I am using a System Monitor device at address 0x3f on i2c-0 bus. This device is configured with the pmbus driver in the device tree.
The problem is that, this 'Sysmon' device is not powered when the linux kernel is loaded. Therefore, when I do a i2cdetect on bus 0 we see '--' at 0x3f which is expected. Now, when I power the Sysmon using my UI, the device is added by linux and we see a '3f' on running the i2cdetect.
Now, I want the pmbus driver to detect this device and change it to 'UU' so that I can see all the pmbus attributes in sysfs.
Can I do it from userspace and how? If no, can you suggest how can I tackle this.
If I force power the device using hardware and then load linux, the pmbus driver detects this device and reserves it. But I'm not allowed to force power the device.
Device Tree:
i2c@ff020000
{
compatible = "cdns,i2c-r1p14", "cdns,i2c-r1p10";
status = "okay";
interrupt-parent = <0x4>;
interrupts = <0x0 0x11 0x4>;
reg = <0x0 0xff020000 0x0 0x1000>;
#address-cells = <0x1>;
#size-cells = <0x0>;
power-domains = <0x15>;
clocks = <0x3 0x3d>;
clock-frequency = <0x186a0>;
pinctrl-names = "default", "gpio";
pinctrl-0 = <0x16>;
pinctrl-1 = <0x17>;
scl-gpios = <0x18 0x4a 0x0>;
sda-gpios = <0x18 0x4b 0x0>;
fpga1sysmon0@3f {
compatible = "general,pmbus";
reg = <0x3f>;
};
PS: I'm a beginner and this is my 1st question on Stack Overflow. Please bear with me for any mistakes I've made.
what about enabling the sysmon in /etc/init.d/rcS (assuming you are using busybox init) or in systemd /etc/rc.local.
the following will load the driver for an LTC2978 at address 0x60 on I2C bus #1:
$ modprobe pmbus
$ echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
you can put that in
/etc/init.d/rcS or /etc/rc.local
see also https://www.kernel.org/doc/Documentation/hwmon/pmbus