linux/sound/soc/codecs/dmic.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * dmic.c  --  SoC audio for Generic Digital MICs
 *
 * Author: Liam Girdwood <lrg@slimlogic.co.uk>
 */

#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/soc.h>
#include <sound/soc-dapm.h>

#define MAX_MODESWITCH_DELAY 70
static int modeswitch_delay;
module_param(modeswitch_delay, uint, 0644);

static int wakeup_delay;
module_param(wakeup_delay, uint, 0644);

struct dmic {
	struct gpio_desc *gpio_en;
	struct regulator *vref;
	int wakeup_delay;
	/* Delay after DMIC mode switch */
	int modeswitch_delay;
};

static int dmic_daiops_trigger(struct snd_pcm_substream *substream,
			       int cmd, struct snd_soc_dai *dai)
{
	struct snd_soc_component *component = dai->component;
	struct dmic *dmic = snd_soc_component_get_drvdata(component);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_STOP:
		if (dmic->modeswitch_delay)
			mdelay(dmic->modeswitch_delay);

		break;
	}

	return 0;
}

static const struct snd_soc_dai_ops dmic_dai_ops = {
	.trigger	= dmic_daiops_trigger,
};

static int dmic_aif_event(struct snd_soc_dapm_widget *w,
			  struct snd_kcontrol *kcontrol, int event) {
	struct snd_soc_component *component = snd_soc_dapm_to_component(w->dapm);
	struct dmic *dmic = snd_soc_component_get_drvdata(component);
	int ret = 0;

	switch (event) {
	case SND_SOC_DAPM_POST_PMU:
		if (dmic->gpio_en)
			gpiod_set_value_cansleep(dmic->gpio_en, 1);

		if (dmic->vref) {
			ret = regulator_enable(dmic->vref);
			if (ret)
				return ret;
		}

		if (dmic->wakeup_delay)
			msleep(dmic->wakeup_delay);
		break;
	case SND_SOC_DAPM_POST_PMD:
		if (dmic->gpio_en)
			gpiod_set_value_cansleep(dmic->gpio_en, 0);

		if (dmic->vref)
			ret = regulator_disable(dmic->vref);

		break;
	}

	return ret;
}

static struct snd_soc_dai_driver dmic_dai = {
	.name = "dmic-hifi",
	.capture = {
		.stream_name = "Capture",
		.channels_min = 1,
		.channels_max = 8,
		.rates = SNDRV_PCM_RATE_CONTINUOUS,
		.formats = SNDRV_PCM_FMTBIT_S32_LE
			| SNDRV_PCM_FMTBIT_S24_LE
			| SNDRV_PCM_FMTBIT_S16_LE
			| SNDRV_PCM_FMTBIT_DSD_U8
			| SNDRV_PCM_FMTBIT_DSD_U16_LE
			| SNDRV_PCM_FMTBIT_DSD_U32_LE
			| SNDRV_PCM_FMTBIT_DSD_U16_BE
			| SNDRV_PCM_FMTBIT_DSD_U32_BE,
	},
	.ops    = &dmic_dai_ops,
};

static int dmic_component_probe(struct snd_soc_component *component)
{
	struct dmic *dmic;

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

	dmic->vref = devm_regulator_get_optional(component->dev, "vref");
	if (IS_ERR(dmic->vref)) {
		if (PTR_ERR(dmic->vref) != -ENODEV)
			return dev_err_probe(component->dev, PTR_ERR(dmic->vref),
					     "Failed to get vref\n");
		dmic->vref = NULL;
	}

	dmic->gpio_en = devm_gpiod_get_optional(component->dev,
						"dmicen", GPIOD_OUT_LOW);
	if (IS_ERR(dmic->gpio_en))
		return PTR_ERR(dmic->gpio_en);

	device_property_read_u32(component->dev, "wakeup-delay-ms",
				 &dmic->wakeup_delay);
	device_property_read_u32(component->dev, "modeswitch-delay-ms",
				 &dmic->modeswitch_delay);
	if (wakeup_delay)
		dmic->wakeup_delay  = wakeup_delay;
	if (modeswitch_delay)
		dmic->modeswitch_delay  = modeswitch_delay;

	if (dmic->modeswitch_delay > MAX_MODESWITCH_DELAY)
		dmic->modeswitch_delay = MAX_MODESWITCH_DELAY;

	snd_soc_component_set_drvdata(component, dmic);

	return 0;
}

static const struct snd_soc_dapm_widget dmic_dapm_widgets[] = {
	SND_SOC_DAPM_AIF_OUT_E("DMIC AIF", "Capture", 0,
			       SND_SOC_NOPM, 0, 0, dmic_aif_event,
			       SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_POST_PMD),
	SND_SOC_DAPM_INPUT("DMic"),
};

static const struct snd_soc_dapm_route intercon[] = {
	{"DMIC AIF", NULL, "DMic"},
};

static const struct snd_soc_component_driver soc_dmic = {
	.probe			= dmic_component_probe,
	.dapm_widgets		= dmic_dapm_widgets,
	.num_dapm_widgets	= ARRAY_SIZE(dmic_dapm_widgets),
	.dapm_routes		= intercon,
	.num_dapm_routes	= ARRAY_SIZE(intercon),
	.idle_bias_on		= 1,
	.use_pmdown_time	= 1,
	.endianness		= 1,
};

static int dmic_dev_probe(struct platform_device *pdev)
{
	int err;
	u32 chans;
	struct snd_soc_dai_driver *dai_drv = &dmic_dai;

	if (pdev->dev.of_node) {
		err = of_property_read_u32(pdev->dev.of_node, "num-channels", &chans);
		if (err && (err != -EINVAL))
			return err;

		if (!err) {
			if (chans < 1 || chans > 8)
				return -EINVAL;

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

			memcpy(dai_drv, &dmic_dai, sizeof(*dai_drv));
			dai_drv->capture.channels_max = chans;
		}
	}

	return devm_snd_soc_register_component(&pdev->dev,
			&soc_dmic, dai_drv, 1);
}

MODULE_ALIAS("platform:dmic-codec");

static const struct of_device_id dmic_dev_match[] = {
	{.compatible = "dmic-codec"},
	{}
};
MODULE_DEVICE_TABLE(of, dmic_dev_match);

static struct platform_driver dmic_driver = {
	.driver = {
		.name = "dmic-codec",
		.of_match_table = dmic_dev_match,
	},
	.probe = dmic_dev_probe,
};

module_platform_driver(dmic_driver);

MODULE_DESCRIPTION("Generic DMIC driver");
MODULE_AUTHOR("Liam Girdwood <lrg@slimlogic.co.uk>");
MODULE_LICENSE("GPL");