Invert SD card detection logic at U-boot

[nirmalluhana]

Hello,

Release: Yocto-Sumo (4.14.78_1.0.0_GA)

Board: i.MX8MQ based custom board

We designed iMX8MQ based custom board with different SD card socket than the EVK has. The card detection logic is inverted on our SD card socket.
Hence, we are not getting the U-boot logs as we tried to boot our custom board using the SD card config. We suspect that we need to change the card detection logic in U-boot and kernel level. 

We changed cd-detection logic using a cd-inverted macro at the U-boot level. Still, we are not able to boot the board.

Can anyone suggest which changes we missed to correct the SD card detection logic at the U-boot level?

Best regards,

Nirmal

[igorpadykov · Accepted solution]

Hi Nirmal

cd logic can be internal and using gpio as described in sect.3.3.6 Device Tree Binding

attached Linux Manual. If using gpio, it can be changed in sd/emmc driver source.

If internal - using CDPL bit in PRES_STATE (Present State) register of uSDHC module.

Regarding "cd-inverted macro at the U-boot" suggest to post it on uboot mail list

U-Boot Info Page 

Please note that for boot ROM uses pinmuxing described in sect.6.1.5.2.4 IOMUX configuration for SD/MMC

i.MX8MQ Reference Manual and cd polarity can not be changed.

Best regards
igor
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