[PATCH 1/2] leds: usb: Add LED trigger for USB gadget activity

[Michal Sojka]

With this patch, USB gadget activity can be signaled by blinking a LED.

Since there is no generic code where to put the trigger for all USB
controllers, each USB controller needs to call the trigger individually.
This patch adds the call only for the musb controller where I can test
it.

Signed-off-by: Michal Sojka <sojka@xxxxxxxxx>
---
 drivers/leds/trigger/Kconfig             |  8 ++++++
 drivers/leds/trigger/Makefile            |  1 +
 drivers/leds/trigger/ledtrig-usbgadget.c | 45 ++++++++++++++++++++++++++++++++
 drivers/usb/musb/musb_gadget.c           |  6 +++--
 include/linux/leds.h                     |  6 +++++
 5 files changed, 64 insertions(+), 2 deletions(-)
 create mode 100644 drivers/leds/trigger/ledtrig-usbgadget.c

diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig
index 49794b4..9562963 100644
--- a/drivers/leds/trigger/Kconfig
+++ b/drivers/leds/trigger/Kconfig
@@ -41,6 +41,14 @@ config LEDS_TRIGGER_IDE_DISK
 	  This allows LEDs to be controlled by IDE disk activity.
 	  If unsure, say Y.
 
+config LEDS_TRIGGER_USBGADGET
+	bool "LED USB Gadget Trigger"
+	depends on (USB_MUSB_GADGET || USB_MUSB_DUAL_ROLE)
+	depends on LEDS_TRIGGERS
+	help
+	  This allows LEDs to be controlled by USB gadget activity.
+	  If unsure, say Y.
+
 config LEDS_TRIGGER_HEARTBEAT
 	tristate "LED Heartbeat Trigger"
 	depends on LEDS_TRIGGERS
diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile
index 1abf48d..45917c0 100644
--- a/drivers/leds/trigger/Makefile
+++ b/drivers/leds/trigger/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_LEDS_TRIGGER_CPU)		+= ledtrig-cpu.o
 obj-$(CONFIG_LEDS_TRIGGER_DEFAULT_ON)	+= ledtrig-default-on.o
 obj-$(CONFIG_LEDS_TRIGGER_TRANSIENT)	+= ledtrig-transient.o
 obj-$(CONFIG_LEDS_TRIGGER_CAMERA)	+= ledtrig-camera.o
+obj-$(CONFIG_LEDS_TRIGGER_USBGADGET)	+= ledtrig-usbgadget.o
diff --git a/drivers/leds/trigger/ledtrig-usbgadget.c b/drivers/leds/trigger/ledtrig-usbgadget.c
new file mode 100644
index 0000000..1eb90da
--- /dev/null
+++ b/drivers/leds/trigger/ledtrig-usbgadget.c
@@ -0,0 +1,45 @@
+/*
+ * LED Trigger for USB Gadget Activity
+ *
+ * Copyright 2014 Michal Sojka <sojka@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/leds.h>
+
+#define BLINK_DELAY 30
+
+DEFINE_LED_TRIGGER(ledtrig_usbgadget);
+static unsigned long usbgadget_blink_delay = BLINK_DELAY;
+
+void ledtrig_usbgadget_activity(void)
+{
+	led_trigger_blink_oneshot(ledtrig_usbgadget,
+				  &usbgadget_blink_delay, &usbgadget_blink_delay, 0);
+}
+EXPORT_SYMBOL(ledtrig_usbgadget_activity);
+
+static int __init ledtrig_usbgadget_init(void)
+{
+	led_trigger_register_simple("usb-gadget", &ledtrig_usbgadget);
+	return 0;
+}
+
+static void __exit ledtrig_usbgadget_exit(void)
+{
+	led_trigger_unregister_simple(ledtrig_usbgadget);
+}
+
+module_init(ledtrig_usbgadget_init);
+module_exit(ledtrig_usbgadget_exit);
+
+MODULE_AUTHOR("Michal Sojka <sojka@xxxxxxxxx>");
+MODULE_DESCRIPTION("LED Trigger for USB Gadget Activity");
+MODULE_LICENSE("GPL");
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index d4aa779..98f8b24 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -42,6 +42,7 @@
 #include <linux/delay.h>
 #include <linux/dma-mapping.h>
 #include <linux/slab.h>
+#include <linux/leds.h>
 
 #include "musb_core.h"
 
@@ -167,11 +168,12 @@ __acquires(ep->musb->lock)
 	if (!dma_mapping_error(&musb->g.dev, request->dma))
 		unmap_dma_buffer(req, musb);
 
-	if (request->status == 0)
+	if (request->status == 0) {
 		dev_dbg(musb->controller, "%s done request %p,  %d/%d\n",
 				ep->end_point.name, request,
 				req->request.actual, req->request.length);
-	else
+		ledtrig_usbgadget_activity();
+	} else
 		dev_dbg(musb->controller, "%s request %p, %d/%d fault %d\n",
 				ep->end_point.name, request,
 				req->request.actual, req->request.length,
diff --git a/include/linux/leds.h b/include/linux/leds.h
index 0287ab2..5d9668e 100644
--- a/include/linux/leds.h
+++ b/include/linux/leds.h
@@ -218,6 +218,12 @@ extern void ledtrig_ide_activity(void);
 static inline void ledtrig_ide_activity(void) {}
 #endif
 
+#ifdef CONFIG_LEDS_TRIGGER_USBGADGET
+extern void ledtrig_usbgadget_activity(void);
+#else
+static inline void ledtrig_usbgadget_activity(void) {}
+#endif
+
 #if defined(CONFIG_LEDS_TRIGGER_CAMERA) || defined(CONFIG_LEDS_TRIGGER_CAMERA_MODULE)
 extern void ledtrig_flash_ctrl(bool on);
 extern void ledtrig_torch_ctrl(bool on);
-- 
2.1.0

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