Hi Marek, Am Montag, den 15.07.2013, 04:05 +0200 schrieb Marek Vasut: > Hi, > > > 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: Fabio Estevam <r49496@xxxxxxxxxxxxx> > > Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx> > > Cc: Shawn Guo <shawn.guo@xxxxxxxxxx> > > Cc: Wolfram Sang <wsa@xxxxxxxxxxxxx> > > Cc: <to-fleischer@xxxxxxxxxxx> > > I so far got confirmation from ALexandre this patch works. Can someone else test > it please? I'd like to roll out a final version to close this issue. > Sorry, I wasn't able to test it until now. I now have the respective hardware at my desk again, so I'll get you a report by latest day after tomorrow. I'll post some comments to the patch itself in the meantime. > One question remain though -- shall we have the PIO as an experimental feature > and disable it by default OR not ? > > Thanks! > > Best regards, > Marek Vasut -- Pengutronix e.K. | Lucas Stach | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-5076 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- 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
