ASoC: clsic-codec: implement recommended DSP2 power control sequences

Change-Id: Ie34b21b7688776abe3b850bde17178bb8a8fdc44
Signed-off-by: Simon Trimmer <[email protected]>

Author: simontrimmer

drivers/mfd/clsic/clsic-tables.c

@@ -734,6 +734,7 @@ bool clsic_volatile_register(struct device *dev, unsigned int reg)
 	case TACNA_ASYNC_SAMPLE_RATE_STATUS2:
 	case TACNA_DSP_CLOCK3:
 	case TACNA_DSP_CLOCK4:
+	case CLSIC_DSP2_PWR_CTRL:
 	case TACNA_FLL1_CONTROL5:
 	case TACNA_FLL1_CONTROL6:
 	case TACNA_FLL2_CONTROL5:

include/linux/mfd/clsic/registers.h

@@ -166,6 +166,14 @@
 #define CLSIC_PDM_CLK_SRC_WIDTH					 3
 
 /* (0x17218) DSP2_PWR_CTRL */
+#define CLSIC_DSP2_POWER_OFF_OK				0x00000200
+#define CLSIC_DSP2_POWER_OFF_OK_MASK			0x00000200
+#define CLSIC_DSP2_POWER_OFF_OK_SHIFT				 9
+#define CLSIC_DSP2_POWER_OFF_OK_WIDTH				 1
+#define CLSIC_DSP2_POWER_OK				0x00000100
+#define CLSIC_DSP2_POWER_OK_MASK			0x00000100
+#define CLSIC_DSP2_POWER_OK_SHIFT				 8
+#define CLSIC_DSP2_POWER_OK_WIDTH				 1
 #define CLSIC_DSP2_RST_N				0x00000004
 #define CLSIC_DSP2_RST_N_MASK				0x00000004
 #define CLSIC_DSP2_RST_N_SHIFT					 2

sound/soc/codecs/clsic-codec.c

@@ -121,18 +121,45 @@ static int clsic_dsp_power_ev(struct snd_soc_dapm_widget *w,
 	struct wm_adsp *dsps = snd_soc_codec_get_drvdata(codec);
 	struct wm_adsp *dsp = &dsps[w->shift];
 	unsigned int freq;
+	unsigned int val;
 	int ret;
 
 	switch (event) {
 	case SND_SOC_DAPM_PRE_PMU:
-		/* write to DSP2_PWR_CTRL to enable core */
-		ret = regmap_write(dsp->regmap, CLSIC_DSP2_PWR_CTRL,
-				   CLSIC_DSP2_RST_N);
-		if (ret) {
-			dev_err(codec->dev, "Failed to enable DSP2: %d\n", ret);
+		/*
+		 * This PRE_PMU steps through the process of closing the power
+		 * switches, removing isolation logic and de-asserting reset
+		 * through a series of writes. If the DSP is not in the default
+		 * state then it will be reset.
+		 *
+		 *				SHUTOFF ISOLATE RST_N
+		 * Starting state		1	1	0
+		 * Close power switches		0	1	0
+		 * Remove isolation		0	0	0
+		 * (check powered)
+		 * De-assert reset		0	0	1
+		 */
+		regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL,
+			     CLSIC_DSP2_ISOLATE_ENABLE);
+		/* Performed in different writes to maintain separation */
+		regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL, 0);
+
+		ret = regmap_read(tacna->regmap, CLSIC_DSP2_PWR_CTRL, &val);
+		if (ret || !(val & CLSIC_DSP2_POWER_OK)) {
+			dev_err(codec->dev,
+				"Failed to enable DSP2 power: %d (0x%x)\n",
+				ret, val);
 			return ret;
 		}
 
+		ret = regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL,
+			     CLSIC_DSP2_RST_N);
+		if (ret) {
+			dev_err(codec->dev,
+				"Failed to de-assert reset: %d\n", ret);
+			goto error;
+		}
+
 		ret = regmap_read(tacna->regmap, TACNA_DSP_CLOCK3, &freq);
 		if (ret) {
 			dev_err(codec->dev,
@@ -157,13 +184,31 @@ static int clsic_dsp_power_ev(struct snd_soc_dapm_widget *w,
 	case SND_SOC_DAPM_PRE_PMD:
 		ret = wm_halo_early_event(w, kcontrol, event);
 		clsic_dsp_memory_disable(priv);
+
+		/*
+		 * This PRE_PMD steps through the process of shutting down the
+		 * DSP.
+		 *
+		 *				SHUTOFF ISOLATE RST_N
+		 * Assert reset			0	0	0
+		 * Apply isolation logic	0	1	0
+		 * Open power switches		1	1	0
+		 */
+		regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL, 0);
+
+		regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL,
+			     CLSIC_DSP2_ISOLATE_ENABLE);
+
+		regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL,
+			     CLSIC_DSP2_ISOLATE_ENABLE | CLSIC_DSP2_SHUTOFF);
+
 		return ret;
 	default:
 		return 0;
 	}
 
 error:
-	regmap_write(dsp->regmap, CLSIC_DSP2_PWR_CTRL,
+	regmap_write(tacna->regmap, CLSIC_DSP2_PWR_CTRL,
 		     CLSIC_DSP2_ISOLATE_ENABLE | CLSIC_DSP2_SHUTOFF);
 	return ret;
 }