]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
ASoC: atmel-i2s: add driver for the new Atmel I2S controller
authorCyrille Pitchen <cyrille.pitchen@atmel.com>
Fri, 25 May 2018 12:34:26 +0000 (15:34 +0300)
committerMark Brown <broonie@kernel.org>
Tue, 29 May 2018 14:37:21 +0000 (15:37 +0100)
This patch adds support for the Atmel I2S controller embedded into
sama5d2x SoCs.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
sound/soc/atmel/Kconfig
sound/soc/atmel/Makefile
sound/soc/atmel/atmel-i2s.c [new file with mode: 0644]

index dcee145dd17922ac2f81b2fb92a4085d3754e78d..64b784e96f844d3c77efe4eb8623dc3a23de2d20 100644 (file)
@@ -88,4 +88,13 @@ config SND_ATMEL_SOC_TSE850_PCM5142
        help
          Say Y if you want to add support for the ASoC driver for the
          Axentia TSE-850 with a PCM5142 codec.
+
+config SND_ATMEL_SOC_I2S
+       tristate "Atmel ASoC driver for boards using I2S"
+       depends on OF && (ARCH_AT91 || COMPILE_TEST)
+       select SND_SOC_GENERIC_DMAENGINE_PCM
+       select REGMAP_MMIO
+       help
+         Say Y or M if you want to add support for Atmel ASoc driver for boards
+         using I2S.
 endif
index 4440646416e8754271f25d365ea9f43cc4e9c17c..cd87cb4bcff51841a899cc583a6387e1cbf9a416 100644 (file)
@@ -3,10 +3,12 @@
 snd-soc-atmel-pcm-pdc-objs := atmel-pcm-pdc.o
 snd-soc-atmel-pcm-dma-objs := atmel-pcm-dma.o
 snd-soc-atmel_ssc_dai-objs := atmel_ssc_dai.o
+snd-soc-atmel-i2s-objs := atmel-i2s.o
 
 obj-$(CONFIG_SND_ATMEL_SOC_PDC) += snd-soc-atmel-pcm-pdc.o
 obj-$(CONFIG_SND_ATMEL_SOC_DMA) += snd-soc-atmel-pcm-dma.o
 obj-$(CONFIG_SND_ATMEL_SOC_SSC) += snd-soc-atmel_ssc_dai.o
+obj-$(CONFIG_SND_ATMEL_SOC_I2S) += snd-soc-atmel-i2s.o
 
 # AT91 Machine Support
 snd-soc-sam9g20-wm8731-objs := sam9g20_wm8731.o
diff --git a/sound/soc/atmel/atmel-i2s.c b/sound/soc/atmel/atmel-i2s.c
new file mode 100644 (file)
index 0000000..5d3b5af
--- /dev/null
@@ -0,0 +1,765 @@
+/*
+ * Driver for Atmel I2S controller
+ *
+ * Copyright (C) 2015 Atmel Corporation
+ *
+ * Author: Cyrille Pitchen <cyrille.pitchen@atmel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+#include <sound/soc.h>
+#include <sound/dmaengine_pcm.h>
+
+#define ATMEL_I2SC_MAX_TDM_CHANNELS    8
+
+/*
+ * ---- I2S Controller Register map ----
+ */
+#define ATMEL_I2SC_CR          0x0000  /* Control Register */
+#define ATMEL_I2SC_MR          0x0004  /* Mode Register */
+#define ATMEL_I2SC_SR          0x0008  /* Status Register */
+#define ATMEL_I2SC_SCR         0x000c  /* Status Clear Register */
+#define ATMEL_I2SC_SSR         0x0010  /* Status Set Register */
+#define ATMEL_I2SC_IER         0x0014  /* Interrupt Enable Register */
+#define ATMEL_I2SC_IDR         0x0018  /* Interrupt Disable Register */
+#define ATMEL_I2SC_IMR         0x001c  /* Interrupt Mask Register */
+#define ATMEL_I2SC_RHR         0x0020  /* Receiver Holding Register */
+#define ATMEL_I2SC_THR         0x0024  /* Transmitter Holding Register */
+#define ATMEL_I2SC_VERSION     0x0028  /* Version Register */
+
+/*
+ * ---- Control Register (Write-only) ----
+ */
+#define ATMEL_I2SC_CR_RXEN     BIT(0)  /* Receiver Enable */
+#define ATMEL_I2SC_CR_RXDIS    BIT(1)  /* Receiver Disable */
