ptp: add debugfs support for ptp_qoriq

This patch is to add debugfs support for ptp_qoriq. Current debugfs
supports to control fiper1/fiper2 loopback mode. If the loopback mode
is enabled, the fiper1/fiper2 pulse is looped back into trigger1/
trigger2 input. This is very useful for validating hardware and driver
without external hardware. Below is an example to enable fiper1 loopback.

echo 1 > /sys/kernel/debug/2d10e00.ptp_clock/fiper1-loopback

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 101 insertions, 0 deletions

diff --git a/drivers/ptp/ptp_qoriq_debugfs.c b/drivers/ptp/ptp_qoriq_debugfs.c
new file mode 100644
index 000000000000..d904332b240d
--- /dev/null
+++ b/drivers/ptp/ptp_qoriq_debugfs.c
@@ -0,0 +1,101 @@
+// SPDX-License-Identifier: GPL-2.0+
+/* Copyright 2019 NXP
+ */
+#include <linux/device.h>
+#include <linux/debugfs.h>
+#include <linux/fsl/ptp_qoriq.h>
+
+static int ptp_qoriq_fiper1_lpbk_get(void *data, u64 *val)
+{
+	struct qoriq_ptp *qoriq_ptp = data;
+	struct qoriq_ptp_registers *regs = &qoriq_ptp->regs;
+	u32 ctrl;
+
+	ctrl = qoriq_read(&regs->ctrl_regs->tmr_ctrl);
+	*val = ctrl & PP1L ? 1 : 0;
+
+	return 0;
+}
+
+static int ptp_qoriq_fiper1_lpbk_set(void *data, u64 val)
+{
+	struct qoriq_ptp *qoriq_ptp = data;
+	struct qoriq_ptp_registers *regs = &qoriq_ptp->regs;
+	u32 ctrl;
+
+	ctrl = qoriq_read(&regs->ctrl_regs->tmr_ctrl);
+	if (val == 0)
+		ctrl &= ~PP1L;
+	else
+		ctrl |= PP1L;
+
+	qoriq_write(&regs->ctrl_regs->tmr_ctrl, ctrl);
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(ptp_qoriq_fiper1_fops, ptp_qoriq_fiper1_lpbk_get,
+			ptp_qoriq_fiper1_lpbk_set, "%llu\n");
+
+static int ptp_qoriq_fiper2_lpbk_get(void *data, u64 *val)
+{
+	struct qoriq_ptp *qoriq_ptp = data;
+	struct qoriq_ptp_registers *regs = &qoriq_ptp->regs;
+	u32 ctrl;
+
+	ctrl = qoriq_read(&regs->ctrl_regs->tmr_ctrl);
+	*val = ctrl & PP2L ? 1 : 0;
+
+	return 0;
+}
+
+static int ptp_qoriq_fiper2_lpbk_set(void *data, u64 val)
+{
+	struct qoriq_ptp *qoriq_ptp = data;
+	struct qoriq_ptp_registers *regs = &qoriq_ptp->regs;
+	u32 ctrl;
+
+	ctrl = qoriq_read(&regs->ctrl_regs->tmr_ctrl);
+	if (val == 0)
+		ctrl &= ~PP2L;
+	else
+		ctrl |= PP2L;
+
+	qoriq_write(&regs->ctrl_regs->tmr_ctrl, ctrl);
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(ptp_qoriq_fiper2_fops, ptp_qoriq_fiper2_lpbk_get,
+			ptp_qoriq_fiper2_lpbk_set, "%llu\n");
+
+void ptp_qoriq_create_debugfs(struct qoriq_ptp *qoriq_ptp)
+{
+	struct dentry *root;
+
+	root = debugfs_create_dir(dev_name(qoriq_ptp->dev), NULL);
+	if (IS_ERR(root))
+		return;
+	if (!root)
+		goto err_root;
+
+	qoriq_ptp->debugfs_root = root;
+
+	if (!debugfs_create_file("fiper1-loopback", 0600, root, qoriq_ptp,
+				 &ptp_qoriq_fiper1_fops))
+		goto err_node;
+	if (!debugfs_create_file("fiper2-loopback", 0600, root, qoriq_ptp,
+				 &ptp_qoriq_fiper2_fops))
+		goto err_node;
+	return;
+
+err_node:
+	debugfs_remove_recursive(root);
+	qoriq_ptp->debugfs_root = NULL;
+err_root:
+	dev_err(qoriq_ptp->dev, "failed to initialize debugfs\n");
+}
+
+void ptp_qoriq_remove_debugfs(struct qoriq_ptp *qoriq_ptp)
+{
+	debugfs_remove_recursive(qoriq_ptp->debugfs_root);
+	qoriq_ptp->debugfs_root = NULL;
+}