On Mon, Nov 26, 2012 at 2:02 PM, Jinqiang Zeng <jinqiangzeng@gmail.com> wrote:
first creat a device class,then register a device to the kernel. using the following functions: struct class *class_create(struct module *owner, char *name)； struct class_device *class_device_create(struct class *cls, struct class_device *parent, dev_t devt, struct device *device, char *fmt, ...)
2012/11/26 Manavendra Nath Manav <mnm.kernel@gmail.com>
On Sat, Nov 24, 2012 at 2:20 PM, Manavendra Nath Manav <mnm.kernel@gmail.com> wrote:
Hi RK
On Sat, Nov 24, 2012 at 2:03 PM, Manavendra Nath Manav <mnm.kernel@gmail.com> wrote:
I have written a simple UART serial driver in embedded Linux running busybox with mdev rules. I have provided .dev_name as "ttyC2C" in my driver code.
static struct uart_driver serial_omap_reg = { .owner = THIS_MODULE, .driver_name = "Omap-C2C-Serial", .dev_name = "ttyC2C", .nr = OMAP_MAX_HSUART_PORTS, .cons = NULL, };
However the node is getting created in
./sys/devices/platform/omap_c2c_uart.0/tty/ttyC2C0 ./sys/class/tty/ttyC2C0
/ # ls -l ./sys/class/tty/ttyC2C0 lrwxrwxrwx 1 root 0 0 Jan 1 00:14 ./sys/class/tty/ttyC2C0 -> ../../devices/platform/omap_c2c_uart.0/tty/ttyC2C0
/ # ls -l ./sys/devices/platform/omap_c2c_uart.0/tty/ttyC2C0 -r--r--r-- 1 root 0 4096 Jan 1 00:14 dev lrwxrwxrwx 1 root 0 0 Jan 1 00:14 device -> ../../../omap_c2c_uart.0 drwxr-xr-x 2 root 0 0 Jan 1 00:14 power lrwxrwxrwx 1 root 0 0 Jan 1 00:14 subsystem -> ../../../../../class/tty -rw-r--r-- 1 root 0 4096 Jan 1 00:14 uevent / #
The mdev rules for tty are:
tty 0:5 0666 tty.* 0:0 0620
How to get device node as /dev/ttyC2C ?
-- Manavendra Nath Manav
can you help me on following issue?
-- Manavendra Nath Manav
In "Essential Linux Device Drivers" book, it says that that the driver name in "struct platform_driver" and "struct uart_driver" should be same. I modified the code according but still /dev/ttyC2C node is not being populated.
-- Manavendra Nath Manav
When i add .major and .minor to the struct uart_driver and create the device node manually using "mknod" then the driver works fine. Why the kernel (3.4.0) is not able to create it automatically? -- Manavendra Nath Manav