+#define ATMEL_I2SC_CR_CKEN     BIT(2)  /* Clock Enable */
+#define ATMEL_I2SC_CR_CKDIS    BIT(3)  /* Clock Disable */
+#define ATMEL_I2SC_CR_TXEN     BIT(4)  /* Transmitter Enable */
+#define ATMEL_I2SC_CR_TXDIS    BIT(5)  /* Transmitter Disable */
+#define ATMEL_I2SC_CR_SWRST    BIT(7)  /* Software Reset */
+
+/*
+ * ---- Mode Register (Read/Write) ----
+ */
+#define ATMEL_I2SC_MR_MODE_MASK                GENMASK(0, 0)
+#define ATMEL_I2SC_MR_MODE_SLAVE       (0 << 0)
+#define ATMEL_I2SC_MR_MODE_MASTER      (1 << 0)
+
+#define ATMEL_I2SC_MR_DATALENGTH_MASK          GENMASK(4, 2)
+#define ATMEL_I2SC_MR_DATALENGTH_32_BITS       (0 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_24_BITS       (1 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_20_BITS       (2 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_18_BITS       (3 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_16_BITS       (4 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_16_BITS_COMPACT       (5 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_8_BITS                (6 << 2)
+#define ATMEL_I2SC_MR_DATALENGTH_8_BITS_COMPACT        (7 << 2)
+
+#define ATMEL_I2SC_MR_FORMAT_MASK      GENMASK(7, 6)
+#define ATMEL_I2SC_MR_FORMAT_I2S       (0 << 6)
+#define ATMEL_I2SC_MR_FORMAT_LJ                (1 << 6)  /* Left Justified */
+#define ATMEL_I2SC_MR_FORMAT_TDM       (2 << 6)
+#define ATMEL_I2SC_MR_FORMAT_TDMLJ     (3 << 6)
+
+/* Left audio samples duplicated to right audio channel */
+#define ATMEL_I2SC_MR_RXMONO           BIT(8)
+
+/* Receiver uses one DMA channel ... */
+#define ATMEL_I2SC_MR_RXDMA_MASK       GENMASK(9, 9)
+#define ATMEL_I2SC_MR_RXDMA_SINGLE     (0 << 9)  /* for all audio channels */
+#define ATMEL_I2SC_MR_RXDMA_MULTIPLE   (1 << 9)  /* per audio channel */
+
+/* I2SDO output of I2SC is internally connected to I2SDI input */
+#define ATMEL_I2SC_MR_RXLOOP           BIT(10)
+
+/* Left audio samples duplicated to right audio channel */
+#define ATMEL_I2SC_MR_TXMONO           BIT(12)
+
+/* Transmitter uses one DMA channel ... */
+#define ATMEL_I2SC_MR_TXDMA_MASK       GENMASK(13, 13)
+#define ATMEL_I2SC_MR_TXDMA_SINGLE     (0 << 13)  /* for all audio channels */
+#define ATMEL_I2SC_MR_TXDME_MULTIPLE   (1 << 13)  /* per audio channel */
+
+/* x sample transmitted when underrun */
+#define ATMEL_I2SC_MR_TXSAME_MASK      GENMASK(14, 14)
+#define ATMEL_I2SC_MR_TXSAME_ZERO      (0 << 14)  /* Zero sample */
+#define ATMEL_I2SC_MR_TXSAME_PREVIOUS  (1 << 14)  /* Previous sample */
+
+/* Audio Clock to I2SC Master Clock ratio */
+#define ATMEL_I2SC_MR_IMCKDIV_MASK     GENMASK(21, 16)
+#define ATMEL_I2SC_MR_IMCKDIV(div) \
+       (((div) << 16) & ATMEL_I2SC_MR_IMCKDIV_MASK)
+
+/* Master Clock to fs ratio */
+#define ATMEL_I2SC_MR_IMCKFS_MASK      GENMASK(29, 24)
+#define ATMEL_I2SC_MR_IMCKFS(fs) \
+       (((fs) << 24) & ATMEL_I2SC_MR_IMCKFS_MASK)
+
+/* Master Clock mode */
+#define ATMEL_I2SC_MR_IMCKMODE_MASK    GENMASK(30, 30)
+/* 0: No master clock generated (selected clock drives I2SCK pin) */
+#define ATMEL_I2SC_MR_IMCKMODE_I2SCK   (0 << 30)
+/* 1: master clock generated (internally generated clock drives I2SMCK pin) */
