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From:   Richard Leitner <dev@g0hl1n.net>
To:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     gregkh@linuxfoundation.org, stern@rowland.harvard.edu,
        linux@roeck-us.net, mathias.nyman@linux.intel.com,
        johan@kernel.org, felipe.balbi@linux.intel.com,
        ekorenevsky@gmail.com, peter.chen@nxp.com, drake@endlessm.com,
        joe@perches.com, Richard Leitner <richard.leitner@skidata.com>
Subject: [PATCH] usb: core: introduce per-port over-current counters
Date:   Mon, 19 Feb 2018 13:01:07 +0100
Message-Id: <20180219120107.20434-1-dev@g0hl1n.net>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Richard Leitner <richard.leitner@skidata.com>

For some userspace applications information on the number of
over-current conditions at specific USB hub ports is relevant. Therefore
introduce a oc_counter in the usb port struct which is exported via
sysfs.

Signed-off-by: Richard Leitner <richard.leitner@skidata.com>
---
Tested on an i.MX6DL based board.
---
 drivers/usb/core/hub.c  |  4 +++-
 drivers/usb/core/hub.h  |  1 +
 drivers/usb/core/port.c | 10 ++++++++++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index c5c1f6cf3228..448fba1e1827 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -5104,8 +5104,10 @@ static void port_event(struct usb_hub *hub, int port1)
 
 	if (portchange & USB_PORT_STAT_C_OVERCURRENT) {
 		u16 status = 0, unused;
+		port_dev->oc_count++;
 
-		dev_dbg(&port_dev->dev, "over-current change\n");
+		dev_dbg(&port_dev->dev, "over-current change #%u\n",
+			port_dev->oc_count);
 		usb_clear_port_feature(hdev, port1,
 				USB_PORT_FEAT_C_OVER_CURRENT);
 		msleep(100);	/* Cool down */
diff --git a/drivers/usb/core/hub.h b/drivers/usb/core/hub.h
index 2a700ccc868c..b5cf567bf9e2 100644
--- a/drivers/usb/core/hub.h
+++ b/drivers/usb/core/hub.h
@@ -100,6 +100,7 @@ struct usb_port {
 	unsigned int is_superspeed:1;
 	unsigned int usb3_lpm_u1_permit:1;
 	unsigned int usb3_lpm_u2_permit:1;
+	unsigned int oc_count;
 };
 
 #define to_usb_port(_dev) \
diff --git a/drivers/usb/core/port.c b/drivers/usb/core/port.c
index 1a01e9ad3804..0bfe410eb8a7 100644
--- a/drivers/usb/core/port.c
+++ b/drivers/usb/core/port.c
@@ -41,6 +41,15 @@ static ssize_t connect_type_show(struct device *dev,
 }
 static DEVICE_ATTR_RO(connect_type);
 
+static ssize_t oc_count_show(struct device *dev, struct device_attribute *attr,
+			     char *buf)
+{
+	struct usb_port *port_dev = to_usb_port(dev);
+
+	return sprintf(buf, "%u\n", port_dev->oc_count);
+}
+static DEVICE_ATTR_RO(oc_count);
+
 static ssize_t usb3_lpm_permit_show(struct device *dev,
 			      struct device_attribute *attr, char *buf)
 {
@@ -109,6 +118,7 @@ static DEVICE_ATTR_RW(usb3_lpm_permit);
 
 static struct attribute *port_dev_attrs[] = {
 	&dev_attr_connect_type.attr,
+	&dev_attr_oc_count.attr,
 	NULL,
 };
 
-- 
2.11.0