root/sound/soc/bcm/bcm63xx-i2s-whistler.c
// SPDX-License-Identifier: GPL-2.0-or-later
// linux/sound/bcm/bcm63xx-i2s-whistler.c
// BCM63xx whistler i2s driver
// Copyright (c) 2020 Broadcom Corporation
// Author: Kevin-Ke Li <kevin-ke.li@broadcom.com>

#include <linux/clk.h>
#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include "bcm63xx-i2s.h"

#define DRV_NAME "brcm-i2s"

static bool brcm_i2s_wr_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case I2S_TX_CFG ... I2S_TX_DESC_IFF_LEN:
        case I2S_TX_CFG_2 ... I2S_RX_DESC_IFF_LEN:
        case I2S_RX_CFG_2 ... I2S_REG_MAX:
                return true;
        default:
                return false;
        }
}

static bool brcm_i2s_rd_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case I2S_TX_CFG ... I2S_REG_MAX:
                return true;
        default:
                return false;
        }
}

static bool brcm_i2s_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case I2S_TX_CFG:
        case I2S_TX_IRQ_CTL:
        case I2S_TX_DESC_IFF_ADDR:
        case I2S_TX_DESC_IFF_LEN:
        case I2S_TX_DESC_OFF_ADDR:
        case I2S_TX_DESC_OFF_LEN:
        case I2S_TX_CFG_2:
        case I2S_RX_CFG:
        case I2S_RX_IRQ_CTL:
        case I2S_RX_DESC_OFF_ADDR:
        case I2S_RX_DESC_OFF_LEN:
        case I2S_RX_DESC_IFF_LEN:
        case I2S_RX_DESC_IFF_ADDR:
        case I2S_RX_CFG_2:
                return true;
        default:
                return false;
        }
}

static const struct regmap_config brcm_i2s_regmap_config = {
        .reg_bits = 32,
        .reg_stride = 4,
        .val_bits = 32,
        .max_register = I2S_REG_MAX,
        .writeable_reg = brcm_i2s_wr_reg,
        .readable_reg = brcm_i2s_rd_reg,
        .volatile_reg = brcm_i2s_volatile_reg,
        .cache_type = REGCACHE_FLAT,
};

static int bcm63xx_i2s_hw_params(struct snd_pcm_substream *substream,
                                 struct snd_pcm_hw_params *params,
                                 struct snd_soc_dai *dai)
{
        int ret = 0;
        struct bcm_i2s_priv *i2s_priv = snd_soc_dai_get_drvdata(dai);

        ret = clk_set_rate(i2s_priv->i2s_clk, params_rate(params));
        if (ret < 0)
                dev_err(i2s_priv->dev,
                        "Can't set sample rate, err: %d\n", ret);

        return ret;
}

static int bcm63xx_i2s_startup(struct snd_pcm_substream *substream,
                               struct snd_soc_dai *dai)
{
        unsigned int slavemode;
        struct bcm_i2s_priv *i2s_priv = snd_soc_dai_get_drvdata(dai);
        struct regmap *regmap_i2s = i2s_priv->regmap_i2s;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                regmap_update_bits(regmap_i2s, I2S_TX_CFG,
                                   I2S_TX_OUT_R | I2S_TX_DATA_ALIGNMENT |
                                   I2S_TX_DATA_ENABLE | I2S_TX_CLOCK_ENABLE,
                                   I2S_TX_OUT_R | I2S_TX_DATA_ALIGNMENT |
                                   I2S_TX_DATA_ENABLE | I2S_TX_CLOCK_ENABLE);
                regmap_write(regmap_i2s, I2S_TX_IRQ_CTL, 0);
                regmap_write(regmap_i2s, I2S_TX_IRQ_IFF_THLD, 0);
                regmap_write(regmap_i2s, I2S_TX_IRQ_OFF_THLD, 1);

