[alsa-devel] [PATCH 1/2] ASoC: wm_adsp: Set ADSP1 clock rate to match sys clock

[Chris Rattray]

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 at opensource.wolfsonmicro.com>
---
 sound/soc/codecs/wm_adsp.c |   35 +++++++++++++++++++++++++++++++++++
 sound/soc/codecs/wm_adsp.h |    3 +++
 2 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/sound/soc/codecs/wm_adsp.c b/sound/soc/codecs/wm_adsp.c
index 9a3f220..739dab6 100644
--- a/sound/soc/codecs/wm_adsp.c
+++ b/sound/soc/codecs/wm_adsp.c
@@ -75,6 +75,8 @@
 #define ADSP1_CONTROL_30                  0x24
 #define ADSP1_CONTROL_31                  0x26
 
+#define ADSP1_CLOCKING 38
+
 /*
  * ADSP1 Control 19
  */
@@ -103,6 +105,13 @@
 #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
@@ -817,12 +826,38 @@ 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_CLOCKING,
+						 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;
diff --git a/sound/soc/codecs/wm_adsp.h b/sound/soc/codecs/wm_adsp.h
index 41206d7..cb8871a 100644
--- a/sound/soc/codecs/wm_adsp.h
+++ b/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;
 
-- 
1.7.2.5