/*
 * NAU85L40 ALSA SoC audio driver
 *
 * Copyright 2016 Nuvoton Technology Corp.
 * Author: John Hsu <KCHSU0@nuvoton.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/pm.h>
#include <linux/i2c.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/slab.h>
#include <linux/of_device.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/soc-dapm.h>
#include <sound/initval.h>
#include <sound/tlv.h>
#include "nau8540.h"


#define NAU_FREF_MAX 13500000
#define NAU_FVCO_MAX 100000000
#define NAU_FVCO_MIN 90000000

/* the maximum frequency of CLK_ADC */
#define CLK_ADC_MAX 6144000

/* scaling for mclk from sysclk_src output */
static const struct nau8540_fll_attr mclk_src_scaling[] = {
       { 1, 0x0 },
       { 2, 0x2 },
       { 4, 0x3 },
       { 8, 0x4 },
       { 16, 0x5 },
       { 32, 0x6 },
       { 3, 0x7 },
       { 6, 0xa },
       { 12, 0xb },
       { 24, 0xc },
};

/* ratio for input clk freq */
static const struct nau8540_fll_attr fll_ratio[] = {
       { 512000, 0x01 },
       { 256000, 0x02 },
       { 128000, 0x04 },
       { 64000, 0x08 },
       { 32000, 0x10 },
       { 8000, 0x20 },
       { 4000, 0x40 },
};

static const struct nau8540_fll_attr fll_pre_scalar[] = {
       { 1, 0x0 },
       { 2, 0x1 },
       { 4, 0x2 },
       { 8, 0x3 },
};

/* over sampling rate */
static const struct nau8540_osr_attr osr_adc_sel[] = {
       { 32, 3 },      /* OSR 32, SRC 1/8 */
       { 64, 2 },      /* OSR 64, SRC 1/4 */
       { 128, 1 },     /* OSR 128, SRC 1/2 */
       { 256, 0 },     /* OSR 256, SRC 1 */
};

static const struct reg_default nau8540_reg_defaults[] = {
       {NAU8540_REG_POWER_MANAGEMENT, 0x0000},
       {NAU8540_REG_CLOCK_CTRL, 0x0000},
       {NAU8540_REG_CLOCK_SRC, 0x0000},
       {NAU8540_REG_FLL1, 0x0001},
       {NAU8540_REG_FLL2, 0x3126},
       {NAU8540_REG_FLL3, 0x0008},
       {NAU8540_REG_FLL4, 0x0010},
       {NAU8540_REG_FLL5, 0xC000},
       {NAU8540_REG_FLL6, 0x6000},
       {NAU8540_REG_FLL_VCO_RSV, 0xF13C},
       {NAU8540_REG_PCM_CTRL0, 0x000B},
       {NAU8540_REG_PCM_CTRL1, 0x3010},
       {NAU8540_REG_PCM_CTRL2, 0x0800},
       {NAU8540_REG_PCM_CTRL3, 0x0000},
       {NAU8540_REG_PCM_CTRL4, 0x000F},
       {NAU8540_REG_ALC_CONTROL_1, 0x0000},
       {NAU8540_REG_ALC_CONTROL_2, 0x700B},
       {NAU8540_REG_ALC_CONTROL_3, 0x0022},
       {NAU8540_REG_ALC_CONTROL_4, 0x1010},
       {NAU8540_REG_ALC_CONTROL_5, 0x1010},
       {NAU8540_REG_NOTCH_FIL1_CH1, 0x0000},
       {NAU8540_REG_NOTCH_FIL2_CH1, 0x0000},
       {NAU8540_REG_NOTCH_FIL1_CH2, 0x0000},
       {NAU8540_REG_NOTCH_FIL2_CH2, 0x0000},
       {NAU8540_REG_NOTCH_FIL1_CH3, 0x0000},
       {NAU8540_REG_NOTCH_FIL2_CH3, 0x0000},
       {NAU8540_REG_NOTCH_FIL1_CH4, 0x0000},
       {NAU8540_REG_NOTCH_FIL2_CH4, 0x0000},
       {NAU8540_REG_HPF_FILTER_CH12, 0x0000},
       {NAU8540_REG_HPF_FILTER_CH34, 0x0000},
       {NAU8540_REG_ADC_SAMPLE_RATE, 0x0002},
       {NAU8540_REG_DIGITAL_GAIN_CH1, 0x0400},
       {NAU8540_REG_DIGITAL_GAIN_CH2, 0x0400},
       {NAU8540_REG_DIGITAL_GAIN_CH3, 0x0400},
       {NAU8540_REG_DIGITAL_GAIN_CH4, 0x0400},
       {NAU8540_REG_DIGITAL_MUX, 0x00E4},
       {NAU8540_REG_GPIO_CTRL, 0x0000},
       {NAU8540_REG_MISC_CTRL, 0x0000},
       {NAU8540_REG_I2C_CTRL, 0xEFFF},
       {NAU8540_REG_VMID_CTRL, 0x0000},
       {NAU8540_REG_MUTE, 0x0000},
       {NAU8540_REG_ANALOG_ADC1, 0x0011},
       {NAU8540_REG_ANALOG_ADC2, 0x0020},
       {NAU8540_REG_ANALOG_PWR, 0x0000},
       {NAU8540_REG_MIC_BIAS, 0x0004},
       {NAU8540_REG_REFERENCE, 0x0000},
       {NAU8540_REG_FEPGA1, 0x0000},
       {NAU8540_REG_FEPGA2, 0x0000},
       {NAU8540_REG_FEPGA3, 0x0101},
       {NAU8540_REG_FEPGA4, 0x0101},
       {NAU8540_REG_PWR, 0x0000},
};

