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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 10 months ago

jp-bennett commented 10 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 10 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 8 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