root/sound/atmel/ac97c.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Driver for Atmel AC97C
 *
 * Copyright (C) 2005-2009 Atmel Corporation
 */
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/bitmap.h>
#include <linux/device.h>
#include <linux/atmel_pdc.h>
#include <linux/gpio/consumer.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/io.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/ac97_codec.h>
#include <sound/memalloc.h>

#include "ac97c.h"

/* Serialize access to opened variable */
static DEFINE_MUTEX(opened_mutex);

struct atmel_ac97c {
        struct clk                      *pclk;
        struct platform_device          *pdev;

        struct snd_pcm_substream        *playback_substream;
        struct snd_pcm_substream        *capture_substream;
        struct snd_card                 *card;
        struct snd_pcm                  *pcm;
        struct snd_ac97                 *ac97;
        struct snd_ac97_bus             *ac97_bus;

        u64                             cur_format;
        unsigned int                    cur_rate;
        int                             playback_period, capture_period;
        /* Serialize access to opened variable */
        spinlock_t                      lock;
        void __iomem                    *regs;
        int                             irq;
        int                             opened;
        struct gpio_desc                *reset_pin;
};

#define get_chip(card) ((struct atmel_ac97c *)(card)->private_data)

#define ac97c_writel(chip, reg, val)                    \
        __raw_writel((val), (chip)->regs + AC97C_##reg)
#define ac97c_readl(chip, reg)                          \
        __raw_readl((chip)->regs + AC97C_##reg)

static const struct snd_pcm_hardware atmel_ac97c_hw = {
        .info                   = (SNDRV_PCM_INFO_MMAP
                                  | SNDRV_PCM_INFO_MMAP_VALID
                                  | SNDRV_PCM_INFO_INTERLEAVED
                                  | SNDRV_PCM_INFO_BLOCK_TRANSFER
                                  | SNDRV_PCM_INFO_JOINT_DUPLEX
                                  | SNDRV_PCM_INFO_RESUME
                                  | SNDRV_PCM_INFO_PAUSE),
        .formats                = (SNDRV_PCM_FMTBIT_S16_BE
                                  | SNDRV_PCM_FMTBIT_S16_LE),
        .rates                  = (SNDRV_PCM_RATE_CONTINUOUS),
        .rate_min               = 4000,
        .rate_max               = 48000,
        .channels_min           = 1,
        .channels_max           = 2,
        .buffer_bytes_max       = 2 * 2 * 64 * 2048,
        .period_bytes_min       = 4096,
        .period_bytes_max       = 4096,
        .periods_min            = 6,
        .periods_max            = 64,
};

static int atmel_ac97c_playback_open(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;

        guard(mutex)(&opened_mutex);
        chip->opened++;
        runtime->hw = atmel_ac97c_hw;
        if (chip->cur_rate) {
                runtime->hw.rate_min = chip->cur_rate;
                runtime->hw.rate_max = chip->cur_rate;
        }
        if (chip->cur_format)
                runtime->hw.formats = pcm_format_to_bits(chip->cur_format);
        chip->playback_substream = substream;
        return 0;
}

static int atmel_ac97c_capture_open(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;

        guard(mutex)(&opened_mutex);
        chip->opened++;
        runtime->hw = atmel_ac97c_hw;
        if (chip->cur_rate) {
                runtime->hw.rate_min = chip->cur_rate;
                runtime->hw.rate_max = chip->cur_rate;
        }
        if (chip->cur_format)
                runtime->hw.formats = pcm_format_to_bits(chip->cur_format);
        chip->capture_substream = substream;
        return 0;
}

static int atmel_ac97c_playback_close(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);

        guard(mutex)(&opened_mutex);
        chip->opened--;
        if (!chip->opened) {
                chip->cur_rate = 0;
                chip->cur_format = 0;
        }

        chip->playback_substream = NULL;

        return 0;
}

static int atmel_ac97c_capture_close(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);

        guard(mutex)(&opened_mutex);
        chip->opened--;
        if (!chip->opened) {
                chip->cur_rate = 0;
                chip->cur_format = 0;
        }

        chip->capture_substream = NULL;

        return 0;
}

static int atmel_ac97c_playback_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *hw_params)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);

