[PATCH can-next v5 1/2] can: add tx/rx LED trigger support

[Fabio Baltieri]

This patch implements the functions to add two LED triggers, named
<ifname>-tx and <ifname>-rx, to a canbus device driver.

Triggers are called from specific handlers by each CAN device driver and
can be disabled altogether with a Kconfig option.

The implementation keeps the LED on when the interface is UP and blinks
the LED on network activity at a configurable rate.

This only supports can-dev based drivers, as it uses some support field
in the can_priv structure.

Supported drivers should call devm_can_led_init() and can_led_event() as
needed.

Cleanup is handled automatically by devres, so no *_exit function is
needed.

Supported events are:
- CAN_LED_EVENT_OPEN: turn on tx/rx LEDs
- CAN_LED_EVENT_STOP: turn off tx/rx LEDs
- CAN_LED_EVENT_TX: trigger tx LED blink
- CAN_LED_EVENT_RX: trigger tx LED blink

Cc: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Cc: Wolfgang Grandegger <wg@xxxxxxxxxxxxxx>
Cc: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Fabio Baltieri <fabio.baltieri@xxxxxxxxx>
---

Hello,

so, v5, renamed can_led_init to devm_can_led_init like other devres based
functions.

Also, I'm reposting implementation into flexcan in 2/2... I have a small
patchset for others embedded can drivers to be tested which I can post in
another thread if this patch is accepted.

Fabio

 drivers/net/can/Kconfig  |  12 ++++++
 drivers/net/can/Makefile |   2 +
 drivers/net/can/led.c    | 102 +++++++++++++++++++++++++++++++++++++++++++++++
 include/linux/can/dev.h  |   8 ++++
 include/linux/can/led.h  |  34 ++++++++++++++++
 5 files changed, 158 insertions(+)
 create mode 100644 drivers/net/can/led.c
 create mode 100644 include/linux/can/led.h

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index bb709fd..19dec19 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -54,6 +54,18 @@ config CAN_CALC_BITTIMING
 	  arguments "tq", "prop_seg", "phase_seg1", "phase_seg2" and "sjw".
 	  If unsure, say Y.
 
+config CAN_LEDS
+	bool "Enable LED triggers for Netlink based drivers"
+	depends on CAN_DEV
+	depends on LEDS_CLASS
+	select LEDS_TRIGGERS
+	---help---
+	  This option adds two LED triggers for packet receive and transmit
+	  events on each supported CAN device.
+
+	  Say Y here if you are working on a system with led-class supported
+	  LEDs and you want to use them as canbus activity indicators.
+
 config CAN_AT91
 	tristate "Atmel AT91 onchip CAN controller"
 	depends on CAN_DEV && (ARCH_AT91SAM9263 || ARCH_AT91SAM9X5)
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index 938be37..24ee98b 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -8,6 +8,8 @@ obj-$(CONFIG_CAN_SLCAN)		+= slcan.o
 obj-$(CONFIG_CAN_DEV)		+= can-dev.o
 can-dev-y			:= dev.o
 
