ASoC: cros_ec_codec: Add codec driver for Cros EC

Add a codec driver to control ChromeOS EC codec.

Use EC Host command to enable/disable I2S recording and control other
configurations.

Signed-off-by: Cheng-Yi Chiang <cychiang@chromium.org>
Reviewed-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -3693,6 +3693,7 @@ S:	Maintained
 R:	Enric Balletbo i Serra <enric.balletbo@collabora.com>
 R:	Guenter Roeck <groeck@chromium.org>
 F:	Documentation/devicetree/bindings/sound/google,cros-ec-codec.txt
+F:	sound/soc/codecs/cros_ec_codec.*
 
 CIRRUS LOGIC AUDIO CODEC DRIVERS
 M:	Brian Austin <brian.austin@cirrus.com>

sound/soc/codecs/Kconfig

@@ -50,6 +50,7 @@ config SND_SOC_ALL_CODECS
 	select SND_SOC_BT_SCO
 	select SND_SOC_BD28623
 	select SND_SOC_CQ0093VC
+	select SND_SOC_CROS_EC_CODEC if MFD_CROS_EC
 	select SND_SOC_CS35L32 if I2C
 	select SND_SOC_CS35L33 if I2C
 	select SND_SOC_CS35L34 if I2C
@@ -459,6 +460,13 @@ config SND_SOC_CPCAP
 config SND_SOC_CQ0093VC
 	tristate
 
+config SND_SOC_CROS_EC_CODEC
+	tristate "codec driver for ChromeOS EC"
+	depends on MFD_CROS_EC
+	help
+	  If you say yes here you will get support for the
+	  ChromeOS Embedded Controller's Audio Codec.
+
 config SND_SOC_CS35L32
 	tristate "Cirrus Logic CS35L32 CODEC"
 	depends on I2C

sound/soc/codecs/Makefile

@@ -42,6 +42,7 @@ snd-soc-bd28623-objs := bd28623.o
 snd-soc-bt-sco-objs := bt-sco.o
 snd-soc-cpcap-objs := cpcap.o
 snd-soc-cq93vc-objs := cq93vc.o
+snd-soc-cros-ec-codec-objs := cros_ec_codec.o
 snd-soc-cs35l32-objs := cs35l32.o
 snd-soc-cs35l33-objs := cs35l33.o
 snd-soc-cs35l34-objs := cs35l34.o
@@ -312,6 +313,7 @@ obj-$(CONFIG_SND_SOC_BD28623)	+= snd-soc-bd28623.o
 obj-$(CONFIG_SND_SOC_BT_SCO)	+= snd-soc-bt-sco.o
 obj-$(CONFIG_SND_SOC_CQ0093VC) += snd-soc-cq93vc.o
 obj-$(CONFIG_SND_SOC_CPCAP)	+= snd-soc-cpcap.o
+obj-$(CONFIG_SND_SOC_CROS_EC_CODEC)	+= snd-soc-cros-ec-codec.o
 obj-$(CONFIG_SND_SOC_CS35L32)	+= snd-soc-cs35l32.o
 obj-$(CONFIG_SND_SOC_CS35L33)	+= snd-soc-cs35l33.o
 obj-$(CONFIG_SND_SOC_CS35L34)	+= snd-soc-cs35l34.o

