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frank-zago / ch341-i2c-spi-gpio

WinChipHead CH341 linux driver for I2C, SPI and GPIO mode
GNU General Public License v2.0
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udev for SPI #26

Open jp-bennett opened 8 months ago

jp-bennett commented 8 months ago

I'm trying to put together udev rules for firing up an SPI device automatically on plug. I think there's an issue, that the ch341-spi driver doesn't actually expose what SPI number the USB has grabbed. So, on most systems, that will be "/sys/class/spi_master/spi0" but if the system has an existing SPI bus, I suspect the CH341 may become SPI1 instead. Would it be possible to set a udev ENV value that identifies which SPI bus number the driver is using? Or is there an easier solution?

frank-zago commented 8 months ago

This is not managed by the driver, but the spi subsystem. Run "udevadm monitor", plug the device, and see if you get what you need.

mjsir911 commented 6 months ago

https://github.com/rogerjames99/spi-ch341-usb & https://github.com/rogerjames99/spi-ch341-usb/blob/master/udev/90-ch341-spi.rules seems to work somewhat.

After copying that file to /etc/udev/rules.d/, all I need to do to set up the device is:

echo spidev 0 | sudo tee /sys/class/spi_master/spi1/new_device