        /* Set restrictions to params. */
        guard(mutex)(&opened_mutex);
        chip->cur_rate = params_rate(hw_params);
        chip->cur_format = params_format(hw_params);

        return 0;
}

static int atmel_ac97c_capture_hw_params(struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *hw_params)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);

        /* Set restrictions to params. */
        guard(mutex)(&opened_mutex);
        chip->cur_rate = params_rate(hw_params);
        chip->cur_format = params_format(hw_params);

        return 0;
}

static int atmel_ac97c_playback_prepare(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        int block_size = frames_to_bytes(runtime, runtime->period_size);
        unsigned long word = ac97c_readl(chip, OCA);
        int retval;

        chip->playback_period = 0;
        word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));

        /* assign channels to AC97C channel A */
        switch (runtime->channels) {
        case 1:
                word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
                break;
        case 2:
                word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
                        | AC97C_CH_ASSIGN(PCM_RIGHT, A);
                break;
        default:
                /* TODO: support more than two channels */
                return -EINVAL;
        }
        ac97c_writel(chip, OCA, word);

        /* configure sample format and size */
        word = ac97c_readl(chip, CAMR);
        if (chip->opened <= 1)
                word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
        else
                word |= AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;

        switch (runtime->format) {
        case SNDRV_PCM_FORMAT_S16_LE:
                break;
        case SNDRV_PCM_FORMAT_S16_BE:
                word &= ~(AC97C_CMR_CEM_LITTLE);
                break;
        default:
                word = ac97c_readl(chip, OCA);
                word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
                ac97c_writel(chip, OCA, word);
                return -EINVAL;
        }

        /* Enable underrun interrupt on channel A */
        word |= AC97C_CSR_UNRUN;

        ac97c_writel(chip, CAMR, word);

        /* Enable channel A event interrupt */
        word = ac97c_readl(chip, IMR);
        word |= AC97C_SR_CAEVT;
        ac97c_writel(chip, IER, word);

        /* set variable rate if needed */
        if (runtime->rate != 48000) {
                word = ac97c_readl(chip, MR);
                word |= AC97C_MR_VRA;
                ac97c_writel(chip, MR, word);
        } else {
                word = ac97c_readl(chip, MR);
                word &= ~(AC97C_MR_VRA);
                ac97c_writel(chip, MR, word);
        }

        retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_FRONT_DAC_RATE,
                        runtime->rate);
        if (retval)
                dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
                                runtime->rate);

        /* Initialize and start the PDC */
        writel(runtime->dma_addr, chip->regs + ATMEL_PDC_TPR);
        writel(block_size / 2, chip->regs + ATMEL_PDC_TCR);
        writel(runtime->dma_addr + block_size, chip->regs + ATMEL_PDC_TNPR);
        writel(block_size / 2, chip->regs + ATMEL_PDC_TNCR);

        return retval;
}

static int atmel_ac97c_capture_prepare(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        int block_size = frames_to_bytes(runtime, runtime->period_size);
        unsigned long word = ac97c_readl(chip, ICA);
        int retval;

        chip->capture_period = 0;
        word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));

        /* assign channels to AC97C channel A */
        switch (runtime->channels) {
        case 1:
                word |= AC97C_CH_ASSIGN(PCM_LEFT, A);
                break;
        case 2:
                word |= AC97C_CH_ASSIGN(PCM_LEFT, A)
                        | AC97C_CH_ASSIGN(PCM_RIGHT, A);
                break;
        default:
                /* TODO: support more than two channels */
                return -EINVAL;
        }
        ac97c_writel(chip, ICA, word);

