platform/x86: asus-wmi: support toggling POST sound

Add support for toggling the BIOS POST sound on some ASUS laptops.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Luke D. Jones <luke@ljones.dev>
Link: https://lore.kernel.org/r/20240404001652.86207-5-luke@ljones.dev
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

Documentation/ABI/testing/sysfs-platform-asus-wmi

@@ -194,3 +194,12 @@ Contact:	"Luke Jones" <luke@ljones.dev>
 Description:
 		Set the target temperature limit of the Nvidia dGPU:
 			* min=75, max=87
+
+What:		/sys/devices/platform/<platform>/boot_sound
+Date:		Apr 2024
+KernelVersion:	6.10
+Contact:	"Luke Jones" <luke@ljones.dev>
+Description:
+		Set if the BIOS POST sound is played on boot.
+			* 0 - False,
+			* 1 - True

drivers/platform/x86/asus-wmi.c

@@ -2115,6 +2115,54 @@ static ssize_t panel_od_store(struct device *dev,
 }
 static DEVICE_ATTR_RW(panel_od);
 
+/* Bootup sound ***************************************************************/
+
+static ssize_t boot_sound_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
+{
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+	int result;
+
+	result = asus_wmi_get_devstate_simple(asus, ASUS_WMI_DEVID_BOOT_SOUND);
+	if (result < 0)
+		return result;
+
+	return sysfs_emit(buf, "%d\n", result);
+}
+
+static ssize_t boot_sound_store(struct device *dev,
+			      struct device_attribute *attr,
+			      const char *buf, size_t count)
+{
+	int result, err;
+	u32 snd;
+
+	struct asus_wmi *asus = dev_get_drvdata(dev);
+
+	result = kstrtou32(buf, 10, &snd);
+	if (result)
+		return result;
+
+	if (snd > 1)
+		return -EINVAL;
+
+	err = asus_wmi_set_devstate(ASUS_WMI_DEVID_BOOT_SOUND, snd, &result);
+	if (err) {
+		pr_warn("Failed to set boot sound: %d\n", err);
+		return err;
+	}
+
+	if (result > 1) {
+		pr_warn("Failed to set panel boot sound (result): 0x%x\n", result);
+		return -EIO;
+	}
+
+	sysfs_notify(&asus->platform_device->dev.kobj, NULL, "boot_sound");
+
+	return count;
+}
+static DEVICE_ATTR_RW(boot_sound);
+
 /* Mini-LED mode **************************************************************/
 static ssize_t mini_led_mode_show(struct device *dev,
 				   struct device_attribute *attr, char *buf)
@@ -4207,6 +4255,7 @@ static struct attribute *platform_attributes[] = {
 	&dev_attr_ppt_platform_sppt.attr,
 	&dev_attr_nv_dynamic_boost.attr,
 	&dev_attr_nv_temp_target.attr,
+	&dev_attr_boot_sound.attr,
 	&dev_attr_panel_od.attr,
 	&dev_attr_mini_led_mode.attr,
 	&dev_attr_available_mini_led_mode.attr,
@@ -4259,6 +4308,8 @@ static umode_t asus_sysfs_is_visible(struct kobject *kobj,
 		ok = asus->nv_dyn_boost_available;
 	else if (attr == &dev_attr_nv_temp_target.attr)
 		ok = asus->nv_temp_tgt_available;
+	else if (attr == &dev_attr_boot_sound.attr)
+		devid = ASUS_WMI_DEVID_BOOT_SOUND;
 	else if (attr == &dev_attr_panel_od.attr)
 		ok = asus->panel_overdrive_available;
 	else if (attr == &dev_attr_mini_led_mode.attr)

include/linux/platform_data/x86/asus-wmi.h

@@ -137,6 +137,9 @@
 /* TUF laptop RGB power/state */
 #define ASUS_WMI_DEVID_TUF_RGB_STATE	0x00100057
 
+/* Bootup sound control */
+#define ASUS_WMI_DEVID_BOOT_SOUND	0x00130022
+
 /* DSTS masks */
 #define ASUS_WMI_DSTS_STATUS_BIT	0x00000001
 #define ASUS_WMI_DSTS_UNKNOWN_BIT	0x00000002