ASoC: Add codec driver for AK5386

Adds a driver for Asahi Kasei's AK5386 Single-ended 24-Bit 192kHz
delta-sigma ADC. The device has no control port interface but an
optional RESET/PDN GPIO pin.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 152 insertions, 0 deletions

diff --git a/sound/soc/codecs/ak5386.c b/sound/soc/codecs/ak5386.c
new file mode 100644
index 000000000000..1f303983ae02
--- /dev/null
+++ b/sound/soc/codecs/ak5386.c
@@ -0,0 +1,152 @@
+/*
+ * ALSA SoC driver for
+ *    Asahi Kasei AK5386 Single-ended 24-Bit 192kHz delta-sigma ADC
+ *
+ * (c) 2013 Daniel Mack <zonque@gmail.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.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/of_device.h>
+#include <sound/soc.h>
+#include <sound/pcm.h>
+#include <sound/initval.h>
+
+struct ak5386_priv {
+	int reset_gpio;
+};
+
+static struct snd_soc_codec_driver soc_codec_ak5386;
+
+static int ak5386_set_dai_fmt(struct snd_soc_dai *codec_dai,
+			      unsigned int format)
+{
+	struct snd_soc_codec *codec = codec_dai->codec;
+
+	format &= SND_SOC_DAIFMT_FORMAT_MASK;
+	if (format != SND_SOC_DAIFMT_LEFT_J &&
+	    format != SND_SOC_DAIFMT_I2S) {
+		dev_err(codec->dev, "Invalid DAI format\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int ak5386_hw_params(struct snd_pcm_substream *substream,
+			    struct snd_pcm_hw_params *params,
+			    struct snd_soc_dai *dai)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	struct ak5386_priv *priv = snd_soc_codec_get_drvdata(codec);
+
+	/*
+	 * From the datasheet:
+	 *
+	 * All external clocks (MCLK, SCLK and LRCK) must be present unless
+	 * PDN pin = “L”. If these clocks are not provided, the AK5386 may
+	 * draw excess current due to its use of internal dynamically
+	 * refreshed logic. If the external clocks are not present, place
+	 * the AK5386 in power-down mode (PDN pin = “L”).
+	 */
+
+	if (gpio_is_valid(priv->reset_gpio))
+		gpio_set_value(priv->reset_gpio, 1);
+
+	return 0;
+}
+
+static int ak5386_hw_free(struct snd_pcm_substream *substream,
+			  struct snd_soc_dai *dai)
+{
+	struct snd_soc_codec *codec = dai->codec;
+	struct ak5386_priv *priv = snd_soc_codec_get_drvdata(codec);
+
+	if (gpio_is_valid(priv->reset_gpio))
+		gpio_set_value(priv->reset_gpio, 0);
+
+	return 0;
+}
+
+static const struct snd_soc_dai_ops ak5386_dai_ops = {
+	.set_fmt	= ak5386_set_dai_fmt,
+	.hw_params	= ak5386_hw_params,
+	.hw_free	= ak5386_hw_free,
+};
+
+static struct snd_soc_dai_driver ak5386_dai = {
+	.name		= "ak5386-hifi",
+	.capture	= {
+		.stream_name	= "Capture",
+		.channels_min	= 1,
+		.channels_max	= 2,
+		.rates		= SNDRV_PCM_RATE_8000_192000,
+		.formats	= SNDRV_PCM_FMTBIT_S8     |
+				  SNDRV_PCM_FMTBIT_S16_LE |
+				  SNDRV_PCM_FMTBIT_S24_LE |
+				  SNDRV_PCM_FMTBIT_S24_3LE,
+	},
+	.ops	= &ak5386_dai_ops,
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id ak5386_dt_ids[] = {
+	{ .compatible = "asahi-kasei,ak5386", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, ak5386_dt_ids);
+#endif
+
+static int ak5386_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct ak5386_priv *priv;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+
+	priv->reset_gpio = -EINVAL;
+	dev_set_drvdata(dev, priv);
+
+	if (of_match_device(of_match_ptr(ak5386_dt_ids), dev))
+		priv->reset_gpio = of_get_named_gpio(dev->of_node,
+						      "reset-gpio", 0);
+
+	if (gpio_is_valid(priv->reset_gpio))
+		if (devm_gpio_request_one(dev, priv->reset_gpio,
+					  GPIOF_OUT_INIT_LOW,
+					  "AK5386 Reset"))
+			priv->reset_gpio = -EINVAL;
+
+	return snd_soc_register_codec(dev, &soc_codec_ak5386,
+				      &ak5386_dai, 1);
+}
+
+static int ak5386_remove(struct platform_device *pdev)
+{
+	snd_soc_unregister_codec(&pdev->dev);
+	return 0;
+}
+
+static struct platform_driver ak5386_driver = {
+	.probe		= ak5386_probe,
+	.remove		= ak5386_remove,
+	.driver		= {
+		.name	= "ak5386",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(ak5386_dt_ids),
+	},
+};
+
+module_platform_driver(ak5386_driver);
+
+MODULE_DESCRIPTION("ASoC driver for AK5386 ADC");
+MODULE_AUTHOR("Daniel Mack <zonque@gmail.com>");
+MODULE_LICENSE("GPL");