sound/soc/codecs/cros_ec_codec.c

@@ -0,0 +1,441 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Driver for ChromeOS Embedded Controller codec.
+ *
+ * This driver uses the cros-ec interface to communicate with the ChromeOS
+ * EC for audio function.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mfd/cros_ec.h>
+#include <linux/mfd/cros_ec_commands.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/soc.h>
+#include <sound/tlv.h>
+
+#define DRV_NAME "cros-ec-codec"
+
+/**
+ * struct cros_ec_codec_data - ChromeOS EC codec driver data.
+ * @dev:		Device structure used in sysfs.
+ * @ec_device:		cros_ec_device structure to talk to the physical device.
+ * @component:		Pointer to the component.
+ * @max_dmic_gain:	Maximum gain in dB supported by EC codec.
+ */
+struct cros_ec_codec_data {
+	struct device *dev;
+	struct cros_ec_device *ec_device;
+	struct snd_soc_component *component;
+	unsigned int max_dmic_gain;
+};
+
+static const DECLARE_TLV_DB_SCALE(ec_mic_gain_tlv, 0, 100, 0);
+
+static int ec_command_get_gain(struct snd_soc_component *component,
+			       struct ec_param_codec_i2s *param,
+			       struct ec_response_codec_gain *resp)
+{
+	struct cros_ec_codec_data *codec_data =
+		snd_soc_component_get_drvdata(component);
+	struct cros_ec_device *ec_device = codec_data->ec_device;
+	u8 buffer[sizeof(struct cros_ec_command) +
+		  max(sizeof(struct ec_param_codec_i2s),
+		      sizeof(struct ec_response_codec_gain))];
+	struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
+	int ret;
+
+	msg->version = 0;
+	msg->command = EC_CMD_CODEC_I2S;
+	msg->outsize = sizeof(struct ec_param_codec_i2s);
+	msg->insize = sizeof(struct ec_response_codec_gain);
+
+	memcpy(msg->data, param, msg->outsize);
+
+	ret = cros_ec_cmd_xfer_status(ec_device, msg);
+	if (ret > 0)
+		memcpy(resp, msg->data, msg->insize);
+
+	return ret;
+}
+
+/*
+ * Wrapper for EC command without response.
+ */
+static int ec_command_no_resp(struct snd_soc_component *component,
+			      struct ec_param_codec_i2s *param)
+{
+	struct cros_ec_codec_data *codec_data =
+		snd_soc_component_get_drvdata(component);
+	struct cros_ec_device *ec_device = codec_data->ec_device;
+	u8 buffer[sizeof(struct cros_ec_command) +
+		  sizeof(struct ec_param_codec_i2s)];
+	struct cros_ec_command *msg = (struct cros_ec_command *)&buffer;
+
+	msg->version = 0;
+	msg->command = EC_CMD_CODEC_I2S;
+	msg->outsize = sizeof(struct ec_param_codec_i2s);
+	msg->insize = 0;
+
+	memcpy(msg->data, param, msg->outsize);
+
+	return cros_ec_cmd_xfer_status(ec_device, msg);
+}
+
+static int set_i2s_config(struct snd_soc_component *component,
+			  enum ec_i2s_config i2s_config)
+{
+	struct ec_param_codec_i2s param;
+
+	dev_dbg(component->dev, "%s set I2S format to %u\n", __func__,
+		i2s_config);
+
+	param.cmd = EC_CODEC_I2S_SET_CONFIG;
+	param.i2s_config = i2s_config;
+
+	return ec_command_no_resp(component, &param);
+}
+
+static int cros_ec_i2s_set_dai_fmt(struct snd_soc_dai *dai, unsigned int fmt)
+{
+	struct snd_soc_component *component = dai->component;
+	enum ec_i2s_config i2s_config;
+
+	switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
+	case SND_SOC_DAIFMT_CBS_CFS:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
+	case SND_SOC_DAIFMT_NB_NF:
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
+	case SND_SOC_DAIFMT_I2S:
+		i2s_config = EC_DAI_FMT_I2S;
+		break;
+
+	case SND_SOC_DAIFMT_RIGHT_J:
+		i2s_config = EC_DAI_FMT_RIGHT_J;
+		break;
+
+	case SND_SOC_DAIFMT_LEFT_J:
+		i2s_config = EC_DAI_FMT_LEFT_J;
+		break;
+
+	case SND_SOC_DAIFMT_DSP_A:
+		i2s_config = EC_DAI_FMT_PCM_A;
+		break;
+
+	case SND_SOC_DAIFMT_DSP_B:
+		i2s_config = EC_DAI_FMT_PCM_B;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return set_i2s_config(component, i2s_config);
+}
+
