root/sound/soc/tegra/tegra20_ac97.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * tegra20_ac97.c - Tegra20 AC97 platform driver
 *
 * Copyright (c) 2012 Lucas Stach <dev@lynxeye.de>
 *
 * Partly based on code copyright/by:
 *
 * Copyright (c) 2011,2012 Toradex Inc.
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/reset.h>
#include <linux/slab.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/dmaengine_pcm.h>

#include "tegra20_ac97.h"

#define DRV_NAME "tegra20-ac97"

static struct tegra20_ac97 *workdata;

static void tegra20_ac97_codec_reset(struct snd_ac97 *ac97)
{
        u32 readback;
        unsigned long timeout;

        /*
         * The reset line is not driven by DAC pad group, have to toggle GPIO.
         * The RESET line is active low but this is abstracted by the GPIO
         * library.
         */
        gpiod_set_value(workdata->reset_gpio, 1);
        udelay(2);

        gpiod_set_value(workdata->reset_gpio, 0);
        udelay(2);

        timeout = jiffies + msecs_to_jiffies(100);

        do {
                regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
                if (readback & TEGRA20_AC97_STATUS1_CODEC1_RDY)
                        break;
                usleep_range(1000, 2000);
        } while (!time_after(jiffies, timeout));
}

static void tegra20_ac97_codec_warm_reset(struct snd_ac97 *ac97)
{
        u32 readback;
        unsigned long timeout;

        /*
         * although sync line is driven by the DAC pad group warm reset using
         * the controller cmd is not working, have to toggle sync line
         * manually.
         */
        gpiod_direction_output(workdata->sync_gpio, 1);
        udelay(2);
        gpiod_set_value(workdata->sync_gpio, 0);
        udelay(2);

        timeout = jiffies + msecs_to_jiffies(100);

        do {
                regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
                if (readback & TEGRA20_AC97_STATUS1_CODEC1_RDY)
                        break;
                usleep_range(1000, 2000);
        } while (!time_after(jiffies, timeout));
}

static unsigned short tegra20_ac97_codec_read(struct snd_ac97 *ac97_snd,
                                              unsigned short reg)
{
        u32 readback;
        unsigned long timeout;

        regmap_write(workdata->regmap, TEGRA20_AC97_CMD,
                     (((reg | 0x80) << TEGRA20_AC97_CMD_CMD_ADDR_SHIFT) &
                      TEGRA20_AC97_CMD_CMD_ADDR_MASK) |
                     TEGRA20_AC97_CMD_BUSY);

        timeout = jiffies + msecs_to_jiffies(100);

        do {
                regmap_read(workdata->regmap, TEGRA20_AC97_STATUS1, &readback);
                if (readback & TEGRA20_AC97_STATUS1_STA_VALID1)
                        break;
                usleep_range(1000, 2000);
        } while (!time_after(jiffies, timeout));

        return ((readback & TEGRA20_AC97_STATUS1_STA_DATA1_MASK) >>
                TEGRA20_AC97_STATUS1_STA_DATA1_SHIFT);
}

static void tegra20_ac97_codec_write(struct snd_ac97 *ac97_snd,
                                     unsigned short reg, unsigned short val)
{
        u32 readback;
        unsigned long timeout;

        regmap_write(workdata->regmap, TEGRA20_AC97_CMD,
                     ((reg << TEGRA20_AC97_CMD_CMD_ADDR_SHIFT) &
                      TEGRA20_AC97_CMD_CMD_ADDR_MASK) |
                     ((val << TEGRA20_AC97_CMD_CMD_DATA_SHIFT) &
                      TEGRA20_AC97_CMD_CMD_DATA_MASK) |
                     TEGRA20_AC97_CMD_BUSY);

        timeout = jiffies + msecs_to_jiffies(100);

        do {
                regmap_read(workdata->regmap, TEGRA20_AC97_CMD, &readback);
                if (!(readback & TEGRA20_AC97_CMD_BUSY))
                        break;
                usleep_range(1000, 2000);
        } while (!time_after(jiffies, timeout));
}

static struct snd_ac97_bus_ops tegra20_ac97_ops = {
        .read           = tegra20_ac97_codec_read,
        .write          = tegra20_ac97_codec_write,
        .reset          = tegra20_ac97_codec_reset,
        .warm_reset     = tegra20_ac97_codec_warm_reset,
};

static inline void tegra20_ac97_start_playback(struct tegra20_ac97 *ac97)
{
        regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
                           TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN,
                           TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN);

        regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
                           TEGRA20_AC97_CTRL_PCM_DAC_EN |
                           TEGRA20_AC97_CTRL_STM_EN,
                           TEGRA20_AC97_CTRL_PCM_DAC_EN |
                           TEGRA20_AC97_CTRL_STM_EN);
}

static inline void tegra20_ac97_stop_playback(struct tegra20_ac97 *ac97)
{
        regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
                           TEGRA20_AC97_FIFO_SCR_PB_QRT_MT_EN, 0);

