gutelfuldead / template_dev_driver

Template kernel /dev character driver

Character Driver /dev Kernel Module Example

This driver allows controlling of the ip core through,

1. devicetree
2. /sys/device/virtual
3. ioctls

The driver will be mounted as

/dev/templateDriver_0x<fpga mmap address>

Control through /sys/device/virtual

User can read and write registers and bit fields through the virtual sysfs directory. For example

$ pwd
/sys/devices/virtual/templateDriver/templateDriver_0x43c00000/ip_registers
$ ls -la
total 0
drwxr-xr-x    2 root     root             0 Jan  1 00:14 .
drwxr-xr-x    4 root     root             0 Jan  1 00:00 ..
-r--r--r--    1 root     root          4096 Jan  1 00:14 fpga_addr
--w-------    1 root     root          4096 Jan  1 00:14 reset
-rw-r--r--    1 root     root          4096 Jan  1 00:14 template_dts_entry
$ cat fpga_addr
0x43c00000
$ echo 1 > reset

ioctl commands

All ioctl commands can be viewed in template-driver.h. Example code for using the ioctls can be seen in apps/template-test.c.

Device Tree Doc

Template Driver Device Tree Doc

Required properties: - compatible: Should be "usr,template-core" - interrupt-names: Should be "interrupt" - interrupt-parent: Should be <&intc> - interrupts: Should contain interrupts lines. - reg: Should contain registers location and length. - usr,template-dts-entry: used to test grabbing data from devicetree in kmod

Example:

template-core0: template-core@43c00000 {
        compatible = "usr,template-core";
        interrupt-names = "interrupt";
        interrupt-parent = <&intc>;
        interrupts = <0 29 4>;
        reg = <0x43c00000 0x10000>;
        usr,template-dts-entry = <400>;
};