                /* TX and RX block each have an independent bit to indicate
                 * if it is generating the clock for the I2S bus. The bus
                 * clocks need to be generated from either the TX or RX block,
                 * but not both
                 */
                regmap_read(regmap_i2s, I2S_RX_CFG_2, &slavemode);
                if (slavemode & I2S_RX_SLAVE_MODE_MASK)
                        regmap_update_bits(regmap_i2s, I2S_TX_CFG_2,
                                           I2S_TX_SLAVE_MODE_MASK,
                                           I2S_TX_MASTER_MODE);
                else
                        regmap_update_bits(regmap_i2s, I2S_TX_CFG_2,
                                           I2S_TX_SLAVE_MODE_MASK,
                                           I2S_TX_SLAVE_MODE);
        } else {
                regmap_update_bits(regmap_i2s, I2S_RX_CFG,
                                   I2S_RX_IN_R | I2S_RX_DATA_ALIGNMENT |
                                   I2S_RX_CLOCK_ENABLE,
                                   I2S_RX_IN_R | I2S_RX_DATA_ALIGNMENT |
                                   I2S_RX_CLOCK_ENABLE);
                regmap_write(regmap_i2s, I2S_RX_IRQ_CTL, 0);
                regmap_write(regmap_i2s, I2S_RX_IRQ_IFF_THLD, 0);
                regmap_write(regmap_i2s, I2S_RX_IRQ_OFF_THLD, 1);

                regmap_read(regmap_i2s, I2S_TX_CFG_2, &slavemode);
                if (slavemode & I2S_TX_SLAVE_MODE_MASK)
                        regmap_update_bits(regmap_i2s, I2S_RX_CFG_2,
                                           I2S_RX_SLAVE_MODE_MASK, 0);
                else
                        regmap_update_bits(regmap_i2s, I2S_RX_CFG_2,
                                           I2S_RX_SLAVE_MODE_MASK,
                                           I2S_RX_SLAVE_MODE);
        }
        return 0;
}

static void bcm63xx_i2s_shutdown(struct snd_pcm_substream *substream,
                                struct snd_soc_dai *dai)
{
        unsigned int enabled, slavemode;
        struct bcm_i2s_priv *i2s_priv = snd_soc_dai_get_drvdata(dai);
        struct regmap *regmap_i2s = i2s_priv->regmap_i2s;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                regmap_update_bits(regmap_i2s, I2S_TX_CFG,
                                   I2S_TX_OUT_R | I2S_TX_DATA_ALIGNMENT |
                                   I2S_TX_DATA_ENABLE | I2S_TX_CLOCK_ENABLE, 0);
                regmap_write(regmap_i2s, I2S_TX_IRQ_CTL, 1);
                regmap_write(regmap_i2s, I2S_TX_IRQ_IFF_THLD, 4);
                regmap_write(regmap_i2s, I2S_TX_IRQ_OFF_THLD, 4);

                regmap_read(regmap_i2s, I2S_TX_CFG_2, &slavemode);
                slavemode = slavemode & I2S_TX_SLAVE_MODE_MASK;
                if (!slavemode) {
                        regmap_read(regmap_i2s, I2S_RX_CFG, &enabled);
                        enabled = enabled & I2S_RX_ENABLE_MASK;
                        if (enabled)
                                regmap_update_bits(regmap_i2s, I2S_RX_CFG_2,
                                                   I2S_RX_SLAVE_MODE_MASK,
                                                   I2S_RX_MASTER_MODE);
                }
                regmap_update_bits(regmap_i2s, I2S_TX_CFG_2,
                                   I2S_TX_SLAVE_MODE_MASK,
                                   I2S_TX_SLAVE_MODE);
        } else {
                regmap_update_bits(regmap_i2s, I2S_RX_CFG,
                                   I2S_RX_IN_R | I2S_RX_DATA_ALIGNMENT |
                                   I2S_RX_CLOCK_ENABLE, 0);
                regmap_write(regmap_i2s, I2S_RX_IRQ_CTL, 1);
                regmap_write(regmap_i2s, I2S_RX_IRQ_IFF_THLD, 4);
                regmap_write(regmap_i2s, I2S_RX_IRQ_OFF_THLD, 4);

                regmap_read(regmap_i2s, I2S_RX_CFG_2, &slavemode);
                slavemode = slavemode & I2S_RX_SLAVE_MODE_MASK;
                if (!slavemode) {
                        regmap_read(regmap_i2s, I2S_TX_CFG, &enabled);
                        enabled = enabled & I2S_TX_ENABLE_MASK;
                        if (enabled)
                                regmap_update_bits(regmap_i2s, I2S_TX_CFG_2,
                                                   I2S_TX_SLAVE_MODE_MASK,
                                                   I2S_TX_MASTER_MODE);
                }

