新增LED设备--从上层到底层理解安卓架构之内核篇

test-leds{compatible = "test,leds";led1-work = <&gpio1 23 GPIO_ACTIVE_LOW>;led2-work = <&gpio1 24 GPIO_ACTIVE_LOW>;status = "okay";};

#include <linux/errno.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/slab.h>#include <linux/input.h>#include <linux/init.h>#include <linux/serio.h>#include <linux/delay.h>#include <linux/clk.h>#include <linux/gpio.h>#include <linux/platform_device.h>#include <linux/miscdevice.h>#include <linux/of.h>#include <linux/of_device.h>#include <linux/of_address.h>#include <linux/of_platform.h>#include <linux/of_gpio.h>#include <asm/io.h>#include <asm/uaccess.h>#include <linux/cdev.h>
MODULE_AUTHOR("embeddedtech");MODULE_LICENSE("Dual BSD/GPL");
#define LEDCTRL_MAGIC 'k'#define LED1CTRL_ON_CMD _IO (LEDCTRL_MAGIC, 1)#define LED1CTRL_OFF_CMD _IO (LEDCTRL_MAGIC, 2)#define LED2CTRL_ON_CMD _IO (LEDCTRL_MAGIC, 3)#define LED2CTRL_OFF_CMD _IO (LEDCTRL_MAGIC, 4)
struct led_data {int led1_pin; //led1引脚int led2_pin; //led2引脚};

struct led_data led_info;/** Open the device; in fact, there's nothing to do here.*/int testled_open (struct inode *inode, struct file *filp){return 0;}

ssize_t testled_read(struct file *file, char __user *buff, size_t count, loff_t *offp){return 0;}

ssize_t testled_write(struct file *file, const char __user *buff, size_t count, loff_t *offp){return 0;}

static long testled_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg){ switch (cmd) { case LED1CTRL_ON_CMD: { gpio_direction_output(led_info.led1_pin,1); break; } case LED1CTRL_OFF_CMD: { gpio_direction_output(led_info.led1_pin,0); break; } case LED2CTRL_ON_CMD: { gpio_direction_output(led_info.led2_pin,1); break;} case LED2CTRL_OFF_CMD: {gpio_direction_output(led_info.led2_pin,0); break;} default: { printk("testled compat Default %d\n",cmd); break;}}return 0;}

long testled_ioctl(struct file *file, unsigned int cmd, unsigned long arg){switch (cmd) {case LED1CTRL_ON_CMD: {gpio_direction_output(led_info.led1_pin,1);break;}case LED1CTRL_OFF_CMD: {gpio_direction_output(led_info.led1_pin,0);break;}case LED2CTRL_ON_CMD: {gpio_direction_output(led_info.led2_pin,1);break;}case LED2CTRL_OFF_CMD: {gpio_direction_output(led_info.led2_pin,0);break;}default: {printk("testled Default %d\n",cmd);break;}}return 0;

}

static int testled_release(struct inode *node, struct file *file){return 0;}

/** Our various sub-devices.*//* Device 0 uses remap_pfn_range */static struct file_operations testled_remap_ops = {.owner = THIS_MODULE,.open = testled_open,.release = testled_release,.read = testled_read,.write = testled_write,.unlocked_ioctl = testled_ioctl,.compat_ioctl = testled_compat_ioctl,};

static struct miscdevice testled_misc = {.minor = MISC_DYNAMIC_MINOR,.name = "test-led",.fops = &testled_remap_ops,};/** Module housekeeping.*/

static int testled_probe(struct platform_device *pdev){int ret;struct device_node *led_node = pdev->dev.of_node;//enum of_gpio_flags work_flags;

ret = misc_register(&testled_misc);if(ret < 0){pr_err("testled_misc_register fails!!!\n");return ret;}

