[PATCH v4] drm: exynos: Add driver for HDMI audio interface

[Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>]

The hdmi-codec interface added in this patch is required to properly
support HDMI audio. Currently the audio part of the SoC internal
HDMI transmitter is configured with fixed values, which makes HDMI
audio working by chance, only on boards having an external audio
codec connected in parallel with the HDMI audio transmitter's input
I2S interface.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@xxxxxxxxxxx>
Reviewed-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>

---
Changes since v3:
 - removed unregister_audio_device() function, added missing
   audio platform device unregistration in probe(),
 - 'enable' field in struct hdmi_audio replace with 'mute',
 - audio infoframe initialization moved from the bind()
   callback to probe().

Changes since v2:
 - u8 replaced with bool type,
 - the  HDMI codec iec.status data used directly for setting up
   the HDMI controller registers rather than using hard coded
   constants,
 - constants used for configuring the HDMI_AUI_CON register
   instead of plain numbers,
 - if/IS_ERR/return replaced with PTR_ERR_OR_ZERO().

Changes since v1:
 - rebased onto v4.14-rc1 and adapted locking

Changes since RFC version:
 - fixed hdmi-codec locking issue
 - added a comment documenting struct hdmi_contex::mutex
---
 drivers/gpu/drm/exynos/Kconfig       |   1 +
 drivers/gpu/drm/exynos/exynos_hdmi.c | 250 ++++++++++++++++++++++++++---------
 drivers/gpu/drm/exynos/regs-hdmi.h   |   8 +-
 3 files changed, 194 insertions(+), 65 deletions(-)

diff --git a/drivers/gpu/drm/exynos/Kconfig b/drivers/gpu/drm/exynos/Kconfig
index 305dc3d4ff77..5a7c9d8abd6b 100644
--- a/drivers/gpu/drm/exynos/Kconfig
+++ b/drivers/gpu/drm/exynos/Kconfig
@@ -3,6 +3,7 @@ config DRM_EXYNOS
 	depends on OF && DRM && (ARCH_S3C64XX || ARCH_EXYNOS || ARCH_MULTIPLATFORM)
 	select DRM_KMS_HELPER
 	select VIDEOMODE_HELPERS
+	select SND_SOC_HDMI_CODEC if SND_SOC
 	help
 	  Choose this option if you have a Samsung SoC EXYNOS chipset.
 	  If M is selected the module will be called exynosdrm.
diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 1309b1c9e074..82d1b7e2febe 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -40,7 +40,7 @@
 #include <linux/component.h>
 #include <linux/mfd/syscon.h>
 #include <linux/regmap.h>
-
+#include <sound/hdmi-codec.h>
 #include <drm/exynos_drm.h>

 #include <media/cec-notifier.h>
@@ -111,12 +111,18 @@ struct hdmi_driver_data {
 	struct string_array_spec clk_muxes;
 };

+struct hdmi_audio {
+	struct platform_device		*pdev;
+	struct hdmi_audio_infoframe	infoframe;
+	struct hdmi_codec_params	params;
+	bool				mute;
+};
+
 struct hdmi_context {
 	struct drm_encoder		encoder;
 	struct device			*dev;
 	struct drm_device		*drm_dev;
 	struct drm_connector		connector;
-	bool				powered;
 	bool				dvi_mode;
 	struct delayed_work		hotplug_work;
 	struct cec_notifier		*notifier;
@@ -136,6 +142,11 @@ struct hdmi_context {
 	struct regulator		*reg_hdmi_en;
 	struct exynos_drm_clk		phy_clk;
 	struct drm_bridge		*bridge;
+
+	/* mutex protecting subsequent fields below */
+	struct mutex			mutex;
+	struct hdmi_audio		audio;
+	bool				powered;
 };

 static inline struct hdmi_context *encoder_to_hdmi(struct drm_encoder *e)
@@ -776,6 +787,22 @@ static int hdmi_clk_set_parents(struct hdmi_context *hdata, bool to_phy)
 	return ret;
 }

