Re: [PATCH v1] ALSA: hda: cs35l41: Support mute notifications for CS35L41 HDA

Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx> · Tue, 29 Aug 2023 15:18:12 +0100

On 25/08/2023 13:13, Takashi Iwai wrote:
On Fri, 25 Aug 2023 14:05:25 +0200,
Stefan Binding wrote:
From: Vitaly Rodionov <vitalyr@xxxxxxxxxxxxxxxxxxxxx>

Some laptops require a hardware based mute system, where when a hotkey
is pressed, it forces the amp to be muted.

For CS35L41, when the hotkey is pressed, an acpi notification is sent
to the CS35L41 Device Node. The driver needs to handle this notification
and call a _DSM function to retrieve the mute state.

Since the amp is only muted during playback, the driver will only mute
or unmute if playback is occurring, otherwise it will save the mute
state for when playback starts.

Only one handler can be registered for the acpi notification, but all
amps need to receive that notification, we can register a single handler
inside the Realtek HDA driver, so that it can then notify through the
component framework.

Signed-off-by: Vitaly Rodionov <vitalyr@xxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stefan Binding <sbinding@xxxxxxxxxxxxxxxxxxxxx>
We don't do normally in this way.  The ACPI hot key handling is done
via user-space, and user-space daemon triggers the mute of the
system.

Can't the ACPI notify the key event on those machines?

This feature is not the "normal" mute button on a keyboard, it is a 
custom request
from a manufacturer which only mutes the audio on the speakers.
On previous generations, this was achieved using a GPIO controlled by 
the BIOS/EC.
However, since CS35L41 does not have such GPIO, we must control it by 
other means.

Our solution, which we have to share with the Windows driver, it to use ACPI
notifications to tell the driver to mute the amps when the shortcut is 
pressed.

Does this seem like a valid exception to the typical approach?

Thanks,

Stefan



thanks,

Takashi

---
  sound/pci/hda/cs35l41_hda.c   | 92 ++++++++++++++++++++++++++++++-----
  sound/pci/hda/cs35l41_hda.h   |  3 ++
  sound/pci/hda/hda_component.h |  3 ++
  sound/pci/hda/patch_realtek.c | 48 +++++++++++++++++-
  4 files changed, 132 insertions(+), 14 deletions(-)

diff --git a/sound/pci/hda/cs35l41_hda.c b/sound/pci/hda/cs35l41_hda.c
index f9b77353c266..609e63b34d6d 100644
--- a/sound/pci/hda/cs35l41_hda.c
+++ b/sound/pci/hda/cs35l41_hda.c
@@ -33,6 +33,9 @@
  #define CAL_AMBIENT_DSP_CTL_NAME	"CAL_AMBIENT"
  #define CAL_DSP_CTL_TYPE		5
  #define CAL_DSP_CTL_ALG			205
+#define CS35L41_UUID			"50d90cdc-3de4-4f18-b528-c7fe3b71f40d"
+#define CS35L41_DSM_GET_MUTE		5
+#define CS35L41_NOTIFY_EVENT		0x91
  
  static bool firmware_autostart = 1;
  module_param(firmware_autostart, bool, 0444);
@@ -520,6 +523,31 @@ static void cs35l41_hda_play_start(struct device *dev)
  
  }
  
+static void cs35l41_mute(struct device *dev, bool mute)
+{
+	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
+	struct regmap *reg = cs35l41->regmap;
+
+	dev_dbg(dev, "Mute(%d:%d) Playback Started: %d\n", mute, cs35l41->mute_override,
+		cs35l41->playback_started);
+
+	if (cs35l41->playback_started) {
+		if (mute || cs35l41->mute_override) {
+			dev_dbg(dev, "Muting\n");
+			regmap_multi_reg_write(reg, cs35l41_hda_mute, ARRAY_SIZE(cs35l41_hda_mute));
+		} else {
+			dev_dbg(dev, "Unmuting\n");
+			if (cs35l41->firmware_running) {
+				regmap_multi_reg_write(reg, cs35l41_hda_unmute_dsp,
+						ARRAY_SIZE(cs35l41_hda_unmute_dsp));
+			} else {
+				regmap_multi_reg_write(reg, cs35l41_hda_unmute,
+						ARRAY_SIZE(cs35l41_hda_unmute));
+			}
+		}
+	}
+}
+
  static void cs35l41_hda_play_done(struct device *dev)
  {
  	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
@@ -529,13 +557,7 @@ static void cs35l41_hda_play_done(struct device *dev)
  
  	cs35l41_global_enable(dev, reg, cs35l41->hw_cfg.bst_type, 1, NULL,
  			      cs35l41->firmware_running);
-	if (cs35l41->firmware_running) {
-		regmap_multi_reg_write(reg, cs35l41_hda_unmute_dsp,
-				       ARRAY_SIZE(cs35l41_hda_unmute_dsp));
-	} else {
-		regmap_multi_reg_write(reg, cs35l41_hda_unmute,
-				       ARRAY_SIZE(cs35l41_hda_unmute));
-	}
+	cs35l41_mute(dev, false);
  }
  
  static void cs35l41_hda_pause_start(struct device *dev)
@@ -545,7 +567,7 @@ static void cs35l41_hda_pause_start(struct device *dev)
  
  	dev_dbg(dev, "Pause (Start)\n");
  