led_info.led1_pin = of_get_named_gpio(led_node, "led1-work", 0);if(!gpio_is_valid(led_info.led1_pin)){pr_err("led1 pin invaild: %d",led_info.led1_pin);ret = -ENODEV;goto probe_fail;}

ret = gpio_request(led_info.led1_pin, "led1_pin");if(ret < 0){pr_err("led1 pin request failed.");goto probe_fail;}

led_info.led2_pin = of_get_named_gpio(led_node, "led2-work", 0);if(!gpio_is_valid(led_info.led2_pin)){pr_err("led2 pin invaild: %d",led_info.led2_pin);ret = -ENODEV;goto probe_fail;}

ret = gpio_request(led_info.led2_pin, "led2_pin");if(ret < 0){pr_err("led2 pin request failed.");goto probe_fail;}
printk("led1 pin is: %d,led2 pin is: %d",led_info.led1_pin,led_info.led2_pin);return 0;

probe_fail:

return ret;}

static int testled_remove(struct platform_device *pdev){pr_err("testled_misc_remove!!!\n");misc_deregister(&testled_misc);return 0;}

static struct of_device_id testled_table[] = {{ .compatible = "test,leds",}, //Compatible node must match dts{ },};

static struct platform_driver testled_driver = {.probe = testled_probe,.remove = testled_remove,.driver = {.name = "test_leds",.owner = THIS_MODULE,.of_match_table = testled_table,}};

static int testled_init(void){int ret;ret = platform_driver_register(&testled_driver);if(ret < 0)pr_err("platform_register_driver fails!!!\n");pr_err("platform_register_driver succeeds :ret=%d!!!\n",ret);return ret;}



static void testled_cleanup(void){platform_driver_unregister(&testled_driver);}

module_init(testled_init);module_exit(testled_cleanup);

obj-$(CONFIG_GPIO_TEST_LED) += gpio-testled.o

config GPIO_TEST_LEDbool "select test leds"default y

CONFIG_GPIO_TEST_LED=y

/dev/test_leds 0666 system system

#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <fcntl.h>#include <linux/ioctl.h>
#define LEDCTRL_MAGIC 'k'#define LED1CTRL_ON_CMD _IO (LEDCTRL_MAGIC, 1)#define LED1CTRL_OFF_CMD _IO (LEDCTRL_MAGIC, 2)#define LED2CTRL_ON_CMD _IO (LEDCTRL_MAGIC, 3)#define LED2CTRL_OFF_CMD _IO (LEDCTRL_MAGIC, 4)

int main(){int i = 0;int dev_fd;dev_fd = open("/dev/test-led",O_RDWR | O_NONBLOCK);if ( dev_fd == -1 ) {printf("Cann't open file /dev/test-led\n");exit(1);}printf("Led1 on\n");ioctl (dev_fd, LED1CTRL_ON_CMD,0);getchar();ioctl (dev_fd, LED1CTRL_OFF_CMD,0);printf("led1 off\n");
printf("Led2 on\n");ioctl (dev_fd, LED2CTRL_ON_CMD,0);getchar();ioctl (dev_fd, LED2CTRL_OFF_CMD,0);printf("led2 off\n");
close(dev_fd);return 0;}

2）Android.mkLOCAL_PATH:= $(call my-dir)include $(CLEAR_VARS)

LOCAL_SRC_FILES:= \gpioleds_test.c

LOCAL_SHARED_LIBRARIES := \liblog \libc \libutils \libcrypto \libhardware \

LOCAL_MODULE := gpioleds_test

LOCAL_MODULE_TAGS :=

LOCAL_MODULE_PATH := $(LOCAL_PATH)

LOCAL_CFLAGS +=-D_FORTIFY_SOURCE=0

LOCAL_CFLAGS += -U_FORTIFY_SOURCE -D_FORTIFY_SOURCE=0

include $(BUILD_EXECUTABLE

mmm external/gpioleds_test/

Chmod 777 /data/user/gpioleds_test./ data/user/gpioleds_test