ASoC: wm_adsp: Set ADSP1 clock rate to match sys clock

Sets the ADSP1 clock rate to match the system clock
rate. To support this the codec driver provides
details of register containing the system clock
control bits.
Signed-off-by: Chris Rattray <crattray@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm_adsp.c

@@ -103,6 +103,13 @@
 #define ADSP1_START_SHIFT                      0  /* DSP1_START */
 #define ADSP1_START_WIDTH                      1  /* DSP1_START */
 
+/*
+ * ADSP1 Control 31
+ */
+#define ADSP1_CLK_SEL_MASK                0x0007  /* CLK_SEL_ENA */
+#define ADSP1_CLK_SEL_SHIFT                    0  /* CLK_SEL_ENA */
+#define ADSP1_CLK_SEL_WIDTH                    3  /* CLK_SEL_ENA */
+
 #define ADSP2_CONTROL  0
 #define ADSP2_CLOCKING 1
 #define ADSP2_STATUS1  4
@@ -806,12 +813,38 @@ int wm_adsp1_event(struct snd_soc_dapm_widget *w,
 	struct wm_adsp *dsps = snd_soc_codec_get_drvdata(codec);
 	struct wm_adsp *dsp = &dsps[w->shift];
 	int ret;
+	int val;
 
 	switch (event) {
 	case SND_SOC_DAPM_POST_PMU:
 		regmap_update_bits(dsp->regmap, dsp->base + ADSP1_CONTROL_30,
 				   ADSP1_SYS_ENA, ADSP1_SYS_ENA);
 
+		/*
+		 * For simplicity set the DSP clock rate to be the
+		 * SYSCLK rate rather than making it configurable.
+		 */
+		if(dsp->sysclk_reg) {
+			ret = regmap_read(dsp->regmap, dsp->sysclk_reg, &val);
+			if (ret != 0) {
+				adsp_err(dsp, "Failed to read SYSCLK state: %d\n",
+				ret);
+				return ret;
+			}
+
+			val = (val & dsp->sysclk_mask)
+				>> dsp->sysclk_shift;
+
+			ret = regmap_update_bits(dsp->regmap,
+						 dsp->base + ADSP1_CONTROL_31,
+						 ADSP1_CLK_SEL_MASK, val);
+			if (ret != 0) {
+				adsp_err(dsp, "Failed to set clock rate: %d\n",
+					 ret);
+				return ret;
+			}
+		}
+
 		ret = wm_adsp_load(dsp);
 		if (ret != 0)
 			goto err;

sound/soc/codecs/wm_adsp.h

@@ -40,6 +40,9 @@ struct wm_adsp {
 	struct regmap *regmap;
 
 	int base;
+	int sysclk_reg;
+	int sysclk_mask;
+	int sysclk_shift;
 
 	struct list_head alg_regions;