/*
 * tas5720.c - ALSA SoC Texas Instruments TAS5720 Mono Audio Amplifier
 *
 * Copyright (C)2015-2016 Texas Instruments Incorporated -  http://www.ti.com
 *
 * Author: Andreas Dannenberg <dannenberg@ti.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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 */

#include <linux/module.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/i2c.h>
#include <linux/pm_runtime.h>
#include <linux/regmap.h>
#include <linux/slab.h>
#include <linux/regulator/consumer.h>
#include <linux/delay.h>

#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/soc-dapm.h>
#include <sound/tlv.h>

#include "tas5720.h"

/* Define how often to check (and clear) the fault status register (in ms) */
#define TAS5720_FAULT_CHECK_INTERVAL            200

static const char * const tas5720_supply_names[] = {
        "dvdd",         /* Digital power supply. Connect to 3.3-V supply. */
        "pvdd",         /* Class-D amp and analog power supply (connected). */
};

#define TAS5720_NUM_SUPPLIES    ARRAY_SIZE(tas5720_supply_names)

struct tas5720_data {
        struct snd_soc_codec *codec;
        struct regmap *regmap;
        struct i2c_client *tas5720_client;
        struct regulator_bulk_data supplies[TAS5720_NUM_SUPPLIES];
        struct delayed_work fault_check_work;
        unsigned int last_fault;
};

static int tas5720_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;
        unsigned int rate = params_rate(params);
        bool ssz_ds;
        int ret;

        switch (rate) {
        case 44100:
        case 48000:
                ssz_ds = false;
                break;
        case 88200:
        case 96000:
                ssz_ds = true;
                break;
        default:
                dev_err(codec->dev, "unsupported sample rate: %u\n", rate);
                return -EINVAL;
        }

        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL1_REG,
                                  TAS5720_SSZ_DS, ssz_ds);
        if (ret < 0) {
                dev_err(codec->dev, "error setting sample rate: %d\n", ret);
                return ret;
        }

        return 0;
}

static int tas5720_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
{
        struct snd_soc_codec *codec = dai->codec;
        u8 serial_format;
        int ret;

        if ((fmt & SND_SOC_DAIFMT_MASTER_MASK) != SND_SOC_DAIFMT_CBS_CFS) {
                dev_vdbg(codec->dev, "DAI Format master is not found\n");
                return -EINVAL;
        }

        switch (fmt & (SND_SOC_DAIFMT_FORMAT_MASK |
                       SND_SOC_DAIFMT_INV_MASK)) {
        case (SND_SOC_DAIFMT_I2S | SND_SOC_DAIFMT_NB_NF):
                /* 1st data bit occur one BCLK cycle after the frame sync */
                serial_format = TAS5720_SAIF_I2S;
                break;
        case (SND_SOC_DAIFMT_DSP_A | SND_SOC_DAIFMT_NB_NF):
                /*
                 * Note that although the TAS5720 does not have a dedicated DSP
                 * mode it doesn't care about the LRCLK duty cycle during TDM
                 * operation. Therefore we can use the device's I2S mode with
                 * its delaying of the 1st data bit to receive DSP_A formatted
                 * data. See device datasheet for additional details.
                 */
                serial_format = TAS5720_SAIF_I2S;
                break;
        case (SND_SOC_DAIFMT_DSP_B | SND_SOC_DAIFMT_NB_NF):
                /*
                 * Similar to DSP_A, we can use the fact that the TAS5720 does
                 * not care about the LRCLK duty cycle during TDM to receive
                 * DSP_B formatted data in LEFTJ mode (no delaying of the 1st
                 * data bit).
                 */
                serial_format = TAS5720_SAIF_LEFTJ;
                break;
        case (SND_SOC_DAIFMT_LEFT_J | SND_SOC_DAIFMT_NB_NF):
                /* No delay after the frame sync */
                serial_format = TAS5720_SAIF_LEFTJ;
                break;
        default:
                dev_vdbg(codec->dev, "DAI Format is not found\n");
                return -EINVAL;
        }

