Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx> wrote: > Hello Michal, > > On Fri, Nov 23, 2018 at 03:15:11PM +0000, Vokáč Michal wrote: > > On 22.11.2018 20:03, Uwe Kleine-König wrote: > > > On Thu, Nov 22, 2018 at 04:46:39PM +0000, Vokáč Michal wrote: > > >> On 22.11.2018 17:23, Uwe Kleine-König wrote: > > >>> 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?) > > > > My test setup is as follows: > > - SoC is i.MX6DL or i.MX6S - I have three board variants in total. > > - Pin used for PWM/GPIO is PAD_GPIO9. > > - The pin is not connected to any circuit. Just a test point. > > - pinctrl setup in DT: > > - for "pwm": > > - fsl,pins = <MX6QDL_PAD_GPIO_9__PWM1_OUT 0x8> > > - IOMUXC_SW_MUX_CTL_PAD_GPIO09 = 0x00000004 > > - IOMUXC_SW_PAD_CTL_PAD_GPIO09 = 0x00000008 > > > > - for "gpio": > > - fsl,pins = <MX6QDL_PAD_GPIO_9__GPIO1_IO09 0xb000> > > - IOMUXC_SW_MUX_CTL_PAD_GPIO09 = 0x00000005 > > - IOMUXC_SW_PAD_CTL_PAD_GPIO09 = 0x0000b000 > > FTR: I suggested 0x0000b080 here, but 0x0000b000 is just fine. > > > Test scenario: > > > > - In bootloader configure the pin as GPIO output, set it LOW (0V). > > I set it LOW to start in the oposite state than I want to end up in. > > - Boot Linux > > - Use sysfs to configure the PWM to produce some signal. > > - In the PWM driver select the "pwm" pinctrl state. > > - Measure the output - expected waveform on the scope. > > - Use sysfs to stop the PWM "echo 0 > /sys/class/pwm/pwmchip0/pwm0/enable° > > - In the PWM driver select the "gpio" pinctrl state. > > - Then in the PWM driver: > > > > a) non-working variant > > - Do not request the GPIO - so do not touch its pad control reg. > > It is set as output from the bootloader, data register = 0. > > - Measure voltage on the output > > - against GND = 0V > > - against VCC = 0V > > - Measure resistance against VCC: Hi-Z > > > > The pin is in Hi-Z mode. That is fine but that does not satisfy any > > logic level. > > > > b) working variant > > - Request the GPIO, configure it as input. > > - Measure voltage on the output > > - against GND = VCC (3.3V) > > - against VCC = 0V > > - Measure resistance against VCC = 91.1kOhm > > > > The pull-up is active. > > Thanks for your detailed test. So DSE = 0 doesn't work as I (and I think > Lothar) expected. > > @Lothar: if Michal did something different than you expected, please > tell us with a few more details. > No, Michal's findings are in sync with what I checked here. Lothar Waßmann -- ___________________________________________________________ Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10 Geschäftsführer: Matthias Kaussen Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 www.karo-electronics.de | info@xxxxxxxxxxxxxxxxxxx ___________________________________________________________
