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IR-RX

Module Introduction​

The main function of the infrared receiving module is to receive infrared signals.

Functional Introduction​

alt text On the K1 platform, the demodulated electrical signal received by the external infrared receiver (demodulator) is decoded in the driver and the kernel IR framework and the event is reported.

Source Code Structure Introduction​

The IR-RX controller driver code is under the drivers/media/rc directory:

drivers/media/rc
|--rc-ir-raw.c            # Kernel IR framework interface code
|--ir-nec-decoder.c       # Kernel IR decoding electrical signal code
|--ir-spacemit.c          # K1 IR driver

Key Features

Feature
Configurable noise threshold
32Bytes RX FIFO

Configuration Introduction

It mainly includes driver enable configuration and DTS configuration.

CONFIG Configuration​

CONFIG_IR_SPACEMIT=y

Symbol: IR_SPACEMIT [=y]
Device Drivers
    -> Remote Controller support (RC_CORE [=y])
        -> Remote Controller devices (RC_DEVICES [=y])
            -> SPACEMIT IR remote Recriver control (IR_SPACEMIT [=y])

DTS Configuration​

Pinctrl​

You can view arch/riscv/boot/dts/spacemit/k1-x_pinctrl.dtsi in the Linux repository and refer to the configured PWM node configuration as follows:

    pinctrl_ir_rx_1: ir_rx_1_grp {
        pinctrl-single,pins = <
            K1X_PADCONF(GPIO_79, MUX_MODE1, (EDGE_NONE | PULL_UP | PAD_3V_DS4))     /* ir_rx */
        >;
    };

DTSI Configuration Example​

Configure the base address and clock reset resources of the IR controller in DTSI. Normally, there is no need to change it.

    ircrx: irc-rx@d4017f00 {
        compatible = "spacemit,k1x-irc";
        reg = <0x0 0xd4017f00 0x0 0x100>;
        interrupts = <69>;
        interrupt-parent = <&intc>;
        clocks = <&ccu CLK_IR>;
        resets = <&reset RESET_IR>;
        clock-frequency = <102400000>;
        status = "disabled";
    };

DTS Configuration Example​

The complete DTS configuration is as follows:

    &ircrx {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_ir_rx_1>;
        status = "okay";
    };

Interface Description

Test Introduction​

Based on the K1 platform, an external infrared demodulator can be connected to the pin configured by the above IR. The remote control sends a signal to the demodulator, and the code value is received at the application layer.

API Introduction​

Commonly used:

int ir_raw_event_store_with_filter(struct rc_dev *dev, struct ir_raw_event *ev)
The interface implemented by the IR framework is called in the driver to complete the signal storage, decoding, and event reporting in the interrupt callback function.

FAQ