[PATCH can-next v3 1/2] can: add tx/rx LED trigger support

From: Fabio Baltieri
Date: Mon Jul 30 2012 - 15:19:03 EST


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 can_led_init(), can_led_exit() and
can_led_event() as 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>
---

Hi all!

This is the v3 of my CAN LED trigger patch. It's a major refactoring of the v2
that was discussed about three months ago concluding with the idea that
implementing the oneshot triggering code in the LED framework would be a better
solution.

This is the old thread for reference:
http://marc.info/?l=linux-can&m=133521499002898&w=2

So, generic oneshot trigger code is now merged in mainline (see 5bb629c), and
these are the changes in the v3:

- use the new led_trigger_blink_oneshot() function for LED triggering
- use kasprintf() and led_trigger_{un}register_simple for LED allocation
- add some usage note in the comments

The resulting code is quite simple now and - I think - a bit less intrusive.
Still, I hope on some feedback from the community as I don't have that much
hardware to test it - this version has been tested mainly on an x86 with a
custom usb-can interface.

In 2/2 there is a sample implementation for the flexcan driver, which is
basically unchanged from the old version.

Any comments?
Fabio

drivers/net/can/Kconfig | 12 ++++++
drivers/net/can/Makefile | 2 +
drivers/net/can/led.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/can/dev.h | 8 ++++
include/linux/can/led.h | 38 +++++++++++++++++++
5 files changed, 159 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..68c4f30
--- /dev/null
+++ b/drivers/net/can/led.c
@@ -0,0 +1,99 @@
+/*
+ * 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/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);
+
+/*
+ * Register CAN LED triggers for a CAN device
+ *
+ * This is normally called from a driver's probe function
+ */
+void can_led_init(struct net_device *netdev)
+{
+ struct can_priv *priv = netdev_priv(netdev);
+
+ priv->tx_led_trig_name = kasprintf(GFP_KERNEL, "%s-tx", netdev->name);
+ if (!priv->tx_led_trig_name)
+ goto tx_led_failed;
+
+ priv->rx_led_trig_name = kasprintf(GFP_KERNEL, "%s-rx", netdev->name);
+ if (!priv->rx_led_trig_name)
+ goto rx_led_failed;
+
+ 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);
+
+ return;
+
+rx_led_failed:
+ kfree(priv->tx_led_trig_name);
+ priv->tx_led_trig_name = NULL;
+tx_led_failed:
+ return;
+}
+EXPORT_SYMBOL_GPL(can_led_init);
+
+/*
+ * Unregister CAN LED triggers for a CAN device
+ *
+ * This is normally called from a driver's remove function
+ */
+void can_led_exit(struct net_device *netdev)
+{
+ struct can_priv *priv = netdev_priv(netdev);
+
+ 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);
+}
+EXPORT_SYMBOL_GPL(can_led_exit);
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..274c7fd
--- /dev/null
+++ b/include/linux/can/led.h
@@ -0,0 +1,38 @@
+/*
+ * 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 can_led_init(struct net_device *netdev);
+void can_led_exit(struct net_device *netdev);
+#else
+static inline void can_led_event(struct net_device *netdev,
+ enum can_led_event event)
+{
+}
+static inline void can_led_init(struct net_device *netdev)
+{
+}
+static inline void can_led_exit(struct net_device *netdev)
+{
+}
+#endif
+
+#endif
--
1.7.11.rc1.9.gf623ca1.dirty

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