Dear Marek Vasut, > Analyze and rework the PIO mode operation. The PIO mode operation > was unreliable on MX28, by analyzing the bus with LA, the checks > for when data were available or were to be sent were wrong. > > The PIO WRITE has to be completely reworked as it multiple problems. > The MX23 datasheet helped here, see comments in the code for details. > The problems boil down to: > - RUN bit in CTRL0 must be set after DATA register was written > - The PIO transfer must be 4 bytes long tops, otherwise use > clock stretching. > Both of these fixes are implemented. > > The PIO READ operation can only be done for up to four bytes as > we are unable to read out the data from the DATA register fast > enough. > > This patch also tries to document the investigation within the > code. > > Signed-off-by: Marek Vasut <marex@xxxxxxx> > Cc: Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> > Cc: Christoph Baumann <cb@xxxxxxx> > Cc: Fabio Estevam <r49496@xxxxxxxxxxxxx> > Cc: Shawn Guo <shawn.guo@xxxxxxxxxx> > Cc: Torsten Fleischer <to-fleischer@xxxxxxxxxxx> > Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx> Please discard that previous submission, looks like I'm still not at home on my new laptop and some of the email addresses got corrupted. This one shall be OK. I appologize for the double-post. Best regards, Marek Vasut -- 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
