ALSA: hda - Add a quirk model for fixing Huawei Matebook X right speaker

[ This is rather a revival of the patch Tomas sent in months ago, but
  applying only with the quirk model option -- tiwai ]

Hard coded coefficients to make Huawuei Matebook X right speaker
work. The Matebook X has a ALC298, please refer to bug 197801 on
how these numbers were reverse engineered from the Windows driver

The reversed engineered sequence represents a repeating pattern
of verbs, and the only values that are changing periodically are
written on indexes 0x23 and 0x25:

0x500, 0x23
0x400, VALUE1
0x500, 0x25
0x400, VALUE2

* skipped reading sequences (0x500 - 0xc00 sequences are ignored)
* static values from reverse engineering are used

NOTE: since a significant risk is still considered, this is provided
as an experimental fix that isn't applied as default for now.  For
enabling the fix, you'll have to choose huawei-mbx-stereo via model
option of snd-hda-intel module.

If we get feedback from users that this works stably, we may apply it
per default.

[ Some coding style fixes and replacement with AC_VERB_* by tiwai ]

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=197801
Signed-off-by: Tomas Espeleta <tomas.espeleta@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Documentation/sound/hd-audio/models.rst

@@ -260,6 +260,9 @@ alc295-hp-x360
     HP Spectre X360 fixups
 alc-sense-combo
     Headset button support for Chrome platform
+huawei-mbx-stereo
+    Enable initialization verbs for Huawei MBX stereo speakers;
+    might be risky, try this at your own risk
 
 ALC66x/67x/892
 ==============

sound/pci/hda/patch_realtek.c

@@ -3762,6 +3762,72 @@ static void alc269_x101_hp_automute_hook(struct hda_codec *codec,
 			    vref);
 }
 
+/*
+ * Magic sequence to make Huawei Matebook X right speaker working (bko#197801)
+ */
+struct hda_alc298_mbxinit {
+	unsigned char value_0x23;
+	unsigned char value_0x25;
+};
+
+static void alc298_huawei_mbx_stereo_seq(struct hda_codec *codec,
+					 const struct hda_alc298_mbxinit *initval,
+					 bool first)
+{
+	snd_hda_codec_write(codec, 0x06, 0, AC_VERB_SET_DIGI_CONVERT_3, 0x0);
+	alc_write_coef_idx(codec, 0x26, 0xb000);
+
+	if (first)
+		snd_hda_codec_write(codec, 0x21, 0, AC_VERB_GET_PIN_SENSE, 0x0);
+
+	snd_hda_codec_write(codec, 0x6, 0, AC_VERB_SET_DIGI_CONVERT_3, 0x80);
+	alc_write_coef_idx(codec, 0x26, 0xf000);
+	alc_write_coef_idx(codec, 0x23, initval->value_0x23);
+
+	if (initval->value_0x23 != 0x1e)
+		alc_write_coef_idx(codec, 0x25, initval->value_0x25);
+
+	snd_hda_codec_write(codec, 0x20, 0, AC_VERB_SET_COEF_INDEX, 0x26);
+	snd_hda_codec_write(codec, 0x20, 0, AC_VERB_SET_PROC_COEF, 0xb010);
+}
+
+static void alc298_fixup_huawei_mbx_stereo(struct hda_codec *codec,
+					   const struct hda_fixup *fix,
+					   int action)
+{
+	/* Initialization magic */
+	static const struct hda_alc298_mbxinit dac_init[] = {
+		{0x0c, 0x00}, {0x0d, 0x00}, {0x0e, 0x00}, {0x0f, 0x00},
+		{0x10, 0x00}, {0x1a, 0x40}, {0x1b, 0x82}, {0x1c, 0x00},
+		{0x1d, 0x00}, {0x1e, 0x00}, {0x1f, 0x00},
+		{0x20, 0xc2}, {0x21, 0xc8}, {0x22, 0x26}, {0x23, 0x24},
+		{0x27, 0xff}, {0x28, 0xff}, {0x29, 0xff}, {0x2a, 0x8f},
+		{0x2b, 0x02}, {0x2c, 0x48}, {0x2d, 0x34}, {0x2e, 0x00},
+		{0x2f, 0x00},
+		{0x30, 0x00}, {0x31, 0x00}, {0x32, 0x00}, {0x33, 0x00},
+		{0x34, 0x00}, {0x35, 0x01}, {0x36, 0x93}, {0x37, 0x0c},
+		{0x38, 0x00}, {0x39, 0x00}, {0x3a, 0xf8}, {0x38, 0x80},
+		{}
+	};
+	const struct hda_alc298_mbxinit *seq;
+
+	if (action != HDA_FIXUP_ACT_INIT)
+		return;
+
+	/* Start */
+	snd_hda_codec_write(codec, 0x06, 0, AC_VERB_SET_DIGI_CONVERT_3, 0x00);
+	snd_hda_codec_write(codec, 0x06, 0, AC_VERB_SET_DIGI_CONVERT_3, 0x80);
+	alc_write_coef_idx(codec, 0x26, 0xf000);
+	alc_write_coef_idx(codec, 0x22, 0x31);
+	alc_write_coef_idx(codec, 0x23, 0x0b);
+	alc_write_coef_idx(codec, 0x25, 0x00);
+	snd_hda_codec_write(codec, 0x20, 0, AC_VERB_SET_COEF_INDEX, 0x26);
+	snd_hda_codec_write(codec, 0x20, 0, AC_VERB_SET_PROC_COEF, 0xb010);
+
+	for (seq = dac_init; seq->value_0x23; seq++)
+		alc298_huawei_mbx_stereo_seq(codec, seq, seq == dac_init);
+}
+
 static void alc269_fixup_x101_headset_mic(struct hda_codec *codec,
 				     const struct hda_fixup *fix, int action)
 {
@@ -5787,6 +5853,7 @@ enum {
 	ALC255_FIXUP_DUMMY_LINEOUT_VERB,
 	ALC255_FIXUP_DELL_HEADSET_MIC,
 	ALC256_FIXUP_HUAWEI_MACH_WX9_PINS,
+	ALC298_FIXUP_HUAWEI_MBX_STEREO,
 	ALC295_FIXUP_HP_X360,
 	ALC221_FIXUP_HP_HEADSET_MIC,
 	ALC285_FIXUP_LENOVO_HEADPHONE_NOISE,
@@ -6095,6 +6162,12 @@ static const struct hda_fixup alc269_fixups[] = {
 		.chained = true,
 		.chain_id = ALC255_FIXUP_MIC_MUTE_LED
 	},
+	[ALC298_FIXUP_HUAWEI_MBX_STEREO] = {
+		.type = HDA_FIXUP_FUNC,
+		.v.func = alc298_fixup_huawei_mbx_stereo,
+		.chained = true,
+		.chain_id = ALC255_FIXUP_MIC_MUTE_LED
+	},
 	[ALC269_FIXUP_ASUS_X101_FUNC] = {
 		.type = HDA_FIXUP_FUNC,
 		.v.func = alc269_fixup_x101_headset_mic,
@@ -7272,6 +7345,7 @@ static const struct hda_model_fixup alc269_fixup_models[] = {
 	{.id = ALC225_FIXUP_HEADSET_JACK, .name = "alc-headset-jack"},
 	{.id = ALC295_FIXUP_CHROME_BOOK, .name = "alc-chrome-book"},
 	{.id = ALC299_FIXUP_PREDATOR_SPK, .name = "predator-spk"},
+	{.id = ALC298_FIXUP_HUAWEI_MBX_STEREO, .name = "huawei-mbx-stereo"},
 	{}
 };
 #define ALC225_STANDARD_PINS \