+static int hdmi_audio_infoframe_apply(struct hdmi_context *hdata)
+{
+	struct hdmi_audio_infoframe *infoframe = &hdata->audio.infoframe;
+	u8 buf[HDMI_INFOFRAME_SIZE(AUDIO)];
+	int len;
+
+	len = hdmi_audio_infoframe_pack(infoframe, buf, sizeof(buf));
+	if (len < 0)
+		return len;
+
+	hdmi_reg_writeb(hdata, HDMI_AUI_CON, HDMI_AUI_CON_EVERY_VSYNC);
+	hdmi_reg_write_buf(hdata, HDMI_AUI_HEADER0, buf, len);
+
+	return 0;
+}
+
 static void hdmi_reg_infoframes(struct hdmi_context *hdata)
 {
 	struct drm_display_mode *m = &hdata->encoder.crtc->state->mode;
@@ -812,15 +839,7 @@ static void hdmi_reg_infoframes(struct hdmi_context *hdata)
 		hdmi_reg_write_buf(hdata, HDMI_VSI_DATA(0), buf + 3, ret - 3);
 	}

-	ret = hdmi_audio_infoframe_init(&frm.audio);
-	if (!ret) {
-		frm.audio.channels = 2;
-		ret = hdmi_audio_infoframe_pack(&frm.audio, buf, sizeof(buf));
-	}
-	if (ret > 0) {
-		hdmi_reg_writeb(hdata, HDMI_AUI_CON, HDMI_AUI_CON_EVERY_VSYNC);
-		hdmi_reg_write_buf(hdata, HDMI_AUI_HEADER0, buf, ret);
-	}
+	hdmi_audio_infoframe_apply(hdata);
 }

 static enum drm_connector_status hdmi_detect(struct drm_connector *connector,
@@ -1010,23 +1029,18 @@ static void hdmi_reg_acr(struct hdmi_context *hdata, u32 freq)
 	hdmi_reg_writeb(hdata, HDMI_ACR_CON, 4);
 }

-static void hdmi_audio_init(struct hdmi_context *hdata)
+static void hdmi_audio_config(struct hdmi_context *hdata)
 {
-	u32 sample_rate, bits_per_sample;
-	u32 data_num, bit_ch, sample_frq;
-	u32 val;
-
-	sample_rate = 44100;
-	bits_per_sample = 16;
+	u32 bit_ch = 1;
+	u32 data_num, val;
+	int i;

-	switch (bits_per_sample) {
+	switch (hdata->audio.params.sample_width) {
 	case 20:
 		data_num = 2;
-		bit_ch = 1;
 		break;
 	case 24:
 		data_num = 3;
-		bit_ch = 1;
 		break;
 	default:
 		data_num = 1;
@@ -1034,7 +1048,7 @@ static void hdmi_audio_init(struct hdmi_context *hdata)
 		break;
 	}

-	hdmi_reg_acr(hdata, sample_rate);
+	hdmi_reg_acr(hdata, hdata->audio.params.sample_rate);

 	hdmi_reg_writeb(hdata, HDMI_I2S_MUX_CON, HDMI_I2S_IN_DISABLE
 				| HDMI_I2S_AUD_I2S | HDMI_I2S_CUV_I2S_ENABLE
@@ -1044,12 +1058,6 @@ static void hdmi_audio_init(struct hdmi_context *hdata)
 			| HDMI_I2S_CH1_EN | HDMI_I2S_CH2_EN);

 	hdmi_reg_writeb(hdata, HDMI_I2S_MUX_CUV, HDMI_I2S_CUV_RL_EN);
-
-	sample_frq = (sample_rate == 44100) ? 0 :
-			(sample_rate == 48000) ? 2 :
-			(sample_rate == 32000) ? 3 :
-			(sample_rate == 96000) ? 0xa : 0x0;
-
 	hdmi_reg_writeb(hdata, HDMI_I2S_CLK_CON, HDMI_I2S_CLK_DIS);
 	hdmi_reg_writeb(hdata, HDMI_I2S_CLK_CON, HDMI_I2S_CLK_EN);

@@ -1073,31 +1081,24 @@ static void hdmi_audio_init(struct hdmi_context *hdata)
 			| HDMI_I2S_SET_SDATA_BIT(data_num)
 			| HDMI_I2S_BASIC_FORMAT);

