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Subject[PATCH PROOF OF CONCEPT 3/2] trigger: ledtrig-usbport: read initial state from DT
Date
This allows specifying USB ports that should be observed by a trigger
right after activating it. Example:

usb {
gpios = <&gpio 0 GPIO_ACTIVE_HIGH>;
linux,default-trigger = "usbport";
usb-controllers = <&ohci>, <&ehci>, <&xhci>;
usb-ports = "1", "1", "1";
};

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
drivers/leds/trigger/ledtrig-usbport.c | 72 ++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)

diff --git a/drivers/leds/trigger/ledtrig-usbport.c b/drivers/leds/trigger/ledtrig-usbport.c
index eb20a8f..5724f63 100644
--- a/drivers/leds/trigger/ledtrig-usbport.c
+++ b/drivers/leds/trigger/ledtrig-usbport.c
@@ -12,8 +12,10 @@
#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/provider.h>
#include "../leds.h"

struct usbport_trig_port {
@@ -94,6 +96,75 @@ static bool usbport_trig_match(struct usbport_trig_data *usbport_data,
return false;
}

+static int usbport_trig_new_port(struct usbport_trig_data *usbport_data,
+ int busnum, const char *suffix)
+{
+ struct usbport_trig_port *port;
+ size_t len;
+ int tmp;
+
+ tmp = busnum;
+ len = 1;
+ while (tmp >= 10) {
+ tmp /= 10;
+ len++;
+ }
+ len++; /* '-' */
+ len += strlen(suffix);
+ len++; /* '\0' */
+
+ port = kzalloc(sizeof(*port), GFP_KERNEL);
+ if (!port)
+ return -ENOMEM;
+
+ port->name = kzalloc(len, GFP_KERNEL);
+ if (!port->name) {
+ kfree(port);
+ return -ENOMEM;
+ }
+ snprintf(port->name, len, "%d-%s", busnum, suffix);
+
+ list_add_tail(&port->list, &usbport_data->ports);
+
+ return 0;
+}
+
+static int usbport_trig_fill(struct usbport_trig_data *usbport_data)
+{
+ struct device_node *np = usbport_data->led_cdev->dev->of_node;
+ struct of_phandle_args args;
+ int count, i;
+ int err = 0;
+
+ if (!np)
+ return -ENOENT;
+
+ count = of_property_count_strings(np, "usb-ports");
+ if (count < 0)
+ return count;
+
+ for (i = 0; i < count; i++) {
+ const char *port;
+ struct usb_hcd *hcd;
+
+ err = of_property_read_string_index(np, "usb-ports", i, &port);
+ if (err)
+ continue;
+
+ err = of_parse_phandle_with_args(np, "usb-controllers", "#usb-cells", i, &args);
+ if (err)
+ continue;
+
+ hcd = of_hcd_get_from_provider(&args);
+ if (!IS_ERR(hcd))
+ usbport_trig_new_port(usbport_data, hcd->self.busnum, port);
+
+ of_node_put(args.np);
+ }
+
+ return err;
+}
+
static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
void *data)
{
@@ -129,6 +200,7 @@ static void usbport_trig_activate(struct led_classdev *led_cdev)
return;
usbport_data->led_cdev = led_cdev;
INIT_LIST_HEAD(&usbport_data->ports);
+ usbport_trig_fill(usbport_data);
usbport_data->nb.notifier_call = usbport_trig_notify,
led_cdev->trigger_data = usbport_data;

--
1.8.4.5
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