+#define ATMEL_I2SC_MR_IMCKMODE_I2SMCK  (1 << 30)
+
+/* Slot Width */
+/* 0: slot is 32 bits wide for DATALENGTH = 18/20/24 bits. */
+/* 1: slot is 24 bits wide for DATALENGTH = 18/20/24 bits. */
+#define ATMEL_I2SC_MR_IWS              BIT(31)
+
+/*
+ * ---- Status Registers ----
+ */
+#define ATMEL_I2SC_SR_RXEN     BIT(0)  /* Receiver Enabled */
+#define ATMEL_I2SC_SR_RXRDY    BIT(1)  /* Receive Ready */
+#define ATMEL_I2SC_SR_RXOR     BIT(2)  /* Receive Overrun */
+
+#define ATMEL_I2SC_SR_TXEN     BIT(4)  /* Transmitter Enabled */
+#define ATMEL_I2SC_SR_TXRDY    BIT(5)  /* Transmit Ready */
+#define ATMEL_I2SC_SR_TXUR     BIT(6)  /* Transmit Underrun */
+
+/* Receive Overrun Channel */
+#define ATMEL_I2SC_SR_RXORCH_MASK      GENMASK(15, 8)
+#define ATMEL_I2SC_SR_RXORCH(ch)       (1 << (((ch) & 0x7) + 8))
+
+/* Transmit Underrun Channel */
+#define ATMEL_I2SC_SR_TXURCH_MASK      GENMASK(27, 20)
+#define ATMEL_I2SC_SR_TXURCH(ch)       (1 << (((ch) & 0x7) + 20))
+
+/*
+ * ---- Interrupt Enable/Disable/Mask Registers ----
+ */
+#define ATMEL_I2SC_INT_RXRDY   ATMEL_I2SC_SR_RXRDY
+#define ATMEL_I2SC_INT_RXOR    ATMEL_I2SC_SR_RXOR
+#define ATMEL_I2SC_INT_TXRDY   ATMEL_I2SC_SR_TXRDY
+#define ATMEL_I2SC_INT_TXUR    ATMEL_I2SC_SR_TXUR
+
+static const struct regmap_config atmel_i2s_regmap_config = {
+       .reg_bits = 32,
+       .reg_stride = 4,
+       .val_bits = 32,
+       .max_register = ATMEL_I2SC_VERSION,
+};
+
+struct atmel_i2s_gck_param {
+       int             fs;
+       unsigned long   mck;
+       int             imckdiv;
+       int             imckfs;
+};
+
+#define I2S_MCK_12M288         12288000UL
+#define I2S_MCK_11M2896                11289600UL
+
+/* mck = (32 * (imckfs+1) / (imckdiv+1)) * fs */
+static const struct atmel_i2s_gck_param gck_params[] = {
+       /* mck = 12.288MHz */
+       {  8000, I2S_MCK_12M288, 0, 47},        /* mck = 1536 fs */
+       { 16000, I2S_MCK_12M288, 1, 47},        /* mck =  768 fs */
+       { 24000, I2S_MCK_12M288, 3, 63},        /* mck =  512 fs */
+       { 32000, I2S_MCK_12M288, 3, 47},        /* mck =  384 fs */
+       { 48000, I2S_MCK_12M288, 7, 63},        /* mck =  256 fs */
+       { 64000, I2S_MCK_12M288, 7, 47},        /* mck =  192 fs */
+       { 96000, I2S_MCK_12M288, 7, 31},        /* mck =  128 fs */
+       {192000, I2S_MCK_12M288, 7, 15},        /* mck =   64 fs */
+
+       /* mck = 11.2896MHz */
+       { 11025, I2S_MCK_11M2896, 1, 63},       /* mck = 1024 fs */
+       { 22050, I2S_MCK_11M2896, 3, 63},       /* mck =  512 fs */
+       { 44100, I2S_MCK_11M2896, 7, 63},       /* mck =  256 fs */
+       { 88200, I2S_MCK_11M2896, 7, 31},       /* mck =  128 fs */
+       {176400, I2S_MCK_11M2896, 7, 15},       /* mck =   64 fs */
+};
+
+struct atmel_i2s_dev;
+
+struct atmel_i2s_caps {
+       int     (*mck_init)(struct atmel_i2s_dev *, struct device_node *np);
+};
+
+struct atmel_i2s_dev {
+       struct device                           *dev;
+       struct regmap                           *regmap;
+       struct clk                              *pclk;
+       struct clk                              *gclk;
+       struct clk                              *aclk;
+       struct snd_dmaengine_dai_dma_data       playback;