-	/* Configure register related to CUV information */
-	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_0, HDMI_I2S_CH_STATUS_MODE_0
-			| HDMI_I2S_2AUD_CH_WITHOUT_PREEMPH
-			| HDMI_I2S_COPYRIGHT
-			| HDMI_I2S_LINEAR_PCM
-			| HDMI_I2S_CONSUMER_FORMAT);
-	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_1, HDMI_I2S_CD_PLAYER);
-	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_2, HDMI_I2S_SET_SOURCE_NUM(0));
-	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_3, HDMI_I2S_CLK_ACCUR_LEVEL_2
-			| HDMI_I2S_SET_SMP_FREQ(sample_frq));
-	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_4,
-			HDMI_I2S_ORG_SMP_FREQ_44_1
-			| HDMI_I2S_WORD_LEN_MAX24_24BITS
-			| HDMI_I2S_WORD_LEN_MAX_24BITS);
+	/* Configuration of the audio channel status registers */
+	for (i = 0; i < HDMI_I2S_CH_ST_MAXNUM; i++)
+		hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST(i),
+				hdata->audio.params.iec.status[i]);

 	hdmi_reg_writeb(hdata, HDMI_I2S_CH_ST_CON, HDMI_I2S_CH_STATUS_RELOAD);
 }

-static void hdmi_audio_control(struct hdmi_context *hdata, bool onoff)
+static void hdmi_audio_control(struct hdmi_context *hdata)
 {
+	bool enable = !hdata->audio.mute;
+
 	if (hdata->dvi_mode)
 		return;

-	hdmi_reg_writeb(hdata, HDMI_AUI_CON, onoff ? 2 : 0);
-	hdmi_reg_writemask(hdata, HDMI_CON_0, onoff ?
+	hdmi_reg_writeb(hdata, HDMI_AUI_CON, enable ?
+			HDMI_AVI_CON_EVERY_VSYNC : HDMI_AUI_CON_NO_TRAN);
+	hdmi_reg_writemask(hdata, HDMI_CON_0, enable ?
 			HDMI_ASP_EN : HDMI_ASP_DIS, HDMI_ASP_MASK);
 }

@@ -1428,13 +1429,14 @@ static void hdmiphy_conf_apply(struct hdmi_context *hdata)
 	hdmiphy_wait_for_pll(hdata);
 }

+/* Should be called with hdata->mutex mutex held */
 static void hdmi_conf_apply(struct hdmi_context *hdata)
 {
 	hdmi_start(hdata, false);
 	hdmi_conf_init(hdata);
-	hdmi_audio_init(hdata);
+	hdmi_audio_config(hdata);
 	hdmi_mode_apply(hdata);
-	hdmi_audio_control(hdata, true);
+	hdmi_audio_control(hdata);
 }

 static void hdmi_set_refclk(struct hdmi_context *hdata, bool on)
@@ -1446,6 +1448,7 @@ static void hdmi_set_refclk(struct hdmi_context *hdata, bool on)
 			   SYSREG_HDMI_REFCLK_INT_CLK, on ? ~0 : 0);
 }

+/* Should be called with hdata->mutex mutex held. */
 static void hdmiphy_enable(struct hdmi_context *hdata)
 {
 	if (hdata->powered)
@@ -1468,6 +1471,7 @@ static void hdmiphy_enable(struct hdmi_context *hdata)
 	hdata->powered = true;
 }

+/* Should be called with hdata->mutex mutex held. */
 static void hdmiphy_disable(struct hdmi_context *hdata)
 {
 	if (!hdata->powered)
@@ -1493,28 +1497,38 @@ static void hdmi_enable(struct drm_encoder *encoder)
 {
 	struct hdmi_context *hdata = encoder_to_hdmi(encoder);

+	mutex_lock(&hdata->mutex);
+
 	hdmiphy_enable(hdata);
 	hdmi_conf_apply(hdata);
+
+	mutex_unlock(&hdata->mutex);
 }

 static void hdmi_disable(struct drm_encoder *encoder)
 {
 	struct hdmi_context *hdata = encoder_to_hdmi(encoder);

-	if (!hdata->powered)
+	mutex_lock(&hdata->mutex);
+
+	if (hdata->powered) {
+		/*
+		 * The SFRs of VP and Mixer are updated by Vertical Sync of
+		 * Timing generator which is a part of HDMI so the sequence
+		 * to disable TV Subsystem should be as following,
+		 *	VP -> Mixer -> HDMI
+		 *
+		 * To achieve such sequence HDMI is disabled together with
+		 * HDMI PHY, via pipe clock callback.
+		 */
+		mutex_unlock(&hdata->mutex);
+		cancel_delayed_work(&hdata->hotplug_work);
+		cec_notifier_set_phys_addr(hdata->notifier,
+					   CEC_PHYS_ADDR_INVALID);
 		return;
+	}