        /* configure sample format and size */
        word = ac97c_readl(chip, CAMR);
        if (chip->opened <= 1)
                word = AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;
        else
                word |= AC97C_CMR_DMAEN | AC97C_CMR_SIZE_16;

        switch (runtime->format) {
        case SNDRV_PCM_FORMAT_S16_LE:
                break;
        case SNDRV_PCM_FORMAT_S16_BE:
                word &= ~(AC97C_CMR_CEM_LITTLE);
                break;
        default:
                word = ac97c_readl(chip, ICA);
                word &= ~(AC97C_CH_MASK(PCM_LEFT) | AC97C_CH_MASK(PCM_RIGHT));
                ac97c_writel(chip, ICA, word);
                return -EINVAL;
        }

        /* Enable overrun interrupt on channel A */
        word |= AC97C_CSR_OVRUN;

        ac97c_writel(chip, CAMR, word);

        /* Enable channel A event interrupt */
        word = ac97c_readl(chip, IMR);
        word |= AC97C_SR_CAEVT;
        ac97c_writel(chip, IER, word);

        /* set variable rate if needed */
        if (runtime->rate != 48000) {
                word = ac97c_readl(chip, MR);
                word |= AC97C_MR_VRA;
                ac97c_writel(chip, MR, word);
        } else {
                word = ac97c_readl(chip, MR);
                word &= ~(AC97C_MR_VRA);
                ac97c_writel(chip, MR, word);
        }

        retval = snd_ac97_set_rate(chip->ac97, AC97_PCM_LR_ADC_RATE,
                        runtime->rate);
        if (retval)
                dev_dbg(&chip->pdev->dev, "could not set rate %d Hz\n",
                                runtime->rate);

        /* Initialize and start the PDC */
        writel(runtime->dma_addr, chip->regs + ATMEL_PDC_RPR);
        writel(block_size / 2, chip->regs + ATMEL_PDC_RCR);
        writel(runtime->dma_addr + block_size, chip->regs + ATMEL_PDC_RNPR);
        writel(block_size / 2, chip->regs + ATMEL_PDC_RNCR);

        return retval;
}

static int
atmel_ac97c_playback_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        unsigned long camr, ptcr = 0;

        camr = ac97c_readl(chip, CAMR);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_START:
                ptcr = ATMEL_PDC_TXTEN;
                camr |= AC97C_CMR_CENA | AC97C_CSR_ENDTX;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
                ptcr |= ATMEL_PDC_TXTDIS;
                if (chip->opened <= 1)
                        camr &= ~AC97C_CMR_CENA;
                break;
        default:
                return -EINVAL;
        }

        ac97c_writel(chip, CAMR, camr);
        writel(ptcr, chip->regs + ATMEL_PDC_PTCR);
        return 0;
}

static int
atmel_ac97c_capture_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct atmel_ac97c *chip = snd_pcm_substream_chip(substream);
        unsigned long camr, ptcr = 0;

        camr = ac97c_readl(chip, CAMR);
        ptcr = readl(chip->regs + ATMEL_PDC_PTSR);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_START:
                ptcr = ATMEL_PDC_RXTEN;
                camr |= AC97C_CMR_CENA | AC97C_CSR_ENDRX;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_STOP:
                ptcr |= ATMEL_PDC_RXTDIS;
                if (chip->opened <= 1)
                        camr &= ~AC97C_CMR_CENA;
                break;
        default:
                return -EINVAL;
        }

        ac97c_writel(chip, CAMR, camr);
        writel(ptcr, chip->regs + ATMEL_PDC_PTCR);
        return 0;
}

static snd_pcm_uframes_t
atmel_ac97c_playback_pointer(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c      *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime  *runtime = substream->runtime;
        snd_pcm_uframes_t       frames;
        unsigned long           bytes;

        bytes = readl(chip->regs + ATMEL_PDC_TPR);
        bytes -= runtime->dma_addr;

