root/sound/soc/stm/stm32_adfsdm.c
// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part of STM32 DFSDM ASoC DAI driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Authors: Arnaud Pouliquen <arnaud.pouliquen@st.com>
 *          Olivier Moysan <olivier.moysan@st.com>
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>
#include <linux/iio/iio.h>
#include <linux/iio/consumer.h>
#include <linux/iio/adc/stm32-dfsdm-adc.h>

#include <sound/pcm.h>
#include <sound/soc.h>

#define STM32_ADFSDM_DRV_NAME "stm32-adfsdm"

#define DFSDM_MAX_PERIOD_SIZE   (PAGE_SIZE / 2)
#define DFSDM_MAX_PERIODS       6

struct stm32_adfsdm_priv {
        struct snd_soc_dai_driver dai_drv;
        struct snd_pcm_substream *substream;
        struct device *dev;

        /* IIO */
        struct iio_channel *iio_ch;
        struct iio_cb_buffer *iio_cb;
        bool iio_active;

        /* PCM buffer */
        unsigned char *pcm_buff;
        unsigned int pos;

        struct mutex lock; /* protect against race condition on iio state */
};

static const struct snd_pcm_hardware stm32_adfsdm_pcm_hw = {
        .info = SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
                SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_PAUSE,
        .formats = SNDRV_PCM_FMTBIT_S16_LE | SNDRV_PCM_FMTBIT_S32_LE,

        .channels_min = 1,
        .channels_max = 1,

        .periods_min = 2,
        .periods_max = DFSDM_MAX_PERIODS,

        .period_bytes_max = DFSDM_MAX_PERIOD_SIZE,
        .buffer_bytes_max = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE
};

static void stm32_adfsdm_shutdown(struct snd_pcm_substream *substream,
                                  struct snd_soc_dai *dai)
{
        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);

        mutex_lock(&priv->lock);
        if (priv->iio_active) {
                iio_channel_stop_all_cb(priv->iio_cb);
                priv->iio_active = false;
        }
        mutex_unlock(&priv->lock);
}

static int stm32_adfsdm_dai_prepare(struct snd_pcm_substream *substream,
                                    struct snd_soc_dai *dai)
{
        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
        int ret;

        mutex_lock(&priv->lock);
        if (priv->iio_active) {
                iio_channel_stop_all_cb(priv->iio_cb);
                priv->iio_active = false;
        }

        ret = iio_write_channel_attribute(priv->iio_ch,
                                          substream->runtime->rate, 0,
                                          IIO_CHAN_INFO_SAMP_FREQ);
        if (ret < 0) {
                dev_err(dai->dev, "%s: Failed to set %d sampling rate\n",
                        __func__, substream->runtime->rate);
                goto out;
        }

        if (!priv->iio_active) {
                ret = iio_channel_start_all_cb(priv->iio_cb);
                if (!ret)
                        priv->iio_active = true;
                else
                        dev_err(dai->dev, "%s: IIO channel start failed (%d)\n",
                                __func__, ret);
        }

out:
        mutex_unlock(&priv->lock);

        return ret;
}

static int stm32_adfsdm_set_sysclk(struct snd_soc_dai *dai, int clk_id,
                                   unsigned int freq, int dir)
{
        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(dai);
        ssize_t size;
        char str_freq[10];

        dev_dbg(dai->dev, "%s: Enter for freq %d\n", __func__, freq);

        /* Set IIO frequency if CODEC is master as clock comes from SPI_IN */

        snprintf(str_freq, sizeof(str_freq), "%u\n", freq);
        size = iio_write_channel_ext_info(priv->iio_ch, "spi_clk_freq",
                                          str_freq, sizeof(str_freq));
        if (size != sizeof(str_freq)) {
                dev_err(dai->dev, "%s: Failed to set SPI clock\n",
                        __func__);
                return -EINVAL;
        }
        return 0;
}

static const struct snd_soc_dai_ops stm32_adfsdm_dai_ops = {
        .shutdown = stm32_adfsdm_shutdown,
        .prepare = stm32_adfsdm_dai_prepare,
        .set_sysclk = stm32_adfsdm_set_sysclk,
};

