device tree dallas 1 wire ubuntu - loads but odd behaviour

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1

Hi All,

A puzzle:

the following device tree

`


/*
* Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
2

Oh, by the way …the blob is loaded:

grubby@ubuntu-armhf:~/python/projects$ cat $SLOTS
0: 54:PF—
1: 55:PF—
2: 56:PF—
3: 57:PF—
4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G
5: ff:P-O-L Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI
6: ff:P-O-L Override Board Name,00A0,Override Manuf,w1

3

Well it says it loads – but it does not work. Help appreciated!

Thanks

Matt

4

Which kernel - “uname -a”? I don’t think you can change the pinmux for pins under 3.12 yet - well I couldn’t anyway, although it worked for me under 3.8. Check by doing “grep 44e10840 /sys/kernel/debug/pinctrl/44e10800.pinmux/pins” - is it 00000037? Is the pin actually pulled up? Test with a multimeter and/or add an external pullup resistor.

5

Pretty recent, actually, Mike…

3.8.13-bone20

And the pins are changing – it’s outputing 37:

sudo cat $PINS|grep 840
pin 16 (44e10840) 00000037 pinctrl-single

and the multimeter says it is pulled up.

I used a different overlay tree as well – and get the same thing

/dts-v1/;
/plugin/;

/ {
compatible = “ti,beaglebone”, “ti,beaglebone-black”;
part-number = “BB-W1”;
version = “00A0”;

exclusive-use = “P9.15”, “gpio1_16”;

fragment@0 {
target = <&am33xx_pinmux>;
overlay {
bb_w1_pins: pinmux_bb_w1_pins {
pinctrl-single,pins = <
0x040 0x37 /*pin P9_15 input with pullup mode 7 - w1-gpio */

;
};
};
};

fragment@1 {
target = <&ocp>;
overlay {
onewire@0 {
status = “okay”;
compatible = “w1-gpio”;
pinctrl-names = “default”;
pinctrl-0 = <&bb_w1_pins>;

gpios = <&gpio2 16 0>; /grrr I think this means gpio1_16 (using 1 to 4 instread of 0-3)/
};
};
};
};

I’d greatly appreciate any help on this I can get!

Kind regards

Matt

6

Matt,
Did you solve your problem? I have a very similar issue to yours right now. I’ve been trying to find a solution for a few days.

Andrew