[U-Boot] [RFC] Make i2c probe opt-outable?
Tom Rini
trini at ti.com
Fri May 18 20:43:19 CEST 2012
On 05/18/2012 11:26 AM, Wolfgang Denk wrote:
> Dear Tom Rini,
>
> In message<4FB674CD.8030502 at 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.
--
Tom
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