Hello!
Which driver version are you using? This helps me verify what I should be seeing in your logs. 1.12.4?
Has anyone been able to successfully use the MM6108 at 1.8V?
Yes! We have had customers successfully bring up the MM6108 with a 1.8V VDDIO. I don’t believe this will be your problem.
mmc2: error -110 whilst initialising SDIO card
A -110 errno on this platform translates to -ETIMEDOUT. With the timing of the errors in relation to the registration of the host controller driver. I’m suspicious the MM6108 isn’t booting correctly or is possibly held in reset. Are you able to capture the reset line - pin 23 - of the Alfa module?
the SDIO data lines were still static.
Were these traces captured with a Logic Analyzer of fairly high sample rate (>250MS/s)? If so, are you able to export and share the Logic files (.sal) of the early init sequence?
When compared to Mmc1: Timeout waiting for hardware interrupt it doesn’t look like the driver initialisation is getting far enough in the process to send data - I’m not seeing any of the Morse Micro info logs for example. This lack of logging could of course be due to DEBUG not being enabled, printk verbosity, or dynamic debug parameters - if enabled.
More logging would generally be helpful here, including within the mmc host controller driver. Are you able to turn the log level up?