Fix an unsigned value overflow in the error handling code in the
Atmel PWM driver.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Since 43cc71eed1, 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>
This is a LED driver using the PWM on newer SOCs from Atmel; brightness is
controlled by changing the PWM duty cycle. So for example if you've set up
two leds labeled "pwm0" and "pwm1":
echo 0 > /sys/class/leds/pwm2/brightness # off (0%)
echo 80 > /sys/class/leds/pwm2/brightness
echo 255 > /sys/class/leds/pwm2/brightness # on (100%)
Note that "brightness" here isn't linear; maybe that should change. Going
from 4 to 8 probably doubles perceived brightness, while 244 to 248 is
imperceptible.
This is mostly intended to be a simple example of PWM, although it's
realistic since LCD backlights are often driven with PWM to conserve
battery power (and offer brightness options).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Cc: Richard Purdie <rpurdie@rpsys.net>
Cc: Andrew Victor <linux@maxim.org.za>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Li Zefan