CH341 Driver for Synology DSM 7

The ch431.c source is copied from the Linux source tree:

https://github.com/torvalds/linux/blob/f2950b78547ffb8475297ada6b92bc2d774d5461/drivers/usb/serial/ch341.c

This is the newest version that compiles and works, between v4.10-rc3 and v4.10-rc4. I have only tested on my RS1221+.

Build

The Synology Package build process requires root for some weird reason I don't quiet understand, so you might want do this in a virtual machine to avoid messing with your own environment.

1. Setup the build environment.

Please refer to this and this document.

After installing the toolchian, get yourself root for the whole process.

sudo su

All remaining steps assume that you are in the root shell.

2. Clone the source.

Assuming your toolkit is located at /toolkit as described in the document above, change it if yours not.

mkdir -p /toolkit/source
cd /toolkit/source
git clone https://github.com/chenzhuoyu/dsm7-ch341 ch341

The directory name MUST be ch341, NOT dsm7-ch341, and it MUST in directory /toolkit/source.

3. Build the driver.

rm -vrf /toolkit/build_env/ds.v1000-7.0/source  # clean up previous build products
/toolkit/pkgscripts-ng/PkgCreate.py -p v1000 ch341

Replace the v1000 with your actual platform. You can find out which platform your NAS is using on this page.

If successful, the build product should be at /toolkit/build_env/ds.v1000-7.0/source/ch341/ch341.ko. Again, replace v1000 with your actual platform.

4. Load the driver into kernel.

Manage to copy the ch341.ko to the /lib/modules directory on your NAS.

For example, you can scp it from your build environment to the /tmp directory on your NAS, and execute sudo mv /tmp/ch341.ko /lib/modules on your NAS to move it into place.

Once the file is in place, execute the following commands on your NAS:

sudo modprobe usbserial
sudo insmod /lib/modules/ch341.ko

And voilà, you got a working CH341 driver.

Automatically load at boot

Please ensure your driver works before rebooting or performing any of the following steps, otherwise your NAS might not be able to boot again !

All the steps below should executed on your NAS. Requires root access.

Make sure your driver is in /lib/modules.
Create depmod as a symlink to kmod.

DSM 7 does not ship with depmod, so we need to create one manually.

sudo ln -s /usr/bin/kmod /sbin/depmod

sudo echo 'ch341:' >> /lib/modules/modules.dep
sudo depmod

Ignore any warnings the depmod command might generate.

Create a .conf file in /lib/modules-load.d with content:

File name is irrelevant, as long as it has the .conf extension, but conventionally it should be 70-usb-serial.conf.

usbserial
ch341

Reboot.

After a successful reboot, you can use lsmod to ensure your driver was loaded.

chenzhuoyu / dsm7-ch341