ASoC: fsl-ssi: Move sysfs stats to debugfs

Interrupt statistics of fsl_ssi are mainly for debugging purpose. Most
of those interrupts show error states, e.g. under/overflow.
The stats should be exposed via debugfs instead of sysfs.

This patch moves the statistics file to debugfs.
Signed-off-by: NMarkus Pargmann <mpa@pengutronix.de>
Signed-off-by: NMark Brown <broonie@linaro.org>

sound/soc/fsl/fsl_ssi.c

@@ -35,6 +35,7 @@
 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
+#include <linux/debugfs.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/slab.h>
@@ -114,6 +115,14 @@ static inline void write_ssi_mask(u32 __iomem *addr, u32 clear, u32 set)
 		    CCSR_SSI_SIER_RDMAE | CCSR_SSI_SIER_RIE | \
 		    CCSR_SSI_SIER_ROE0_EN | CCSR_SSI_SIER_ROE1_EN)
 
+#define FSLSSI_SIER_DBG_RX_FLAGS (CCSR_SSI_SIER_RFF0_EN | \
+		CCSR_SSI_SIER_RLS_EN | CCSR_SSI_SIER_RFS_EN | \
+		CCSR_SSI_SIER_ROE0_EN | CCSR_SSI_SIER_RFRC_EN)
+#define FSLSSI_SIER_DBG_TX_FLAGS (CCSR_SSI_SIER_TFE0_EN | \
+		CCSR_SSI_SIER_TLS_EN | CCSR_SSI_SIER_TFS_EN | \
+		CCSR_SSI_SIER_TUE0_EN | CCSR_SSI_SIER_TFRC_EN)
+#define FSLSSI_SISR_MASK (FSLSSI_SIER_DBG_RX_FLAGS | FSLSSI_SIER_DBG_TX_FLAGS)
+
 /**
  * fsl_ssi_private: per-SSI private data
  *
@@ -133,7 +142,6 @@ struct fsl_ssi_private {
 	unsigned int irq;
 	unsigned int fifo_depth;
 	struct snd_soc_dai_driver cpu_dai_drv;
-	struct device_attribute dev_attr;
 	struct platform_device *pdev;
 
 	bool new_binding;
@@ -175,6 +183,8 @@ struct fsl_ssi_private {
 		unsigned int tfe1;
 		unsigned int tfe0;
 	} stats;
+	struct dentry *dbg_dir;
+	struct dentry *dbg_stats;
 
 	char name[1];
 };
@@ -203,7 +213,7 @@ 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 = read_ssi(&ssi->sisr) & SIER_FLAGS;
+	sisr = read_ssi(&ssi->sisr) & FSLSSI_SISR_MASK;
 
 	if (sisr & CCSR_SSI_SISR_RFRC) {
 		ssi_private->stats.rfrc++;
@@ -323,6 +333,102 @@ static irqreturn_t fsl_ssi_isr(int irq, void *dev_id)
 	return ret;
 }
 
+#if IS_ENABLED(CONFIG_DEBUG_FS)
+/* 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 (FSLSSI_SISR_MASK & CCSR_SSI_SIER_##flag) \
+			seq_printf(s, #name "=%u\n", ssi_private->stats.name); \
+	} while (0)
+
+
+/**
+ * fsl_sysfs_ssi_show: display SSI statistics
+ *
+ * Display the statistics for the current SSI device.  To avoid confusion,
+ * we only show those counts that are enabled.
+ */
+static ssize_t fsl_ssi_stats_show(struct seq_file *s, void *unused)
+{
+	struct fsl_ssi_private *ssi_private = s->private;
+
+	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 0;
+}
+
+static int fsl_ssi_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, fsl_ssi_stats_show, inode->i_private);
+}
+
+static const struct file_operations fsl_ssi_stats_ops = {
+	.open = fsl_ssi_stats_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+static int fsl_ssi_debugfs_create(struct fsl_ssi_private *ssi_private,
+		struct device *dev)
+{
+	ssi_private->dbg_dir = debugfs_create_dir(dev_name(dev), NULL);
+	if (!ssi_private->dbg_dir)
+		return -ENOMEM;
+
+	ssi_private->dbg_stats = debugfs_create_file("stats", S_IRUGO,
+			ssi_private->dbg_dir, ssi_private, &fsl_ssi_stats_ops);
+	if (!ssi_private->dbg_stats) {
+		debugfs_remove(ssi_private->dbg_dir);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void fsl_ssi_debugfs_remove(struct fsl_ssi_private *ssi_private)
+{
+	debugfs_remove(ssi_private->dbg_stats);
+	debugfs_remove(ssi_private->dbg_dir);
+}
+
+#else
+
+static int fsl_ssi_debugfs_create(struct fsl_ssi_private *ssi_private,
+		struct device *dev)
+{
+	return 0;
+}
+
+static void fsl_ssi_debugfs_remove(struct fsl_ssi_private *ssi_private)
+{
+}
+
+#endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
+
 static void fsl_ssi_setup_ac97(struct fsl_ssi_private *ssi_private)
 {
 	struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
@@ -991,56 +1097,6 @@ static struct snd_ac97_bus_ops fsl_ssi_ac97_ops = {
 	.write		= fsl_ssi_ac97_write,
 };
 
-/* 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.  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 = 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;
-}
-
 /**
  * Make every character in a string lower-case
  */
@@ -1233,20 +1289,6 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 		}
 	}
 
-	/* Initialize the the device_attribute structure */
-	dev_attr = &ssi_private->dev_attr;
-	sysfs_attr_init(&dev_attr->attr);
-	dev_attr->attr.name = "statistics";
-	dev_attr->attr.mode = S_IRUGO;
-	dev_attr->show = fsl_sysfs_ssi_show;
-
-	ret = device_create_file(&pdev->dev, dev_attr);
-	if (ret) {
-		dev_err(&pdev->dev, "could not create sysfs %s file\n",
-			ssi_private->dev_attr.attr.name);
-		goto error_clk;
-	}
-
 	/* Register with ASoC */
 	dev_set_drvdata(&pdev->dev, ssi_private);
 
@@ -1257,6 +1299,10 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 		goto error_dev;
 	}
 
+	ret = fsl_ssi_debugfs_create(ssi_private, &pdev->dev);
+	if (ret)
+		goto error_dbgfs;
+
 	if (ssi_private->ssi_on_imx) {
 		if (!ssi_private->use_dma) {
 
@@ -1326,6 +1372,9 @@ static int fsl_ssi_probe(struct platform_device *pdev)
 		imx_pcm_fiq_exit(pdev);
 
 error_pcm:
+	fsl_ssi_debugfs_remove(ssi_private);
+
+error_dbgfs:
 	snd_soc_unregister_component(&pdev->dev);
 
 error_dev:
@@ -1349,10 +1398,11 @@ static int fsl_ssi_remove(struct platform_device *pdev)
 {
 	struct fsl_ssi_private *ssi_private = dev_get_drvdata(&pdev->dev);
 
+	fsl_ssi_debugfs_remove(ssi_private);
+
 	if (!ssi_private->new_binding)
 		platform_device_unregister(ssi_private->pdev);
 	snd_soc_unregister_component(&pdev->dev);
-	device_remove_file(&pdev->dev, &ssi_private->dev_attr);
 	if (ssi_private->ssi_on_imx) {
 		if (!IS_ERR(ssi_private->baudclk))
 			clk_disable_unprepare(ssi_private->baudclk);