[PATCH V2 2/2] usb: core: read USB ports from DT in the usbport LED trigger driver

["Rafał Miłecki" <zajec5@gmail.com>]

From: Rafał Miłecki <rafal@milecki.pl>

This adds support for using description of relation between LEDs and USB
ports from device tree. If DT has properly described LEDs, trigger will
know when to turn them on.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
V2: Update to use "led-triggers"
---
 drivers/usb/core/ledtrig-usbport.c | 54 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/drivers/usb/core/ledtrig-usbport.c b/drivers/usb/core/ledtrig-usbport.c
index 1713248ab15a..aee80748eb7a 100644
--- a/drivers/usb/core/ledtrig-usbport.c
+++ b/drivers/usb/core/ledtrig-usbport.c
@@ -11,8 +11,10 @@
 #include <linux/device.h>
 #include <linux/leds.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/slab.h>
 #include <linux/usb.h>
+#include <linux/usb/of.h>
 
 struct usbport_trig_data {
 	struct led_classdev *led_cdev;
@@ -123,6 +125,55 @@ static const struct attribute_group ports_group = {
  * Adding & removing ports
  ***************************************/
 
+/**
+ * usbport_trig_port_observed - Check if port should be observed
+ */
+static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data,
+				       struct usb_device *usb_dev, int port1)
+{
+	struct device *dev = usbport_data->led_cdev->dev;
+	struct device_node *led_np = dev->of_node;
+	struct of_phandle_args args;
+	struct device_node *port_np;
+	int count, i;
+
+	if (!led_np)
+		return false;
+
+	/* Get node of port being added */
+	port_np = usb_of_get_child_node(usb_dev->dev.of_node, port1);
+	if (!port_np)
+		return false;
+
+	/* Amount of ports this LED references */
+	count = of_count_phandle_with_args(led_np, "led-triggers", NULL);
+	if (count < 0) {
+		dev_warn(dev, "Failed to get USB ports for %s\n",
+			 led_np->full_name);
+		return false;
+	}
+
+	/* Check if port is on this LED's list */
+	for (i = 0; i < count; i++) {
+		int err;
+
+		err = of_parse_phandle_with_args(led_np, "led-triggers", NULL,
+						 i, &args);
+		if (err) {
+			dev_err(dev, "Failed to get USB port phandle at index %d: %d\n",
+				i, err);
+			continue;
+		}
+
+		of_node_put(args.np);
+
+		if (args.np == port_np)
+			return true;
+	}
+
+	return false;
+}
+
 static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
 				 struct usb_device *usb_dev,
 				 const char *hub_name, int portnum)
@@ -141,6 +192,8 @@ static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
 	port->data = usbport_data;
 	port->hub = usb_dev;
 	port->portnum = portnum;
+	port->observed = usbport_trig_port_observed(usbport_data, usb_dev,
+						    portnum);
 
 	len = strlen(hub_name) + 8;
 	port->port_name = kzalloc(len, GFP_KERNEL);
@@ -255,6 +308,7 @@ static void usbport_trig_activate(struct led_classdev *led_cdev)
 	if (err)
 		goto err_free;
 	usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
+	usbport_trig_update_count(usbport_data);
 
 	/* Notifications */
 	usbport_data->nb.notifier_call = usbport_trig_notify,
-- 
2.11.0