platform/x86: lg-laptop: Add support for the HDAP opregion field

Various LG notebooks have a special field called "HDAP" inside
the ACPI operation region handled by the lg-laptop driver:

Field (XIN1, AnyAcc, Lock, Preserve)
{
DMSG, 8,
HDAP, 8,
Offset (0x10),
P80B, 8,
P81B, 8,
P82B, 8,
P83B, 8,
P84B, 8,
P85B, 8,
P86B, 8,
P87B, 8,
Offset (0x3E8),
PMSG, 1600
}

This field is set to 1/0 when the HD audio device is enabled/disabled
using the _PS0/_PS3 ACPI control methods. Add support for this field
to avoid printing warning messages when AML bytecode writes data
into it.

Reported-by: Peter Chubb <[e-mail]>
Tested-by: Peter Chubb <[e-mail]>
Signed-off-by: Armin Wolf <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Reviewed-by: Ilpo Järvinen <[e-mail]>
Signed-off-by: Ilpo Järvinen <[e-mail]>

drivers/platform/x86/lg-laptop.c

···
 #include <linux/leds.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/string_choices.h>
 #include <linux/types.h>
 
 #include <acpi/battery.h>
···
 #define LG_ADDRESS_SPACE_ID			0x8F
 
 #define LG_ADDRESS_SPACE_DEBUG_FLAG_ADR		0x00
+#define LG_ADDRESS_SPACE_HD_AUDIO_POWER_ADDR	0x01
 #define LG_ADDRESS_SPACE_FAN_MODE_ADR		0x03
 
 #define LG_ADDRESS_SPACE_DTTM_FLAG_ADR		0x20
···
 	byte = value & 0xFF;
 
 	switch (address) {
+	case LG_ADDRESS_SPACE_HD_AUDIO_POWER_ADDR:
+		/*
+		 * The HD audio power field is not affected by the DTTM flag,
+		 * so we have to manually check fw_debug.
+		 */
+		if (fw_debug)
+			dev_dbg(dev, "HD audio power %s\n", str_enabled_disabled(byte));
+
+		return AE_OK;
 	case LG_ADDRESS_SPACE_FAN_MODE_ADR:
 		/*
 		 * The fan mode field is not affected by the DTTM flag, so we