        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL1_REG,
                                  TAS5720_SAIF_FORMAT_MASK,
                                  serial_format);
        if (ret < 0) {
                dev_err(codec->dev, "error setting SAIF format: %d\n", ret);
                return ret;
        }

        return 0;
}

static int tas5720_set_dai_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;
        unsigned int first_slot;
        int ret;

        if (!tx_mask) {
                dev_err(codec->dev, "tx masks must not be 0\n");
                return -EINVAL;
        }

        /*
         * Determine the first slot that is being requested. We will only
         * use the first slot that is found since the TAS5720 is a mono
         * amplifier.
         */
        first_slot = __ffs(tx_mask);

        if (first_slot > 7) {
                dev_err(codec->dev, "slot selection out of bounds (%u)\n",
                        first_slot);
                return -EINVAL;
        }

        /* Enable manual TDM slot selection (instead of I2C ID based) */
        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL1_REG,
                                  TAS5720_TDM_CFG_SRC, TAS5720_TDM_CFG_SRC);
        if (ret < 0)
                goto error_snd_soc_update_bits;

        /* Configure the TDM slot to process audio from */
        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL2_REG,
                                  TAS5720_TDM_SLOT_SEL_MASK, first_slot);
        if (ret < 0)
                goto error_snd_soc_update_bits;

        return 0;

error_snd_soc_update_bits:
        dev_err(codec->dev, "error configuring TDM mode: %d\n", ret);
        return ret;
}

static int tas5720_mute(struct snd_soc_dai *dai, int mute)
{
        struct snd_soc_codec *codec = dai->codec;
        int ret;

        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL2_REG,
                                  TAS5720_MUTE, mute ? TAS5720_MUTE : 0);
        if (ret < 0) {
                dev_err(codec->dev, "error (un-)muting device: %d\n", ret);
                return ret;
        }

        return 0;
}

static void tas5720_fault_check_work(struct work_struct *work)
{
        struct tas5720_data *tas5720 = container_of(work, struct tas5720_data,
                        fault_check_work.work);
        struct device *dev = tas5720->codec->dev;
        unsigned int curr_fault;
        int ret;

        ret = regmap_read(tas5720->regmap, TAS5720_FAULT_REG, &curr_fault);
        if (ret < 0) {
                dev_err(dev, "failed to read FAULT register: %d\n", ret);
                goto out;
        }

        /* Check/handle all errors except SAIF clock errors */
        curr_fault &= TAS5720_OCE | TAS5720_DCE | TAS5720_OTE;

        /*
         * Only flag errors once for a given occurrence. This is needed as
         * the TAS5720 will take time clearing the fault condition internally
         * during which we don't want to bombard the system with the same
         * error message over and over.
         */
        if ((curr_fault & TAS5720_OCE) && !(tas5720->last_fault & TAS5720_OCE))
                dev_crit(dev, "experienced an over current hardware fault\n");

        if ((curr_fault & TAS5720_DCE) && !(tas5720->last_fault & TAS5720_DCE))
                dev_crit(dev, "experienced a DC detection fault\n");

        if ((curr_fault & TAS5720_OTE) && !(tas5720->last_fault & TAS5720_OTE))
                dev_crit(dev, "experienced an over temperature fault\n");

        /* Store current fault value so we can detect any changes next time */
        tas5720->last_fault = curr_fault;

        if (!curr_fault)
                goto out;

        /*
         * Periodically toggle SDZ (shutdown bit) H->L->H to clear any latching
         * faults as long as a fault condition persists. Always going through
         * the full sequence no matter the first return value to minimizes
         * chances for the device to end up in shutdown mode.
         */
        ret = regmap_write_bits(tas5720->regmap, TAS5720_POWER_CTRL_REG,
                                TAS5720_SDZ, 0);
        if (ret < 0)
                dev_err(dev, "failed to write POWER_CTRL register: %d\n", ret);

        ret = regmap_write_bits(tas5720->regmap, TAS5720_POWER_CTRL_REG,
                                TAS5720_SDZ, TAS5720_SDZ);
        if (ret < 0)
                dev_err(dev, "failed to write POWER_CTRL register: %d\n", ret);

out:
        /* Schedule the next fault check at the specified interval */
        schedule_delayed_work(&tas5720->fault_check_work,
                              msecs_to_jiffies(TAS5720_FAULT_CHECK_INTERVAL));
}

