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

[Fabio Baltieri]

Hi Marc,

On Mon, Jul 30, 2012 at 11:17:53PM +0200, Marc Kleine-Budde wrote:
> On 07/30/2012 09:20 PM, Fabio Baltieri wrote:
> > 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
> 
> Looks quite clean now. Can you provide a devm implementation, too?
> 
> Marc
> > 
> >  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);
> 
> Can you provide a devm implementation for can_led?

Sounds reasonable, you mean like a devm_kasprintf implementation to
remove kfree and unwinding code?

Fabio

> > +
> > +/*
> > + * 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
> > 
> 
> 
> -- 
> Pengutronix e.K.                  | Marc Kleine-Budde           |
> Industrial Linux Solutions        | Phone: +49-231-2826-924     |
> Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
> Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |
> 


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