+       struct snd_dmaengine_dai_dma_data       capture;
+       unsigned int                            fmt;
+       const struct atmel_i2s_gck_param        *gck_param;
+       const struct atmel_i2s_caps             *caps;
+};
+
+static irqreturn_t atmel_i2s_interrupt(int irq, void *dev_id)
+{
+       struct atmel_i2s_dev *dev = dev_id;
+       unsigned int sr, imr, pending, ch, mask;
+       irqreturn_t ret = IRQ_NONE;
+
+       regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
+       regmap_read(dev->regmap, ATMEL_I2SC_IMR, &imr);
+       pending = sr & imr;
+
+       if (!pending)
+               return IRQ_NONE;
+
+       if (pending & ATMEL_I2SC_INT_RXOR) {
+               mask = ATMEL_I2SC_SR_RXOR;
+
+               for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
+                       if (sr & ATMEL_I2SC_SR_RXORCH(ch)) {
+                               mask |= ATMEL_I2SC_SR_RXORCH(ch);
+                               dev_err(dev->dev,
+                                       "RX overrun on channel %d\n", ch);
+                       }
+               }
+               regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
+               ret = IRQ_HANDLED;
+       }
+
+       if (pending & ATMEL_I2SC_INT_TXUR) {
+               mask = ATMEL_I2SC_SR_TXUR;
+
+               for (ch = 0; ch < ATMEL_I2SC_MAX_TDM_CHANNELS; ++ch) {
+                       if (sr & ATMEL_I2SC_SR_TXURCH(ch)) {
+                               mask |= ATMEL_I2SC_SR_TXURCH(ch);
+                               dev_err(dev->dev,
+                                       "TX underrun on channel %d\n", ch);
+                       }
+               }
+               regmap_write(dev->regmap, ATMEL_I2SC_SCR, mask);
+               ret = IRQ_HANDLED;
+       }
+
+       return ret;
+}
+
+#define ATMEL_I2S_RATES                SNDRV_PCM_RATE_8000_192000
+
+#define ATMEL_I2S_FORMATS      (SNDRV_PCM_FMTBIT_S8 |          \
+                                SNDRV_PCM_FMTBIT_S16_LE |      \
+                                SNDRV_PCM_FMTBIT_S18_3LE |     \
+                                SNDRV_PCM_FMTBIT_S20_3LE |     \
+                                SNDRV_PCM_FMTBIT_S24_3LE |     \
+                                SNDRV_PCM_FMTBIT_S24_LE |      \
+                                SNDRV_PCM_FMTBIT_S32_LE)
+
+static int atmel_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+       struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+       dev->fmt = fmt;
+       return 0;
+}
+
+static int atmel_i2s_prepare(struct snd_pcm_substream *substream,
+                            struct snd_soc_dai *dai)
+{
+       struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+       bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
+       unsigned int rhr, sr = 0;
+
+       if (is_playback) {
+               regmap_read(dev->regmap, ATMEL_I2SC_SR, &sr);
+               if (sr & ATMEL_I2SC_SR_RXRDY) {
+                       /*
+                        * The RX Ready flag should not be set. However if here,
+                        * we flush (read) the Receive Holding Register to start
+                        * from a clean state.
