Bluetooth: add LED trigger for indicating HCI is powered up

Add support for LED triggers to the Bluetooth subsystem and add kernel
config symbol BT_LEDS for it.

For now one trigger for indicating "HCI is powered up" is supported.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

5 files changed, 116 insertions, 0 deletions

diff --git a/net/bluetooth/Kconfig b/net/bluetooth/Kconfig
index 95d1a66ba03a..06c31b9a68b0 100644
--- a/net/bluetooth/Kconfig
+++ b/net/bluetooth/Kconfig
@@ -69,6 +69,15 @@ config BT_6LOWPAN
         help
           IPv6 compression over Bluetooth Low Energy.
 
+config BT_LEDS
+        bool "Enable LED triggers"
+        depends on BT
+        depends on LEDS_CLASS
+        select LEDS_TRIGGERS
+        help
+          This option selects a few LED triggers for different
+          Bluetooth events.
+
 config BT_SELFTEST
         bool "Bluetooth self testing support"
         depends on BT && DEBUG_KERNEL
diff --git a/net/bluetooth/Makefile b/net/bluetooth/Makefile
index 2b15ae8c1def..b3ff12eb9b6d 100644
--- a/net/bluetooth/Makefile
+++ b/net/bluetooth/Makefile
@@ -17,6 +17,7 @@ bluetooth-y := af_bluetooth.o hci_core.o hci_conn.o hci_event.o mgmt.o \
 
 bluetooth-$(CONFIG_BT_BREDR) += sco.o
 bluetooth-$(CONFIG_BT_HS) += a2mp.o amp.o
+bluetooth-$(CONFIG_BT_LEDS) += leds.o
 bluetooth-$(CONFIG_BT_DEBUGFS) += hci_debugfs.o
 bluetooth-$(CONFIG_BT_SELFTEST) += selftest.o
 
diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 883c821a9e78..88f1ef3589d8 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -40,6 +40,7 @@
 #include "hci_request.h"
 #include "hci_debugfs.h"
 #include "smp.h"
+#include "leds.h"
 
 static void hci_rx_work(struct work_struct *work);
 static void hci_cmd_work(struct work_struct *work);
@@ -1395,6 +1396,7 @@ static int hci_dev_do_open(struct hci_dev *hdev)
                 hci_dev_set_flag(hdev, HCI_RPA_EXPIRED);
                 set_bit(HCI_UP, &hdev->flags);
                 hci_sock_dev_event(hdev, HCI_DEV_UP);
+                hci_leds_update_powered(hdev, true);
                 if (!hci_dev_test_flag(hdev, HCI_SETUP) &&
                     !hci_dev_test_flag(hdev, HCI_CONFIG) &&
                     !hci_dev_test_flag(hdev, HCI_UNCONFIGURED) &&
@@ -1532,6 +1534,8 @@ int hci_dev_do_close(struct hci_dev *hdev)
                 return 0;
         }
 
+        hci_leds_update_powered(hdev, false);
+
         /* Flush RX and TX works */
         flush_work(&hdev->tx_work);
         flush_work(&hdev->rx_work);
@@ -3067,6 +3071,8 @@ int hci_register_dev(struct hci_dev *hdev)
         if (error < 0)
                 goto err_wqueue;
 
+        hci_leds_init(hdev);
+
         hdev->rfkill = rfkill_alloc(hdev->name, &hdev->dev,
                                     RFKILL_TYPE_BLUETOOTH, &hci_rfkill_ops,
                                     hdev);
@@ -3128,6 +3134,8 @@ void hci_unregister_dev(struct hci_dev *hdev)
 
         id = hdev->id;
 
+        hci_leds_exit(hdev);
+
         write_lock(&hci_dev_list_lock);
         list_del(&hdev->list);
         write_unlock(&hci_dev_list_lock);
diff --git a/net/bluetooth/leds.c b/net/bluetooth/leds.c
new file mode 100644
index 000000000000..ded7c88eaccc
--- /dev/null
+++ b/net/bluetooth/leds.c
@@ -0,0 +1,80 @@
+/*
+ * Copyright 2015, Heiner Kallweit <hkallweit1@gmail.com>
+ *
+ * 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 <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "leds.h"
+
+struct hci_basic_led_trigger {
+        struct led_trigger      led_trigger;
+        struct hci_dev          *hdev;
+};
+
+#define to_hci_basic_led_trigger(arg) container_of(arg, \
+                        struct hci_basic_led_trigger, led_trigger)
+
+void hci_leds_update_powered(struct hci_dev *hdev, bool enabled)
+{
+        if (hdev->power_led)
+                led_trigger_event(hdev->power_led,
+                                  enabled ? LED_FULL : LED_OFF);
+}
+
+static void power_activate(struct led_classdev *led_cdev)
+{
+        struct hci_basic_led_trigger *htrig;
+        bool powered;
+
+        htrig = to_hci_basic_led_trigger(led_cdev->trigger);
+        powered = test_bit(HCI_UP, &htrig->hdev->flags);
+
+        led_trigger_event(led_cdev->trigger, powered ? LED_FULL : LED_OFF);
+}
+
+static struct led_trigger *led_allocate_basic(struct hci_dev *hdev,
+                        void (*activate)(struct led_classdev *led_cdev),
+                        const char *name)
+{
+        struct hci_basic_led_trigger *htrig;
+
+        htrig = devm_kzalloc(&hdev->dev, sizeof(*htrig), GFP_KERNEL);
+        if (!htrig)
+                return NULL;
+
+        htrig->hdev = hdev;
+        htrig->led_trigger.activate = activate;
+        htrig->led_trigger.name = devm_kasprintf(&hdev->dev, GFP_KERNEL,
+                                                 "%s-%s", hdev->name,
+                                                 name);
+        if (!htrig->led_trigger.name)
+                goto err_alloc;
+
+        if (led_trigger_register(&htrig->led_trigger))
+                goto err_register;
+
+        return &htrig->led_trigger;
+
+err_register:
+        devm_kfree(&hdev->dev, (void *)htrig->led_trigger.name);
+err_alloc:
+        devm_kfree(&hdev->dev, htrig);
+        return NULL;
+}
+
+void hci_leds_init(struct hci_dev *hdev)
+{
+        /* initialize power_led */
+        hdev->power_led = led_allocate_basic(hdev, power_activate, "power");
+}
+
+void hci_leds_exit(struct hci_dev *hdev)
+{
+        if (hdev->power_led)
+                led_trigger_unregister(hdev->power_led);
+}
diff --git a/net/bluetooth/leds.h b/net/bluetooth/leds.h
new file mode 100644
index 000000000000..068261a4e12c
--- /dev/null
+++ b/net/bluetooth/leds.h
@@ -0,0 +1,18 @@
+/*
+ * Copyright 2015, Heiner Kallweit <hkallweit1@gmail.com>
+ *
+ * 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.
+ */
+
+#if IS_ENABLED(CONFIG_BT_LEDS)
+void hci_leds_update_powered(struct hci_dev *hdev, bool enabled);
+void hci_leds_init(struct hci_dev *hdev);
+void hci_leds_exit(struct hci_dev *hdev);
+#else
+static inline void hci_leds_update_powered(struct hci_dev *hdev,
+                                           bool enabled) {}
+static inline void hci_leds_init(struct hci_dev *hdev) {}
+static inline void hci_leds_exit(struct hci_dev *hdev) {}
+#endif