Hello Michal, On Thu, Nov 22, 2018 at 04:46:39PM +0000, Vokáč Michal wrote: > On 22.11.2018 17:23, Uwe Kleine-König wrote: > > On Thu, Nov 22, 2018 at 03:42:14PM +0000, Vokáč Michal wrote: > >> On 16.11.2018 09:25, Uwe Kleine-König wrote: > >>> On Fri, Nov 16, 2018 at 08:34:30AM +0100, Lothar Waßmann wrote: > >>>> No. You can disable the output driver via pinctrl, so that only the > >>>> selected pull-up/down is relevant. The pin function and GPIO register > >>>> settings don't matter at all in this case. > >> > >> Lothar, please can you be more specific how would you do that? IFAIK the > >> pull-up/down internal resistors have effect only if the pin is configured > >> as GPIO *input* (on i.MX6 at least). See the TRM, 29.4.2.2 Output driver: > >> > >> "Internal pull-up, pull-down resistors, and pad keeper are disabled in > >> output mode." This would mean you'd have to rely on an external pull up for your use case. I wouldn't be surprised however if DSE=0 wouldn't count as "output mode". Given the reliability of NXP documentation I wouldn't bet neither on one nor the other possibility. > > So I'd expect this to really work on i.MX6 but not the earlier SoCs > > without a gpio specifier. > > Maybe you would expect it to work but I already tested and measured > that weeks ago ;) It did not work. Which pin/gpio do we talk about? Which i.MX6 variant did you test this on? (Assuming i.MX6D or i.MX6Q and PAD_DISP0_DATA09, did you try setting IOMUXC_SW_MUX_CTL_PAD_DISP0_DATA09 (0x020E0194) = 0x00000005 IOMUXC_SW_PAD_CTL_PAD_DISP0_DATA09 (0x020E04A8) = 0x0000b080 and then play with GPIO 4.30 direction and output value?) Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