static bool nau8540_readable_reg(struct device *dev, unsigned int reg)
{
       switch (reg) {
       case NAU8540_REG_POWER_MANAGEMENT ... NAU8540_REG_FLL_VCO_RSV:
       case NAU8540_REG_PCM_CTRL0 ... NAU8540_REG_PCM_CTRL4:
       case NAU8540_REG_ALC_CONTROL_1 ... NAU8540_REG_ALC_CONTROL_5:
       case NAU8540_REG_ALC_GAIN_CH12 ... NAU8540_REG_ADC_SAMPLE_RATE:
       case NAU8540_REG_DIGITAL_GAIN_CH1 ... NAU8540_REG_DIGITAL_MUX:
       case NAU8540_REG_P2P_CH1 ... NAU8540_REG_I2C_CTRL:
       case NAU8540_REG_I2C_DEVICE_ID:
       case NAU8540_REG_VMID_CTRL ... NAU8540_REG_MUTE:
       case NAU8540_REG_ANALOG_ADC1 ... NAU8540_REG_PWR:
               return true;
       default:
               return false;
       }

}

static bool nau8540_writeable_reg(struct device *dev, unsigned int reg)
{
       switch (reg) {
       case NAU8540_REG_SW_RESET ... NAU8540_REG_FLL_VCO_RSV:
       case NAU8540_REG_PCM_CTRL0 ... NAU8540_REG_PCM_CTRL4:
       case NAU8540_REG_ALC_CONTROL_1 ... NAU8540_REG_ALC_CONTROL_5:
       case NAU8540_REG_NOTCH_FIL1_CH1 ... NAU8540_REG_ADC_SAMPLE_RATE:
       case NAU8540_REG_DIGITAL_GAIN_CH1 ... NAU8540_REG_DIGITAL_MUX:
       case NAU8540_REG_GPIO_CTRL ... NAU8540_REG_I2C_CTRL:
       case NAU8540_REG_RST:
       case NAU8540_REG_VMID_CTRL ... NAU8540_REG_MUTE:
       case NAU8540_REG_ANALOG_ADC1 ... NAU8540_REG_PWR:
               return true;
       default:
               return false;
       }
}

static bool nau8540_volatile_reg(struct device *dev, unsigned int reg)
{
       switch (reg) {
       case NAU8540_REG_SW_RESET:
       case NAU8540_REG_ALC_GAIN_CH12 ... NAU8540_REG_ALC_STATUS:
       case NAU8540_REG_P2P_CH1 ... NAU8540_REG_PEAK_CH4:
       case NAU8540_REG_I2C_DEVICE_ID:
       case NAU8540_REG_RST:
               return true;
       default:
               return false;
       }
}


static const DECLARE_TLV_DB_MINMAX(adc_vol_tlv, -12800, 3600);
static const DECLARE_TLV_DB_MINMAX(fepga_gain_tlv, -100, 3600);

static const struct snd_kcontrol_new nau8540_snd_controls[] = {
       SOC_SINGLE_TLV("Mic1 Volume", NAU8540_REG_DIGITAL_GAIN_CH1,
               0, 0x520, 0, adc_vol_tlv),
       SOC_SINGLE_TLV("Mic2 Volume", NAU8540_REG_DIGITAL_GAIN_CH2,
               0, 0x520, 0, adc_vol_tlv),
       SOC_SINGLE_TLV("Mic3 Volume", NAU8540_REG_DIGITAL_GAIN_CH3,
               0, 0x520, 0, adc_vol_tlv),
       SOC_SINGLE_TLV("Mic4 Volume", NAU8540_REG_DIGITAL_GAIN_CH4,
               0, 0x520, 0, adc_vol_tlv),