-	regmap_multi_reg_write(reg, cs35l41_hda_mute, ARRAY_SIZE(cs35l41_hda_mute));
+	cs35l41_mute(dev, true);
  	cs35l41_global_enable(dev, reg, cs35l41->hw_cfg.bst_type, 0, NULL,
  			      cs35l41->firmware_running);
  }
@@ -1073,6 +1095,44 @@ static int cs35l41_create_controls(struct cs35l41_hda *cs35l41)
  	return 0;
  }
  
+static int cs35l41_get_acpi_mute_state(struct cs35l41_hda *cs35l41, acpi_handle handle)
+{
+	guid_t guid;
+	union acpi_object *ret;
+	int mute = -ENODEV;
+
+	guid_parse(CS35L41_UUID, &guid);
+
+	if (acpi_check_dsm(handle, &guid, 0, BIT(CS35L41_DSM_GET_MUTE))) {
+		ret = acpi_evaluate_dsm(handle, &guid, 0, CS35L41_DSM_GET_MUTE, NULL);
+		mute = *ret->buffer.pointer;
+		dev_dbg(cs35l41->dev, "CS35L41_DSM_GET_MUTE: %d\n", mute);
+	}
+
+	dev_dbg(cs35l41->dev, "%s: %d\n", __func__, mute);
+
+	return mute;
+}
+
+static void cs35l41_acpi_device_notify(acpi_handle handle, u32 event, struct device *dev)
+{
+	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
+	int mute;
+
+	if (event != CS35L41_NOTIFY_EVENT)
+		return;
+
+	mute = cs35l41_get_acpi_mute_state(cs35l41, handle);
+	if (mute < 0) {
+		dev_warn(cs35l41->dev, "Unable to retrieve mute state: %d\n", mute);
+		return;
+	}
+
+	dev_dbg(cs35l41->dev, "Requesting mute value: %d\n", mute);
+	cs35l41->mute_override = (mute > 0);
+	cs35l41_mute(cs35l41->dev, cs35l41->mute_override);
+}
+
  static int cs35l41_hda_bind(struct device *dev, struct device *master, void *master_data)
  {
  	struct cs35l41_hda *cs35l41 = dev_get_drvdata(dev);
@@ -1114,6 +1174,11 @@ static int cs35l41_hda_bind(struct device *dev, struct device *master, void *mas
  	comps->playback_hook = cs35l41_hda_playback_hook;
  	comps->pre_playback_hook = cs35l41_hda_pre_playback_hook;
  	comps->post_playback_hook = cs35l41_hda_post_playback_hook;
+	comps->acpi_notify = cs35l41_acpi_device_notify;
+	comps->adev = cs35l41->dacpi;
+
+	cs35l41->mute_override = cs35l41_get_acpi_mute_state(cs35l41,
+						acpi_device_handle(cs35l41->dacpi)) > 0;
  
  	mutex_unlock(&cs35l41->fw_mutex);
  
@@ -1387,8 +1452,8 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
  		return -ENODEV;
  	}
  
+	cs35l41->dacpi = adev;
  	physdev = get_device(acpi_get_first_physical_node(adev));
-	acpi_dev_put(adev);
  
  	sub = acpi_get_subsystem_id(ACPI_HANDLE(physdev));
  	if (IS_ERR(sub))
@@ -1498,6 +1563,7 @@ static int cs35l41_hda_read_acpi(struct cs35l41_hda *cs35l41, const char *hid, i
  	hw_cfg->valid = false;
  	hw_cfg->gpio1.valid = false;
  	hw_cfg->gpio2.valid = false;
+	acpi_dev_put(cs35l41->dacpi);
  put_physdev:
  	put_device(physdev);
  
@@ -1601,10 +1667,7 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
  	if (ret)
  		goto err;
  
-	ret = regmap_multi_reg_write(cs35l41->regmap, cs35l41_hda_mute,
-				     ARRAY_SIZE(cs35l41_hda_mute));
-	if (ret)
-		goto err;
+	cs35l41_mute(cs35l41->dev, true);
  
  	INIT_WORK(&cs35l41->fw_load_work, cs35l41_fw_load_work);
  	mutex_init(&cs35l41->fw_mutex);
@@ -1641,6 +1704,7 @@ int cs35l41_hda_probe(struct device *dev, const char *device_name, int id, int i
  	if (cs35l41_safe_reset(cs35l41->regmap, cs35l41->hw_cfg.bst_type))
  		gpiod_set_value_cansleep(cs35l41->reset_gpio, 0);
  	gpiod_put(cs35l41->reset_gpio);
+	acpi_dev_put(cs35l41->dacpi);
  	kfree(cs35l41->acpi_subsystem_id);
  
  	return ret;
@@ -1659,6 +1723,8 @@ void cs35l41_hda_remove(struct device *dev)
  
  	component_del(cs35l41->dev, &cs35l41_hda_comp_ops);
  
