Re: [PATCH v2] i2c: mv64xxx: Add bus error recovery

[Mark Tomlinson]

On Tue, 2020-08-25 at 11:26 +0200, Wolfram Sang wrote:
> On Tue, Aug 25, 2020 at 10:52:54AM +1200, Mark Tomlinson wrote:
> 
> This adds i2c bus recovery to the mv64xxx driver.
> 
> Implement bus recovery to recover from SCL/SDA stuck low.
> 
> This uses the generic recovery function, setting the clock/data lines as
> GPIO pins, and sending 9 clocks to try and recover the bus.
> 
> Signed-off-by: Mark Tomlinson <mark.tomlinson@xxxxxxxxxxxxxxxxxxx>
> ---
> Changes in v2:
>  - use generic GPIO recovery function.
> 
> Thank you for doing that! Glad to see the new helper function works for
> you as well. The initialization code is all well, but I wonder about the
> use of i2c_recover_bus(). Recovery should be tried only if it is
> detected that SDA is pulled low when the bus should be free. So, you
> shouldn't call i2c_recover_bus() in unconditionally in probe(). Can your
> HW detect if SDA is stuck low?

We actually don't need this call, as the bootloader checks and leaves the
bus in a good state. I will remove this from the patch.