int key; wait_event_interruptible(gpio_key_wait, !is_key_buf_empty()); key = get_key(); err = copy_to_user(buf, &key, 4); return 4; } static struct file_operations gpio_key_drv = { .owner = THIS_MODULE, .read = gpio_key_drv_read, };
static irqreturn_t gpio_key_isr(int irq, void *dev_id){ struct gpio_key *gpio_key = dev_id; int val; int key; val = gpiod_get_value(gpio_key->gpiod); printk("key %d %d\n", gpio_key->gpio, val); key = (gpio_key->gpio << 8) | val; put_key(key); wake_up_interruptible(&gpio_key_wait); return IRQ_HANDLED; }
static int gpio_key_probe(struct platform_device *pdev){ int err; struct device_node *node = pdev->dev.of_node; int count; int i; enum of_gpio_flags flag;
count = of_gpio_count(node); if (!count){ printk("%s %s line %d, there isn't any gpio available\n", __FILE__, __FUNCTION__, __LINE__); return -1; }
gpio_keys_100ask = kzalloc(sizeof(struct gpio_key) * count, GFP_KERNEL); for (i = 0; i < count; i++){ gpio_keys_100ask[i].gpio = of_get_gpio_flags(node, i, &flag); if (gpio_keys_100ask[i].gpio < 0){ printk("%s %s line %d, of_get_gpio_flags fail\n", __FILE__, __FUNCTION__, __LINE__); return -1; } gpio_keys_100ask[i].gpiod = gpio_to_desc(gpio_keys_100ask[i].gpio); gpio_keys_100ask[i].flag = flag & OF_GPIO_ACTIVE_LOW; gpio_keys_100ask[i].irq = gpio_to_irq(gpio_keys_100ask[i].gpio); } for (i = 0; i < count; i++){ err = request_irq(gpio_keys_100ask[i].irq, gpio_key_isr, IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING, "100ask_gpio_key", &gpio_keys_100ask[i]); }
major = register_chrdev(0, "100ask_gpio_key", &gpio_key_drv); gpio_key_class = class_create(THIS_MODULE, "100ask_gpio_key_class"); if (IS_ERR(gpio_key_class)) { printk("%s %s line %d\n", __FILE__, __FUNCTION__, __LINE__); unregister_chrdev(major, "100ask_gpio_key"); return PTR_ERR(gpio_key_class); } device_create(gpio_key_class, NULL, MKDEV(major, 0), NULL, "100ask_gpio_key"); return 0; } static int gpio_key_remove(struct platform_device *pdev){ struct device_node *node = pdev->dev.of_node; int count; int i; device_destroy(gpio_key_class, MKDEV(major, 0)); class_destroy(gpio_key_class); unregister_chrdev(major, "100ask_gpio_key"); count = of_gpio_count(node); for (i = 0; i < count; i++){ free_irq(gpio_keys_100ask[i].irq, &gpio_keys_100ask[i]); } kfree(gpio_keys_100ask); return 0; } static const struct of_device_id ask100_keys[] = { { .compatible = "100ask,gpio_key" }, { }, }; static struct platform_driver gpio_keys_driver = { .probe = gpio_key_probe, .remove = gpio_key_remove, .driver = { .name = "100ask_gpio_key", .of_match_table = ask100_keys, }, }; static int __init gpio_key_init(void){ int err; err = platform_driver_register(&gpio_keys_driver); return err; } static void __exit gpio_key_exit(void){ platform_driver_unregister(&gpio_keys_driver); } module_init(gpio_key_init); module_exit(gpio_key_exit); MODULE_LICENSE("GPL");
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