       SOC_SINGLE_TLV("Frontend PGA1 Volume", NAU8540_REG_FEPGA3,
               0, 0x25, 0, fepga_gain_tlv),
       SOC_SINGLE_TLV("Frontend PGA2 Volume", NAU8540_REG_FEPGA3,
               8, 0x25, 0, fepga_gain_tlv),
       SOC_SINGLE_TLV("Frontend PGA3 Volume", NAU8540_REG_FEPGA4,
               0, 0x25, 0, fepga_gain_tlv),
       SOC_SINGLE_TLV("Frontend PGA4 Volume", NAU8540_REG_FEPGA4,
               8, 0x25, 0, fepga_gain_tlv),
};

static const char * const adc_channel[] = {
       "ADC channel 1", "ADC channel 2", "ADC channel 3", "ADC channel 4"
};
static SOC_ENUM_SINGLE_DECL(
       digital_ch4_enum, NAU8540_REG_DIGITAL_MUX, 6, adc_channel);

static const struct snd_kcontrol_new digital_ch4_mux =
       SOC_DAPM_ENUM("Digital CH4 Select", digital_ch4_enum);

static SOC_ENUM_SINGLE_DECL(
       digital_ch3_enum, NAU8540_REG_DIGITAL_MUX, 4, adc_channel);

static const struct snd_kcontrol_new digital_ch3_mux =
       SOC_DAPM_ENUM("Digital CH3 Select", digital_ch3_enum);

static SOC_ENUM_SINGLE_DECL(
       digital_ch2_enum, NAU8540_REG_DIGITAL_MUX, 2, adc_channel);

static const struct snd_kcontrol_new digital_ch2_mux =
       SOC_DAPM_ENUM("Digital CH2 Select", digital_ch2_enum);

static SOC_ENUM_SINGLE_DECL(
       digital_ch1_enum, NAU8540_REG_DIGITAL_MUX, 0, adc_channel);

static const struct snd_kcontrol_new digital_ch1_mux =
       SOC_DAPM_ENUM("Digital CH1 Select", digital_ch1_enum);

static const struct snd_soc_dapm_widget nau8540_dapm_widgets[] = {
       SND_SOC_DAPM_SUPPLY("MICBIAS2", NAU8540_REG_MIC_BIAS, 11, 0, NULL, 0),
       SND_SOC_DAPM_SUPPLY("MICBIAS1", NAU8540_REG_MIC_BIAS, 10, 0, NULL, 0),

       SND_SOC_DAPM_INPUT("MIC1"),
       SND_SOC_DAPM_INPUT("MIC2"),
       SND_SOC_DAPM_INPUT("MIC3"),
       SND_SOC_DAPM_INPUT("MIC4"),

       SND_SOC_DAPM_PGA("Frontend PGA1", NAU8540_REG_PWR, 12, 0, NULL, 0),
       SND_SOC_DAPM_PGA("Frontend PGA2", NAU8540_REG_PWR, 13, 0, NULL, 0),
       SND_SOC_DAPM_PGA("Frontend PGA3", NAU8540_REG_PWR, 14, 0, NULL, 0),
       SND_SOC_DAPM_PGA("Frontend PGA4", NAU8540_REG_PWR, 15, 0, NULL, 0),

       SND_SOC_DAPM_ADC("ADC1", NULL,
               NAU8540_REG_POWER_MANAGEMENT, 0, 0),
       SND_SOC_DAPM_ADC("ADC2", NULL,
               NAU8540_REG_POWER_MANAGEMENT, 1, 0),
       SND_SOC_DAPM_ADC("ADC3", NULL,
               NAU8540_REG_POWER_MANAGEMENT, 2, 0),
       SND_SOC_DAPM_ADC("ADC4", NULL,
               NAU8540_REG_POWER_MANAGEMENT, 3, 0),

       SND_SOC_DAPM_PGA("ADC CH1", NAU8540_REG_ANALOG_PWR, 0, 0, NULL, 0),
       SND_SOC_DAPM_PGA("ADC CH2", NAU8540_REG_ANALOG_PWR, 1, 0, NULL, 0),
       SND_SOC_DAPM_PGA("ADC CH3", NAU8540_REG_ANALOG_PWR, 2, 0, NULL, 0),
       SND_SOC_DAPM_PGA("ADC CH4", NAU8540_REG_ANALOG_PWR, 3, 0, NULL, 0),

       SND_SOC_DAPM_MUX("Digital CH4 Mux",
               SND_SOC_NOPM, 0, 0, &digital_ch4_mux),
       SND_SOC_DAPM_MUX("Digital CH3 Mux",
               SND_SOC_NOPM, 0, 0, &digital_ch3_mux),
       SND_SOC_DAPM_MUX("Digital CH2 Mux",
               SND_SOC_NOPM, 0, 0, &digital_ch2_mux),
       SND_SOC_DAPM_MUX("Digital CH1 Mux",
               SND_SOC_NOPM, 0, 0, &digital_ch1_mux),