        frames = bytes_to_frames(runtime, bytes);
        if (frames >= runtime->buffer_size)
                frames -= runtime->buffer_size;
        return frames;
}

static snd_pcm_uframes_t
atmel_ac97c_capture_pointer(struct snd_pcm_substream *substream)
{
        struct atmel_ac97c      *chip = snd_pcm_substream_chip(substream);
        struct snd_pcm_runtime  *runtime = substream->runtime;
        snd_pcm_uframes_t       frames;
        unsigned long           bytes;

        bytes = readl(chip->regs + ATMEL_PDC_RPR);
        bytes -= runtime->dma_addr;

        frames = bytes_to_frames(runtime, bytes);
        if (frames >= runtime->buffer_size)
                frames -= runtime->buffer_size;
        return frames;
}

static const struct snd_pcm_ops atmel_ac97_playback_ops = {
        .open           = atmel_ac97c_playback_open,
        .close          = atmel_ac97c_playback_close,
        .hw_params      = atmel_ac97c_playback_hw_params,
        .prepare        = atmel_ac97c_playback_prepare,
        .trigger        = atmel_ac97c_playback_trigger,
        .pointer        = atmel_ac97c_playback_pointer,
};

static const struct snd_pcm_ops atmel_ac97_capture_ops = {
        .open           = atmel_ac97c_capture_open,
        .close          = atmel_ac97c_capture_close,
        .hw_params      = atmel_ac97c_capture_hw_params,
        .prepare        = atmel_ac97c_capture_prepare,
        .trigger        = atmel_ac97c_capture_trigger,
        .pointer        = atmel_ac97c_capture_pointer,
};

static irqreturn_t atmel_ac97c_interrupt(int irq, void *dev)
{
        struct atmel_ac97c      *chip  = (struct atmel_ac97c *)dev;
        irqreturn_t             retval = IRQ_NONE;
        u32                     sr     = ac97c_readl(chip, SR);
        u32                     casr   = ac97c_readl(chip, CASR);
        u32                     cosr   = ac97c_readl(chip, COSR);
        u32                     camr   = ac97c_readl(chip, CAMR);

        if (sr & AC97C_SR_CAEVT) {
                struct snd_pcm_runtime *runtime;
                int offset, next_period, block_size;
                dev_dbg(&chip->pdev->dev, "channel A event%s%s%s%s%s%s\n",
                        (casr & AC97C_CSR_OVRUN)   ? " OVRUN"   : "",
                        (casr & AC97C_CSR_RXRDY)   ? " RXRDY"   : "",
                        (casr & AC97C_CSR_UNRUN)   ? " UNRUN"   : "",
                        (casr & AC97C_CSR_TXEMPTY) ? " TXEMPTY" : "",
                        (casr & AC97C_CSR_TXRDY)   ? " TXRDY"   : "",
                        !casr                      ? " NONE"    : "");
                if ((casr & camr) & AC97C_CSR_ENDTX) {
                        runtime = chip->playback_substream->runtime;
                        block_size = frames_to_bytes(runtime, runtime->period_size);
                        chip->playback_period++;

                        if (chip->playback_period == runtime->periods)
                                chip->playback_period = 0;
                        next_period = chip->playback_period + 1;
                        if (next_period == runtime->periods)
                                next_period = 0;

                        offset = block_size * next_period;

                        writel(runtime->dma_addr + offset, chip->regs + ATMEL_PDC_TNPR);
                        writel(block_size / 2, chip->regs + ATMEL_PDC_TNCR);

                        snd_pcm_period_elapsed(chip->playback_substream);
                }
                if ((casr & camr) & AC97C_CSR_ENDRX) {
                        runtime = chip->capture_substream->runtime;
                        block_size = frames_to_bytes(runtime, runtime->period_size);
                        chip->capture_period++;

                        if (chip->capture_period == runtime->periods)
                                chip->capture_period = 0;
                        next_period = chip->capture_period + 1;
                        if (next_period == runtime->periods)
                                next_period = 0;

