Tool/software:
Hello,
We’ve encountered a strange issue with I2C—initially on our custom boards (with our custom builds), and later also on the SK-AM64B board when using default images. The problem occurs in all tested U-Boot versions 2024.04 and 2025.01, but is not present in 2023.04.
The observed behavior is as follows:
U-Boot 2023.04-ti-g836606420854 (May 09 2024 - 05:42:45 +0000) SoC: AM64X SR2.0 HS-FS Model: Texas Instruments AM642 SK Board: AM64B-SKEVM rev A DRAM: 2 GiB Core: 90 devices, 33 uclasses, devicetree: separate NAND: 0 MiB MMC: mmc@fa00000: 1 Loading Environment from nowhere... OK In: serial@2800000 Out: serial@2800000 Err: serial@2800000 Net: eth0: ethernet@8000000port@1, eth1: ethernet@8000000port@2 Hit any key to stop autoboot: 0 => => i2c probe Valid chip addresses: 30 51 => i2c bus Bus 0: i2c@20000000 (active 0) 30: pmic@30, offset len 1, flags 0 51: generic_51, offset len 1, flags 0 Bus 1: i2c@20010000 70: gpio@70, offset len 1, flags 0 =>
but with u-boot 2025.01:
U-Boot 2025.01-00406-gcd91d7360181 (Mar 25 2025 - 16:14:37 +0000) SoC: AM64X SR2.0 HS-FS Model: Texas Instruments AM642 SK Board: AM64B-SKEVM rev A DRAM: 2 GiB Core: 95 devices, 33 uclasses, devicetree: separate MMC: mmc@fa00000: 1 Loading Environment from nowhere... OK In: serial@2800000 Out: serial@2800000 Err: serial@2800000 Failed to probe prueth driver Net: eth0: ethernet@8000000port@1, eth1: ethernet@8000000port@2 Hit any key to stop autoboot: 0 => i2c probe ti_sci system-controller@44043000: Message not acknowledged ti-sci-pm-domains power-controller: ti_sci_power_domain_on: get_device(102) failed (-19) Default I2C bus 0 not found => i2c bus Bus 0: i2c@20000000 Bus 1: i2c@20010000 (active 1) 70: gpio@70, offset len 1, flags 0 =>
I understand that the default image initially uses the EVM board device tree, and after board detection is completed, it switches to the SK board device tree.
We’re seeing a similar issue on our custom boards. The problem appears to be related to which default device tree is used before board detection takes place. We have two board revisions: r0 and r1.
If we set the r0 device tree as the default, then I2C0 works on r0 boards but fails on r1 boards. Conversely, if we set the r1 device tree as the default, I2C0 works on r1 boards but fails on r0 boards.
