Hi there!
on custom AM37x board running 2.6.37 this was enough to enable gpio 67:
echo 71 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio71/direction
echo 1 > /sys/class/gpio/gpio71/value
However, with DT configured linux-4.2 compiled using omap2plus_defconfig
this no longer works.
Using devmme2 utility, these are register values read from system running
2.6.37 kernel.
CONTROL_SYSCONFIG 0x48002010: 0x1
CONTROL_PADCONF_DSS_DATA0 0x480020DC: 0x1040104
CONTROL_PADCONF_OFF 0x48002270: 0x0
CONTROL_DEVCONF0 0x48002274: 0x5000000
GPIO_SYSCONFIG 0x49052010: 0x15
GPIO_CTRL 0x49052030: 0x0
GPIO_OE 0x49052034: 0xFFFFFF17
GPIO_DATAOUT 0x4905203C: 0x80
Relevant bits are the same on 4.2 kernel. Also, zeroing OE and writing
to GPIO_DATAOUT it is possible to enable gpio81 and 80, 83, 69 (light LED),
but not gpio71 or 70 or 69 (muxing done with DT) For testing purposes
function drivers/gpio/gpio-omap.c:omap_gpio_restore_context was set to
no-op. Any pointers where to look next?
Thank you,
ladis
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