                        offset = block_size * next_period;

                        writel(runtime->dma_addr + offset, chip->regs + ATMEL_PDC_RNPR);
                        writel(block_size / 2, chip->regs + ATMEL_PDC_RNCR);
                        snd_pcm_period_elapsed(chip->capture_substream);
                }
                retval = IRQ_HANDLED;
        }

        if (sr & AC97C_SR_COEVT) {
                dev_info(&chip->pdev->dev, "codec channel event%s%s%s%s%s\n",
                         (cosr & AC97C_CSR_OVRUN)   ? " OVRUN"   : "",
                         (cosr & AC97C_CSR_RXRDY)   ? " RXRDY"   : "",
                         (cosr & AC97C_CSR_TXEMPTY) ? " TXEMPTY" : "",
                         (cosr & AC97C_CSR_TXRDY)   ? " TXRDY"   : "",
                         !cosr                      ? " NONE"    : "");
                retval = IRQ_HANDLED;
        }

        if (retval == IRQ_NONE) {
                dev_err(&chip->pdev->dev, "spurious interrupt sr 0x%08x "
                                "casr 0x%08x cosr 0x%08x\n", sr, casr, cosr);
        }

        return retval;
}

static const struct ac97_pcm at91_ac97_pcm_defs[] = {
        /* Playback */
        {
                .exclusive = 1,
                .r = { {
                        .slots = ((1 << AC97_SLOT_PCM_LEFT)
                                  | (1 << AC97_SLOT_PCM_RIGHT)),
                } },
        },
        /* PCM in */
        {
                .stream = 1,
                .exclusive = 1,
                .r = { {
                        .slots = ((1 << AC97_SLOT_PCM_LEFT)
                                        | (1 << AC97_SLOT_PCM_RIGHT)),
                } }
        },
        /* Mic in */
        {
                .stream = 1,
                .exclusive = 1,
                .r = { {
                        .slots = (1<<AC97_SLOT_MIC),
                } }
        },
};

static int atmel_ac97c_pcm_new(struct atmel_ac97c *chip)
{
        struct snd_pcm          *pcm;
        struct snd_pcm_hardware hw = atmel_ac97c_hw;
        int                     retval;

        retval = snd_ac97_pcm_assign(chip->ac97_bus,
                                     ARRAY_SIZE(at91_ac97_pcm_defs),
                                     at91_ac97_pcm_defs);
        if (retval)
                return retval;

        retval = snd_pcm_new(chip->card, chip->card->shortname, 0, 1, 1, &pcm);
        if (retval)
                return retval;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &atmel_ac97_capture_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &atmel_ac97_playback_ops);

        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV,
                        &chip->pdev->dev, hw.periods_min * hw.period_bytes_min,
                        hw.buffer_bytes_max);

        pcm->private_data = chip;
        pcm->info_flags = 0;
        strscpy(pcm->name, chip->card->shortname);
        chip->pcm = pcm;

        return 0;
}

static int atmel_ac97c_mixer_new(struct atmel_ac97c *chip)
{
        struct snd_ac97_template template;
        memset(&template, 0, sizeof(template));
        template.private_data = chip;
        return snd_ac97_mixer(chip->ac97_bus, &template, &chip->ac97);
}

static void atmel_ac97c_write(struct snd_ac97 *ac97, unsigned short reg,
                unsigned short val)
{
        struct atmel_ac97c *chip = get_chip(ac97);
        unsigned long word;
        int timeout = 40;

        word = (reg & 0x7f) << 16 | val;

        do {
                if (ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) {
                        ac97c_writel(chip, COTHR, word);
                        return;
                }
                udelay(1);
        } while (--timeout);

        dev_dbg(&chip->pdev->dev, "codec write timeout\n");
}

static unsigned short atmel_ac97c_read(struct snd_ac97 *ac97,
                unsigned short reg)
{
        struct atmel_ac97c *chip = get_chip(ac97);
        unsigned long word;
        int timeout = 40;
        int write = 10;

