usb: dwc3: debugfs: add support for changing port mode

This makes testing a lot easier when trying to
switch between host and device modes.
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/dwc3/core.h

@@ -154,6 +154,7 @@
 #define DWC3_GCTL_CLK_PIPEHALF	(2)
 #define DWC3_GCTL_CLK_MASK	(3)
 
+#define DWC3_GCTL_PRTCAP(n)	(((n) & (3 << 12)) >> 12)
 #define DWC3_GCTL_PRTCAPDIR(n)	(n << 12)
 #define DWC3_GCTL_PRTCAP_HOST	1
 #define DWC3_GCTL_PRTCAP_DEVICE	2

drivers/usb/dwc3/debugfs.c

@@ -405,6 +405,80 @@ static const struct file_operations dwc3_regdump_fops = {
 	.release		= single_release,
 };
 
+static int dwc3_mode_show(struct seq_file *s, void *unused)
+{
+	struct dwc3		*dwc = s->private;
+	unsigned long		flags;
+	u32			reg;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	switch (DWC3_GCTL_PRTCAP(reg)) {
+	case DWC3_GCTL_PRTCAP_HOST:
+		seq_printf(s, "host\n");
+		break;
+	case DWC3_GCTL_PRTCAP_DEVICE:
+		seq_printf(s, "device\n");
+		break;
+	case DWC3_GCTL_PRTCAP_OTG:
+		seq_printf(s, "OTG\n");
+		break;
+	default:
+		seq_printf(s, "UNKNOWN %08x\n", DWC3_GCTL_PRTCAP(reg));
+	}
+
+	return 0;
+}
+
+static int dwc3_mode_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, dwc3_mode_show, inode->i_private);
+}
+
+static ssize_t dwc3_mode_write(struct file *file,
+		const char __user *ubuf, size_t count, loff_t *ppos)
+{
+	struct seq_file		*s = file->private_data;
+	struct dwc3		*dwc = s->private;
+	unsigned long		flags;
+	u32			reg;
+	char			buf[32];
+
+	if (copy_from_user(&buf, ubuf, min_t(size_t, sizeof(buf) - 1, count)))
+		return -EFAULT;
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	reg &= ~(DWC3_GCTL_PRTCAPDIR(DWC3_GCTL_PRTCAP_OTG));
+
+	if (!strncmp(buf, "host", 4))
+		reg |= DWC3_GCTL_PRTCAP(DWC3_GCTL_PRTCAP_HOST);
+
+	if (!strncmp(buf, "device", 6))
+		reg |= DWC3_GCTL_PRTCAP(DWC3_GCTL_PRTCAP_DEVICE);
+
+	if (!strncmp(buf, "otg", 3))
+		reg |= DWC3_GCTL_PRTCAP(DWC3_GCTL_PRTCAP_OTG);
+
+	spin_lock_irqsave(&dwc->lock, flags);
+	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
+	spin_unlock_irqrestore(&dwc->lock, flags);
+
+	return count;
+}
+
+static const struct file_operations dwc3_mode_fops = {
+	.open			= dwc3_mode_open,
+	.write			= dwc3_mode_write,
+	.read			= seq_read,
+	.llseek			= seq_lseek,
+	.release		= single_release,
+};
+
 int __devinit dwc3_debugfs_init(struct dwc3 *dwc)
 {
 	struct dentry		*root;
@@ -425,6 +499,14 @@ int __devinit dwc3_debugfs_init(struct dwc3 *dwc)
 		ret = PTR_ERR(file);
 		goto err1;
 	}
+
+	file = debugfs_create_file("mode", S_IRUGO | S_IWUSR, root,
+			dwc, &dwc3_mode_fops);
+	if (IS_ERR(file)) {
+		ret = PTR_ERR(file);
+		goto err1;
+	}
+
 	return 0;
 
 err1: