[Letux-kernel] twl gpios / headset detect on gta04a5

Andreas Kemnade andreas at kemnade.info
Sun Sep 23 19:21:40 CEST 2018


On Sun, 23 Sep 2018 18:51:11 +0200
Andreas Kemnade <andreas at kemnade.info> wrote:

> Hi,
> 
> I am looking at the headset stuff.
> The detection is at gpio492 on gta04a5 if I
> understand everything right.
> I exported that and no reaction there on plugging
> And then I am wondering:
> root at gta04:/sys/class/gpio/gpio492# twl-i2c.sh GPIO r 0x13
> 0x00
> # twl-i2c.sh GPIO r 0x14
> 0x00
> 
> No pullups/downs enabled?!
> Hmm, floating inputs there?!
> 
> twl-i2c.sh GPIO w 0x13 0x20
> 
> does the trick. the exported gpio shows values. But are the pullup/down
> values correct there?

beagleboard e.g. has something like this:
&twl_gpio {
        ti,use-leds;
        /* pullups: BIT(1) */
        ti,pullups = <0x000002>;
        /*
         * pulldowns:
         * BIT(2), BIT(6), BIT(7), BIT(8), BIT(13)
         * BIT(15), BIT(16), BIT(17)
         */
        ti,pulldowns = <0x03a1c4>;
};

Regards,
Andreas
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