+static int set_i2s_sample_depth(struct snd_soc_component *component,
+				enum ec_sample_depth_value depth)
+{
+	struct ec_param_codec_i2s param;
+
+	dev_dbg(component->dev, "%s set depth to %u\n", __func__, depth);
+
+	param.cmd = EC_CODEC_SET_SAMPLE_DEPTH;
+	param.depth = depth;
+
+	return ec_command_no_resp(component, &param);
+}
+
+static int set_i2s_bclk(struct snd_soc_component *component, uint32_t bclk)
+{
+	struct ec_param_codec_i2s param;
+
+	dev_dbg(component->dev, "%s set i2s bclk to %u\n", __func__, bclk);
+
+	param.cmd = EC_CODEC_I2S_SET_BCLK;
+	param.bclk = bclk;
+
+	return ec_command_no_resp(component, &param);
+}
+
+static int cros_ec_i2s_hw_params(struct snd_pcm_substream *substream,
+				 struct snd_pcm_hw_params *params,
+				 struct snd_soc_dai *dai)
+{
+	struct snd_soc_component *component = dai->component;
+	unsigned int rate, bclk;
+	int ret;
+
+	rate = params_rate(params);
+	if (rate != 48000)
+		return -EINVAL;
+
+	switch (params_format(params)) {
+	case SNDRV_PCM_FORMAT_S16_LE:
+		ret = set_i2s_sample_depth(component, EC_CODEC_SAMPLE_DEPTH_16);
+		break;
+	case SNDRV_PCM_FORMAT_S24_LE:
+		ret = set_i2s_sample_depth(component, EC_CODEC_SAMPLE_DEPTH_24);
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (ret < 0)
+		return ret;
+
+	bclk = snd_soc_params_to_bclk(params);
+	return set_i2s_bclk(component, bclk);
+}
+
+static const struct snd_soc_dai_ops cros_ec_i2s_dai_ops = {
+	.hw_params = cros_ec_i2s_hw_params,
+	.set_fmt = cros_ec_i2s_set_dai_fmt,
+};
+
+struct snd_soc_dai_driver cros_ec_dai[] = {
+	{
+		.name = "cros_ec_codec I2S",
+		.id = 0,
+		.capture = {
+			.stream_name = "I2S Capture",
+			.channels_min = 2,
+			.channels_max = 2,
+			.rates = SNDRV_PCM_RATE_48000,
+			.formats = SNDRV_PCM_FMTBIT_S16_LE |
+				   SNDRV_PCM_FMTBIT_S24_LE,
+		},
+		.ops = &cros_ec_i2s_dai_ops,
+	}
+};
+
+static int get_ec_mic_gain(struct snd_soc_component *component,
+			   u8 *left, u8 *right)
+{
+	struct ec_param_codec_i2s param;
+	struct ec_response_codec_gain resp;
+	int ret;
+
+	param.cmd = EC_CODEC_GET_GAIN;
+
+	ret = ec_command_get_gain(component, &param, &resp);
+	if (ret < 0)
+		return ret;
+
+	*left = resp.left;
+	*right = resp.right;
+
+	return 0;
+}
+
+static int mic_gain_get(struct snd_kcontrol *kcontrol,
+			struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *component =
+		snd_soc_kcontrol_component(kcontrol);
+	u8 left, right;
+	int ret;
+
+	ret = get_ec_mic_gain(component, &left, &right);
+	if (ret)
+		return ret;
+
+	ucontrol->value.integer.value[0] = left;
+	ucontrol->value.integer.value[1] = right;
+
+	return 0;
+}
+
+static int set_ec_mic_gain(struct snd_soc_component *component,
+			   u8 left, u8 right)
+{
+	struct ec_param_codec_i2s param;
+
+	dev_dbg(component->dev, "%s set mic gain to %u, %u\n",
+		__func__, left, right);
+
+	param.cmd = EC_CODEC_SET_GAIN;
+	param.gain.left = left;
+	param.gain.right = right;
+
+	return ec_command_no_resp(component, &param);
+}
+
+static int mic_gain_put(struct snd_kcontrol *kcontrol,
+			struct snd_ctl_elem_value *ucontrol)
+{
+	struct snd_soc_component *component =
+		snd_soc_kcontrol_component(kcontrol);
+	struct cros_ec_codec_data *codec_data =
+		snd_soc_component_get_drvdata(component);
+	int left = ucontrol->value.integer.value[0];
+	int right = ucontrol->value.integer.value[1];
+	unsigned int max_dmic_gain = codec_data->max_dmic_gain;
+
+	if (left > max_dmic_gain || right > max_dmic_gain)
+		return -EINVAL;
+
+	return set_ec_mic_gain(component, (u8)left, (u8)right);
+}
+
+static struct snd_kcontrol_new mic_gain_control =
+	SOC_DOUBLE_EXT_TLV("EC Mic Gain", SND_SOC_NOPM, SND_SOC_NOPM, 0, 0, 0,
+			   mic_gain_get, mic_gain_put, ec_mic_gain_tlv);
+
+static int enable_i2s(struct snd_soc_component *component, int enable)
+{