static const struct snd_soc_dai_driver stm32_adfsdm_dai = {
        .capture = {
                    .channels_min = 1,
                    .channels_max = 1,
                    .formats = SNDRV_PCM_FMTBIT_S16_LE |
                               SNDRV_PCM_FMTBIT_S32_LE,
                    .rates = SNDRV_PCM_RATE_CONTINUOUS,
                    .rate_min = 8000,
                    .rate_max = 192000,
                    },
        .ops = &stm32_adfsdm_dai_ops,
};

static const struct snd_soc_component_driver stm32_adfsdm_dai_component = {
        .name = "stm32_dfsdm_audio",
        .legacy_dai_naming = 1,
};

static void stm32_memcpy_32to16(void *dest, const void *src, size_t n)
{
        unsigned int i = 0;
        u16 *d = (u16 *)dest, *s = (u16 *)src;

        s++;
        for (i = n >> 1; i > 0; i--) {
                *d++ = *s++;
                s++;
        }
}

static int stm32_afsdm_pcm_cb(const void *data, size_t size, void *private)
{
        struct stm32_adfsdm_priv *priv = private;
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(priv->substream);
        u8 *pcm_buff = priv->pcm_buff;
        u8 *src_buff = (u8 *)data;
        unsigned int old_pos = priv->pos;
        size_t buff_size = snd_pcm_lib_buffer_bytes(priv->substream);
        size_t period_size = snd_pcm_lib_period_bytes(priv->substream);
        size_t cur_size, src_size = size;
        snd_pcm_format_t format = priv->substream->runtime->format;

        if (format == SNDRV_PCM_FORMAT_S16_LE)
                src_size >>= 1;
        cur_size = src_size;

        dev_dbg(rtd->dev, "%s: buff_add :%p, pos = %d, size = %zu\n",
                __func__, &pcm_buff[priv->pos], priv->pos, src_size);

        if ((priv->pos + src_size) > buff_size) {
                if (format == SNDRV_PCM_FORMAT_S16_LE)
                        stm32_memcpy_32to16(&pcm_buff[priv->pos], src_buff,
                                            buff_size - priv->pos);
                else
                        memcpy(&pcm_buff[priv->pos], src_buff,
                               buff_size - priv->pos);
                cur_size -= buff_size - priv->pos;
                priv->pos = 0;
        }

        if (format == SNDRV_PCM_FORMAT_S16_LE)
                stm32_memcpy_32to16(&pcm_buff[priv->pos],
                                    &src_buff[src_size - cur_size], cur_size);
        else
                memcpy(&pcm_buff[priv->pos], &src_buff[src_size - cur_size],
                       cur_size);

        priv->pos = (priv->pos + cur_size) % buff_size;

        if (cur_size != src_size || (old_pos && (old_pos % period_size < size)))
                snd_pcm_period_elapsed(priv->substream);

        return 0;
}

static int stm32_adfsdm_trigger(struct snd_soc_component *component,
                                struct snd_pcm_substream *substream, int cmd)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct stm32_adfsdm_priv *priv =
                snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
                priv->pos = 0;
                return stm32_dfsdm_get_buff_cb(priv->iio_ch->indio_dev,
                                               stm32_afsdm_pcm_cb, priv);
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
                return stm32_dfsdm_release_buff_cb(priv->iio_ch->indio_dev);
        }

        return -EINVAL;
}

static int stm32_adfsdm_pcm_open(struct snd_soc_component *component,
                                 struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct stm32_adfsdm_priv *priv = snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
        int ret;

        ret =  snd_soc_set_runtime_hwparams(substream, &stm32_adfsdm_pcm_hw);
        if (!ret)
                priv->substream = substream;

        return ret;
}

static int stm32_adfsdm_pcm_close(struct snd_soc_component *component,
                                  struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct stm32_adfsdm_priv *priv =
                snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));

        priv->substream = NULL;

        return 0;
}

static snd_pcm_uframes_t stm32_adfsdm_pcm_pointer(
                                            struct snd_soc_component *component,
                                            struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct stm32_adfsdm_priv *priv =
                snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));

        return bytes_to_frames(substream->runtime, priv->pos);
}

static int stm32_adfsdm_pcm_hw_params(struct snd_soc_component *component,
                                      struct snd_pcm_substream *substream,
                                      struct snd_pcm_hw_params *params)
{
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct stm32_adfsdm_priv *priv =
                snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));

        priv->pcm_buff = substream->runtime->dma_area;

        return iio_channel_cb_set_buffer_watermark(priv->iio_cb,
                                                   params_period_size(params));
}

static int stm32_adfsdm_pcm_new(struct snd_soc_component *component,
                                struct snd_soc_pcm_runtime *rtd)
{
        struct snd_pcm *pcm = rtd->pcm;
        struct stm32_adfsdm_priv *priv =
                snd_soc_dai_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0));
        unsigned int size = DFSDM_MAX_PERIODS * DFSDM_MAX_PERIOD_SIZE;

