When trying the driver on a Laser 128, the install logic identified the machine as a IIe (reasonable) but subsequent access to the device was inconsistent - reads gave bad data but was seeing something increment once a minute.
On possibility is that the driver's IIe path doesn't work at all with the IIc System Clock device. This would suggest making a dedicated IIc System Clock version of the driver, or adding Laser 128 detection to the IIc path.
When trying the driver on a Laser 128, the install logic identified the machine as a IIe (reasonable) but subsequent access to the device was inconsistent - reads gave bad data but was seeing something increment once a minute.
On possibility is that the driver's IIe path doesn't work at all with the IIc System Clock device. This would suggest making a dedicated IIc System Clock version of the driver, or adding Laser 128 detection to the IIc path.