Hi, Any further comments on this? Regards, Harini On Fri, Dec 12, 2014 at 9:48 AM, Harini Katakam <harinik@xxxxxxxxxx> wrote: > This series implements workarounds for some bugs in Cadence I2C controller. > > - The I2C controller when configured in Master Mode generates invalid read transactions. > When HOLD bit is set and HW timeout occurs, invalid read transactions are > generated on the bus. This will affect repeated start conditions and large > data transfer condtions where transfer_size_register has to be updated again. > The transfer size register rolls over erroneously under these conditions. > Note that this HW timeout cannot be disabled even if the interrupt is unused. > Errata link: http://www.xilinx.com/support/answers/61664.html > > -The I2C controller when configured in Master Mode is the missing master completion interrupt. > During repeated start condition, the driver has to set the HOLD bit for > the set of transfer being done together and clear the HOLD bit just before > the last transfer. But the controller does not indicate completion when > a read/receive transfer is done if the HOLD bit is set. This affects > all repeated start operation where a read/receive transfer is not > the last transfer. > Errata link: http://www.xilinx.com/support/answers/61665.html > > To address the above, > - >252 byte transfers are done such that transfer_size never becomes zero. > - timeout register value is increased (even though the driver doesn't use this). > - A check is performed to see if there is any transfer following a > read/receive transfer in the set of messages using repeated start. > An error is returned in such cases because if we proceed, completion interrupt > is never obtained and a SW timeout will occur. > > Harini Katakam (2): > i2c: cadence: Handle > 252 byte transfers > i2c: cadence: Check for errata condition involving master receive > > drivers/i2c/busses/i2c-cadence.c | 185 +++++++++++++++++++++++--------------- > 1 file changed, 112 insertions(+), 73 deletions(-) > > -- > 1.7.9.5 > -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
