diff --git a/Documentation/ABI/testing/sysfs-platform-dfl-port b/Documentation/ABI/testing/sysfs-platform-dfl-port
index 1ab3e6f..c2660e4 100644
--- a/Documentation/ABI/testing/sysfs-platform-dfl-port
+++ b/Documentation/ABI/testing/sysfs-platform-dfl-port
@@ -46,3 +46,31 @@ Contact:	Wu Hao <hao.wu@intel.com>
 Description:	Read-write. Read or set AFU latency tolerance reporting value.
 		Set ltr to 1 if the AFU can tolerate latency >= 40us or set it
 		to 0 if it is latency sensitive.
+
+What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcmd
+Date:		August 2019
+KernelVersion:	5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Write-only. User writes command to this interface to set
+		userclock to AFU.
+
+What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqsts
+Date:		August 2019
+KernelVersion:	5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. Read this file to get the status of issued command
+		to userclck_freqcmd.
+
+What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcntrcmd
+Date:		August 2019
+KernelVersion:	5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Write-only. User writes command to this interface to set
+		userclock counter.
+
+What:		/sys/bus/platform/devices/dfl-port.0/userclk_freqcntrsts
+Date:		August 2019
+KernelVersion:	5.4
+Contact:	Wu Hao <hao.wu@intel.com>
+Description:	Read-only. Read this file to get the status of issued command
+		to userclck_freqcntrcmd.
diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index e955149..f0b45f2 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c
@@ -274,17 +274,126 @@ static int port_get_id(struct platform_device *pdev)
 }
 static DEVICE_ATTR_RO(power_state);
 
+static ssize_t
+userclk_freqcmd_store(struct device *dev, struct device_attribute *attr,
+		      const char *buf, size_t count)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	u64 userclk_freq_cmd;
+	void __iomem *base;
+
+	if (kstrtou64(buf, 0, &userclk_freq_cmd))
+		return -EINVAL;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+	mutex_lock(&pdata->lock);
+	writeq(userclk_freq_cmd, base + PORT_HDR_USRCLK_CMD0);
+	mutex_unlock(&pdata->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(userclk_freqcmd);
+
+static ssize_t
+userclk_freqcntrcmd_store(struct device *dev, struct device_attribute *attr,
+			  const char *buf, size_t count)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	u64 userclk_freqcntr_cmd;
+	void __iomem *base;
+
+	if (kstrtou64(buf, 0, &userclk_freqcntr_cmd))
+		return -EINVAL;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+	mutex_lock(&pdata->lock);
+	writeq(userclk_freqcntr_cmd, base + PORT_HDR_USRCLK_CMD1);
+	mutex_unlock(&pdata->lock);
+
+	return count;
+}
+static DEVICE_ATTR_WO(userclk_freqcntrcmd);
+
+static ssize_t
+userclk_freqsts_show(struct device *dev, struct device_attribute *attr,
+		     char *buf)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	u64 userclk_freqsts;
+	void __iomem *base;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+	mutex_lock(&pdata->lock);
+	userclk_freqsts = readq(base + PORT_HDR_USRCLK_STS0);
+	mutex_unlock(&pdata->lock);
+
+	return sprintf(buf, "0x%llx\n", (unsigned long long)userclk_freqsts);
+}
+static DEVICE_ATTR_RO(userclk_freqsts);
+
+static ssize_t
+userclk_freqcntrsts_show(struct device *dev, struct device_attribute *attr,
+			 char *buf)
+{
+	struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
+	u64 userclk_freqcntrsts;
+	void __iomem *base;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+	mutex_lock(&pdata->lock);
+	userclk_freqcntrsts = readq(base + PORT_HDR_USRCLK_STS1);
+	mutex_unlock(&pdata->lock);
+
+	return sprintf(buf, "0x%llx\n",
+		       (unsigned long long)userclk_freqcntrsts);
+}
+static DEVICE_ATTR_RO(userclk_freqcntrsts);
+
 static struct attribute *port_hdr_attrs[] = {
 	&dev_attr_id.attr,
 	&dev_attr_ltr.attr,
 	&dev_attr_ap1_event.attr,
 	&dev_attr_ap2_event.attr,
 	&dev_attr_power_state.attr,
+	&dev_attr_userclk_freqcmd.attr,
+	&dev_attr_userclk_freqcntrcmd.attr,
+	&dev_attr_userclk_freqsts.attr,
+	&dev_attr_userclk_freqcntrsts.attr,
 	NULL,
 };
 
+static umode_t port_hdr_attrs_visible(struct kobject *kobj,
+				      struct attribute *attr, int n)
+{
+	struct device *dev = kobj_to_dev(kobj);
+	umode_t mode = attr->mode;
+	void __iomem *base;
+
+	base = dfl_get_feature_ioaddr_by_id(dev, PORT_FEATURE_ID_HEADER);
+
+	if (dfl_feature_revision(base) > 0) {
+		/*
+		 * userclk sysfs interfaces are only visible in case port
+		 * revision is 0, as hardware with revision >0 doesn't
+		 * support this.
+		 */
+		if (attr == &dev_attr_userclk_freqcmd.attr ||
+		    attr == &dev_attr_userclk_freqcntrcmd.attr ||
+		    attr == &dev_attr_userclk_freqsts.attr ||
+		    attr == &dev_attr_userclk_freqcntrsts.attr)
+			mode = 0;
+	}
+
+	return mode;
+}
+
 static const struct attribute_group port_hdr_group = {
-	.attrs = port_hdr_attrs,
+	.attrs      = port_hdr_attrs,
+	.is_visible = port_hdr_attrs_visible,
 };
 
 static int port_hdr_init(struct platform_device *pdev,
diff --git a/drivers/fpga/dfl.h b/drivers/fpga/dfl.h
index 856ea4e..9f0e656 100644
--- a/drivers/fpga/dfl.h
+++ b/drivers/fpga/dfl.h
@@ -120,6 +120,10 @@
 #define PORT_HDR_CAP		0x30
 #define PORT_HDR_CTRL		0x38
 #define PORT_HDR_STS		0x40
+#define PORT_HDR_USRCLK_CMD0	0x50
+#define PORT_HDR_USRCLK_CMD1	0x58
+#define PORT_HDR_USRCLK_STS0	0x60
+#define PORT_HDR_USRCLK_STS1	0x68
 
 /* Port Capability Register Bitfield */
 #define PORT_CAP_PORT_NUM	GENMASK_ULL(1, 0)	/* ID of this port */
@@ -355,6 +359,11 @@ static inline bool dfl_feature_is_port(void __iomem *base)
 		(FIELD_GET(DFH_ID, v) == DFH_ID_FIU_PORT);
 }
 
+static inline u8 dfl_feature_revision(void __iomem *base)
+{
+	return (u8)FIELD_GET(DFH_REVISION, readq(base + DFH));
+}
+
 /**
  * struct dfl_fpga_enum_info - DFL FPGA enumeration information
  *