static int tas5720_codec_probe(struct snd_soc_codec *codec)
{
        struct tas5720_data *tas5720 = snd_soc_codec_get_drvdata(codec);
        unsigned int device_id;
        int ret;

        tas5720->codec = codec;

        ret = regulator_bulk_enable(ARRAY_SIZE(tas5720->supplies),
                                    tas5720->supplies);
        if (ret != 0) {
                dev_err(codec->dev, "failed to enable supplies: %d\n", ret);
                return ret;
        }

        ret = regmap_read(tas5720->regmap, TAS5720_DEVICE_ID_REG, &device_id);
        if (ret < 0) {
                dev_err(codec->dev, "failed to read device ID register: %d\n",
                        ret);
                goto probe_fail;
        }

        if (device_id != TAS5720_DEVICE_ID) {
                dev_err(codec->dev, "wrong device ID. expected: %u read: %u\n",
                        TAS5720_DEVICE_ID, device_id);
                ret = -ENODEV;
                goto probe_fail;
        }

        /* Set device to mute */
        ret = snd_soc_update_bits(codec, TAS5720_DIGITAL_CTRL2_REG,
                                  TAS5720_MUTE, TAS5720_MUTE);
        if (ret < 0)
                goto error_snd_soc_update_bits;

        /*
         * Enter shutdown mode - our default when not playing audio - to
         * minimize current consumption. On the TAS5720 there is no real down
         * side doing so as all device registers are preserved and the wakeup
         * of the codec is rather quick which we do using a dapm widget.
         */
        ret = snd_soc_update_bits(codec, TAS5720_POWER_CTRL_REG,
                                  TAS5720_SDZ, 0);
        if (ret < 0)
                goto error_snd_soc_update_bits;

        INIT_DELAYED_WORK(&tas5720->fault_check_work, tas5720_fault_check_work);

        return 0;

error_snd_soc_update_bits:
        dev_err(codec->dev, "error configuring device registers: %d\n", ret);

probe_fail:
        regulator_bulk_disable(ARRAY_SIZE(tas5720->supplies),
                               tas5720->supplies);
        return ret;
}

static int tas5720_codec_remove(struct snd_soc_codec *codec)
{
        struct tas5720_data *tas5720 = snd_soc_codec_get_drvdata(codec);
        int ret;

        cancel_delayed_work_sync(&tas5720->fault_check_work);

        ret = regulator_bulk_disable(ARRAY_SIZE(tas5720->supplies),
                                     tas5720->supplies);
        if (ret < 0)
                dev_err(codec->dev, "failed to disable supplies: %d\n", ret);

        return ret;
};

static int tas5720_dac_event(struct snd_soc_dapm_widget *w,
                             struct snd_kcontrol *kcontrol, int event)
{
        struct snd_soc_codec *codec = snd_soc_dapm_to_codec(w->dapm);
        struct tas5720_data *tas5720 = snd_soc_codec_get_drvdata(codec);
        int ret;

        if (event & SND_SOC_DAPM_POST_PMU) {
                /* Take TAS5720 out of shutdown mode */
                ret = snd_soc_update_bits(codec, TAS5720_POWER_CTRL_REG,
                                          TAS5720_SDZ, TAS5720_SDZ);
                if (ret < 0) {
                        dev_err(codec->dev, "error waking codec: %d\n", ret);
                        return ret;
                }

                /*
                 * Observe codec shutdown-to-active time. The datasheet only
                 * lists a nominal value however just use-it as-is without
                 * additional padding to minimize the delay introduced in
                 * starting to play audio (actually there is other setup done
                 * by the ASoC framework that will provide additional delays,
                 * so we should always be safe).
                 */
                msleep(25);

                /* Turn on TAS5720 periodic fault checking/handling */
                tas5720->last_fault = 0;
                schedule_delayed_work(&tas5720->fault_check_work,
                                msecs_to_jiffies(TAS5720_FAULT_CHECK_INTERVAL));
        } else if (event & SND_SOC_DAPM_PRE_PMD) {
                /* Disable TAS5720 periodic fault checking/handling */
                cancel_delayed_work_sync(&tas5720->fault_check_work);

