ASoC: wm_adsp: Enable DVFS for ADSP2

Some ADSP devices can make use of DVFS to optimise power consumption
depending on the operating frequency of the DSP core. Implement
support for this in the generic ADSP code.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm_adsp.h

@@ -18,6 +18,8 @@
 
 #include "wmfw.h"
 
+struct regulator;
+
 struct wm_adsp_region {
 	int type;
 	unsigned int base;
@@ -34,6 +36,8 @@ struct wm_adsp {
 
 	const struct wm_adsp_region *mem;
 	int num_mems;
+
+	struct regulator *dvfs;
 };
 
 #define WM_ADSP1(wname, num) \
@@ -46,6 +50,7 @@ struct wm_adsp {
 	.shift = num, .event = wm_adsp2_event, \
 	.event_flags = SND_SOC_DAPM_POST_PMU | SND_SOC_DAPM_PRE_PMD }
 
+int wm_adsp2_init(struct wm_adsp *adsp, bool dvfs);
 int wm_adsp1_event(struct snd_soc_dapm_widget *w,
 		   struct snd_kcontrol *kcontrol, int event);
 int wm_adsp2_event(struct snd_soc_dapm_widget *w,