                regmap_update_bits(regmap_i2s, I2S_RX_CFG_2,
                                   I2S_RX_SLAVE_MODE_MASK, I2S_RX_SLAVE_MODE);
        }
}

static const struct snd_soc_dai_ops bcm63xx_i2s_dai_ops = {
        .startup = bcm63xx_i2s_startup,
        .shutdown = bcm63xx_i2s_shutdown,
        .hw_params = bcm63xx_i2s_hw_params,
};

static struct snd_soc_dai_driver bcm63xx_i2s_dai = {
        .name = DRV_NAME,
        .playback = {
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_192000,
                .formats = SNDRV_PCM_FMTBIT_S32_LE,
        },
        .capture = {
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_192000,
                .formats = SNDRV_PCM_FMTBIT_S32_LE,
        },
        .ops = &bcm63xx_i2s_dai_ops,
        .symmetric_rate = 1,
        .symmetric_channels = 1,
};

static const struct snd_soc_component_driver bcm63xx_i2s_component = {
        .name = "bcm63xx",
        .legacy_dai_naming = 1,
};

static int bcm63xx_i2s_dev_probe(struct platform_device *pdev)
{
        int ret = 0;
        void __iomem *regs;
        struct bcm_i2s_priv *i2s_priv;
        struct regmap *regmap_i2s;
        struct clk *i2s_clk;

        i2s_priv = devm_kzalloc(&pdev->dev, sizeof(*i2s_priv), GFP_KERNEL);
        if (!i2s_priv)
                return -ENOMEM;

        i2s_clk = devm_clk_get(&pdev->dev, "i2sclk");
        if (IS_ERR(i2s_clk)) {
                dev_err(&pdev->dev, "%s: cannot get a brcm clock: %ld\n",
                                        __func__, PTR_ERR(i2s_clk));
                return PTR_ERR(i2s_clk);
        }

        regs = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(regs)) {
                ret = PTR_ERR(regs);
                return ret;
        }

        regmap_i2s = devm_regmap_init_mmio(&pdev->dev,
                                        regs, &brcm_i2s_regmap_config);
        if (IS_ERR(regmap_i2s))
                return PTR_ERR(regmap_i2s);

        regmap_update_bits(regmap_i2s, I2S_MISC_CFG,
                           I2S_PAD_LVL_LOOP_DIS_MASK,
                           I2S_PAD_LVL_LOOP_DIS_ENABLE);

        ret = devm_snd_soc_register_component(&pdev->dev,
                                              &bcm63xx_i2s_component,
                                              &bcm63xx_i2s_dai, 1);
        if (ret) {
                dev_err(&pdev->dev, "failed to register the dai\n");
                return ret;
        }

        i2s_priv->dev = &pdev->dev;
        i2s_priv->i2s_clk = i2s_clk;
        i2s_priv->regmap_i2s = regmap_i2s;
        dev_set_drvdata(&pdev->dev, i2s_priv);

        ret = bcm63xx_soc_platform_probe(pdev, i2s_priv);
        if (ret)
                dev_err(&pdev->dev, "failed to register the pcm\n");

        return ret;
}

static void bcm63xx_i2s_dev_remove(struct platform_device *pdev)
{
        bcm63xx_soc_platform_remove(pdev);
}

#ifdef CONFIG_OF
static const struct of_device_id snd_soc_bcm_audio_match[] = {
        {.compatible = "brcm,bcm63xx-i2s"},
        { }
};
#endif

static struct platform_driver bcm63xx_i2s_driver = {
        .driver = {
                .name = DRV_NAME,
                .of_match_table = of_match_ptr(snd_soc_bcm_audio_match),
        },
        .probe = bcm63xx_i2s_dev_probe,
        .remove = bcm63xx_i2s_dev_remove,
};

module_platform_driver(bcm63xx_i2s_driver);

MODULE_AUTHOR("Kevin,Li <kevin-ke.li@broadcom.com>");
MODULE_DESCRIPTION("Broadcom DSL XPON ASOC I2S Interface");
MODULE_LICENSE("GPL v2");