-	/*
-	 * The SFRs of VP and Mixer are updated by Vertical Sync of
-	 * Timing generator which is a part of HDMI so the sequence
-	 * to disable TV Subsystem should be as following,
-	 *	VP -> Mixer -> HDMI
-	 *
-	 * To achieve such sequence HDMI is disabled together with HDMI PHY, via
-	 * pipe clock callback.
-	 */
-	cancel_delayed_work(&hdata->hotplug_work);
-	cec_notifier_set_phys_addr(hdata->notifier, CEC_PHYS_ADDR_INVALID);
+	mutex_unlock(&hdata->mutex);
 }

 static const struct drm_encoder_helper_funcs exynos_hdmi_encoder_helper_funcs = {
@@ -1527,6 +1541,99 @@ static const struct drm_encoder_funcs exynos_hdmi_encoder_funcs = {
 	.destroy = drm_encoder_cleanup,
 };

+static void hdmi_audio_shutdown(struct device *dev, void *data)
+{
+	struct hdmi_context *hdata = dev_get_drvdata(dev);
+
+	mutex_lock(&hdata->mutex);
+
+	hdata->audio.mute = true;
+
+	if (hdata->powered)
+		hdmi_audio_control(hdata);
+
+	mutex_unlock(&hdata->mutex);
+}
+
+static int hdmi_audio_hw_params(struct device *dev, void *data,
+				struct hdmi_codec_daifmt *daifmt,
+				struct hdmi_codec_params *params)
+{
+	struct hdmi_context *hdata = dev_get_drvdata(dev);
+
+	if (daifmt->fmt != HDMI_I2S || daifmt->bit_clk_inv ||
+	    daifmt->frame_clk_inv || daifmt->bit_clk_master ||
+	    daifmt->frame_clk_master) {
+		dev_err(dev, "%s: Bad flags %d %d %d %d\n", __func__,
+			daifmt->bit_clk_inv, daifmt->frame_clk_inv,
+			daifmt->bit_clk_master,
+			daifmt->frame_clk_master);
+		return -EINVAL;
+	}
+
+	mutex_lock(&hdata->mutex);
+
+	hdata->audio.params = *params;
+
+	if (hdata->powered) {
+		hdmi_audio_config(hdata);
+		hdmi_audio_infoframe_apply(hdata);
+	}
+
+	mutex_unlock(&hdata->mutex);
+
+	return 0;
+}
+
+static int hdmi_audio_digital_mute(struct device *dev, void *data, bool mute)
+{
+	struct hdmi_context *hdata = dev_get_drvdata(dev);
+
+	mutex_lock(&hdata->mutex);
+
+	hdata->audio.mute = mute;
+
+	if (hdata->powered)
+		hdmi_audio_control(hdata);
+
+	mutex_unlock(&hdata->mutex);
+
+	return 0;
+}
+
+static int hdmi_audio_get_eld(struct device *dev, void *data, uint8_t *buf,
+			      size_t len)
+{
+	struct hdmi_context *hdata = dev_get_drvdata(dev);
+	struct drm_connector *connector = &hdata->connector;
+
+	memcpy(buf, connector->eld, min(sizeof(connector->eld), len));
+
+	return 0;
+}
+
+static const struct hdmi_codec_ops audio_codec_ops = {
+	.hw_params = hdmi_audio_hw_params,
+	.audio_shutdown = hdmi_audio_shutdown,
+	.digital_mute = hdmi_audio_digital_mute,
+	.get_eld = hdmi_audio_get_eld,
+};
+
+static int hdmi_register_audio_device(struct hdmi_context *hdata)
+{
+	struct hdmi_codec_pdata codec_data = {
+		.ops = &audio_codec_ops,
+		.max_i2s_channels = 6,
+		.i2s = 1,
+	};
+
+	hdata->audio.pdev = platform_device_register_data(
+		hdata->dev, HDMI_CODEC_DRV_NAME, PLATFORM_DEVID_AUTO,
+		&codec_data, sizeof(codec_data));
+
+	return PTR_ERR_OR_ZERO(hdata->audio.pdev);
+}
+
 static void hdmi_hotplug_work_func(struct work_struct *work)
 {
 	struct hdmi_context *hdata;
@@ -1602,11 +1709,14 @@ static void hdmiphy_clk_enable(struct exynos_drm_clk *clk, bool enable)
 {
 	struct hdmi_context *hdata = container_of(clk, struct hdmi_context,
 						  phy_clk);
+	mutex_lock(&hdata->mutex);

 	if (enable)
 		hdmiphy_enable(hdata);
 	else
 		hdmiphy_disable(hdata);
+
+	mutex_unlock(&hdata->mutex);
 }

 static int hdmi_bridge_init(struct hdmi_context *hdata)
@@ -1817,6 +1927,7 @@ static int hdmi_get_phy_io(struct hdmi_context *hdata)

 static int hdmi_probe(struct platform_device *pdev)
 {
+	struct hdmi_audio_infoframe *audio_infoframe;
 	struct device *dev = &pdev->dev;
 	struct hdmi_context *hdata;
 	struct resource *res;
@@ -1832,6 +1943,8 @@ static int hdmi_probe(struct platform_device *pdev)

 	hdata->dev = dev;

