Hi, > > From: Hubert Streidl <hubert.streidl@xxxxxxxxxxxx> > > > > By default the PMIC DA9063 2-wire interface is SMBus compliant. This > > means the PMIC will automatically reset the interface when the clock > > signal ceases for more than the SMBus timeout of 35 ms. > > > > If the I2C driver / device is not capable of creating atomic I2C > > transactions, a context change can cause a ceasing of the clock signal. > > This can happen if for example a real-time thread is scheduled. Then > > the DA9063 in SMBus mode will reset the 2-wire interface. Subsequently > > a write message could end up in the wrong register. This could cause > > unpredictable system behavior. > > > > The DA9063 PMIC also supports an I2C compliant mode for the 2-wire > > interface. This mode does not reset the interface when the clock > > signal ceases. Thus the problem depicted above does not occur. > > > > This patch tests for the bus functionality "I2C_FUNC_I2C". It can > > reasonably be assumed that the bus cannot obey SMBus timings if this > > functionality is set. SMBus commands most probably are emulated in > > this case which is prone to the latency issue described above. > > > > This patch enables the I2C bus mode if I2C_FUNC_I2C is set or > > otherwise enables the SMBus mode for a native SMBus controller which > > doesn't have I2C_FUNC_I2C set. > > > > Signed-off-by: Hubert Streidl <hubert.streidl@xxxxxxxxxxxx> > > Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx> > > Thanks for your efforts. Looks sensible to me, so: > > Reviewed-by: Adam Thomson <Adam.Thomson.Opensource@xxxxxxxxxxx> Is the patch already on the way upstream? Is https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/log/?h=for-mfd-next the right place to watch for mainlining progress? Thanks, Mark