                /* Place TAS5720 in shutdown mode to minimize current draw */
                ret = snd_soc_update_bits(codec, TAS5720_POWER_CTRL_REG,
                                          TAS5720_SDZ, 0);
                if (ret < 0) {
                        dev_err(codec->dev, "error shutting down codec: %d\n",
                                ret);
                        return ret;
                }
        }

        return 0;
}

#ifdef CONFIG_PM
static int tas5720_suspend(struct snd_soc_codec *codec)
{
        struct tas5720_data *tas5720 = snd_soc_codec_get_drvdata(codec);
        int ret;

        regcache_cache_only(tas5720->regmap, true);
        regcache_mark_dirty(tas5720->regmap);

        ret = regulator_bulk_disable(ARRAY_SIZE(tas5720->supplies),
                                     tas5720->supplies);
        if (ret < 0)
                dev_err(codec->dev, "failed to disable supplies: %d\n", ret);

        return ret;
}

static int tas5720_resume(struct snd_soc_codec *codec)
{
        struct tas5720_data *tas5720 = snd_soc_codec_get_drvdata(codec);
        int ret;

        ret = regulator_bulk_enable(ARRAY_SIZE(tas5720->supplies),
                                    tas5720->supplies);
        if (ret < 0) {
                dev_err(codec->dev, "failed to enable supplies: %d\n", ret);
                return ret;
        }

        regcache_cache_only(tas5720->regmap, false);

        ret = regcache_sync(tas5720->regmap);
        if (ret < 0) {
                dev_err(codec->dev, "failed to sync regcache: %d\n", ret);
                return ret;
        }

        return 0;
}
#else
#define tas5720_suspend NULL
#define tas5720_resume NULL
#endif

static bool tas5720_is_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case TAS5720_DEVICE_ID_REG:
        case TAS5720_FAULT_REG:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config tas5720_regmap_config = {
        .reg_bits = 8,
        .val_bits = 8,

        .max_register = TAS5720_MAX_REG,
        .cache_type = REGCACHE_RBTREE,
        .volatile_reg = tas5720_is_volatile_reg,
};

/*
 * DAC analog gain. There are four discrete values to select from, ranging
 * from 19.2 dB to 26.3dB.
 */
static const DECLARE_TLV_DB_RANGE(dac_analog_tlv,
        0x0, 0x0, TLV_DB_SCALE_ITEM(1920, 0, 0),
        0x1, 0x1, TLV_DB_SCALE_ITEM(2070, 0, 0),
        0x2, 0x2, TLV_DB_SCALE_ITEM(2350, 0, 0),
        0x3, 0x3, TLV_DB_SCALE_ITEM(2630, 0, 0),
);

/*
 * DAC digital volumes. From -103.5 to 24 dB in 0.5 dB steps. Note that
 * setting the gain below -100 dB (register value <0x7) is effectively a MUTE
 * as per device datasheet.
 */
static DECLARE_TLV_DB_SCALE(dac_tlv, -10350, 50, 0);

static const struct snd_kcontrol_new tas5720_snd_controls[] = {
        SOC_SINGLE_TLV("Speaker Driver Playback Volume",
                       TAS5720_VOLUME_CTRL_REG, 0, 0xff, 0, dac_tlv),
        SOC_SINGLE_TLV("Speaker Driver Analog Gain", TAS5720_ANALOG_CTRL_REG,
                       TAS5720_ANALOG_GAIN_SHIFT, 3, 0, dac_analog_tlv),
};

static const struct snd_soc_dapm_widget tas5720_dapm_widgets[] = {
        SND_SOC_DAPM_AIF_IN("DAC IN", "Playback", 0, SND_SOC_NOPM, 0, 0),
        SND_SOC_DAPM_DAC_E("DAC", NULL, SND_SOC_NOPM, 0, 0, tas5720_dac_event,
                           SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD),
        SND_SOC_DAPM_OUTPUT("OUT")
};

static const struct snd_soc_dapm_route tas5720_audio_map[] = {
        { "DAC", NULL, "DAC IN" },
        { "OUT", NULL, "DAC" },
};

static struct snd_soc_codec_driver soc_codec_dev_tas5720 = {
        .probe = tas5720_codec_probe,
        .remove = tas5720_codec_remove,
        .suspend = tas5720_suspend,
        .resume = tas5720_resume,