+	struct ec_param_codec_i2s param;
+
+	dev_dbg(component->dev, "%s set i2s to %u\n", __func__, enable);
+
+	param.cmd = EC_CODEC_I2S_ENABLE;
+	param.i2s_enable = enable;
+
+	return ec_command_no_resp(component, &param);
+}
+
+static int cros_ec_i2s_enable_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);
+
+	switch (event) {
+	case SND_SOC_DAPM_PRE_PMU:
+		dev_dbg(component->dev,
+			"%s got SND_SOC_DAPM_PRE_PMU event\n", __func__);
+		return enable_i2s(component, 1);
+
+	case SND_SOC_DAPM_PRE_PMD:
+		dev_dbg(component->dev,
+			"%s got SND_SOC_DAPM_PRE_PMD event\n", __func__);
+		return enable_i2s(component, 0);
+	}
+
+	return 0;
+}
+
+/*
+ * The goal of this DAPM route is to turn on/off I2S using EC
+ * host command when capture stream is started/stopped.
+ */
+static const struct snd_soc_dapm_widget cros_ec_codec_dapm_widgets[] = {
+	SND_SOC_DAPM_INPUT("DMIC"),
+
+	/*
+	 * Control EC to enable/disable I2S.
+	 */
+	SND_SOC_DAPM_SUPPLY("I2S Enable", SND_SOC_NOPM,
+			    0, 0, cros_ec_i2s_enable_event,
+			    SND_SOC_DAPM_PRE_PMU | SND_SOC_DAPM_PRE_PMD),
+
+	SND_SOC_DAPM_AIF_OUT("I2STX", "I2S Capture", 0, SND_SOC_NOPM, 0, 0),
+};
+
+static const struct snd_soc_dapm_route cros_ec_codec_dapm_routes[] = {
+	{ "I2STX", NULL, "DMIC" },
+	{ "I2STX", NULL, "I2S Enable" },
+};
+
+/*
+ * Read maximum gain from device property and set it to mixer control.
+ */
+static int cros_ec_set_gain_range(struct device *dev)
+{
+	struct soc_mixer_control *control;
+	struct cros_ec_codec_data *codec_data = dev_get_drvdata(dev);
+	int rc;
+
+	rc = device_property_read_u32(dev, "max-dmic-gain",
+				      &codec_data->max_dmic_gain);
+	if (rc)
+		return rc;
+
+	control = (struct soc_mixer_control *)
+				mic_gain_control.private_value;
+	control->max = codec_data->max_dmic_gain;
+	control->platform_max = codec_data->max_dmic_gain;
+
+	return 0;
+}
+
+static int cros_ec_codec_probe(struct snd_soc_component *component)
+{
+	int rc;
+
+	struct cros_ec_codec_data *codec_data =
+		snd_soc_component_get_drvdata(component);
+
+	rc = cros_ec_set_gain_range(codec_data->dev);
+	if (rc)
+		return rc;
+
+	return snd_soc_add_component_controls(component, &mic_gain_control, 1);
+}
+
+static const struct snd_soc_component_driver cros_ec_component_driver = {
+	.probe			= cros_ec_codec_probe,
+	.dapm_widgets		= cros_ec_codec_dapm_widgets,
+	.num_dapm_widgets	= ARRAY_SIZE(cros_ec_codec_dapm_widgets),
+	.dapm_routes		= cros_ec_codec_dapm_routes,
+	.num_dapm_routes	= ARRAY_SIZE(cros_ec_codec_dapm_routes),
+};
+
+/*
+ * Platform device and platform driver fro cros-ec-codec.
+ */
+static int cros_ec_codec_platform_probe(struct platform_device *pd)
+{
+	struct device *dev = &pd->dev;
+	struct cros_ec_device *ec_device = dev_get_drvdata(pd->dev.parent);
+	struct cros_ec_codec_data *codec_data;
+
+	codec_data = devm_kzalloc(dev, sizeof(struct cros_ec_codec_data),
+				  GFP_KERNEL);
+	if (!codec_data)
+		return -ENOMEM;
+
+	codec_data->dev = dev;
+	codec_data->ec_device = ec_device;
+
+	platform_set_drvdata(pd, codec_data);
+
+	return snd_soc_register_component(dev, &cros_ec_component_driver,
+					  cros_ec_dai, ARRAY_SIZE(cros_ec_dai));
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id cros_ec_codec_of_match[] = {
+	{ .compatible = "google,cros-ec-codec" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, cros_ec_codec_of_match);
+#endif
+
+static struct platform_driver cros_ec_codec_platform_driver = {
+	.driver = {
+		.name = DRV_NAME,
+		.of_match_table = of_match_ptr(cros_ec_codec_of_match),
+	},
+	.probe = cros_ec_codec_platform_probe,
+};
+
+module_platform_driver(cros_ec_codec_platform_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("ChromeOS EC codec driver");
+MODULE_AUTHOR("Cheng-Yi Chiang <cychiang@chromium.org>");
+MODULE_ALIAS("platform:" DRV_NAME);