Well, so I think I understand a bit more about the DTS support for GPIO. I
configured the pinctrl for GPIO5 channel, and it seems to have some effect
on the GPIO pins. After the kernel starts up the LEDs are being turned off.
&omap3_pmx_core {
vvv_gpio_pins: pinmux_gpio_pins {
pinctrl-single,pins = <
0x136 (PIN_OUTPUT | MUX_MODE4) /* gpio_137
*/
0x138 (PIN_OUTPUT | MUX_MODE4) /* gpio_138
*/
0x13a (PIN_OUTPUT | MUX_MODE4) /* gpio_139
*/
>;
};
};
&gpio5 {
pinctrl-names = "default";
pinctrl-0 = <&vvv_gpio_pins>;
};
However the GPIO export mechanism from userspace is still not working.
Basically, no matter what value you try to set gpio137-139, they stay low
(although the value in the /sys/class/gpio/gpioXXX/value file is being
changed appropriately. It's as if gpiochip128 is not really associated
with gpio5.
I am also worried about not being able to dump *
/sys/kernel/debug/pinctrl/48002030.pinmux/pins* . The kernel hiccup occurs
on the base 3.11 DTB file, so it's not my change that's causing it.
On Friday, October 25, 2013 3:13:46 PM UTC-4, porkupan wrote:
>
> Trying to dump the pinmux states
> (/sys/kernel/debug/pinctrl/48002030.pinmux/pins) in 3.11 seems to cause a
> kernel crash:
> http://paste.ubuntu.com/6302171/
>
> GPIO access via /sys/class/gpio appears to be nonoperational in 3.11. It
> looks like a reasonable assumption that GPIOs may not be muxed into the
> GPIO pins.
>
> I tried to add a devicetree entry to to force-mux GPIOs:
>
> &omap3_pmx_core {
> vvv_gpio_pins: pinmux_gpio_pins {
> pinctrl-single,pins = <
> 0x134 (PIN_OUTPUT | MUX_MODE4) /*
> gpio_137 */
> 0x135 (PIN_OUTPUT | MUX_MODE4) /*
> gpio_138 */
> 0x136 (PIN_OUTPUT | MUX_MODE4) /*
> gpio_139 */
> >;
> };
> };
>
> &ocp {
> gpio_helper: helper {
> compatible = "ti,omap3-gpio";
> pinctrl-names = "default";
> pinctrl-0 = <&vvv_gpio_pins>;
> status = "okay";
> };
> };
>
> Doesn't seem to do anything. The only indication that the kernel is
> actually trying to parse the fake "helper" device is these lines in the
> message log:
>
> [ 0.369201] omap_gpio helper.26: could not find pctldev for node
> /ocp/pinmux@48002030/pinmux_gpio_pins, deferring probe
> [ 0.369232] platform helper.26: Driver omap_gpio requests probe deferral
> <...>
> [ 3.354125] omap_gpio helper.26: Invalid IRQ resource
>
> Obviously, I have no idea what "compatible" driver should I chose,
> omap3_gpio just sounded like something that could fit. For BBB they
> reference bone-pinmux-helper, which I assume is BBB-specific?
>
> Thanks!
>
>
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