+can-dev-$(CONFIG_CAN_LEDS)	+= led.o
+
 obj-y				+= usb/
 obj-y				+= softing/
 
diff --git a/drivers/net/can/led.c b/drivers/net/can/led.c
new file mode 100644
index 0000000..8b4f6a9
--- /dev/null
+++ b/drivers/net/can/led.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright 2012, Fabio Baltieri <fabio.baltieri@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/device.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/can/dev.h>
+
+#include <linux/can/led.h>
+
+static unsigned long led_delay = 50;
+module_param(led_delay, ulong, 0644);
+MODULE_PARM_DESC(led_delay,
+		"blink delay time for activity leds (msecs, default: 50).");
+
+/*
+ * Trigger a LED event in response to a CAN device event
+ */
+void can_led_event(struct net_device *netdev, enum can_led_event event)
+{
+	struct can_priv *priv = netdev_priv(netdev);
+
+	switch (event) {
+	case CAN_LED_EVENT_OPEN:
+		led_trigger_event(priv->tx_led_trig, LED_FULL);
+		led_trigger_event(priv->rx_led_trig, LED_FULL);
+		break;
+	case CAN_LED_EVENT_STOP:
+		led_trigger_event(priv->tx_led_trig, LED_OFF);
+		led_trigger_event(priv->rx_led_trig, LED_OFF);
+		break;
+	case CAN_LED_EVENT_TX:
+		if (led_delay)
+			led_trigger_blink_oneshot(priv->tx_led_trig,
+						  &led_delay, &led_delay, 1);
+		break;
+	case CAN_LED_EVENT_RX:
+		if (led_delay)
+			led_trigger_blink_oneshot(priv->rx_led_trig,
+						  &led_delay, &led_delay, 1);
+		break;
+	}
+}
+EXPORT_SYMBOL_GPL(can_led_event);
+
+static void can_led_release(struct device *gendev, void *res)
+{
+	struct can_priv *priv = netdev_priv(to_net_dev(gendev));
+
+	led_trigger_unregister_simple(priv->tx_led_trig);
+	led_trigger_unregister_simple(priv->rx_led_trig);
+
+	kfree(priv->tx_led_trig_name);
+	kfree(priv->rx_led_trig_name);
+}
+
+/*
+ * Register CAN LED triggers for a CAN device
+ *
+ * This is normally called from a driver's probe function
+ */
+void devm_can_led_init(struct net_device *netdev)
+{
+	struct can_priv *priv = netdev_priv(netdev);
+	void *res;
+
+	res = devres_alloc(can_led_release, 0, GFP_KERNEL);
+	if (!res)
+		goto err_out;
+
+	priv->tx_led_trig_name = kasprintf(GFP_KERNEL, "%s-tx", netdev->name);
+	if (!priv->tx_led_trig_name)
+		goto err_out;
+
+	priv->rx_led_trig_name = kasprintf(GFP_KERNEL, "%s-rx", netdev->name);
+	if (!priv->rx_led_trig_name)
+		goto err_out_rx;
+
+	led_trigger_register_simple(priv->tx_led_trig_name,
+				    &priv->tx_led_trig);
+	led_trigger_register_simple(priv->rx_led_trig_name,
+				    &priv->rx_led_trig);
+
+	devres_add(&netdev->dev, res);
+
+	return;
+
+err_out_rx:
+	kfree(priv->tx_led_trig_name);
+	priv->tx_led_trig_name = NULL;
+err_out:
+	netdev_err(netdev, "cannot register LED triggers\n");
+	devres_free(res);
+}
+EXPORT_SYMBOL_GPL(devm_can_led_init);
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 2b2fc34..167b04a 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -16,6 +16,7 @@
 #include <linux/can.h>
 #include <linux/can/netlink.h>
 #include <linux/can/error.h>
+#include <linux/can/led.h>
 
 /*
  * CAN mode
@@ -52,6 +53,13 @@ struct can_priv {
 
 	unsigned int echo_skb_max;
 	struct sk_buff **echo_skb;
+
+#ifdef CONFIG_CAN_LEDS
+	struct led_trigger *tx_led_trig;
+	char *tx_led_trig_name;
+	struct led_trigger *rx_led_trig;
+	char *rx_led_trig_name;
+#endif
 };
 
 /*
diff --git a/include/linux/can/led.h b/include/linux/can/led.h
new file mode 100644
index 0000000..946059c
--- /dev/null
+++ b/include/linux/can/led.h
@@ -0,0 +1,34 @@
+/*
+ * Copyright 2012, Fabio Baltieri <fabio.baltieri@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.
+ */
+
+#ifndef CAN_LED_H
+#define CAN_LED_H
+
+#include <linux/leds.h>
+
+enum can_led_event {
+	CAN_LED_EVENT_OPEN,
+	CAN_LED_EVENT_STOP,
+	CAN_LED_EVENT_TX,
+	CAN_LED_EVENT_RX,
+};
+
+#ifdef CONFIG_CAN_LEDS
+void can_led_event(struct net_device *netdev, enum can_led_event event);
+void devm_can_led_init(struct net_device *netdev);
+#else
+static inline void can_led_event(struct net_device *netdev,
+				 enum can_led_event event)
+{
+}
+static inline void devm_can_led_init(struct net_device *netdev)
+{
+}
+#endif
+
+#endif
-- 
1.7.11.rc1.9.gf623ca1.dirty

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/