ASoC: atmel_ssc_dai: refactor the startup and shutdown

In startup function, enable ssc clock and in shutdown function,
disable clock. And also remove disable ssc in shutdown function,
as ssc is disabled in prepare function.
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/atmel/atmel_ssc_dai.c

@@ -204,6 +204,13 @@ static int atmel_ssc_startup(struct snd_pcm_substream *substream,
 	pr_debug("atmel_ssc_startup: SSC_SR=0x%u\n",
 		ssc_readl(ssc_p->ssc->regs, SR));
 
+	/* Enable PMC peripheral clock for this SSC */
+	pr_debug("atmel_ssc_dai: Starting clock\n");
+	clk_enable(ssc_p->ssc->clk);
+
+	/* Reset the SSC to keep it at a clean status */
+	ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
+
 	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
 		dir = 0;
 		dir_mask = SSC_DIR_MASK_PLAYBACK;
@@ -250,11 +257,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
 	dma_params = ssc_p->dma_params[dir];
 
 	if (dma_params != NULL) {
-		ssc_writel(ssc_p->ssc->regs, CR, dma_params->mask->ssc_disable);
-		pr_debug("atmel_ssc_shutdown: %s disabled SSC_SR=0x%08x\n",
-			(dir ? "receive" : "transmit"),
-			ssc_readl(ssc_p->ssc->regs, SR));
-
 		dma_params->ssc = NULL;
 		dma_params->substream = NULL;
 		ssc_p->dma_params[dir] = NULL;
@@ -266,10 +268,6 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
 	ssc_p->dir_mask &= ~dir_mask;
 	if (!ssc_p->dir_mask) {
 		if (ssc_p->initialized) {
-			/* Shutdown the SSC clock. */
-			pr_debug("atmel_ssc_dai: Stopping clock\n");
-			clk_disable(ssc_p->ssc->clk);
-
 			free_irq(ssc_p->ssc->irq, ssc_p);
 			ssc_p->initialized = 0;
 		}
@@ -280,6 +278,10 @@ static void atmel_ssc_shutdown(struct snd_pcm_substream *substream,
 		ssc_p->cmr_div = ssc_p->tcmr_period = ssc_p->rcmr_period = 0;
 	}
 	spin_unlock_irq(&ssc_p->lock);
+
+	/* Shutdown the SSC clock. */
+	pr_debug("atmel_ssc_dai: Stopping clock\n");
+	clk_disable(ssc_p->ssc->clk);
 }
 
 
@@ -625,14 +627,6 @@ static int atmel_ssc_hw_params(struct snd_pcm_substream *substream,
 			rcmr, rfmr, tcmr, tfmr);
 
 	if (!ssc_p->initialized) {
-
-		/* Enable PMC peripheral clock for this SSC */
-		pr_debug("atmel_ssc_dai: Starting clock\n");
-		clk_enable(ssc_p->ssc->clk);
-
-		/* Reset the SSC and its PDC registers */
-		ssc_writel(ssc_p->ssc->regs, CR, SSC_BIT(CR_SWRST));
-
 		ssc_writel(ssc_p->ssc->regs, PDC_RPR, 0);
 		ssc_writel(ssc_p->ssc->regs, PDC_RCR, 0);
 		ssc_writel(ssc_p->ssc->regs, PDC_RNPR, 0);