On 05/18/2012 11:26 AM, Wolfgang Denk wrote:
Dear Tom Rini,
In message4FB674CD.8030502@ti.com you wrote:
But still, the kernel decided i2c probing is dangerous/unreliable, maybe we should follow, or at least allow boards to follow?
The kernel is in a very different situation - it is supposed to run on perfect hardware.
In U-Boot, we have to dead with green hardware that is in a completely unknown state, or with hardware that _might_ be broken in one way or another. For us tools doing low-level accesses are invaluable - even if they include the risk to hang a system.
Right. I'm not suggesting removing i2c probe, I'm just suggesting making it opt-out'able. For example, on the beaglebone I can make i2c probe work as expected. It's just requring that we toggle the I2C_CON enable bit for some reason in probe, but not when we are actually trying to write to a bad address. I'd like to just #undef CONFIG_CMD_I2C_PROBE for the board and be done with it. Otherwise it lists (nearly) every address which is useless.