        .component_driver = {
                .controls               = tas5720_snd_controls,
                .num_controls           = ARRAY_SIZE(tas5720_snd_controls),
                .dapm_widgets           = tas5720_dapm_widgets,
                .num_dapm_widgets       = ARRAY_SIZE(tas5720_dapm_widgets),
                .dapm_routes            = tas5720_audio_map,
                .num_dapm_routes        = ARRAY_SIZE(tas5720_audio_map),
        },
};

/* PCM rates supported by the TAS5720 driver */
#define TAS5720_RATES   (SNDRV_PCM_RATE_44100 | SNDRV_PCM_RATE_48000 |\
                         SNDRV_PCM_RATE_88200 | SNDRV_PCM_RATE_96000)

/* Formats supported by TAS5720 driver */
#define TAS5720_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S18_3LE |\
                         SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_S24_LE)

static struct snd_soc_dai_ops tas5720_speaker_dai_ops = {
        .hw_params      = tas5720_hw_params,
        .set_fmt        = tas5720_set_dai_fmt,
        .set_tdm_slot   = tas5720_set_dai_tdm_slot,
        .digital_mute   = tas5720_mute,
};

/*
 * TAS5720 DAI structure
 *
 * Note that were are advertising .playback.channels_max = 2 despite this being
 * a mono amplifier. The reason for that is that some serial ports such as TI's
 * McASP module have a minimum number of channels (2) that they can output.
 * Advertising more channels than we have will allow us to interface with such
 * a serial port without really any negative side effects as the TAS5720 will
 * simply ignore any extra channel(s) asides from the one channel that is
 * configured to be played back.
 */
static struct snd_soc_dai_driver tas5720_dai[] = {
        {
                .name = "tas5720-amplifier",
                .playback = {
                        .stream_name = "Playback",
                        .channels_min = 1,
                        .channels_max = 2,
                        .rates = TAS5720_RATES,
                        .formats = TAS5720_FORMATS,
                },
                .ops = &tas5720_speaker_dai_ops,
        },
};

static int tas5720_probe(struct i2c_client *client,
                         const struct i2c_device_id *id)
{
        struct device *dev = &client->dev;
        struct tas5720_data *data;
        int ret;
        int i;

        data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        data->tas5720_client = client;
        data->regmap = devm_regmap_init_i2c(client, &tas5720_regmap_config);
        if (IS_ERR(data->regmap)) {
                ret = PTR_ERR(data->regmap);
                dev_err(dev, "failed to allocate register map: %d\n", ret);
                return ret;
        }

        for (i = 0; i < ARRAY_SIZE(data->supplies); i++)
                data->supplies[i].supply = tas5720_supply_names[i];

        ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->supplies),
                                      data->supplies);
        if (ret != 0) {
                dev_err(dev, "failed to request supplies: %d\n", ret);
                return ret;
        }

        dev_set_drvdata(dev, data);

        ret = snd_soc_register_codec(&client->dev,
                                     &soc_codec_dev_tas5720,
                                     tas5720_dai, ARRAY_SIZE(tas5720_dai));
        if (ret < 0) {
                dev_err(dev, "failed to register codec: %d\n", ret);
                return ret;
        }

        return 0;
}

static int tas5720_remove(struct i2c_client *client)
{
        struct device *dev = &client->dev;

        snd_soc_unregister_codec(dev);

        return 0;
}

static const struct i2c_device_id tas5720_id[] = {
        { "tas5720", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, tas5720_id);

#if IS_ENABLED(CONFIG_OF)
static const struct of_device_id tas5720_of_match[] = {
        { .compatible = "ti,tas5720", },
        { },
};
MODULE_DEVICE_TABLE(of, tas5720_of_match);
#endif

static struct i2c_driver tas5720_i2c_driver = {
        .driver = {
                .name = "tas5720",
                .of_match_table = of_match_ptr(tas5720_of_match),
        },
        .probe = tas5720_probe,
        .remove = tas5720_remove,
        .id_table = tas5720_id,
};

module_i2c_driver(tas5720_i2c_driver);

MODULE_AUTHOR("Andreas Dannenberg <dannenberg@ti.com>");
MODULE_DESCRIPTION("TAS5720 Audio amplifier driver");
MODULE_LICENSE("GPL");