Hello Lucas, Thank you for the reply. > -----Original Message----- > From: Lucas Stach [mailto:l.stach@xxxxxxxxxxxxxx] > Sent: Wednesday, July 05, 2017 2:52 PM > To: Mayur Nande > Cc: barebox@xxxxxxxxxxxxxxxxxxx > Subject: Re: Earliest possible GPIO toggle on i.mx6 > > Am Mittwoch, den 05.07.2017, 12:41 +0000 schrieb Mayur Nande: > > Hello all, > > > > I have a question regarding the earliest possible GPIO toggle with > > barebox on imx6. We use boards with imx6 quad core processor (from > > Phytec). In our hardware design we have a push button controller which > > has a "KILL" pin attached to one of the GPIO pins on i.mx6. The > > requirement is that this pin should be set to 1 within 400 ms of power > > on. I tried setting this at various places in barebox with incremental > > improvements starting from the init script, board.c, lowlevel.c and > > then DCD/lowlevel.c combination. > > > > The best performance I got was by setting the iomux registers > > (IOMUXC_SW_MUX_CTL_PAD and IOMUXC_SW_PAD_CTL_PAD) in DCD > and the GPIO > > direction and value registers in lowlevel.c (since GPIO controller > > registers are not accessible with DCD). Even with this, I get the GPIO > > set in around 460-475ms at the best. I understand that some of the > > time here is used by the hardware for voltage regulation/crystal > > stabilization which probably we can't do anything about. > > If lowlevel.c is too late already, the only chance to make this work is setting > the DCD padctl to configure a pull-up/down to satisfy the KILL pin. Then in > the board file set up the GPIO and switch the padctl to neutral state. Ok, I will try this. > Still 400ms sound like a awfully long time to reach lowlevel init. What is your > boot source, i.e. where is the barebox binary stored? The bootsource is external 8GB SD/MMC card. Warm Regards, Mayur _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
