On Tue, Jun 24, 2014 at 10:07 AM, Stefano Babic sbabic@denx.de 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 otavio@ossystems.com.br 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 benoit.thebaudeau@advansee.com, Fabio Estevam fabio.estevam@freescale.com and Eric Bénard eric@eukrea.com for helping to properly trace this down.
Signed-off-by: Otavio Salvador otavio@ossystems.com.br Acked-by: Stefano Babic sbabic@denx.de