// SPDX-License-Identifier: GPL-2.0
/*
 * Internal DAC codec for cv1800b based CPUs
 */

#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/bitfield.h>
#include <linux/bits.h>
#include <sound/soc.h>
#include <linux/io.h>

#define CV1800B_TXDAC_CTRL0   0x00
#define CV1800B_TXDAC_CTRL1   0x04
#define CV1800B_TXDAC_STATUS  0x08
#define CV1800B_TXDAC_AFE0    0x0c
#define CV1800B_TXDAC_AFE1    0x10
#define CV1800B_TXDAC_ANA0    0x20
#define CV1800B_TXDAC_ANA1    0x24
#define CV1800B_TXDAC_ANA2    0x28

/* cv1800b_TXDAC_CTRL0 */
#define REG_TXDAC_EN GENMASK(0, 0)
#define REG_I2S_RX_EN GENMASK(1, 1)

/* cv1800b_TXDAC_CTRL1 */
#define REG_TXDAC_CIC_OPT GENMASK(1, 0)

/* cv1800b_TXDAC_AFE0 */
#define REG_TXDAC_INIT_DLY_CNT GENMASK(5, 0)

/* cv1800b_TXDAC_ANA2 */
#define TXDAC_OW_VAL_L_MASK GENMASK(7, 0)
#define TXDAC_OW_VAL_R_MASK GENMASK(15, 8)
#define TXDAC_OW_EN_L_MASK GENMASK(16, 16)
#define TXDAC_OW_EN_R_MASK GENMASK(17, 17)

struct cv1800b_priv {
        void __iomem *regs;
        struct device *dev;
};

enum decimation_values {
        DECIMATION_64 = 0,
        DECIMATION_128,
        DECIMATION_256,
        DECIMATION_512,
};

static void cv1800b_dac_enable(struct cv1800b_priv *priv, bool enable)
{
        u32 val;

        val = readl(priv->regs + CV1800B_TXDAC_CTRL0);
        val = u32_replace_bits(val, enable, REG_TXDAC_EN);
        val = u32_replace_bits(val, enable, REG_I2S_RX_EN);
        writel(val, priv->regs + CV1800B_TXDAC_CTRL0);
}

/*
 * Control the DAC overwrite bits. When enabled, the DAC outputs the fixed
 * overwrite value instead of samples from the I2S input.
 */
static void cv1800b_dac_mute(struct cv1800b_priv *priv, bool enable)
{
        u32 val;

        val = readl(priv->regs + CV1800B_TXDAC_ANA2);
        val = u32_replace_bits(val, enable, TXDAC_OW_EN_L_MASK);
        val = u32_replace_bits(val, enable, TXDAC_OW_EN_R_MASK);
        writel(val, priv->regs + CV1800B_TXDAC_ANA2);
}

static int cv1800b_dac_decimation(struct cv1800b_priv *priv, u8 dec)
{
        u32 val;

        if (dec > 3)
                return -EINVAL;

        val = readl(priv->regs + CV1800B_TXDAC_CTRL1);
        val = u32_replace_bits(val, dec, REG_TXDAC_CIC_OPT);
        writel(val, priv->regs + CV1800B_TXDAC_CTRL1);
        return 0;
}

static int cv1800b_dac_dly(struct cv1800b_priv *priv, u32 dly)
{
        u32 val;

        if (dly > 63)
                return -EINVAL;

        val = readl(priv->regs + CV1800B_TXDAC_AFE0);
        val = u32_replace_bits(val, dly, REG_TXDAC_INIT_DLY_CNT);
        writel(val, priv->regs + CV1800B_TXDAC_AFE0);
        return 0;
}

static int cv1800b_dac_hw_params(struct snd_pcm_substream *substream,
                                 struct snd_pcm_hw_params *params,
                                 struct snd_soc_dai *dai)
{
        struct cv1800b_priv *priv = snd_soc_dai_get_drvdata(dai);
        int ret;
        unsigned int rate = params_rate(params);

        if (rate != 48000) {
                dev_err(priv->dev, "rate %u is not supported\n", rate);
                return -EINVAL;
        }
        /* Clear DAC overwrite so playback uses I2S data. */
        cv1800b_dac_mute(priv, false);
        /* minimal decimation for 48kHz is 64*/
        ret = cv1800b_dac_decimation(priv, DECIMATION_64);
        if (ret)
                return ret;

        /* value is taken from vendors driver 48kHz
         * tested on sg2000 and sg2002.
         */
        ret = cv1800b_dac_dly(priv, 0x19);
        if (ret)
                return ret;

        return 0;
}

static int cv1800b_dac_dai_trigger(struct snd_pcm_substream *substream, int cmd,
                                   struct snd_soc_dai *dai)
{
        struct cv1800b_priv *priv = snd_soc_dai_get_drvdata(dai);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                cv1800b_dac_enable(priv, true);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                cv1800b_dac_enable(priv, false);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static const struct snd_soc_dai_ops cv1800b_dac_dai_ops = {
        .hw_params = cv1800b_dac_hw_params,
        .trigger = cv1800b_dac_dai_trigger,
};

static struct snd_soc_dai_driver cv1800b_dac_dai = {
        .name = "dac-hifi",
        .playback = { .stream_name = "DAC Playback",
                      .channels_min = 2,
                      .channels_max = 2,
                      .rates = SNDRV_PCM_RATE_48000,
                      .formats = SNDRV_PCM_FMTBIT_S16_LE },
        .ops = &cv1800b_dac_dai_ops,
};

static const struct snd_soc_component_driver cv1800b_dac_component = {
        .name = "cv1800b-dac-codec",
};

static int cv1800b_dac_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct cv1800b_priv *priv;

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

        priv->dev = dev;
        priv->regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->regs))
                return PTR_ERR(priv->regs);

        platform_set_drvdata(pdev, priv);
        return devm_snd_soc_register_component(&pdev->dev,
                                               &cv1800b_dac_component,
                                               &cv1800b_dac_dai, 1);
}

static const struct of_device_id cv1800b_dac_of_match[] = {
        { .compatible = "sophgo,cv1800b-sound-dac" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, cv1800b_dac_of_match);

static struct platform_driver cv1800b_dac_driver = {
        .probe = cv1800b_dac_probe,
        .driver = {
                .name = "cv1800b-dac-codec",
                .of_match_table = cv1800b_dac_of_match,
        },
};
module_platform_driver(cv1800b_dac_driver);

MODULE_DESCRIPTION("DAC codec for CV1800B");
MODULE_AUTHOR("Anton D. Stavinskii <stavinsky@gmail.com>");
MODULE_LICENSE("GPL");