       SND_SOC_DAPM_AIF_OUT("AIFTX", "Capture", 0, SND_SOC_NOPM, 0, 0),
};

static const struct snd_soc_dapm_route nau8540_dapm_routes[] = {
       {"Frontend PGA1", NULL, "MIC1"},
       {"Frontend PGA2", NULL, "MIC2"},
       {"Frontend PGA3", NULL, "MIC3"},
       {"Frontend PGA4", NULL, "MIC4"},

       {"ADC1", NULL, "Frontend PGA1"},
       {"ADC2", NULL, "Frontend PGA2"},
       {"ADC3", NULL, "Frontend PGA3"},
       {"ADC4", NULL, "Frontend PGA4"},

       {"ADC CH1", NULL, "ADC1"},
       {"ADC CH2", NULL, "ADC2"},
       {"ADC CH3", NULL, "ADC3"},
       {"ADC CH4", NULL, "ADC4"},

       {"ADC1", NULL, "MICBIAS1"},
       {"ADC2", NULL, "MICBIAS1"},
       {"ADC3", NULL, "MICBIAS2"},
       {"ADC4", NULL, "MICBIAS2"},

       {"Digital CH1 Mux", "ADC channel 1", "ADC CH1"},
       {"Digital CH1 Mux", "ADC channel 2", "ADC CH2"},
       {"Digital CH1 Mux", "ADC channel 3", "ADC CH3"},
       {"Digital CH1 Mux", "ADC channel 4", "ADC CH4"},

       {"Digital CH2 Mux", "ADC channel 1", "ADC CH1"},
       {"Digital CH2 Mux", "ADC channel 2", "ADC CH2"},
       {"Digital CH2 Mux", "ADC channel 3", "ADC CH3"},
       {"Digital CH2 Mux", "ADC channel 4", "ADC CH4"},

       {"Digital CH3 Mux", "ADC channel 1", "ADC CH1"},
       {"Digital CH3 Mux", "ADC channel 2", "ADC CH2"},
       {"Digital CH3 Mux", "ADC channel 3", "ADC CH3"},
       {"Digital CH3 Mux", "ADC channel 4", "ADC CH4"},

       {"Digital CH4 Mux", "ADC channel 1", "ADC CH1"},
       {"Digital CH4 Mux", "ADC channel 2", "ADC CH2"},
       {"Digital CH4 Mux", "ADC channel 3", "ADC CH3"},
       {"Digital CH4 Mux", "ADC channel 4", "ADC CH4"},

       {"AIFTX", NULL, "Digital CH1 Mux"},
       {"AIFTX", NULL, "Digital CH2 Mux"},
       {"AIFTX", NULL, "Digital CH3 Mux"},
       {"AIFTX", NULL, "Digital CH4 Mux"},
};

static int nau8540_clock_check(struct nau8540 *nau8540, int rate, int osr)
{
       int osrate;

       if (osr >= ARRAY_SIZE(osr_adc_sel))
               return -EINVAL;
       osrate = osr_adc_sel[osr].osr;

       if (rate * osr > CLK_ADC_MAX) {
               dev_err(nau8540->dev, "exceed the maximum frequency of CLK_ADC\n");
               return -EINVAL;
       }

       return 0;
}

static int nau8540_hw_params(struct snd_pcm_substream *substream,
       struct snd_pcm_hw_params *params, struct snd_soc_dai *dai)
{
       struct snd_soc_codec *codec = dai->codec;
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);
       unsigned int val_len = 0, osr;

       /* CLK_ADC = OSR * FS
        * ADC clock frequency is defined as Over Sampling Rate (OSR)
        * multiplied by the audio sample rate (Fs). Note that the OSR and Fs
        * values must be selected such that the maximum frequency is less
        * than 6.144 MHz.
        */
       regmap_read(nau8540->regmap, NAU8540_REG_ADC_SAMPLE_RATE, &osr);
       osr &= NAU8540_ADC_OSR_MASK;
       if (nau8540_clock_check(nau8540, params_rate(params), osr))
               return -EINVAL;
       regmap_update_bits(nau8540->regmap, NAU8540_REG_CLOCK_SRC,
               NAU8540_CLK_ADC_SRC_MASK,
               osr_adc_sel[osr].clk_src << NAU8540_CLK_ADC_SRC_SFT);

       switch (params_width(params)) {
       case 16:
               val_len |= NAU8540_I2S_DL_16;
               break;
       case 20:
               val_len |= NAU8540_I2S_DL_20;
               break;
       case 24:
               val_len |= NAU8540_I2S_DL_24;
               break;
       case 32:
               val_len |= NAU8540_I2S_DL_32;
               break;
       default:
               return -EINVAL;
       }

