add device class attributes (9.6)week-4

1 files changed, 36 insertions, 8 deletions

diff --git a/driver/main.c b/driver/main.c
index 2676c9a..92ff9aa 100644
--- a/driver/main.c
+++ b/driver/main.c
@@ -1,3 +1,4 @@
+// #include <linux/cdev.h>
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/module.h>
@@ -6,7 +7,10 @@
 #include "main.h"
 #include "platform.h"
 
-struct class* class;
+// struct cdev *cdev;
+struct device *dev;
+struct class *class;
+dev_t node = 0; // do not register /dev/lork
 
 static int mod_init(void) {
 	int err;
@@ -15,22 +19,43 @@ static int mod_init(void) {
 	class = class_create("lork");
 	if (IS_ERR_OR_NULL(class)) {
 		err = PTR_ERR(class);
-		printk(KERN_ERR "class_create error %d\n", err);
 		goto free_class;
 	}
 
+	// create device (required for device attributes under /sys/class)
+	dev = device_create(class, NULL, node, NULL, "lork");
+	if (IS_ERR_OR_NULL(dev)) {
+		err = PTR_ERR(dev);
+		goto free_device;
+	}
+
 	// create platform driver
 	err = platform_driver_register(&lork_driver);
-	if (err) goto return_err;
+	if (err) goto free_platform_driver;
 
-	// create attribute under /sys/bus/platform/drivers/gpio-extern
-	err = driver_create_file(&lork_driver.driver, &attr);
-	if (err) goto return_err;
+	// create driver attribute under /sys/bus/platform/drivers/gpio-extern
+	err = driver_create_file(&lork_driver.driver, &drv_attr_int);
+	if (err) goto free_drv_attr_int;
+
+	// create device attributes under /sys/class
+	err = device_create_file(dev, &dev_attr_int);
+	if (err) goto free_dev_attr_int;
+	err = device_create_file(dev, &dev_attr_str);
+	if (err) goto free_dev_attr_str;
 
 	printk("%s() OK\n", __PRETTY_FUNCTION__);
 	return 0;
 
-return_err:
+free_dev_attr_str:
+	device_remove_file(dev, &dev_attr_str);
+free_dev_attr_int:
+	device_remove_file(dev, &dev_attr_int);
+free_drv_attr_int:
+	driver_remove_file(&lork_driver.driver, &drv_attr_int);
+free_platform_driver:
+	platform_driver_unregister(&lork_driver);
+free_device:
+	device_destroy(class, node);
 free_class:
 	class_destroy(class);
 	printk("%s() -> %d\n", __PRETTY_FUNCTION__, err);
@@ -38,8 +63,11 @@ free_class:
 }
 
 static void mod_exit(void) {
-	driver_remove_file(&lork_driver.driver, &attr);
+	device_remove_file(dev, &dev_attr_str);
+	device_remove_file(dev, &dev_attr_int);
+	driver_remove_file(&lork_driver.driver, &drv_attr_int);
 	platform_driver_unregister(&lork_driver);
+	device_destroy(class, node);
 	class_destroy(class);
 	printk("%s()\n", __PRETTY_FUNCTION__);
 }