+                        */
+                       dev_dbg(dev->dev, "RXRDY is set\n");
+                       regmap_read(dev->regmap, ATMEL_I2SC_RHR, &rhr);
+               }
+       }
+
+       return 0;
+}
+
+static int atmel_i2s_get_gck_param(struct atmel_i2s_dev *dev, int fs)
+{
+       int i, best;
+
+       if (!dev->gclk || !dev->aclk) {
+               dev_err(dev->dev, "cannot generate the I2S Master Clock\n");
+               return -EINVAL;
+       }
+
+       /*
+        * Find the best possible settings to generate the I2S Master Clock
+        * from the PLL Audio.
+        */
+       dev->gck_param = NULL;
+       best = INT_MAX;
+       for (i = 0; i < ARRAY_SIZE(gck_params); ++i) {
+               const struct atmel_i2s_gck_param *gck_param = &gck_params[i];
+               int val = abs(fs - gck_param->fs);
+
+               if (val < best) {
+                       best = val;
+                       dev->gck_param = gck_param;
+               }
+       }
+
+       return 0;
+}
+
+static int atmel_i2s_hw_params(struct snd_pcm_substream *substream,
+                              struct snd_pcm_hw_params *params,
+                              struct snd_soc_dai *dai)
+{
+       struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+       bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
+       unsigned int mr = 0;
+       int ret;
+
+       switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+       case SND_SOC_DAIFMT_I2S:
+               mr |= ATMEL_I2SC_MR_FORMAT_I2S;
+               break;
+
+       default:
+               dev_err(dev->dev, "unsupported bus format\n");
+               return -EINVAL;
+       }
+
+       switch (dev->fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+       case SND_SOC_DAIFMT_CBS_CFS:
+               /* codec is slave, so cpu is master */
+               mr |= ATMEL_I2SC_MR_MODE_MASTER;
+               ret = atmel_i2s_get_gck_param(dev, params_rate(params));
+               if (ret)
+                       return ret;
+               break;
+
+       case SND_SOC_DAIFMT_CBM_CFM:
+               /* codec is master, so cpu is slave */
+               mr |= ATMEL_I2SC_MR_MODE_SLAVE;
+               dev->gck_param = NULL;
+               break;
+
+       default:
+               dev_err(dev->dev, "unsupported master/slave mode\n");
+               return -EINVAL;
+       }
+
+       switch (params_channels(params)) {
+       case 1:
+               if (is_playback)
+                       mr |= ATMEL_I2SC_MR_TXMONO;
+               else
+                       mr |= ATMEL_I2SC_MR_RXMONO;
+               break;
+       case 2:
+               break;
+       default:
+               dev_err(dev->dev, "unsupported number of audio channels\n");
+               return -EINVAL;
+       }
+
+       switch (params_format(params)) {
+       case SNDRV_PCM_FORMAT_S8:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_8_BITS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S16_LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_16_BITS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S18_3LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_18_BITS | ATMEL_I2SC_MR_IWS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S20_3LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_20_BITS | ATMEL_I2SC_MR_IWS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S24_3LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS | ATMEL_I2SC_MR_IWS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S24_LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_24_BITS;
+               break;
+
+       case SNDRV_PCM_FORMAT_S32_LE:
+               mr |= ATMEL_I2SC_MR_DATALENGTH_32_BITS;
+               break;
+
+       default:
+               dev_err(dev->dev, "unsupported size/endianness for audio samples\n");
+               return -EINVAL;
+       }
+
+       return regmap_write(dev->regmap, ATMEL_I2SC_MR, mr);
