X-Git-Url: http://git.cascardo.eti.br/?p=cascardo%2Fkernel%2Fsamples%2Fchar2%2F.git;a=blobdiff_plain;f=hellochar.c;h=940bfeb837b7ca7ddcbd43aebaa496845a871ae2;hp=a8473920d829a63f383554973541c290bbd54649;hb=HEAD;hpb=10c2d46c6408882fd1eec0b1d59a5dec086040c2

diff --git a/hellochar.c b/hellochar.c
index a847392..940bfeb 100644
--- a/hellochar.c
+++ b/hellochar.c
@@ -25,6 +25,7 @@
 #include <linux/circ_buf.h>
 #include <linux/sched.h>
 #include <linux/completion.h>
+#include <linux/device.h>
 
 MODULE_LICENSE("GPL");
 
@@ -116,6 +117,21 @@ static const struct file_operations hello_fops = {
 	.write = hello_write,
 };
 
+static ssize_t hello_len_show(struct device *dev, struct device_attribute *attr,
+	char *buffer)
+{
+	size_t len = CIRC_CNT(hello->head, hello->tail, MAXLEN);
+	return sprintf(buffer, "%d\n", len);
+}
+
+static const struct device_attribute hello_len_attr = {
+	.attr = { .name = "len", .mode = 0444, },
+	.show = hello_len_show,
+};
+
+static struct class *hello_class;
+static struct device *hello_dev;
+
 static int __init ch_init(void)
 {
 	int r = 0;
@@ -125,11 +141,24 @@ static int __init ch_init(void)
 		r = -ENOMEM;
 		goto out;
 	}
+	hello_class = class_create(THIS_MODULE, "hello");
+	if (IS_ERR(hello_class)) {
+		r = PTR_ERR(hello_class);
+		goto class_out;
+	}
 	memcpy(hello->buf, default_greeting, sizeof(default_greeting));
 	hello->head = sizeof(default_greeting);
 	r = alloc_chrdev_region(&devnum, 0, 256, "hello");
 	if (r)
 		goto reg_out;
+	hello_dev = device_create(hello_class, NULL, devnum, NULL, "hello");
+	if (!hello_dev) {
+		r = -ENODEV;
+		goto dev_out;
+	}
+	r = device_create_file(hello_dev, &hello_len_attr);
+	if (r)
+		goto file_out;
 	dev = cdev_alloc();
 	if (!dev) {
 		r = -ENOMEM;
@@ -143,8 +172,14 @@ static int __init ch_init(void)
 add_out:
 	kfree(dev);
 cdev_out:
+	device_remove_file(hello_dev, &hello_len_attr);
+file_out:
+	device_destroy(hello_class, devnum);
+dev_out:
 	unregister_chrdev_region(devnum, 256);
 reg_out:
+	class_destroy(hello_class);
+class_out:
 	kfree(hello);
 out:
 	return r;
@@ -153,8 +188,11 @@ out:
 static void __exit ch_exit(void)
 {
 	cdev_del(dev);
+	device_remove_file(hello_dev, &hello_len_attr);
+	device_destroy(hello_class, devnum);
 	unregister_chrdev_region(devnum, 256);
 	kfree(hello->buf);
+	class_destroy(hello_class);
 }
 
 module_init(ch_init);