        regmap_update_bits(ac97->regmap, TEGRA20_AC97_CTRL,
                           TEGRA20_AC97_CTRL_PCM_DAC_EN, 0);
}

static inline void tegra20_ac97_start_capture(struct tegra20_ac97 *ac97)
{
        regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
                           TEGRA20_AC97_FIFO_SCR_REC_FULL_EN,
                           TEGRA20_AC97_FIFO_SCR_REC_FULL_EN);
}

static inline void tegra20_ac97_stop_capture(struct tegra20_ac97 *ac97)
{
        regmap_update_bits(ac97->regmap, TEGRA20_AC97_FIFO1_SCR,
                           TEGRA20_AC97_FIFO_SCR_REC_FULL_EN, 0);
}

static int tegra20_ac97_trigger(struct snd_pcm_substream *substream, int cmd,
                                struct snd_soc_dai *dai)
{
        struct tegra20_ac97 *ac97 = snd_soc_dai_get_drvdata(dai);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        case SNDRV_PCM_TRIGGER_RESUME:
                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        tegra20_ac97_start_playback(ac97);
                else
                        tegra20_ac97_start_capture(ac97);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        tegra20_ac97_stop_playback(ac97);
                else
                        tegra20_ac97_stop_capture(ac97);
                break;
        default:
                return -EINVAL;
        }

        return 0;
}

static int tegra20_ac97_probe(struct snd_soc_dai *dai)
{
        struct tegra20_ac97 *ac97 = snd_soc_dai_get_drvdata(dai);

        snd_soc_dai_init_dma_data(dai,  &ac97->playback_dma_data,
                                        &ac97->capture_dma_data);

        return 0;
}

static const struct snd_soc_dai_ops tegra20_ac97_dai_ops = {
        .probe          = tegra20_ac97_probe,
        .trigger        = tegra20_ac97_trigger,
};

static struct snd_soc_dai_driver tegra20_ac97_dai = {
        .name = "tegra-ac97-pcm",
        .playback = {
                .stream_name = "PCM Playback",
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_48000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .capture = {
                .stream_name = "PCM Capture",
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_48000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .ops = &tegra20_ac97_dai_ops,
};

static const struct snd_soc_component_driver tegra20_ac97_component = {
        .name                   = DRV_NAME,
        .legacy_dai_naming      = 1,
};

static bool tegra20_ac97_wr_rd_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case TEGRA20_AC97_CTRL:
        case TEGRA20_AC97_CMD:
        case TEGRA20_AC97_STATUS1:
        case TEGRA20_AC97_FIFO1_SCR:
        case TEGRA20_AC97_FIFO_TX1:
        case TEGRA20_AC97_FIFO_RX1:
                return true;
        default:
                break;
        }

        return false;
}

static bool tegra20_ac97_volatile_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case TEGRA20_AC97_STATUS1:
        case TEGRA20_AC97_FIFO1_SCR:
        case TEGRA20_AC97_FIFO_TX1:
        case TEGRA20_AC97_FIFO_RX1:
                return true;
        default:
                break;
        }

        return false;
}

static bool tegra20_ac97_precious_reg(struct device *dev, unsigned int reg)
{
        switch (reg) {
        case TEGRA20_AC97_FIFO_TX1:
        case TEGRA20_AC97_FIFO_RX1:
                return true;
        default:
                break;
        }

        return false;
}

static const struct regmap_config tegra20_ac97_regmap_config = {
        .reg_bits = 32,
        .reg_stride = 4,
        .val_bits = 32,
        .max_register = TEGRA20_AC97_FIFO_RX1,
        .writeable_reg = tegra20_ac97_wr_rd_reg,
        .readable_reg = tegra20_ac97_wr_rd_reg,
        .volatile_reg = tegra20_ac97_volatile_reg,
        .precious_reg = tegra20_ac97_precious_reg,
        .cache_type = REGCACHE_FLAT,
};

static int tegra20_ac97_platform_probe(struct platform_device *pdev)
{
        struct tegra20_ac97 *ac97;
        struct resource *mem;
        void __iomem *regs;
        int ret = 0;

        ac97 = devm_kzalloc(&pdev->dev, sizeof(struct tegra20_ac97),
                            GFP_KERNEL);
        if (!ac97) {
                ret = -ENOMEM;
                goto err;
        }
        dev_set_drvdata(&pdev->dev, ac97);

        ac97->reset = devm_reset_control_get_exclusive(&pdev->dev, "ac97");
        if (IS_ERR(ac97->reset)) {
                dev_err(&pdev->dev, "Can't retrieve ac97 reset\n");
                ret = PTR_ERR(ac97->reset);
                goto err;
        }

        ac97->clk_ac97 = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(ac97->clk_ac97)) {
                dev_err(&pdev->dev, "Can't retrieve ac97 clock\n");
                ret = PTR_ERR(ac97->clk_ac97);
                goto err;
        }

        regs = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
        if (IS_ERR(regs)) {
                ret = PTR_ERR(regs);
                goto err_clk_put;
        }

        ac97->regmap = devm_regmap_init_mmio(&pdev->dev, regs,
                                            &tegra20_ac97_regmap_config);
        if (IS_ERR(ac97->regmap)) {
                dev_err(&pdev->dev, "regmap init failed\n");
                ret = PTR_ERR(ac97->regmap);
                goto err_clk_put;
        }