+}
+
+static int atmel_i2s_switch_mck_generator(struct atmel_i2s_dev *dev,
+                                         bool enabled)
+{
+       unsigned int mr, mr_mask;
+       unsigned long aclk_rate;
+       int ret;
+
+       mr = 0;
+       mr_mask = (ATMEL_I2SC_MR_IMCKDIV_MASK |
+                  ATMEL_I2SC_MR_IMCKFS_MASK |
+                  ATMEL_I2SC_MR_IMCKMODE_MASK);
+
+       if (!enabled) {
+               /* Disable the I2S Master Clock generator. */
+               ret = regmap_write(dev->regmap, ATMEL_I2SC_CR,
+                                  ATMEL_I2SC_CR_CKDIS);
+               if (ret)
+                       return ret;
+
+               /* Reset the I2S Master Clock generator settings. */
+               ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR,
+                                        mr_mask, mr);
+               if (ret)
+                       return ret;
+
+               /* Disable/unprepare the PMC generated clock. */
+               clk_disable_unprepare(dev->gclk);
+
+               /* Disable/unprepare the PLL audio clock. */
+               clk_disable_unprepare(dev->aclk);
+               return 0;
+       }
+
+       if (!dev->gck_param)
+               return -EINVAL;
+
+       aclk_rate = dev->gck_param->mck * (dev->gck_param->imckdiv + 1);
+
+       /* Fist change the PLL audio clock frequency ... */
+       ret = clk_set_rate(dev->aclk, aclk_rate);
+       if (ret)
+               return ret;
+
+       /*
+        * ... then set the PMC generated clock rate to the very same frequency
+        * to set the gclk parent to aclk.
+        */
+       ret = clk_set_rate(dev->gclk, aclk_rate);
+       if (ret)
+               return ret;
+
+       /* Prepare and enable the PLL audio clock first ... */
+       ret = clk_prepare_enable(dev->aclk);
+       if (ret)
+               return ret;
+
+       /* ... then prepare and enable the PMC generated clock. */
+       ret = clk_prepare_enable(dev->gclk);
+       if (ret)
+               return ret;
+
+       /* Update the Mode Register to generate the I2S Master Clock. */
+       mr |= ATMEL_I2SC_MR_IMCKDIV(dev->gck_param->imckdiv);
+       mr |= ATMEL_I2SC_MR_IMCKFS(dev->gck_param->imckfs);
+       mr |= ATMEL_I2SC_MR_IMCKMODE_I2SMCK;
+       ret = regmap_update_bits(dev->regmap, ATMEL_I2SC_MR, mr_mask, mr);
+       if (ret)
+               return ret;
+
+       /* Finally enable the I2S Master Clock generator. */
+       return regmap_write(dev->regmap, ATMEL_I2SC_CR,
+                           ATMEL_I2SC_CR_CKEN);
+}
+
+static int atmel_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
+                            struct snd_soc_dai *dai)
+{
+       struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+       bool is_playback = (substream->stream == SNDRV_PCM_STREAM_PLAYBACK);
+       bool is_master, mck_enabled;
+       unsigned int cr, mr;
+       int err;
+
+       switch (cmd) {
+       case SNDRV_PCM_TRIGGER_START:
+       case SNDRV_PCM_TRIGGER_RESUME:
+       case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+               cr = is_playback ? ATMEL_I2SC_CR_TXEN : ATMEL_I2SC_CR_RXEN;
+               mck_enabled = true;
+               break;
+       case SNDRV_PCM_TRIGGER_STOP:
+       case SNDRV_PCM_TRIGGER_SUSPEND:
+       case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+               cr = is_playback ? ATMEL_I2SC_CR_TXDIS : ATMEL_I2SC_CR_RXDIS;
+               mck_enabled = false;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       /* Read the Mode Register to retrieve the master/slave state. */
+       err = regmap_read(dev->regmap, ATMEL_I2SC_MR, &mr);
+       if (err)
+               return err;
+       is_master = (mr & ATMEL_I2SC_MR_MODE_MASK) == ATMEL_I2SC_MR_MODE_MASTER;
+
+       /* If master starts, enable the audio clock. */
+       if (is_master && mck_enabled)
