This version is outdated by a newer approved version.
This version (18 Jul 2018 12:33) is a draft.
Approvals: 0/1
This version (18 Jul 2018 12:33) is a draft.Approvals: 0/1
This is an old revision of the document!
Table of Contents
ADGS1408/ADGS1409 8:1/Dual 4:1 Muxes Linux Driver
Supported Devices
Evaluation Boards
Description
This is a mux controller subsystem driver, with an interface for accessing mux controllers. This is done in such a way that several consumers can independently access the same mux controller if one controller controls several multiplexers, thus allowing sharing.
Source Code
Status
| Source | Mainlined? |
|---|---|
| git | [No] |
Files
| Function | File |
|---|---|
| driver | https://github.com/analogdevicesinc/linux/blob/rpi-4.14.y/drivers/mux/adgs140x.c |
Devicetree
Required devicetree properties:
- compatible: Needs to be the name of the device. E.g. “adi,adgs1408”
- reg: The chipselect number used for the device
- spi-max-frequency: Maximum SPI clock frequency.
- #mux-control-cells:is required to be <0>
&spi0 {
pinctrl-names = "default";
pinctrl-0 = <&spi0_pins &spi0_cs_pins>;
cs-gpios = <&gpio 8 1>, <&gpio 7 1>;
status = "okay";
mux: mux-controller@2 {
compatible = "adi,adgs1408";
reg = <0>;
spi-max-frequency = <1000000>;
#mux-control-cells = <0>;
};
}
/ {
adc-mux@3 {
compatible = "io-channel-mux";
io-channels = <&adc 1>;
io-channel-names = "parent";
mux-controls = <&mux>;
channels = "out_a0", "out_a1", "test0", "test1",
"out_b0", "out_b1", "testb0", "testb1";
};
}
A consumer must also be provided to be able to control the mux. In this example we used a regular IIO ADC driver. Which is interfaced with the IIO mux controller consumer.
adc: ad7298@3 {
compatible = "ad7298";
#io-channel-cells = <1>;
spi-max-frequency = <1000000>;
reg = <1>;
};
The mux controller extends the ADC's IO channel that is selected. In this case the selected channels is represented by :
io-channels = <&adc 1>;
in this case voltage0 from ad7298 is the channels multiplexed in IIO.
More Information
- IIO mailing list: linux [dash] iio [at] vger [dot] kernel [dot] org
resources/tools-software/linux-drivers/mux/adgs1408.1531910000.txt.gz · Last modified: 18 Jul 2018 12:33 by Mircea Caprioru