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path: root/drivers/leds/leds-gpio.c
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2009-06-23leds: Add options to have GPIO LEDs start on or keep their stateTrent Piepho
There already is a "default-on" trigger but there are problems with it. For one, it's a inefficient way to do it and requires led trigger support to be compiled in. But the real reason is that is produces a glitch on the LED. The GPIO is allocate with the LED *off*, then *later* when the trigger runs it is turned back on. If the LED was already on via the GPIO's reset default or action of the firmware, this produces a glitch where the LED goes from on to off to on. While normally this is fast enough that it wouldn't be noticeable to a human observer, there are still serious problems. One is that there may be something else on the GPIO line, like a hardware alarm or watchdog, that is fast enough to notice the glitch. Another is that the kernel may panic before the LED is turned back on, thus hanging with the LED in the wrong state. This is not just speculation, but actually happened to me with an embedded system that has an LED which should turn off when the kernel finishes booting, which was left in the incorrect state due to a bug in the OF LED binding code. We also let GPIO LEDs get their initial value from whatever the current state of the GPIO line is. On some systems the LEDs are put into some state by the firmware or hardware before Linux boots, and it is desired to have them keep this state which is otherwise unknown to Linux. This requires that the underlying GPIO driver support reading the value of output GPIOs. Some drivers support this and some do not. The platform device binding gains a field in the platform data "default_state" that controls this. There are three constants defined to select from on, off, or keeping the current state. The OpenFirmware binding uses a property named "default-state" that can be set to "on", "off", or "keep". The default if the property isn't present is off. Signed-off-by: Trent Piepho <xyzzy@speakeasy.org> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Wolfram Sang <w.sang@pengutronix.de> Acked-by: Sean MacLennan <smaclennan@pikatech.com> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-06-23leds: leds-gpio - fix a section mismatchZhenwen Xu
WARNING: drivers/leds/leds-gpio.o(.text+0x153): Section mismatch in reference from the function gpio_led_probe() to the function .devinit.text:create_gpio_led() The function gpio_led_probe() references the function __devinit create_gpio_led(). This is often because gpio_led_probe lacks a __devinit annotation or the annotation of create_gpio_led is wrong. Signed-off-by: Zhenwen Xu <helight.xu@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-08leds: just ignore invalid GPIOs in leds-gpioDavid Brownell
Fix build problems with leds-gpio: CC drivers/leds/leds-gpio.o drivers/leds/leds-gpio.c: In function 'create_gpio_led': drivers/leds/leds-gpio.c:85: warning: 'return' with no value, in function returning non-void Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-06leds: just ignore invalid GPIOs in leds-gpioDavid Brownell
Sometimes it's awkward to make sure that the array in the platform_data handed to the leds-gpio driver has only valid data ... some leds may not be always available, and coping with that currently requires patching or rebuilding the array. This patch fixes that by making it be OK to pass an invalid GPIO (such as "-EINVAL") ... such table entries are skipped. [rpurdie@linux.intel.com: adjusted to apply against other led tree changes] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Tested-by: Diego Dompe <diego.dompe@ridgerun.com> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-06leds: Add suspend/resume state flags to leds-gpioRichard Purdie
Add an option to preserve LED state when suspending/resuming to the LED gpio driver. Based on a suggestion from Robert Jarzmik. Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-06leds: Fix leds-gpio driver multiple module_init/exit usageRichard Purdie
You can't have multiple module_init()/module_exit calls so resort to messy ifdefs potentially pending some code refactoring. Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-04-06leds: Add openfirmware platform device supportTrent Piepho
Add bindings to support LEDs defined as of_platform devices in addition to the existing bindings for platform devices. New options in Kconfig allow the platform binding code and/or the of_platform code to be turned on. The of_platform code is of course only available on archs that have OF support. The existing probe and remove methods are refactored to use new functions create_gpio_led(), to create and register one led, and delete_gpio_led(), to unregister and free one led. The new probe and remove methods for the of_platform driver can then share most of the common probe and remove code with the platform driver. The suspend and resume methods aren't shared, but they are very short. The actual led driving code is the same for LEDs created by either binding. The OF bindings are based on patch by Anton Vorontsov <avorontsov@ru.mvista.com>. They have been extended to allow multiple LEDs per device. Signed-off-by: Trent Piepho <tpiepho@freescale.com> Acked-by: Grant Likely <grant.likely@secretlab.ca> Acked-by: Sean MacLennan <smaclennan@pikatech.com> Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
2009-01-08leds: Add suspend/resume to the core classRichard Purdie
Add suspend/resume to the core class and remove all the now unneeded code from various drivers. Originally the class code couldn't support suspend/resume but since class_device can there is no reason for each driver doing its own suspend/resume anymore.
2008-04-24leds: enable support for blink_set() platform hook in leds-gpioHerbert Valerio Riedel
Enhance leds-gpio to provide hardware-based led flashing by passing through the blink_set() call to a optionally set platform-specific function pointer. Signed-off-by: Herbert Valerio Riedel <hvr@gnu.org> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-04-15leds: fix platform driver hotplug/coldplugKay Sievers
Since 43cc71eed1250755986da4c0f9898f9a635cb3bf, the platform modalias is prefixed with "platform:". Add MODULE_ALIAS() to the hotpluggable platform LED drivers, to re-enable auto loading. [dbrownell@users.sourceforge.net: more drivers, registration fixes] Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-31leds: Remove incorrect use of preempt_count() from leds-gpioDavid Brownell
It appears that we can't just check to see if we're in a task context ... so instead of trying that, just make the relevant leds always schedule a little worklet. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-03-31leds: Fix potential leds-gpio oopsUwe Kleine-König
Call gpio_cansleep only after gpio_request succeeded avoiding an oops. Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com> Acked-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2008-02-07leds: Fix led-gpio active_low default brightnessRaphael Assenat
When gpio_direction_output() is called, led_dat->active_low is used as default value. This means that the led will always be off by default. cdev.brightness should really have been set to LED_OFF unconditionally to reflect this behavior. Signed-off-by: Raphael Assenat <raph@8d.com> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-11-05leds: bugfixes for leds-gpioDavid Brownell
Three bugfixes to the leds-gpio driver, plus minor whitespace tweaks: - Do the INIT_WORK() before registering each LED, so if its trigger becomes immediately active it can schedule work without oopsing.. - Use normal registration, not platform_driver_probe(), so that devices appearing "late" (hotplug type) can still be bound. - Mark the driver remove code as "__devexit", preventing oopses when the underlying device is removed. These issues came up when using this driver with some GPIO expanders living on serial busses, which act unlike "normal" platform devices: they can appear and vanish along with the serial bus driver. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-07-16leds: Teach leds-gpio to handle timer-unsafe GPIOsDavid Brownell
Teach the new leds-gpio driver that some GPIOs can't be accessed from timer callbacks ... which is how all today's standard triggers use them. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
2007-07-16leds: Add generic GPIO LED driverRaphael Assenat
This patch adds support for GPIO connected leds via the new GPIO framework. Information about leds (gpio, polarity, name, default trigger) is passed to the driver via platform_data. Signed-off-by: Raphael Assenat <raph@8d.com> Signed-off-by: Richard Purdie <rpurdie@rpsys.net>