ASoC: trim SSI sysfs statistics in Freescale MPC8610 sound drivers

Optimize the display of SSI statistics in the Freescale MPC8610 sound driver
to display the status count only of the interrupts that were actually enabled.
Previously, it would display the counts of all SISR status bits, even those
that were not enabled.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/fsl/fsl_ssi.c

@@ -60,6 +60,13 @@
 	 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_S24_LE)
 #endif
 
+/* SIER bitflag of interrupts to enable */
+#define SIER_FLAGS (CCSR_SSI_SIER_TFRC_EN | CCSR_SSI_SIER_TDMAE | \
+		    CCSR_SSI_SIER_TIE | CCSR_SSI_SIER_TUE0_EN | \
+		    CCSR_SSI_SIER_TUE1_EN | CCSR_SSI_SIER_RFRC_EN | \
+		    CCSR_SSI_SIER_RDMAE | CCSR_SSI_SIER_RIE | \
+		    CCSR_SSI_SIER_ROE0_EN | CCSR_SSI_SIER_ROE1_EN)
+
 /**
  * fsl_ssi_private: per-SSI private data
  *
@@ -140,7 +147,7 @@ static irqreturn_t fsl_ssi_isr(int irq, void *dev_id)
 	   were interrupted for.  We mask it with the Interrupt Enable register
 	   so that we only check for events that we're interested in.
 	 */
-	sisr = in_be32(&ssi->sisr) & in_be32(&ssi->sier);
+	sisr = in_be32(&ssi->sisr) & SIER_FLAGS;
 
 	if (sisr & CCSR_SSI_SISR_RFRC) {
 		ssi_private->stats.rfrc++;
@@ -324,12 +331,7 @@ static int fsl_ssi_startup(struct snd_pcm_substream *substream,
 		 */
 
 		/* 4. Enable the interrupts and DMA requests */
-		out_be32(&ssi->sier,
-			 CCSR_SSI_SIER_TFRC_EN | CCSR_SSI_SIER_TDMAE |
-			 CCSR_SSI_SIER_TIE | CCSR_SSI_SIER_TUE0_EN |
-			 CCSR_SSI_SIER_TUE1_EN | CCSR_SSI_SIER_RFRC_EN |
-			 CCSR_SSI_SIER_RDMAE | CCSR_SSI_SIER_RIE |
-			 CCSR_SSI_SIER_ROE0_EN | CCSR_SSI_SIER_ROE1_EN);
+		out_be32(&ssi->sier, SIER_FLAGS);
 
 		/*
 		 * Set the watermark for transmit FIFI 0 and receive FIFO 0. We
@@ -590,39 +592,52 @@ static struct snd_soc_dai fsl_ssi_dai_template = {
 	.ops = &fsl_ssi_dai_ops,
 };
 
+/* Show the statistics of a flag only if its interrupt is enabled.  The
+ * compiler will optimze this code to a no-op if the interrupt is not
+ * enabled.
+ */
+#define SIER_SHOW(flag, name) \
+	do { \
+		if (SIER_FLAGS & CCSR_SSI_SIER_##flag) \
+			length += sprintf(buf + length, #name "=%u\n", \
+				ssi_private->stats.name); \
+	} while (0)
+
+
 /**
  * fsl_sysfs_ssi_show: display SSI statistics
  *
- * Display the statistics for the current SSI device.
+ * Display the statistics for the current SSI device.  To avoid confusion,
+ * we only show those counts that are enabled.
  */
 static ssize_t fsl_sysfs_ssi_show(struct device *dev,
 	struct device_attribute *attr, char *buf)
 {
 	struct fsl_ssi_private *ssi_private =
-	container_of(attr, struct fsl_ssi_private, dev_attr);
-	ssize_t length;
-
-	length = sprintf(buf, "rfrc=%u", ssi_private->stats.rfrc);
-	length += sprintf(buf + length, "\ttfrc=%u", ssi_private->stats.tfrc);
-	length += sprintf(buf + length, "\tcmdau=%u", ssi_private->stats.cmdau);
-	length += sprintf(buf + length, "\tcmddu=%u", ssi_private->stats.cmddu);
-	length += sprintf(buf + length, "\trxt=%u", ssi_private->stats.rxt);
-	length += sprintf(buf + length, "\trdr1=%u", ssi_private->stats.rdr1);
-	length += sprintf(buf + length, "\trdr0=%u", ssi_private->stats.rdr0);
-	length += sprintf(buf + length, "\ttde1=%u", ssi_private->stats.tde1);
-	length += sprintf(buf + length, "\ttde0=%u", ssi_private->stats.tde0);
-	length += sprintf(buf + length, "\troe1=%u", ssi_private->stats.roe1);
-	length += sprintf(buf + length, "\troe0=%u", ssi_private->stats.roe0);
-	length += sprintf(buf + length, "\ttue1=%u", ssi_private->stats.tue1);
-	length += sprintf(buf + length, "\ttue0=%u", ssi_private->stats.tue0);
-	length += sprintf(buf + length, "\ttfs=%u", ssi_private->stats.tfs);
-	length += sprintf(buf + length, "\trfs=%u", ssi_private->stats.rfs);
-	length += sprintf(buf + length, "\ttls=%u", ssi_private->stats.tls);
-	length += sprintf(buf + length, "\trls=%u", ssi_private->stats.rls);
-	length += sprintf(buf + length, "\trff1=%u", ssi_private->stats.rff1);
-	length += sprintf(buf + length, "\trff0=%u", ssi_private->stats.rff0);
-	length += sprintf(buf + length, "\ttfe1=%u", ssi_private->stats.tfe1);
-	length += sprintf(buf + length, "\ttfe0=%u\n", ssi_private->stats.tfe0);
+		container_of(attr, struct fsl_ssi_private, dev_attr);
+	ssize_t length = 0;
+
+	SIER_SHOW(RFRC_EN, rfrc);
+	SIER_SHOW(TFRC_EN, tfrc);
+	SIER_SHOW(CMDAU_EN, cmdau);
+	SIER_SHOW(CMDDU_EN, cmddu);
+	SIER_SHOW(RXT_EN, rxt);
+	SIER_SHOW(RDR1_EN, rdr1);
+	SIER_SHOW(RDR0_EN, rdr0);
+	SIER_SHOW(TDE1_EN, tde1);
+	SIER_SHOW(TDE0_EN, tde0);
+	SIER_SHOW(ROE1_EN, roe1);
+	SIER_SHOW(ROE0_EN, roe0);
+	SIER_SHOW(TUE1_EN, tue1);
+	SIER_SHOW(TUE0_EN, tue0);
+	SIER_SHOW(TFS_EN, tfs);
+	SIER_SHOW(RFS_EN, rfs);
+	SIER_SHOW(TLS_EN, tls);
+	SIER_SHOW(RLS_EN, rls);
+	SIER_SHOW(RFF1_EN, rff1);
+	SIER_SHOW(RFF0_EN, rff0);
+	SIER_SHOW(TFE1_EN, tfe1);
+	SIER_SHOW(TFE0_EN, tfe0);
 
 	return length;
 }