+/* Apply a DAPM power sequence.
+ *
+ * We walk over a pre-sorted list of widgets to apply power to. In
+ * order to minimise the number of writes to the device required
+ * multiple widgets will be updated in a single write where possible.
+ * Currently anything that requires more than a single write is not
+ * handled.
+ */
+static void dapm_seq_run(struct snd_soc_codec *codec, struct list_head *list,
+ int event, int sort[])
+{
+ struct snd_soc_dapm_widget *w, *n;
+ LIST_HEAD(pending);
+ int cur_sort = -1;
+ int cur_reg = SND_SOC_NOPM;
+ int ret;
+
+ list_for_each_entry_safe(w, n, list, power_list) {
+ ret = 0;
+
+ /* Do we need to apply any queued changes? */
+ if (sort[w->id] != cur_sort || w->reg != cur_reg) {
+ if (!list_empty(&pending))
+ dapm_seq_run_coalesced(codec, &pending);
+
+ INIT_LIST_HEAD(&pending);
+ cur_sort = -1;
+ cur_reg = SND_SOC_NOPM;
+ }
+
+ switch (w->id) {
+ case snd_soc_dapm_pre:
+ if (!w->event)
+ list_for_each_entry_safe_continue(w, n, list,
+ power_list);
+
+ if (event == SND_SOC_DAPM_STREAM_START)
+ ret = w->event(w,
+ NULL, SND_SOC_DAPM_PRE_PMU);
+ else if (event == SND_SOC_DAPM_STREAM_STOP)
+ ret = w->event(w,
+ NULL, SND_SOC_DAPM_PRE_PMD);
+ break;
+
+ case snd_soc_dapm_post:
+ if (!w->event)
+ list_for_each_entry_safe_continue(w, n, list,
+ power_list);
+
+ if (event == SND_SOC_DAPM_STREAM_START)
+ ret = w->event(w,
+ NULL, SND_SOC_DAPM_POST_PMU);
+ else if (event == SND_SOC_DAPM_STREAM_STOP)
+ ret = w->event(w,
+ NULL, SND_SOC_DAPM_POST_PMD);
+ break;
+
+ case snd_soc_dapm_input:
+ case snd_soc_dapm_output:
+ case snd_soc_dapm_hp:
+ case snd_soc_dapm_mic:
+ case snd_soc_dapm_line:
+ case snd_soc_dapm_spk:
+ /* No register support currently */
+ ret = dapm_generic_apply_power(w);
+ break;
+
+ default:
+ /* Queue it up for application */
+ cur_sort = sort[w->id];
+ cur_reg = w->reg;
+ list_move(&w->power_list, &pending);
+ break;
+ }
+
+ if (ret < 0)
+ pr_err("Failed to apply widget power: %d\n",
+ ret);