        /* Obtain RESET de-asserted */
        ac97->reset_gpio = devm_gpiod_get(&pdev->dev,
                                          "nvidia,codec-reset",
                                          GPIOD_OUT_LOW);
        if (IS_ERR(ac97->reset_gpio)) {
                ret = PTR_ERR(ac97->reset_gpio);
                dev_err(&pdev->dev, "no RESET GPIO supplied: %d\n", ret);
                goto err_clk_put;
        }
        gpiod_set_consumer_name(ac97->reset_gpio, "codec-reset");

        ac97->sync_gpio = devm_gpiod_get(&pdev->dev,
                                         "nvidia,codec-sync",
                                         GPIOD_OUT_LOW);
        if (IS_ERR(ac97->sync_gpio)) {
                ret = PTR_ERR(ac97->sync_gpio);
                dev_err(&pdev->dev, "no codec-sync GPIO supplied: %d\n", ret);
                goto err_clk_put;
        }
        gpiod_set_consumer_name(ac97->sync_gpio, "codec-sync");

        ac97->capture_dma_data.addr = mem->start + TEGRA20_AC97_FIFO_RX1;
        ac97->capture_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        ac97->capture_dma_data.maxburst = 4;

        ac97->playback_dma_data.addr = mem->start + TEGRA20_AC97_FIFO_TX1;
        ac97->playback_dma_data.addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
        ac97->playback_dma_data.maxburst = 4;

        ret = reset_control_assert(ac97->reset);
        if (ret) {
                dev_err(&pdev->dev, "Failed to assert AC'97 reset: %d\n", ret);
                goto err_clk_put;
        }

        ret = clk_prepare_enable(ac97->clk_ac97);
        if (ret) {
                dev_err(&pdev->dev, "clk_enable failed: %d\n", ret);
                goto err_clk_put;
        }

        usleep_range(10, 100);

        ret = reset_control_deassert(ac97->reset);
        if (ret) {
                dev_err(&pdev->dev, "Failed to deassert AC'97 reset: %d\n", ret);
                goto err_clk_disable_unprepare;
        }

        ret = snd_soc_set_ac97_ops(&tegra20_ac97_ops);
        if (ret) {
                dev_err(&pdev->dev, "Failed to set AC'97 ops: %d\n", ret);
                goto err_clk_disable_unprepare;
        }

        ret = snd_soc_register_component(&pdev->dev, &tegra20_ac97_component,
                                         &tegra20_ac97_dai, 1);
        if (ret) {
                dev_err(&pdev->dev, "Could not register DAI: %d\n", ret);
                ret = -ENOMEM;
                goto err_clk_disable_unprepare;
        }

        ret = tegra_pcm_platform_register(&pdev->dev);
        if (ret) {
                dev_err(&pdev->dev, "Could not register PCM: %d\n", ret);
                goto err_unregister_component;
        }

        /* XXX: crufty ASoC AC97 API - only one AC97 codec allowed */
        workdata = ac97;

        return 0;

err_unregister_component:
        snd_soc_unregister_component(&pdev->dev);
err_clk_disable_unprepare:
        clk_disable_unprepare(ac97->clk_ac97);
err_clk_put:
err:
        snd_soc_set_ac97_ops(NULL);
        return ret;
}

static void tegra20_ac97_platform_remove(struct platform_device *pdev)
{
        struct tegra20_ac97 *ac97 = dev_get_drvdata(&pdev->dev);

        tegra_pcm_platform_unregister(&pdev->dev);
        snd_soc_unregister_component(&pdev->dev);

        clk_disable_unprepare(ac97->clk_ac97);

        snd_soc_set_ac97_ops(NULL);
}

static const struct of_device_id tegra20_ac97_of_match[] = {
        { .compatible = "nvidia,tegra20-ac97", },
        {},
};

static struct platform_driver tegra20_ac97_driver = {
        .driver = {
                .name = DRV_NAME,
                .of_match_table = tegra20_ac97_of_match,
        },
        .probe = tegra20_ac97_platform_probe,
        .remove = tegra20_ac97_platform_remove,
};
module_platform_driver(tegra20_ac97_driver);

MODULE_AUTHOR("Lucas Stach");
MODULE_DESCRIPTION("Tegra20 AC97 ASoC driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DEVICE_TABLE(of, tegra20_ac97_of_match);