       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL0,
               NAU8540_I2S_DL_MASK, val_len);

       return 0;
}

static int nau8540_set_fmt(struct snd_soc_dai *dai, unsigned int fmt)
{
       struct snd_soc_codec *codec = dai->codec;
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);
       unsigned int ctrl1_val = 0, ctrl2_val = 0;

       switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
       case SND_SOC_DAIFMT_CBM_CFM:
               ctrl2_val |= NAU8540_I2S_MS_MASTER;
               break;
       case SND_SOC_DAIFMT_CBS_CFS:
               break;
       default:
               return -EINVAL;
       }

       switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
       case SND_SOC_DAIFMT_NB_NF:
               break;
       case SND_SOC_DAIFMT_IB_NF:
               ctrl1_val |= NAU8540_I2S_BP_INV;
               break;
       default:
               return -EINVAL;
       }

       switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
       case SND_SOC_DAIFMT_I2S:
               ctrl1_val |= NAU8540_I2S_DF_I2S;
               break;
       case SND_SOC_DAIFMT_LEFT_J:
               ctrl1_val |= NAU8540_I2S_DF_LEFT;
               break;
       case SND_SOC_DAIFMT_RIGHT_J:
               ctrl1_val |= NAU8540_I2S_DF_RIGTH;
               break;
       case SND_SOC_DAIFMT_DSP_A:
               ctrl1_val |= NAU8540_I2S_DF_PCM_AB;
               break;
       case SND_SOC_DAIFMT_DSP_B:
               ctrl1_val |= NAU8540_I2S_DF_PCM_AB;
               ctrl1_val |= NAU8540_I2S_PCMB_EN;
               break;
       default:
               return -EINVAL;
       }

       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL0,
               NAU8540_I2S_DL_MASK | NAU8540_I2S_DF_MASK |
               NAU8540_I2S_BP_INV | NAU8540_I2S_PCMB_EN, ctrl1_val);
       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL1,
               NAU8540_I2S_MS_MASK | NAU8540_I2S_DO12_OE, ctrl2_val);
       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL2,
               NAU8540_I2S_DO34_OE, 0);

       return 0;
}

/**
 * nau8540_set_tdm_slot - configure DAI TX TDM.
 * @dai: DAI
 * @tx_mask: bitmask representing active TX slots. Ex.
 *                 0xf for normal 4 channel TDM.
 *                 0xf0 for shifted 4 channel TDM
 * @rx_mask: no used.
 * @slots: Number of slots in use.
 * @slot_width: Width in bits for each slot.
 *
 * Configures a DAI for TDM operation. Only support 4 slots TDM.
 */
static int nau8540_set_tdm_slot(struct snd_soc_dai *dai,
       unsigned int tx_mask, unsigned int rx_mask, int slots, int slot_width)
{
       struct snd_soc_codec *codec = dai->codec;
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);
       unsigned int ctrl2_val = 0, ctrl4_val = 0;

       if (slots > 4 || ((tx_mask & 0xf0) && (tx_mask & 0xf)))
               return -EINVAL;

       ctrl4_val |= (NAU8540_TDM_MODE | NAU8540_TDM_OFFSET_EN);
       if (tx_mask & 0xf0) {
               ctrl2_val = 4 * slot_width;
               ctrl4_val |= (tx_mask >> 4);
       } else {
               ctrl4_val |= tx_mask;
       }
       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL4,
               NAU8540_TDM_MODE | NAU8540_TDM_OFFSET_EN |
               NAU8540_TDM_TX_MASK, ctrl4_val);
       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL1,
               NAU8540_I2S_DO12_OE, NAU8540_I2S_DO12_OE);
       regmap_update_bits(nau8540->regmap, NAU8540_REG_PCM_CTRL2,
               NAU8540_I2S_DO34_OE | NAU8540_I2S_TSLOT_L_MASK,
               NAU8540_I2S_DO34_OE | ctrl2_val);

       return 0;
}


static const struct snd_soc_dai_ops nau8540_dai_ops = {
       .hw_params = nau8540_hw_params,
       .set_fmt = nau8540_set_fmt,
       .set_tdm_slot = nau8540_set_tdm_slot,
};

#define NAU8540_RATES SNDRV_PCM_RATE_8000_48000
#define NAU8540_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S20_3LE \
        | SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S32_LE)

static struct snd_soc_dai_driver nau8540_dai = {
       .name = "nau8540-hifi",
       .capture = {
               .stream_name = "Capture",
               .channels_min = 1,
               .channels_max = 4,
               .rates = NAU8540_RATES,
               .formats = NAU8540_FORMATS,
       },
       .ops = &nau8540_dai_ops,
};

