add example for linux device

Signed-off-by: Manuel Traut <manut@linutronix.de>

2 files changed, 125 insertions, 2 deletions

diff --git a/kernel-devel/linux-device/my_example.patch b/kernel-devel/linux-device/my_example.patch
new file mode 100644
index 0000000..6e66c14
--- /dev/null
+++ b/kernel-devel/linux-device/my_example.patch
@@ -0,0 +1,122 @@
+diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
+index c779509..43ae42d 100644
+--- a/drivers/misc/Kconfig
++++ b/drivers/misc/Kconfig
+@@ -51,6 +51,11 @@ config AD525X_DPOT_SPI
+ 	  To compile this driver as a module, choose M here: the
+ 	  module will be called ad525x_dpot-spi.
+ 
++config MY
++	tristate "my driver example"
++	help
++	  just an example for a simple driver dummy
++
+ config ATMEL_PWM
+ 	tristate "Atmel AT32/AT91 PWM support"
+ 	depends on HAVE_CLK
+diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
+index 3e1d801..614a3a2 100644
+--- a/drivers/misc/Makefile
++++ b/drivers/misc/Makefile
+@@ -8,6 +8,7 @@ obj-$(CONFIG_AD525X_DPOT_I2C)	+= ad525x_dpot-i2c.o
+ obj-$(CONFIG_AD525X_DPOT_SPI)	+= ad525x_dpot-spi.o
+ obj-$(CONFIG_INTEL_MID_PTI)	+= pti.o
+ obj-$(CONFIG_ATMEL_PWM)		+= atmel_pwm.o
++obj-$(CONFIG_MY)		+= my.o
+ obj-$(CONFIG_ATMEL_SSC)		+= atmel-ssc.o
+ obj-$(CONFIG_ATMEL_TCLIB)	+= atmel_tclib.o
+ obj-$(CONFIG_BMP085)		+= bmp085.o
+diff --git a/drivers/misc/my.c b/drivers/misc/my.c
+new file mode 100644
+index 0000000..49759ad
+--- /dev/null
++++ b/drivers/misc/my.c
+@@ -0,0 +1,88 @@
++#include <linux/init.h>
++#include <linux/device.h>
++#include <linux/module.h>
++#include <linux/kernel.h>
++#include <linux/slab.h>
++#include <linux/types.h>
++
++#define DEVICE_NAME "mydev"
++static struct class *dummy;
++
++static ssize_t my_show_ro(struct device *my_dev,
++	struct device_attribute *my_attr, char *buf)
++{
++	return scnprintf(buf, PAGE_SIZE, "%s\n", "show some cool value");
++}
++
++static ssize_t my_show_rw(struct device *my_dev,
++	struct device_attribute *my_attr, char *buf)
++{
++	return scnprintf(buf, PAGE_SIZE, "%s\n", "write value and look at dmesg");
++}
++
++static ssize_t my_store_rw(struct device *my_dev,
++	struct device_attribute *my_attr, const char *buf, size_t count)
++{
++	printk(KERN_ERR "my_store_rw: %s", buf);
++	return count;
++}
++
++static DEVICE_ATTR(ro, S_IRUGO, my_show_ro, NULL);
++static DEVICE_ATTR(rw, S_IWUSR | S_IRUGO, my_show_rw, my_store_rw);
++
++static struct attribute *my_dev_attrs[] = {
++	&dev_attr_ro.attr,
++	&dev_attr_rw.attr,
++	NULL,
++};
++
++static struct attribute_group my_dev_attr_group = {
++	.attrs = my_dev_attrs,
++};
++
++static const struct attribute_group *my_dev_attr_groups[] = {
++	&my_dev_attr_group,
++	NULL,
++};
++
++static struct device my_dev = {
++	.init_name = "mydevice",
++};
++
++static int __init my_init(void)
++{
++	int ret = 0;
++
++	dummy = class_create(THIS_MODULE, "dummy");
++	device_initialize(&my_dev);
++	my_dev.groups = my_dev_attr_groups;
++	my_dev.parent = NULL;
++	my_dev.bus = NULL;
++	my_dev.class = dummy;
++	ret = device_add(&my_dev);
++	if (ret) {
++		printk(KERN_ERR "my: device register failed\n");
++		goto failed_dev;
++	}
++	return 0;
++
++failed_dev:
++	device_del(&my_dev);
++	class_destroy(dummy);
++
++	return ret;
++}
++
++static void __exit my_exit(void)
++{
++	device_del(&my_dev);
++	class_destroy(dummy);
++}
++
++MODULE_AUTHOR("Manuel Traut");
++MODULE_DESCRIPTION("just my example");
++MODULE_VERSION("20120412");
++MODULE_LICENSE("GPL");
++
++module_init(my_init);
++module_exit(my_exit);
diff --git a/kernel-devel/linux-device/pres_linux-device_en.tex b/kernel-devel/linux-device/pres_linux-device_en.tex
index 1b87bc7..c234b36 100644
--- a/kernel-devel/linux-device/pres_linux-device_en.tex
+++ b/kernel-devel/linux-device/pres_linux-device_en.tex
@@ -174,6 +174,7 @@ these fields should be initialized before calling the register function:
 \item parent
 \item name
 \item bus
+\item class
 \end{itemize}
 \end{frame}
 
@@ -203,8 +204,8 @@ Attributes can be exported to sysfs by the device driver.
 \begin{lstlisting}[frame=trBL]
 my.c:
 ...
-static DEVICE_ATTR(ro, 0444, my_show_ro, NULL);
-static DEVICE_ATTR(rw, 0644, my_show_rw, my_store_rw);
+static DEVICE_ATTR(ro_example, 0444, my_show_ro, NULL);
+static DEVICE_ATTR(rw_example, 0644, my_show_rw, my_store_rw);
 
 static struct attribute *my_dev_attrs[] = {
   &dev_attr_ro.attr,