+	acpi_dev_put(cs35l41->dacpi);
+
  	pm_runtime_put_noidle(cs35l41->dev);
  
  	if (cs35l41_safe_reset(cs35l41->regmap, cs35l41->hw_cfg.bst_type))
diff --git a/sound/pci/hda/cs35l41_hda.h b/sound/pci/hda/cs35l41_hda.h
index b93bf762976e..ce3f2bb6ffd0 100644
--- a/sound/pci/hda/cs35l41_hda.h
+++ b/sound/pci/hda/cs35l41_hda.h
@@ -10,6 +10,7 @@
  #ifndef __CS35L41_HDA_H__
  #define __CS35L41_HDA_H__
  
+#include <linux/acpi.h>
  #include <linux/efi.h>
  #include <linux/regulator/consumer.h>
  #include <linux/gpio/consumer.h>
@@ -70,6 +71,8 @@ struct cs35l41_hda {
  	bool halo_initialized;
  	bool playback_started;
  	struct cs_dsp cs_dsp;
+	struct acpi_device *dacpi;
+	bool mute_override;
  };
  
  enum halo_state {
diff --git a/sound/pci/hda/hda_component.h b/sound/pci/hda/hda_component.h
index f170aec967c1..c7a9b6a660e5 100644
--- a/sound/pci/hda/hda_component.h
+++ b/sound/pci/hda/hda_component.h
@@ -6,6 +6,7 @@
   *                    Cirrus Logic International Semiconductor Ltd.
   */
  
+#include <linux/acpi.h>
  #include <linux/component.h>
  
  #define HDA_MAX_COMPONENTS	4
@@ -15,6 +16,8 @@ struct hda_component {
  	struct device *dev;
  	char name[HDA_MAX_NAME_SIZE];
  	struct hda_codec *codec;
+	struct acpi_device *adev;
+	void (*acpi_notify)(acpi_handle handle, u32 event, struct device *dev);
  	void (*pre_playback_hook)(struct device *dev, int action);
  	void (*playback_hook)(struct device *dev, int action);
  	void (*post_playback_hook)(struct device *dev, int action);
diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
index a07df6f92960..fd3768e73c15 100644
--- a/sound/pci/hda/patch_realtek.c
+++ b/sound/pci/hda/patch_realtek.c
@@ -6704,19 +6704,65 @@ static void alc287_fixup_legion_15imhg05_speakers(struct hda_codec *codec,
  	}
  }
  
+static void comp_acpi_device_notify(acpi_handle handle, u32 event, void *data)
+{
+	struct hda_codec *cdc = data;
+	struct alc_spec *spec = cdc->spec;
+	int i;
+
+	codec_info(cdc, "ACPI Notification %d\n", event);
+
+	for (i = 0; i < HDA_MAX_COMPONENTS; i++) {
+		if (spec->comps[i].dev && spec->comps[i].acpi_notify)
+			spec->comps[i].acpi_notify(acpi_device_handle(spec->comps[i].adev), event,
+						   spec->comps[i].dev);
+	}
+}
+
  static int comp_bind(struct device *dev)
  {
  	struct hda_codec *cdc = dev_to_hda_codec(dev);
  	struct alc_spec *spec = cdc->spec;
+	struct acpi_device *adev;
+	int ret;
+
+	ret = component_bind_all(dev, spec->comps);
+	if (ret)
+		return ret;
  
-	return component_bind_all(dev, spec->comps);
+	adev = spec->comps[0].adev;
+	if (!acpi_device_handle(adev))
+		return 0;
+
+	ret = acpi_install_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
+					  comp_acpi_device_notify, cdc);
+	if (ret < 0) {
+		codec_warn(cdc, "Failed to install notify handler: %d\n", ret);
+		return 0;
+	}
+
+	codec_dbg(cdc, "Notify handler installed\n");
+
+	return 0;
  }
  
  static void comp_unbind(struct device *dev)
  {
  	struct hda_codec *cdc = dev_to_hda_codec(dev);
  	struct alc_spec *spec = cdc->spec;
+	struct acpi_device *adev;
+	int ret;
+
+	adev = spec->comps[0].adev;
+	if (!acpi_device_handle(adev))
+		goto unbind;
+
+	ret = acpi_remove_notify_handler(adev->handle, ACPI_DEVICE_NOTIFY,
+					 comp_acpi_device_notify);
+	if (ret < 0)
+		codec_warn(cdc, "Failed to uninstall notify handler: %d\n", ret);
  
+unbind:
  	component_unbind_all(dev, spec->comps);
  }
  
--
2.34.1