/**
 * nau8540_calc_fll_param - Calculate FLL parameters.
 * @fll_in: external clock provided to codec.
 * @fs: sampling rate.
 * @fll_param: Pointer to structure of FLL parameters.
 *
 * Calculate FLL parameters to configure codec.
 *
 * Returns 0 for success or negative error code.
 */
static int nau8540_calc_fll_param(unsigned int fll_in,
       unsigned int fs, struct nau8540_fll *fll_param)
{
       u64 fvco, fvco_max;
       unsigned int fref, i, fvco_sel;

       /* Ensure the reference clock frequency (FREF) is <= 13.5MHz by dividing
        * freq_in by 1, 2, 4, or 8 using FLL pre-scalar.
        * FREF = freq_in / NAU8540_FLL_REF_DIV_MASK
        */
       for (i = 0; i < ARRAY_SIZE(fll_pre_scalar); i++) {
               fref = fll_in / fll_pre_scalar[i].param;
               if (fref <= NAU_FREF_MAX)
                       break;
       }
       if (i == ARRAY_SIZE(fll_pre_scalar))
               return -EINVAL;
       fll_param->clk_ref_div = fll_pre_scalar[i].val;

       /* Choose the FLL ratio based on FREF */
       for (i = 0; i < ARRAY_SIZE(fll_ratio); i++) {
               if (fref >= fll_ratio[i].param)
                       break;
       }
       if (i == ARRAY_SIZE(fll_ratio))
               return -EINVAL;
       fll_param->ratio = fll_ratio[i].val;

       /* Calculate the frequency of DCO (FDCO) given freq_out = 256 * Fs.
        * FDCO must be within the 90MHz - 124MHz or the FFL cannot be
        * guaranteed across the full range of operation.
        * FDCO = freq_out * 2 * mclk_src_scaling
        */
       fvco_max = 0;
       fvco_sel = ARRAY_SIZE(mclk_src_scaling);
       for (i = 0; i < ARRAY_SIZE(mclk_src_scaling); i++) {
               fvco = 256 * fs * 2 * mclk_src_scaling[i].param;
               if (fvco > NAU_FVCO_MIN && fvco < NAU_FVCO_MAX &&
                       fvco_max < fvco) {
                       fvco_max = fvco;
                       fvco_sel = i;
               }
       }
       if (ARRAY_SIZE(mclk_src_scaling) == fvco_sel)
               return -EINVAL;
       fll_param->mclk_src = mclk_src_scaling[fvco_sel].val;

       /* Calculate the FLL 10-bit integer input and the FLL 16-bit fractional
        * input based on FDCO, FREF and FLL ratio.
        */
       fvco = div_u64(fvco_max << 16, fref * fll_param->ratio);
       fll_param->fll_int = (fvco >> 16) & 0x3FF;
       fll_param->fll_frac = fvco & 0xFFFF;
       return 0;
}

static void nau8540_fll_apply(struct regmap *regmap,
       struct nau8540_fll *fll_param)
{
       regmap_update_bits(regmap, NAU8540_REG_CLOCK_SRC,
               NAU8540_CLK_SRC_MASK | NAU8540_CLK_MCLK_SRC_MASK,
               NAU8540_CLK_SRC_MCLK | fll_param->mclk_src);
       regmap_update_bits(regmap, NAU8540_REG_FLL1,
               NAU8540_FLL_RATIO_MASK, fll_param->ratio);
       /* FLL 16-bit fractional input */
       regmap_write(regmap, NAU8540_REG_FLL2, fll_param->fll_frac);
       /* FLL 10-bit integer input */
       regmap_update_bits(regmap, NAU8540_REG_FLL3,
               NAU8540_FLL_INTEGER_MASK, fll_param->fll_int);
       /* FLL pre-scaler */
       regmap_update_bits(regmap, NAU8540_REG_FLL4,
               NAU8540_FLL_REF_DIV_MASK,
               fll_param->clk_ref_div << NAU8540_FLL_REF_DIV_SFT);
       regmap_update_bits(regmap, NAU8540_REG_FLL5,
               NAU8540_FLL_CLK_SW_MASK, NAU8540_FLL_CLK_SW_REF);
       regmap_update_bits(regmap,
               NAU8540_REG_FLL6, NAU8540_DCO_EN, 0);
       if (fll_param->fll_frac) {
               regmap_update_bits(regmap, NAU8540_REG_FLL5,
                       NAU8540_FLL_PDB_DAC_EN | NAU8540_FLL_LOOP_FTR_EN |
                       NAU8540_FLL_FTR_SW_MASK,
                       NAU8540_FLL_PDB_DAC_EN | NAU8540_FLL_LOOP_FTR_EN |
                       NAU8540_FLL_FTR_SW_FILTER);
               regmap_update_bits(regmap, NAU8540_REG_FLL6,
                       NAU8540_SDM_EN, NAU8540_SDM_EN);
       } else {
               regmap_update_bits(regmap, NAU8540_REG_FLL5,
                       NAU8540_FLL_PDB_DAC_EN | NAU8540_FLL_LOOP_FTR_EN |
                       NAU8540_FLL_FTR_SW_MASK, NAU8540_FLL_FTR_SW_ACCU);
               regmap_update_bits(regmap,
                       NAU8540_REG_FLL6, NAU8540_SDM_EN, 0);
       }
}