+               err = atmel_i2s_switch_mck_generator(dev, true);
+       if (err)
+               return err;
+
+       err = regmap_write(dev->regmap, ATMEL_I2SC_CR, cr);
+       if (err)
+               return err;
+
+       /* If master stops, disable the audio clock. */
+       if (is_master && !mck_enabled)
+               err = atmel_i2s_switch_mck_generator(dev, false);
+
+       return err;
+}
+
+static const struct snd_soc_dai_ops atmel_i2s_dai_ops = {
+       .prepare        = atmel_i2s_prepare,
+       .trigger        = atmel_i2s_trigger,
+       .hw_params      = atmel_i2s_hw_params,
+       .set_fmt        = atmel_i2s_set_dai_fmt,
+};
+
+static int atmel_i2s_dai_probe(struct snd_soc_dai *dai)
+{
+       struct atmel_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
+
+       snd_soc_dai_init_dma_data(dai, &dev->playback, &dev->capture);
+       return 0;
+}
+
+static struct snd_soc_dai_driver atmel_i2s_dai = {
+       .probe  = atmel_i2s_dai_probe,
+       .playback = {
+               .channels_min = 1,
+               .channels_max = 2,
+               .rates = ATMEL_I2S_RATES,
+               .formats = ATMEL_I2S_FORMATS,
+       },
+       .capture = {
+               .channels_min = 1,
+               .channels_max = 2,
+               .rates = ATMEL_I2S_RATES,
+               .formats = ATMEL_I2S_FORMATS,
+       },
+       .ops = &atmel_i2s_dai_ops,
+       .symmetric_rates = 1,
+};
+
+static const struct snd_soc_component_driver atmel_i2s_component = {
+       .name   = "atmel-i2s",
+};
+
+static int atmel_i2s_sama5d2_mck_init(struct atmel_i2s_dev *dev,
+                                     struct device_node *np)
+{
+       struct clk *muxclk;
+       int err;
+
+       if (!dev->gclk)
+               return 0;
+
+       /* muxclk is optional, so we return error for probe defer only */
+       muxclk = devm_clk_get(dev->dev, "muxclk");
+       if (IS_ERR(muxclk)) {
+               err = PTR_ERR(muxclk);
+               if (err == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+               dev_warn(dev->dev,
+                        "failed to get the I2S clock control: %d\n", err);
+               return 0;
+       }
+
+       return clk_set_parent(muxclk, dev->gclk);
+}
+
+static const struct atmel_i2s_caps atmel_i2s_sama5d2_caps = {
+       .mck_init = atmel_i2s_sama5d2_mck_init,
+};
+
+static const struct of_device_id atmel_i2s_dt_ids[] = {
+       {
+               .compatible = "atmel,sama5d2-i2s",
+               .data = (void *)&atmel_i2s_sama5d2_caps,
+       },
+
+       { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_i2s_dt_ids);
+
+static int atmel_i2s_probe(struct platform_device *pdev)
+{
+       struct device_node *np = pdev->dev.of_node;
+       const struct of_device_id *match;
+       struct atmel_i2s_dev *dev;
+       struct resource *mem;
+       struct regmap *regmap;
+       void __iomem *base;
+       int irq;
+       int err = -ENXIO;
+       unsigned int pcm_flags = 0;
+       unsigned int version;
+
+       /* Get memory for driver data. */
+       dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
+       if (!dev)
+               return -ENOMEM;
+
+       /* Get hardware capabilities. */
+       match = of_match_node(atmel_i2s_dt_ids, np);
+       if (match)
+               dev->caps = match->data;
+
+       /* Map I/O registers. */
+       mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       base = devm_ioremap_resource(&pdev->dev, mem);
+       if (IS_ERR(base))
+               return PTR_ERR(base);
+
+       regmap = devm_regmap_init_mmio(&pdev->dev, base,
+                                      &atmel_i2s_regmap_config);
+       if (IS_ERR(regmap))
+               return PTR_ERR(regmap);
+
+       /* Request IRQ. */
+       irq = platform_get_irq(pdev, 0);
+       if (irq < 0)
+               return irq;
+
+       err = devm_request_irq(&pdev->dev, irq, atmel_i2s_interrupt, 0,
