2 files changed, 67 insertions, 10 deletions

diff --git a/sound/soc/codecs/wm_hubs.c b/sound/soc/codecs/wm_hubs.c
index 4859f07..0278727 100644
--- a/sound/soc/codecs/wm_hubs.c
+++ b/sound/soc/codecs/wm_hubs.c
@@ -144,12 +144,69 @@ static bool wm_hubs_dac_hp_direct(struct snd_soc_codec *codec)
 	return true;
 }
 
+struct wm_hubs_dcs_cache {
+	struct list_head list;
+	unsigned int left;
+	unsigned int right;
+	u16 dcs_cfg;
+};
+
+static bool wm_hubs_dcs_cache_get(struct snd_soc_codec *codec,
+				  struct wm_hubs_dcs_cache **entry)
+{
+	struct wm_hubs_data *hubs = snd_soc_codec_get_drvdata(codec);
+	struct wm_hubs_dcs_cache *cache;
+	unsigned int left, right;
+
+	left = snd_soc_read(codec, WM8993_LEFT_OUTPUT_VOLUME);
+	left &= WM8993_HPOUT1L_VOL_MASK;
+
+	right = snd_soc_read(codec, WM8993_RIGHT_OUTPUT_VOLUME);
+	right &= WM8993_HPOUT1R_VOL_MASK;
+
+	list_for_each_entry(cache, &hubs->dcs_cache, list) {
+		if (cache->left != left || cache->right != right)
+			continue;
+
+		*entry = cache;
+		return true;
+	}
+
+	return false;
+}
+
+static void wm_hubs_dcs_cache_set(struct snd_soc_codec *codec, u16 dcs_cfg)
+{
+	struct wm_hubs_data *hubs = snd_soc_codec_get_drvdata(codec);
+	struct wm_hubs_dcs_cache *cache;
+
+	if (hubs->no_cache_dac_hp_direct)
+		return;
+
+	cache = devm_kzalloc(codec->dev, sizeof(*cache), GFP_KERNEL);
+	if (!cache) {
+		dev_err(codec->dev, "Failed to allocate DCS cache entry\n");
+		return;
+	}
+
+	cache->left = snd_soc_read(codec, WM8993_LEFT_OUTPUT_VOLUME);
+	cache->left &= WM8993_HPOUT1L_VOL_MASK;
+
+	cache->right = snd_soc_read(codec, WM8993_RIGHT_OUTPUT_VOLUME);
+	cache->right &= WM8993_HPOUT1R_VOL_MASK;
+
+	cache->dcs_cfg = dcs_cfg;
+
+	list_add_tail(&cache->list, &hubs->dcs_cache);
+}
+
 /*
  * Startup calibration of the DC servo
  */
 static void calibrate_dc_servo(struct snd_soc_codec *codec)
 {
 	struct wm_hubs_data *hubs = snd_soc_codec_get_drvdata(codec);
+	struct wm_hubs_dcs_cache *cache;
 	s8 offset;
 	u16 reg, reg_l, reg_r, dcs_cfg, dcs_reg;
 
@@ -164,10 +221,11 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
 
 	/* If we're using a digital only path and have a previously
 	 * callibrated DC servo offset stored then use that. */
-	if (wm_hubs_dac_hp_direct(codec) && hubs->dac_hp_direct_dcs) {
-		dev_dbg(codec->dev, "Using cached DC servo offset %x\n",
-			hubs->dac_hp_direct_dcs);
-		snd_soc_write(codec, dcs_reg, hubs->dac_hp_direct_dcs);
+	if (wm_hubs_dac_hp_direct(codec) &&
+	    wm_hubs_dcs_cache_get(codec, &cache)) {
+		dev_dbg(codec->dev, "Using cached DCS offset %x for %d,%d\n",
+			cache->dcs_cfg, cache->left, cache->right);
+		snd_soc_write(codec, dcs_reg, cache->dcs_cfg);
 		wait_for_dc_servo(codec,
 				  WM8993_DCS_TRIG_DAC_WR_0 |
 				  WM8993_DCS_TRIG_DAC_WR_1);
@@ -242,8 +300,8 @@ static void calibrate_dc_servo(struct snd_soc_codec *codec)
 
 	/* Save the callibrated offset if we're in class W mode and
 	 * therefore don't have any analogue signal mixed in. */
-	if (wm_hubs_dac_hp_direct(codec) && !hubs->no_cache_dac_hp_direct)
-		hubs->dac_hp_direct_dcs = dcs_cfg;
+	if (wm_hubs_dac_hp_direct(codec))
+		wm_hubs_dcs_cache_set(codec, dcs_cfg);
 }
 
 /*
@@ -258,9 +316,6 @@ static int wm8993_put_dc_servo(struct snd_kcontrol *kcontrol,
 
 	ret = snd_soc_put_volsw_2r(kcontrol, ucontrol);
 
-	/* Updating the analogue gains invalidates the DC servo cache */
-	hubs->dac_hp_direct_dcs = 0;
-
 	/* If we're applying an offset correction then updating the
 	 * callibration would be likely to introduce further offsets. */
 	if (hubs->dcs_codes_l || hubs->dcs_codes_r || hubs->no_series_update)
@@ -1068,6 +1123,7 @@ int wm_hubs_add_analogue_routes(struct snd_soc_codec *codec,
 	struct wm_hubs_data *hubs = snd_soc_codec_get_drvdata(codec);
 	struct snd_soc_dapm_context *dapm = &codec->dapm;
 
+	INIT_LIST_HEAD(&hubs->dcs_cache);
 	init_completion(&hubs->dcs_done);
 
 	snd_soc_dapm_add_routes(dapm, analogue_routes,
diff --git a/sound/soc/codecs/wm_hubs.h b/sound/soc/codecs/wm_hubs.h
index 71861fc..da2dc89 100644
--- a/sound/soc/codecs/wm_hubs.h
+++ b/sound/soc/codecs/wm_hubs.h
@@ -16,6 +16,7 @@
 
 #include <linux/completion.h>
 #include <linux/interrupt.h>
+#include <linux/list.h>
 #include <sound/control.h>
 
 struct snd_soc_codec;
@@ -32,7 +33,7 @@ struct wm_hubs_data {
 	int no_series_update;
 
 	bool no_cache_dac_hp_direct;
-	u16 dac_hp_direct_dcs;
+	struct list_head dcs_cache;
 	bool (*check_class_w_digital)(struct snd_soc_codec *);
 
 	bool lineout1_se;