platform-rgbctrl.hh

#pragma once
#include <cdefs.h>
#include <stdint.h>
#include <utils.hh>
 
/**
 * An enum representing each of the Sonata's RGB LEDs.
 */
enum class SonataRgbLed
{
    Led0 = 0,
    Led1 = 1,
};
 
/**
 * A driver for the Sonata's RGB LED Controller
 */
struct SonataRgbLedController : private utils::NoCopyNoMove
{
    /**
     * Registers for setting the 8-bit red, green, and blue values
     * for the two RGB Leds.
     */
    uint32_t ledColors[2];
    /**
     * Control Register. See `SonataRgbLedController::ControlFields` for the
     * fields.
     */
    uint32_t control;
    /**
     * Status Register See `SonataRgbLedController::StatusFields` for the
     * fields.
     */
    uint32_t status;
 
    /// Control Register Fields
    enum [[clang::flag_enum]] ControlFields : uint32_t
    {
        /// Write 1 to set RGB LEDs to specified colours.
        ControlSet = 1 << 0,
        /**
         * Write 1 to turn off RGB LEDs.
         * Write to ControlSet to turn on again.
         */
        ControlOff = 1 << 1,
    };
 
    /// Status Register Fields
    enum [[clang::flag_enum]] StatusFields : uint32_t
    {
        /**
         * When asserted controller is idle and new colours can be set,
         * otherwise writes to regLed0, regLed1, and control are ignored.
         */
        StatusIdle = 1 << 0,
    };
 
    /**
     * Blocks until the controller is not busy.
     *
     * The controller can be busy when it is in the process of updating the
     * LEDs. While busy, register writes will be ignored.
     */
    void wait_for_idle() volatile
    {
        while ((status & StatusIdle) == 0)
        {
        }
    }
 
    /**
     * Set the desired Red, Green, and Blue value of an LED. To apply these
     * changes, one needs to run `SonataRgbLedController::update()`.
     */
    void
    rgb(SonataRgbLed led, uint8_t red, uint8_t green, uint8_t blue) volatile
    {
        wait_for_idle();
        ledColors[static_cast<uint32_t>(led)] =
          (static_cast<uint32_t>(blue) << 16) |
          (static_cast<uint32_t>(green) << 8) | static_cast<uint32_t>(red);
    }
 
    /// Update the colours of the LEDs.
    void update() volatile
    {
        wait_for_idle();
        control = ControlSet;
    }
 
    /// Switch all of the RGB LEDs off.
    void off() volatile
    {
        wait_for_idle();
        control = ControlOff;
    }
};
 
static_assert(sizeof(SonataRgbLedController) == 16,
              "The SonataRgbLedController structure is the wrong size.");