Verdin iMX8MM: 1v8 regulator on pca9450 initialization occasionally times out

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I2C Timeout Issue with PCA9450 Regulators on Verdin iMX8M Mini

I understand you’re experiencing intermittent I2C timeout issues with the PCA9450 regulators when upgrading from BSP Kirkstone 6.3.0 to Scarthgap 7.4.0. This is a known issue that has been reported and addressed.

Known Issue and Resolution

Based on the community discussion, there were indeed I2C-related issues with the Verdin iMX8M Mini that affected regulator initialization (1). The problem you’re describing with intermittent I2C timeouts causing regulator initialization failures has been identified and fixed in BSP 6.6.0 and later versions (1).

Power Management Context

The Verdin iMX8M Mini uses the PWR_1V8_MOCI signal to power peripherals on the carrier board, which can deliver up to 250mA (2). When the module is in an off-state, this signal is de-asserted, and the system can be turned on by pressing the power button (2).

Recommendations

  1. Verify BSP Version: Ensure you’re using the correct BSP version. The I2C timeout issues with regulators were resolved in BSP 6.6.0 (1).

  2. Check I2C Configuration: Consider testing without the “single-master” property in your I2C device tree configuration, as this has been identified as a potential contributing factor in similar I2C timeout issues (3).

  3. Build Configuration: When building your custom Yocto image, make sure you’re following the proper build process outlined in the documentation (4). The build requires setting the correct MACHINE variable for verdin-imx8mm and accepting the NXP EULA if needed (4).

Next Steps

Since this appears to be a regression between BSP versions, I recommend:

  • Testing with a known working BSP version (6.6.0 or later) to confirm the fix addresses your issue
  • Reviewing your custom carrier board I2C configuration for any conflicts
  • Checking if your custom modifications might be interfering with the I2C driver improvements

The issue you’re experiencing with USB overcurrent protection being triggered due to PWR_1V8_MOCI initialization failures is consistent with the known I2C timeout problems that were resolved in later BSP releases.

Best regards, Toradex AI Assistant.

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