        word = (0x80 | (reg & 0x7f)) << 16;

        if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0)
                ac97c_readl(chip, CORHR);

retry_write:
        timeout = 40;

        do {
                if ((ac97c_readl(chip, COSR) & AC97C_CSR_TXRDY) != 0) {
                        ac97c_writel(chip, COTHR, word);
                        goto read_reg;
                }
                udelay(10);
        } while (--timeout);

        if (!--write)
                goto timed_out;
        goto retry_write;

read_reg:
        do {
                if ((ac97c_readl(chip, COSR) & AC97C_CSR_RXRDY) != 0) {
                        unsigned short val = ac97c_readl(chip, CORHR);
                        return val;
                }
                udelay(10);
        } while (--timeout);

        if (!--write)
                goto timed_out;
        goto retry_write;

timed_out:
        dev_dbg(&chip->pdev->dev, "codec read timeout\n");
        return 0xffff;
}

static void atmel_ac97c_reset(struct atmel_ac97c *chip)
{
        ac97c_writel(chip, MR,   0);
        ac97c_writel(chip, MR,   AC97C_MR_ENA);
        ac97c_writel(chip, CAMR, 0);
        ac97c_writel(chip, COMR, 0);

        if (!IS_ERR(chip->reset_pin)) {
                gpiod_set_value(chip->reset_pin, 0);
                /* AC97 v2.2 specifications says minimum 1 us. */
                udelay(2);
                gpiod_set_value(chip->reset_pin, 1);
        } else {
                ac97c_writel(chip, MR, AC97C_MR_WRST | AC97C_MR_ENA);
                udelay(2);
                ac97c_writel(chip, MR, AC97C_MR_ENA);
        }
}

static const struct of_device_id atmel_ac97c_dt_ids[] = {
        { .compatible = "atmel,at91sam9263-ac97c", },
        { }
};
MODULE_DEVICE_TABLE(of, atmel_ac97c_dt_ids);

static int atmel_ac97c_probe(struct platform_device *pdev)
{
        struct device                   *dev = &pdev->dev;
        struct snd_card                 *card;
        struct atmel_ac97c              *chip;
        struct resource                 *regs;
        struct clk                      *pclk;
        static const struct snd_ac97_bus_ops    ops = {
                .write  = atmel_ac97c_write,
                .read   = atmel_ac97c_read,
        };
        int                             retval;
        int                             irq;

        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!regs) {
                dev_dbg(&pdev->dev, "no memory resource\n");
                return -ENXIO;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_dbg(&pdev->dev, "could not get irq: %d\n", irq);
                return irq;
        }

        pclk = clk_get(&pdev->dev, "ac97_clk");
        if (IS_ERR(pclk)) {
                dev_dbg(&pdev->dev, "no peripheral clock\n");
                return PTR_ERR(pclk);
        }
        retval = clk_prepare_enable(pclk);
        if (retval)
                goto err_prepare_enable;

        retval = snd_card_new(&pdev->dev, SNDRV_DEFAULT_IDX1,
                              SNDRV_DEFAULT_STR1, THIS_MODULE,
                              sizeof(struct atmel_ac97c), &card);
        if (retval) {
                dev_dbg(&pdev->dev, "could not create sound card device\n");
                goto err_snd_card_new;
        }

        chip = get_chip(card);

        retval = request_irq(irq, atmel_ac97c_interrupt, 0, "AC97C", chip);
        if (retval) {
                dev_dbg(&pdev->dev, "unable to request irq %d\n", irq);
                goto err_request_irq;
        }
        chip->irq = irq;

        spin_lock_init(&chip->lock);

        strscpy(card->driver, "Atmel AC97C");
        strscpy(card->shortname, "Atmel AC97C");
        strscpy(card->longname, "Atmel AC97 controller");