        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
                                       priv->dev, size, size);
        return 0;
}

static int stm32_adfsdm_dummy_cb(const void *data, void *private)
{
        /*
         * This dummy callback is requested by iio_channel_get_all_cb() API,
         * but the stm32_dfsdm_get_buff_cb() API is used instead, to optimize
         * DMA transfers.
         */
        return 0;
}

static void stm32_adfsdm_cleanup(void *data)
{
        iio_channel_release_all_cb(data);
}

static const struct snd_soc_component_driver stm32_adfsdm_soc_platform = {
        .open           = stm32_adfsdm_pcm_open,
        .close          = stm32_adfsdm_pcm_close,
        .hw_params      = stm32_adfsdm_pcm_hw_params,
        .trigger        = stm32_adfsdm_trigger,
        .pointer        = stm32_adfsdm_pcm_pointer,
        .pcm_construct  = stm32_adfsdm_pcm_new,
};

static const struct of_device_id stm32_adfsdm_of_match[] = {
        {.compatible = "st,stm32h7-dfsdm-dai"},
        {}
};
MODULE_DEVICE_TABLE(of, stm32_adfsdm_of_match);

static int stm32_adfsdm_probe(struct platform_device *pdev)
{
        struct stm32_adfsdm_priv *priv;
        struct snd_soc_component *component;
        int ret;

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

        priv->dev = &pdev->dev;
        priv->dai_drv = stm32_adfsdm_dai;
        mutex_init(&priv->lock);

        dev_set_drvdata(&pdev->dev, priv);

        ret = devm_snd_soc_register_component(&pdev->dev,
                                              &stm32_adfsdm_dai_component,
                                              &priv->dai_drv, 1);
        if (ret < 0)
                return ret;

        /* Associate iio channel */
        priv->iio_ch  = devm_iio_channel_get_all(&pdev->dev);
        if (IS_ERR(priv->iio_ch))
                return PTR_ERR(priv->iio_ch);

        priv->iio_cb = iio_channel_get_all_cb(&pdev->dev, &stm32_adfsdm_dummy_cb, NULL);
        if (IS_ERR(priv->iio_cb))
                return PTR_ERR(priv->iio_cb);

        ret = devm_add_action_or_reset(&pdev->dev, stm32_adfsdm_cleanup, priv->iio_cb);
        if (ret < 0)  {
                dev_err(&pdev->dev, "Unable to add action\n");
                return ret;
        }

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

        ret = snd_soc_component_initialize(component,
                                           &stm32_adfsdm_soc_platform,
                                           &pdev->dev);
        if (ret < 0)
                return ret;
#ifdef CONFIG_DEBUG_FS
        component->debugfs_prefix = "pcm";
#endif

        ret = snd_soc_add_component(component, NULL, 0);
        if (ret < 0) {
                dev_err(&pdev->dev, "%s: Failed to register PCM platform\n",
                        __func__);
                return ret;
        }

        pm_runtime_enable(&pdev->dev);

        return ret;
}

static void stm32_adfsdm_remove(struct platform_device *pdev)
{
        snd_soc_unregister_component(&pdev->dev);
        pm_runtime_disable(&pdev->dev);
}

static struct platform_driver stm32_adfsdm_driver = {
        .driver = {
                   .name = STM32_ADFSDM_DRV_NAME,
                   .of_match_table = stm32_adfsdm_of_match,
                   },
        .probe = stm32_adfsdm_probe,
        .remove = stm32_adfsdm_remove,
};

module_platform_driver(stm32_adfsdm_driver);

MODULE_DESCRIPTION("stm32 DFSDM DAI driver");
MODULE_AUTHOR("Arnaud Pouliquen <arnaud.pouliquen@st.com>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" STM32_ADFSDM_DRV_NAME);