AnsweredAssumed Answered

Can not control GPIO after set it to pull high.

Question asked by tsung li wang on Sep 4, 2018
Latest reply on Sep 4, 2018 by igorpadykov

Hi Community,

I'm working on i.MX6 Quad sabre-SD platform and build Android 6 as my image.


I'm trying to control GPIO in u-boot.

According to my customize u-boot, I modify bootload/bootloader/u-boot/board/freescale/FX100/FX100.c like below.







static void enable_lvds(struct display_info_t const *dev)


imx_iomux_v3_setup_pad(MX6_PAD_NANDF_CS2__GPIO6_IO15 | MUX_PAD_CTRL(FX_GPIO_INIT));
/* LVDS_BL_ON */
imx_iomux_v3_setup_pad(MX6_PAD_NANDF_CS3__GPIO6_IO16 | MUX_PAD_CTRL(FX_GPIO_INIT));
/* PAD_SD1_DAT3 for pwm ,GPIO mode */
imx_iomux_v3_setup_pad(MX6_PAD_SD1_DAT3__GPIO1_IO21 | MUX_PAD_CTRL(FX_GPIO_INIT));

gpio_direction_output(BL_PWM, 0);// winmate BL pwm to low level
gpio_direction_output(LVDS_PWR_ON, 0);//winmate Frank BL pwr off
gpio_direction_output(LVDS_BL_ON, 0);// winmate frank for panel pwr seq panel pwr off

gpio_set_value(BL_PWM, 0);
gpio_set_value(LVDS_PWR_ON, 0);
gpio_set_value(LVDS_BL_ON, 0);




gpio_set_value(BL_PWM, 1);
gpio_set_value(LVDS_PWR_ON, 1);
gpio_set_value(LVDS_BL_ON, 1);





As you can see, I tried to define FX_GPIO_INIT to change gpio to 100K PULL DOWN..

But when I set LVDS_PWR_ON to  0 and set it back to 1, it won't work.

I can not control it.


Is there any possibility that I have to set other register mode for NANDF_CS2 ?

Or what else can I do to solve this situation?


Thanks in Advanced!