Dear all,
thanks for your work in supporting the Allwinner devices!!
I am trying to use the 1-wire instructions I found on the wiki here [1]
for connecting some DS18B20 1-wire thermometer to an
A64-OLinuXino-2Ge8G-IND [2]. This single board computer is running a
Debian 11 Bullseye image prepared by the Olimex people [3] and currently
I am running a 5.10.180-olimex kernel.
I understand that I have to create a DeviceTree overlay (that I never
did before), load this overlay in the /boot/uEnv.txt file (that's the
name on the OS I am using) and hope it works. Right?
My (failed) first attempt to write a DeviceTree overlay is described on
the Olimex forums here [4], but I suspect this is the proper channel for
asking for some help on this topic.
Following attempts also failed. I always got a "pin PB0 already
requested by onewire_device; cannot claim for 1c20800.pinctrl:32" error.
These attempts included writing the code directly in the kernel dtb file
(decompiled and compiled with dtc and included in the /boot/kernel.itb
command using mkimage -f kernel.its kernel.itb).
I copy and paste here the latest attempt of DeviceTree overlay here.
```
/dts-v1/;
/plugin/;
/ {
compatible = "allwinner,sun50i-a64",
"olimex,a64-olinuxino";
description = "Enable 1-Wire port";
fragment@0 {
target-path = "/";
__overlay__ {
onewire_device: onewire_device {
compatible = "w1-gpio";
gpios = <&pio 1 0 0>; /* 1: B of PB0; 0: 0 of PB0; 0:
GPIO_ACTIVE_HIGH */
pinctrl-names = "default";
pinctrl-0 = <&my_w1_pin>;
};
};
};
fragment@1 {
target = <&pio>;
__overlay__ {
my_w1_pin: my_w1_pin@0 {
allwinner,pins = "PB0";
allwinner,function = "gpio_in";
allwinner,drive = <0>; /*<SUN4I_PINCTRL_10_MA>*/
allwinner,pull = <1>;
/*<SUN4I_PINCTRL_PULL_UP>*/
};
};
};
};
```
I cannot get rid of this error in the dmesg (unless I specify two
different pins in the two fragments, and then weird things happen, as
explained in [4]):
[] Driver for 1-wire Dallas network protocol.
[] sun50i-a64-pinctrl 1c20800.pinctrl: pin PB0 already requested by
onewire_device; cannot claim for 1c20800.pinctrl:32
[] sun50i-a64-pinctrl 1c20800.pinctrl: pin-32 (1c20800.pinctrl:32)
status -22
[] w1-gpio onewire_device: gpio_request (pin) failed
[] w1-gpio: probe of onewire_device failed with error -22
Thanks for your help!!!
Ilario
[1]: https://linux-sunxi.org/1-Wire
[2]:
https://www.olimex.com/Products/OLinuXino/A64/A64-OLinuXino/open-source-hardware
[3]: https://images.olimex.com/
[4]: https://www.olimex.com/forum/index.php?topic=9266.0
--
Ilario
iocheson...@gmail.com
ila...@sindominio.net
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