/* freq_out must be 256*Fs in order to achieve the best performance */
static int nau8540_set_pll(struct snd_soc_codec *codec, int pll_id, int source,
               unsigned int freq_in, unsigned int freq_out)
{
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);
       struct nau8540_fll fll_param;
       int ret, fs;

       switch (pll_id) {
       case NAU8540_CLK_FLL_MCLK:
               regmap_update_bits(nau8540->regmap, NAU8540_REG_FLL3,
                       NAU8540_FLL_CLK_SRC_MASK, NAU8540_FLL_CLK_SRC_MCLK);
               break;

       case NAU8540_CLK_FLL_BLK:
               regmap_update_bits(nau8540->regmap, NAU8540_REG_FLL3,
                       NAU8540_FLL_CLK_SRC_MASK, NAU8540_FLL_CLK_SRC_BLK);
               break;

       case NAU8540_CLK_FLL_FS:
               regmap_update_bits(nau8540->regmap, NAU8540_REG_FLL3,
                       NAU8540_FLL_CLK_SRC_MASK, NAU8540_FLL_CLK_SRC_FS);
               break;

       default:
               dev_err(nau8540->dev, "Invalid clock id (%d)\n", pll_id);
               return -EINVAL;
       }
       dev_dbg(nau8540->dev, "Sysclk is %dHz and clock id is %d\n",
               freq_out, pll_id);

       fs = freq_out / 256;
       ret = nau8540_calc_fll_param(freq_in, fs, &fll_param);
       if (ret < 0) {
               dev_err(nau8540->dev, "Unsupported input clock %d\n", freq_in);
               return ret;
       }
       dev_dbg(nau8540->dev, "mclk_src=%x ratio=%x fll_frac=%x fll_int=%x clk_ref_div=%x\n",
               fll_param.mclk_src, fll_param.ratio, fll_param.fll_frac,
               fll_param.fll_int, fll_param.clk_ref_div);

       nau8540_fll_apply(nau8540->regmap, &fll_param);
       mdelay(2);
       regmap_update_bits(nau8540->regmap, NAU8540_REG_CLOCK_SRC,
               NAU8540_CLK_SRC_MASK, NAU8540_CLK_SRC_VCO);

       return 0;
}

static int nau8540_set_sysclk(struct snd_soc_codec *codec,
       int clk_id, int source, unsigned int freq, int dir)
{
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);

       switch (clk_id) {
       case NAU8540_CLK_DIS:
       case NAU8540_CLK_MCLK:
               regmap_update_bits(nau8540->regmap, NAU8540_REG_CLOCK_SRC,
                       NAU8540_CLK_SRC_MASK, NAU8540_CLK_SRC_MCLK);
               regmap_update_bits(nau8540->regmap, NAU8540_REG_FLL6,
                       NAU8540_DCO_EN, 0);
               break;

       case NAU8540_CLK_INTERNAL:
               regmap_update_bits(nau8540->regmap, NAU8540_REG_FLL6,
                       NAU8540_DCO_EN, NAU8540_DCO_EN);
               regmap_update_bits(nau8540->regmap, NAU8540_REG_CLOCK_SRC,
                       NAU8540_CLK_SRC_MASK, NAU8540_CLK_SRC_VCO);
               break;

       default:
               dev_err(nau8540->dev, "Invalid clock id (%d)\n", clk_id);
               return -EINVAL;
       }

       dev_dbg(nau8540->dev, "Sysclk is %dHz and clock id is %d\n",
               freq, clk_id);

       return 0;
}

static void nau8540_reset_chip(struct regmap *regmap)
{
       regmap_write(regmap, NAU8540_REG_SW_RESET, 0x00);
       regmap_write(regmap, NAU8540_REG_SW_RESET, 0x00);
}

static void nau8540_init_regs(struct nau8540 *nau8540)
{
       struct regmap *regmap = nau8540->regmap;