        chip->card = card;
        chip->pclk = pclk;
        chip->pdev = pdev;
        chip->regs = ioremap(regs->start, resource_size(regs));

        if (!chip->regs) {
                dev_dbg(&pdev->dev, "could not remap register memory\n");
                retval = -ENOMEM;
                goto err_ioremap;
        }

        chip->reset_pin = devm_gpiod_get_index(dev, "ac97", 2, GPIOD_OUT_HIGH);
        if (IS_ERR(chip->reset_pin))
                dev_dbg(dev, "reset pin not available\n");

        atmel_ac97c_reset(chip);

        /* Enable overrun interrupt from codec channel */
        ac97c_writel(chip, COMR, AC97C_CSR_OVRUN);
        ac97c_writel(chip, IER, ac97c_readl(chip, IMR) | AC97C_SR_COEVT);

        retval = snd_ac97_bus(card, 0, &ops, chip, &chip->ac97_bus);
        if (retval) {
                dev_dbg(&pdev->dev, "could not register on ac97 bus\n");
                goto err_ac97_bus;
        }

        retval = atmel_ac97c_mixer_new(chip);
        if (retval) {
                dev_dbg(&pdev->dev, "could not register ac97 mixer\n");
                goto err_ac97_bus;
        }

        retval = atmel_ac97c_pcm_new(chip);
        if (retval) {
                dev_dbg(&pdev->dev, "could not register ac97 pcm device\n");
                goto err_ac97_bus;
        }

        retval = snd_card_register(card);
        if (retval) {
                dev_dbg(&pdev->dev, "could not register sound card\n");
                goto err_ac97_bus;
        }

        platform_set_drvdata(pdev, card);

        dev_info(&pdev->dev, "Atmel AC97 controller at 0x%p, irq = %d\n",
                        chip->regs, irq);

        return 0;

err_ac97_bus:
        iounmap(chip->regs);
err_ioremap:
        free_irq(irq, chip);
err_request_irq:
        snd_card_free(card);
err_snd_card_new:
        clk_disable_unprepare(pclk);
err_prepare_enable:
        clk_put(pclk);
        return retval;
}

static int atmel_ac97c_suspend(struct device *pdev)
{
        struct snd_card *card = dev_get_drvdata(pdev);
        struct atmel_ac97c *chip = card->private_data;

        clk_disable_unprepare(chip->pclk);
        return 0;
}

static int atmel_ac97c_resume(struct device *pdev)
{
        struct snd_card *card = dev_get_drvdata(pdev);
        struct atmel_ac97c *chip = card->private_data;
        int ret = clk_prepare_enable(chip->pclk);

        return ret;
}

static DEFINE_SIMPLE_DEV_PM_OPS(atmel_ac97c_pm, atmel_ac97c_suspend, atmel_ac97c_resume);

static void atmel_ac97c_remove(struct platform_device *pdev)
{
        struct snd_card *card = platform_get_drvdata(pdev);
        struct atmel_ac97c *chip = get_chip(card);

        ac97c_writel(chip, CAMR, 0);
        ac97c_writel(chip, COMR, 0);
        ac97c_writel(chip, MR,   0);

        clk_disable_unprepare(chip->pclk);
        clk_put(chip->pclk);
        iounmap(chip->regs);
        free_irq(chip->irq, chip);

        snd_card_free(card);
}

static struct platform_driver atmel_ac97c_driver = {
        .probe          = atmel_ac97c_probe,
        .remove         = atmel_ac97c_remove,
        .driver         = {
                .name   = "atmel_ac97c",
                .pm     = pm_ptr(&atmel_ac97c_pm),
                .of_match_table = atmel_ac97c_dt_ids,
        },
};
module_platform_driver(atmel_ac97c_driver);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Driver for Atmel AC97 controller");
MODULE_AUTHOR("Hans-Christian Egtvedt <egtvedt@samfundet.no>");