avia,hx711-spi (on spi bus)

Overview

Name:

avia,hx711-spi

Vendor:

avia semiconductor

Used in:

List of boards using this compatible

Driver:

drivers/sensor/hx711_spi/hx711_spi.c

Description

Avia Semiconductor HX711 24-bit ADC Specialized for Load Cells / Strain Gauges on SPI bus

This driver implements the sensor interface. A trigger can be configured for data ready
events (i.e. when the DOUT line is pulled low), which is implemented through a GPIO
interrupt.

To enable the trigger, the user has to supply two pinctrl configs named "default" and
"trigger":
- "default" pinctrl should be identical to the pinctrl supplied to the parent spi node;
- "trigger" pinctrl should include only one pin that specifies the DOUT pin.

For example:

&pinctrl {
  spi0_hx711: spi0_hx711 {
    /* GPIO16 (RX) connects to DOUT, GPIO19 (TX) connects to PD_SCK */
    /* GPIO17 (CS) and GPIO19 (SCK) are not used */
    group1 {
      pinmux = <SPI0_CSN_P17>, <SPI0_SCK_P18>, <SPI0_TX_P19>;
      };

      group2 {
        pinmux = <SPI0_RX_P16>;
        input-enable;
      };
  };
  hx711_trig: hx711_trig {
    /* Assign GPIO16 (DOUT) for use as an interrupt source */
    group1 {
      pinmux = <GPIO_P16>;
      input-enable;
    };
  };
};

&spi0 {
  status = "okay";
  cs-gpios = <&gpio0 17 GPIO_ACTIVE_LOW>;
  pinctrl-0 = <&spi0_hx711>;

  hx711@0 {
    compatible = "avia,hx711";
    reg = <0>;
    spi-max-frequency = <1000000>; /* max 2.5 MHz, min 10 kHz */
    gain = <64>;
    avdd = <5000>; /* mV */
    pinctrl-0 = <&spi0_hx711>;
    pinctrl-1 = <&hx711_trig>;
    pinctrl-names = "default", "trigger";
    dout-trig-gpios = <&gpio0 16 GPIO_ACTIVE_HIGH>;
  };
};

Properties

Node specific propertiesDeprecated node specific propertiesBase properties

Properties not inherited from the base binding file.

Name	Type	Details
gain	int	PGA gain for channel A This property is required. Legal values: 64, 128
avdd	int	AVDD value in millivolts, for converting samples to voltage This property is required.
dout-trig-gpios	phandle-array	GPIO for DOUT and trigger signal indicating a sample is ready
spi-max-frequency	int	Maximum clock frequency of device's SPI interface in Hz This property is required.
duplex	int	Duplex mode, full or half. By default it's always full duplex thus 0 as this is, by far, the most common mode. Use the macros not the actual enum value, here is the concordance list (see dt-bindings/spi/spi.h) 0 SPI_FULL_DUPLEX 2048 SPI_HALF_DUPLEX Legal values: 0, 2048
frame-format	int	Motorola or TI frame format. By default it's always Motorola's, thus 0 as this is, by far, the most common format. Use the macros not the actual enum value, here is the concordance list (see dt-bindings/spi/spi.h) 0 SPI_FRAME_FORMAT_MOTOROLA 32768 SPI_FRAME_FORMAT_TI Legal values: 0, 32768
spi-cpol	boolean	SPI clock polarity which indicates the clock idle state. If it is used, the clock idle state is logic high; otherwise, low.
spi-cpha	boolean	SPI clock phase that indicates on which edge data is sampled. If it is used, data is sampled on the second edge; otherwise, on the first edge.
spi-lsb-first	boolean	The device requires least significant bit first data mode.
spi-hold-cs	boolean	In some cases, it is necessary for the master to manage SPI chip select under software control, so that multiple spi transactions can be performed without releasing it. A typical use case is variable length SPI packets where the first spi transaction reads the length and the second spi transaction reads length bytes.
spi-cs-high	boolean	The device requires the chip select to be active high.
spi-interframe-delay-ns	int	Delay in nanoseconds between SPI words. Default of 0 is special value which will assume to mean half of the SCK period.
spi-cs-setup-delay-ns	int	Delay in nanoseconds to be introduced by the controller after CS is asserted. Also known as enable lead time.
spi-cs-hold-delay-ns	int	Delay in nanoseconds to be introduced by the controller before the CS is de-asserted. Also known as enable lag time.
supply-gpios	phandle-array	GPIO specifier that controls power to the device. This property should be provided when the device has a dedicated switch that controls power to the device. The supply state is entirely the responsibility of the device driver. Contrast with vin-supply.
vin-supply	phandle	Reference to the regulator that controls power to the device. The referenced devicetree node must have a regulator compatible. This property should be provided when device power is supplied by a shared regulator. The supply state is dependent on the request status of all devices fed by the regulator. Contrast with supply-gpios. If both properties are provided then the regulator must be requested before the supply GPIOS is set to an active state, and the supply GPIOS must be set to an inactive state before releasing the regulator.
friendly-name	string	Human readable string describing the sensor. It can be used to distinguish multiple instances of the same model (e.g., lid accelerometer vs. base accelerometer in a laptop) to a host operating system. This property is defined in the Generic Sensor Property Usages of the HID Usage Tables specification (https://usb.org/sites/default/files/hut1_3_0.pdf, section 22.5).
pinctrl-0	phandles	Pin configuration/s for the first state. Content is specific to the selected pin controller driver implementation.
pinctrl-1	phandles	Pin configuration/s for the second state. See pinctrl-0.
pinctrl-2	phandles	Pin configuration/s for the third state. See pinctrl-0.
pinctrl-3	phandles	Pin configuration/s for the fourth state. See pinctrl-0.
pinctrl-4	phandles	Pin configuration/s for the fifth state. See pinctrl-0.
pinctrl-names	string-array	Names for the provided states. The number of names needs to match the number of states.