+	mutex_init(&hdata->mutex);
+
 	ret = hdmi_resources_init(hdata);
 	if (ret) {
 		if (ret != -EPROBE_DEFER)
@@ -1891,12 +2004,26 @@ static int hdmi_probe(struct platform_device *pdev)

 	pm_runtime_enable(dev);

-	ret = component_add(&pdev->dev, &hdmi_component_ops);
+	audio_infoframe = &hdata->audio.infoframe;
+	hdmi_audio_infoframe_init(audio_infoframe);
+	audio_infoframe->coding_type = HDMI_AUDIO_CODING_TYPE_STREAM;
+	audio_infoframe->sample_size = HDMI_AUDIO_SAMPLE_SIZE_STREAM;
+	audio_infoframe->sample_frequency = HDMI_AUDIO_SAMPLE_FREQUENCY_STREAM;
+	audio_infoframe->channels = 2;
+
+	ret = hdmi_register_audio_device(hdata);
 	if (ret)
 		goto err_notifier_put;

+	ret = component_add(&pdev->dev, &hdmi_component_ops);
+	if (ret)
+		goto err_unregister_audio;
+
 	return ret;

+err_unregister_audio:
+	platform_device_unregister(hdata->audio.pdev);
+
 err_notifier_put:
 	cec_notifier_put(hdata->notifier);
 	pm_runtime_disable(dev);
@@ -1920,6 +2047,7 @@ static int hdmi_remove(struct platform_device *pdev)
 	cec_notifier_set_phys_addr(hdata->notifier, CEC_PHYS_ADDR_INVALID);

 	component_del(&pdev->dev, &hdmi_component_ops);
+	platform_device_unregister(hdata->audio.pdev);

 	cec_notifier_put(hdata->notifier);
 	pm_runtime_disable(&pdev->dev);
@@ -1935,6 +2063,8 @@ static int hdmi_remove(struct platform_device *pdev)

 	put_device(&hdata->ddc_adpt->dev);

+	mutex_destroy(&hdata->mutex);
+
 	return 0;
 }

diff --git a/drivers/gpu/drm/exynos/regs-hdmi.h b/drivers/gpu/drm/exynos/regs-hdmi.h
index a0507dc18d9e..04be0f7e8193 100644
--- a/drivers/gpu/drm/exynos/regs-hdmi.h
+++ b/drivers/gpu/drm/exynos/regs-hdmi.h
@@ -419,11 +419,9 @@
 #define HDMI_I2S_DSD_CON		HDMI_I2S_BASE(0x01c)
 #define HDMI_I2S_MUX_CON		HDMI_I2S_BASE(0x020)
 #define HDMI_I2S_CH_ST_CON		HDMI_I2S_BASE(0x024)
-#define HDMI_I2S_CH_ST_0		HDMI_I2S_BASE(0x028)
-#define HDMI_I2S_CH_ST_1		HDMI_I2S_BASE(0x02c)
-#define HDMI_I2S_CH_ST_2		HDMI_I2S_BASE(0x030)
-#define HDMI_I2S_CH_ST_3		HDMI_I2S_BASE(0x034)
-#define HDMI_I2S_CH_ST_4		HDMI_I2S_BASE(0x038)
+/* n must be within range 0...(HDMI_I2S_CH_ST_MAXNUM - 1) */
+#define HDMI_I2S_CH_ST_MAXNUM		5
+#define HDMI_I2S_CH_ST(n)		HDMI_I2S_BASE(0x028 + 4 * (n))
 #define HDMI_I2S_CH_ST_SH_0		HDMI_I2S_BASE(0x03c)
 #define HDMI_I2S_CH_ST_SH_1		HDMI_I2S_BASE(0x040)
 #define HDMI_I2S_CH_ST_SH_2		HDMI_I2S_BASE(0x044)
--
2.13.0

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