       /* Enable Bias/VMID/VMID Tieoff */
       regmap_update_bits(regmap, NAU8540_REG_VMID_CTRL,
               NAU8540_VMID_EN | NAU8540_VMID_SEL_MASK,
               NAU8540_VMID_EN | (0x2 << NAU8540_VMID_SEL_SFT));
       regmap_update_bits(regmap, NAU8540_REG_REFERENCE,
               NAU8540_PRECHARGE_DIS | NAU8540_GLOBAL_BIAS_EN,
               NAU8540_PRECHARGE_DIS | NAU8540_GLOBAL_BIAS_EN);
       mdelay(2);
       regmap_update_bits(regmap, NAU8540_REG_MIC_BIAS,
               NAU8540_PU_PRE, NAU8540_PU_PRE);
       regmap_update_bits(regmap, NAU8540_REG_CLOCK_CTRL,
               NAU8540_CLK_ADC_EN | NAU8540_CLK_I2S_EN,
               NAU8540_CLK_ADC_EN | NAU8540_CLK_I2S_EN);
       /* ADC OSR selection, CLK_ADC = Fs * OSR */
       regmap_update_bits(regmap, NAU8540_REG_ADC_SAMPLE_RATE,
               NAU8540_ADC_OSR_MASK, NAU8540_ADC_OSR_64);
}

static int __maybe_unused nau8540_suspend(struct snd_soc_codec *codec)
{
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);

       regcache_cache_only(nau8540->regmap, true);
       regcache_mark_dirty(nau8540->regmap);

       return 0;
}

static int __maybe_unused nau8540_resume(struct snd_soc_codec *codec)
{
       struct nau8540 *nau8540 = snd_soc_codec_get_drvdata(codec);

       regcache_cache_only(nau8540->regmap, false);
       regcache_sync(nau8540->regmap);

       return 0;
}

static struct snd_soc_codec_driver nau8540_codec_driver = {
       .set_sysclk = nau8540_set_sysclk,
       .set_pll = nau8540_set_pll,
       .suspend = nau8540_suspend,
       .resume = nau8540_resume,
       .suspend_bias_off = true,

       .component_driver = {
               .controls = nau8540_snd_controls,
               .num_controls = ARRAY_SIZE(nau8540_snd_controls),
               .dapm_widgets = nau8540_dapm_widgets,
               .num_dapm_widgets = ARRAY_SIZE(nau8540_dapm_widgets),
               .dapm_routes = nau8540_dapm_routes,
               .num_dapm_routes = ARRAY_SIZE(nau8540_dapm_routes),
       },
};

static const struct regmap_config nau8540_regmap_config = {
       .val_bits = 16,
       .reg_bits = 16,

       .max_register = NAU8540_REG_MAX,
       .readable_reg = nau8540_readable_reg,
       .writeable_reg = nau8540_writeable_reg,
       .volatile_reg = nau8540_volatile_reg,

       .cache_type = REGCACHE_RBTREE,
       .reg_defaults = nau8540_reg_defaults,
       .num_reg_defaults = ARRAY_SIZE(nau8540_reg_defaults),
};

static int nau8540_i2c_probe(struct i2c_client *i2c,
       const struct i2c_device_id *id)
{
       struct device *dev = &i2c->dev;
       struct nau8540 *nau8540 = dev_get_platdata(dev);
       int ret, value;

       if (!nau8540) {
               nau8540 = devm_kzalloc(dev, sizeof(*nau8540), GFP_KERNEL);
               if (!nau8540)
                       return -ENOMEM;
       }
       i2c_set_clientdata(i2c, nau8540);

       nau8540->regmap = devm_regmap_init_i2c(i2c, &nau8540_regmap_config);
       if (IS_ERR(nau8540->regmap))
               return PTR_ERR(nau8540->regmap);
       ret = regmap_read(nau8540->regmap, NAU8540_REG_I2C_DEVICE_ID, &value);
       if (ret < 0) {
               dev_err(dev, "Failed to read device id from the NAU85L40: %d\n",
                       ret);
               return ret;
       }

       nau8540->dev = dev;
       nau8540_reset_chip(nau8540->regmap);
       nau8540_init_regs(nau8540);

       return snd_soc_register_codec(dev,
               &nau8540_codec_driver, &nau8540_dai, 1);
}

static int nau8540_i2c_remove(struct i2c_client *client)
{
       snd_soc_unregister_codec(&client->dev);
       return 0;
}


static const struct i2c_device_id nau8540_i2c_ids[] = {
       { "nau8540", 0 },
       { }
};
MODULE_DEVICE_TABLE(i2c, nau8540_i2c_ids);

#ifdef CONFIG_OF
static const struct of_device_id nau8540_of_ids[] = {
       { .compatible = "nuvoton,nau8540", },
       {}
};
MODULE_DEVICE_TABLE(of, nau8540_of_ids);
#endif

static struct i2c_driver nau8540_i2c_driver = {
       .driver = {
               .name = "nau8540",
               .of_match_table = of_match_ptr(nau8540_of_ids),
       },
       .probe = nau8540_i2c_probe,
       .remove = nau8540_i2c_remove,
       .id_table = nau8540_i2c_ids,
};
module_i2c_driver(nau8540_i2c_driver);

MODULE_DESCRIPTION("ASoC NAU85L40 driver");
MODULE_AUTHOR("John Hsu <KCHSU0@nuvoton.com>");
MODULE_LICENSE("GPL v2");