+                              dev_name(&pdev->dev), dev);
+       if (err)
+               return err;
+
+       /* Get the peripheral clock. */
+       dev->pclk = devm_clk_get(&pdev->dev, "pclk");
+       if (IS_ERR(dev->pclk)) {
+               err = PTR_ERR(dev->pclk);
+               dev_err(&pdev->dev,
+                       "failed to get the peripheral clock: %d\n", err);
+               return err;
+       }
+
+       /* Get audio clocks to generate the I2S Master Clock (I2S_MCK) */
+       dev->aclk = devm_clk_get(&pdev->dev, "aclk");
+       dev->gclk = devm_clk_get(&pdev->dev, "gclk");
+       if (IS_ERR(dev->aclk) && IS_ERR(dev->gclk)) {
+               if (PTR_ERR(dev->aclk) == -EPROBE_DEFER ||
+                   PTR_ERR(dev->gclk) == -EPROBE_DEFER)
+                       return -EPROBE_DEFER;
+               /* Master Mode not supported */
+               dev->aclk = NULL;
+               dev->gclk = NULL;
+       } else if (IS_ERR(dev->gclk)) {
+               err = PTR_ERR(dev->gclk);
+               dev_err(&pdev->dev,
+                       "failed to get the PMC generated clock: %d\n", err);
+               return err;
+       } else if (IS_ERR(dev->aclk)) {
+               err = PTR_ERR(dev->aclk);
+               dev_err(&pdev->dev,
+                       "failed to get the PLL audio clock: %d\n", err);
+               return err;
+       }
+
+       dev->dev = &pdev->dev;
+       dev->regmap = regmap;
+       platform_set_drvdata(pdev, dev);
+
+       /* Do hardware specific settings to initialize I2S_MCK generator */
+       if (dev->caps && dev->caps->mck_init) {
+               err = dev->caps->mck_init(dev, np);
+               if (err)
+                       return err;
+       }
+
+       /* Enable the peripheral clock. */
+       err = clk_prepare_enable(dev->pclk);
+       if (err)
+               return err;
+
+       /* Get IP version. */
+       regmap_read(dev->regmap, ATMEL_I2SC_VERSION, &version);
+       dev_info(&pdev->dev, "hw version: %#x\n", version);
+
+       /* Enable error interrupts. */
+       regmap_write(dev->regmap, ATMEL_I2SC_IER,
+                    ATMEL_I2SC_INT_RXOR | ATMEL_I2SC_INT_TXUR);
+
+       err = devm_snd_soc_register_component(&pdev->dev,
+                                             &atmel_i2s_component,
+                                             &atmel_i2s_dai, 1);
+       if (err) {
+               dev_err(&pdev->dev, "failed to register DAI: %d\n", err);
+               clk_disable_unprepare(dev->pclk);
+               return err;
+       }
+
+       /* Prepare DMA config. */
+       dev->playback.addr      = (dma_addr_t)mem->start + ATMEL_I2SC_THR;
+       dev->playback.maxburst  = 1;
+       dev->capture.addr       = (dma_addr_t)mem->start + ATMEL_I2SC_RHR;
+       dev->capture.maxburst   = 1;
+
+       if (of_property_match_string(np, "dma-names", "rx-tx") == 0)
+               pcm_flags |= SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX;
+       err = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, pcm_flags);
+       if (err) {
+               dev_err(&pdev->dev, "failed to register PCM: %d\n", err);
+               clk_disable_unprepare(dev->pclk);
+               return err;
+       }
+
+       return 0;
+}
+
+static int atmel_i2s_remove(struct platform_device *pdev)
+{
+       struct atmel_i2s_dev *dev = platform_get_drvdata(pdev);
+
+       clk_disable_unprepare(dev->pclk);
+
+       return 0;
+}
+
+static struct platform_driver atmel_i2s_driver = {
+       .driver         = {
+               .name   = "atmel_i2s",
+               .of_match_table = of_match_ptr(atmel_i2s_dt_ids),
+       },
+       .probe          = atmel_i2s_probe,
+       .remove         = atmel_i2s_remove,
+};
+module_platform_driver(atmel_i2s_driver);
+
+MODULE_DESCRIPTION("Atmel I2S Controller driver");
+MODULE_AUTHOR("Cyrille Pitchen <cyrille.pitchen@atmel.com>");
+MODULE_LICENSE("GPL v2");