添加backlight驱动模块框架

Makefile

@@ -3,7 +3,7 @@ CROSS_COMPILE=arm-poky-linux-gnueabi-
 #也可以同时编译多个模块  obj-m += export_symbol.o export_symbol1.o export_symbol2.o
 obj-m := coral.o
 
-coral-objs := main.o led.o light_ring.o ssegment.o ec_version.o buzzer.o fan.o writeprotect.o myname.o cash_drawers.o batteryled.o watchdog.o power.o switches.o
+coral-objs := main.o led.o light_ring.o ssegment.o ec_version.o buzzer.o fan.o writeprotect.o myname.o cash_drawers.o batteryled.o watchdog.o power.o switches.o backlight.o
 
 KERNELDIR := /lib/modules/$(shell uname -r)/build
 ccflags-y += -I./include

backlight.c

@@ -0,0 +1,80 @@
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/uaccess.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/i2c.h>
+#include <linux/acpi.h>
+#include <linux/interrupt.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+#include <linux/poll.h>
+#include <linux/mutex.h>
+#include <linux/delay.h>
+#include "light_ring.h"
+
+
+extern struct kobject *vfiec_kobj;
+static struct kobject *backlight_kobj = NULL;
+
+
+/* ==================== mode ==================== */
+static ssize_t brightness_show(struct kobject *kobj, struct kobj_attribute *attr,
+                         char *buf)
+{
+    static int count = 0;
+    count++;
+
+    return sprintf(buf, "mode_show count=%d\n", count);
+}
+
+static ssize_t brightness_store(struct kobject *kobj, struct kobj_attribute *attr,
+                          const char *buf, size_t count)
+{
+    printk("mode_store kernel rev:%s\n", buf);
+    return count;
+}
+
+static struct kobj_attribute brightness =
+    __ATTR(brightness, 0644, brightness_show, brightness_store);
+
+/* ==================== 属性组 ==================== */
+static struct attribute *backlight_attrs[] = {
+    &brightness.attr,
+    NULL,
+};
+
+static struct attribute_group backlight_attr_group = {
+    .attrs = backlight_attrs,
+};
+
+int backlight_init(void)
+{
+    int ret;
+        /* 创建 /sys/kernel/vfiec/lightring */
+    backlight_kobj = kobject_create_and_add("backlight", vfiec_kobj);
+    if (!backlight_kobj)
+    {
+        ret = -ENOMEM;
+    }
+
+    /* 创建属性文件 */
+    ret = sysfs_create_group(backlight_kobj, &backlight_attr_group);
+    if (ret)
+    {
+        pr_err("Faibacklight to create sysfs group: %d\n", ret);
+    }
+
+    return ret;
+}
+
+void backlight_exit(void)
+{
+    sysfs_remove_group(backlight_kobj, &backlight_attr_group);
+    kobject_put(backlight_kobj);
+}
+

backlight.h

@@ -0,0 +1,7 @@
+#ifndef __BACKLIGHT_H__
+#define __BACKLIGHT_H__
+
+int backlight_init(void);
+void backlight_exit(void);
+
+#endif

main.c

@@ -29,6 +29,7 @@
 #include "watchdog.h"
 #include "power.h"
 #include "switches.h"
+#include "backlight.h"
 
 struct kobject *vfiec_kobj = NULL;
 
@@ -42,6 +43,7 @@ static int __init all_driver_init(void)
         ret = -ENOMEM;
     }
 
+    backlight_init();
     switches_init();
     power_init();
     watchdog_init();
@@ -62,6 +64,7 @@ static int __init all_driver_init(void)
 
 static void __exit all_driver_exit(void)
 {
+    backlight_exit();
     switches_exit();
     power_exit();
     watchdog_exit();