On Tue, Jun 24, 2014 at 10:07 AM, Stefano Babic <[email protected]> wrote:
> What you are describing looks an issue in your pinmux configuration > because you do not set the SION bit, as requested to read back the value > of the GPIO from the Pad Register. Yes, correct. Klaus, please check this commit: commit 7773fd196918826ebaab769e63a4775607f5256c Author: Otavio Salvador <[email protected]> Date: Mon Dec 16 20:44:00 2013 -0200 imx: Easy enabling of SION per-pin using MUX_MODE_SION helper macro The macro allows easy setting in per-pin, as for example: ,---- | imx_iomux_v3_setup_pad(MX6_PAD_NANDF_D1__GPIO_2_1 | MUX_MODE_SION); `---- The IOMUX_CONFIG_SION allows for reading PAD value from PSR register. The following quote from the datasheet: ,---- | ... | 28.4.2.2 GPIO Write Mode | The programming sequence for driving output signals should be as follows: | 1. Configure IOMUX to select GPIO mode (Via IOMUXC), also enable SION if need | to read loopback pad value through PSR | 2. Configure GPIO direction register to output (GPIO_GDIR[GDIR] set to 1b). | 3. Write value to data register (GPIO_DR). | ... `---- This fixes the gpio_get_value to properly work when a GPIO is set for output and has no conflicts. Thanks for Benoît Thébaudeau <[email protected]>, Fabio Estevam <[email protected]> and Eric Bénard <[email protected]> for helping to properly trace this down. Signed-off-by: Otavio Salvador <[email protected]> Acked-by: Stefano Babic <[email protected]> _______________________________________________ U-Boot mailing list [email protected] http://lists.denx.de/mailman/listinfo/u-boot
