system/dev/audio/astro-tdm-output/tas27xx.cpp

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <ddk/protocol/i2c.h>
#include <fbl/algorithm.h>
#include <fbl/alloc_checker.h>

#include <utility>

#include "tas27xx.h"

namespace audio {
namespace astro {

// static
fbl::unique_ptr<Tas27xx> Tas27xx::Create(ddk::I2cChannel&& i2c) {
    fbl::AllocChecker ac;

    auto ptr = fbl::unique_ptr<Tas27xx>(new (&ac) Tas27xx(std::move(i2c)));
    if (!ac.check()) {
        return nullptr;
    }

    return ptr;
}

zx_status_t Tas27xx::Reset() {
    return WriteReg(SW_RESET, 0x01);
}

zx_status_t Tas27xx::SetGain(float gain) {
    gain = fbl::clamp(gain, GetMinGain(), GetMaxGain());
    uint8_t gain_reg = static_cast<uint8_t>(-gain / kGainStep);

    zx_status_t status;
    status = WriteReg(PB_CFG2, gain_reg);
    if (status == ZX_OK) {
        current_gain_ = gain;
    }
    return status;
}

bool Tas27xx::ValidGain(float gain) {
    return (gain <= kMaxGain) && (gain >= kMinGain);
}

zx_status_t Tas27xx::Init() {
    zx_status_t status;

    //Put part in active, but muted state
    Standby();

    // 128 clocks per frame, manually configure dividers
    status = WriteReg(CLOCK_CFG, (0x06 << 2) | 1);
    if (status != ZX_OK)
        return status;

    // 48kHz, FSYNC on high to low transition
    // Disable autorate detection
    status = WriteReg(TDM_CFG0, (1 << 4) | (0x03 << 1) | 1);
    if (status != ZX_OK)
        return status;

    // Left justified, offset 0 bclk, clock on falling edge of sclk
    //  our fsync is on falling edge, so first bit after falling edge is valid
    status = WriteReg(TDM_CFG1, (0 << 1) | 1);
    if (status != ZX_OK)
        return status;

    // Mono (L+R)/2, 32bit sample, 32bit slot
    status = WriteReg(TDM_CFG2, (0x03 << 4) | (0x00 << 2) | 0x03);
    if (status != ZX_OK)
        return status;

    // Left channel slot 0, Right channel slot 1
    status = WriteReg(TDM_CFG3, (1 << 4) | 0);
    if (status != ZX_OK)
        return status;

    // Initial gain -20db
    SetGain(-20);

    // Disable v and i sense, enter active mode
    status = WriteReg(PWR_CTL, (0x03 << 2));
    if (status != ZX_OK)
        return status;

    return ZX_OK;
}

//Standby puts the part in active, but muted state
zx_status_t Tas27xx::Standby() {
    return WriteReg(PWR_CTL, (0x03 << 2) | 0x01);
}

zx_status_t Tas27xx::ExitStandby() {
    return WriteReg(PWR_CTL, (0x03 << 2));
}

uint8_t Tas27xx::ReadReg(uint8_t reg) {
    uint8_t val;
    i2c_.ReadSync(reg, &val, 1);
    return val;
}

zx_status_t Tas27xx::WriteReg(uint8_t reg, uint8_t value) {
    uint8_t write_buf[2];
    write_buf[0] = reg;
    write_buf[1] = value;
    return i2c_.WriteSync(write_buf, 2);
}
} //namespace astro
} //namespace audio