diff options
| author | Márton Németh <nm127@freemail.hu> | 2007-10-31 17:07:12 +0300 |
|---|---|---|
| committer | Richard Purdie <rpurdie@rpsys.net> | 2008-02-07 12:49:38 +0300 |
| commit | 4c79141d28bc290ae307e3f81f5bc909c26faf6e (patch) | |
| tree | 9c6dc51c441dfc1c84cc27ece43087515c06967c /drivers | |
| parent | 6c152beefbf90579d21afc4f7e075b1f801f9a75 (diff) | |
| download | linux-4c79141d28bc290ae307e3f81f5bc909c26faf6e.tar.xz | |
leds: Add support for hardware accelerated LED flashing
Extends the leds subsystem with a blink_set() callback function which can
be optionally implemented by a LED driver. If implemented, the driver can use
the hardware acceleration for blinking a LED.
Signed-off-by: Márton Németh <nm127@freemail.hu>
Signed-off-by: Richard Purdie <rpurdie@rpsys.net>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/leds/Kconfig | 6 | ||||
| -rw-r--r-- | drivers/leds/ledtrig-timer.c | 41 |
2 files changed, 42 insertions, 5 deletions
diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig index cf3a6d4d9475..659448ead685 100644 --- a/drivers/leds/Kconfig +++ b/drivers/leds/Kconfig @@ -152,7 +152,11 @@ config LEDS_TRIGGER_TIMER depends on LEDS_TRIGGERS help This allows LEDs to be controlled by a programmable timer - via sysfs. If unsure, say Y. + via sysfs. Some LED hardware can be programmed to start + blinking the LED without any further software interaction. + For more details read Documentation/leds-class.txt. + + If unsure, say Y. config LEDS_TRIGGER_IDE_DISK bool "LED IDE Disk Trigger" diff --git a/drivers/leds/ledtrig-timer.c b/drivers/leds/ledtrig-timer.c index ed9ff02c77ea..82c55d6e4902 100644 --- a/drivers/leds/ledtrig-timer.c +++ b/drivers/leds/ledtrig-timer.c @@ -77,8 +77,21 @@ static ssize_t led_delay_on_store(struct device *dev, count++; if (count == size) { - timer_data->delay_on = state; - mod_timer(&timer_data->timer, jiffies + 1); + if (timer_data->delay_on != state) { + /* the new value differs from the previous */ + timer_data->delay_on = state; + + /* deactivate previous settings */ + del_timer_sync(&timer_data->timer); + + /* try to activate hardware acceleration, if any */ + if (!led_cdev->blink_set || + led_cdev->blink_set(led_cdev, + &timer_data->delay_on, &timer_data->delay_off)) { + /* no hardware acceleration, blink via timer */ + mod_timer(&timer_data->timer, jiffies + 1); + } + } ret = count; } @@ -110,8 +123,21 @@ static ssize_t led_delay_off_store(struct device *dev, count++; if (count == size) { - timer_data->delay_off = state; - mod_timer(&timer_data->timer, jiffies + 1); + if (timer_data->delay_off != state) { + /* the new value differs from the previous */ + timer_data->delay_off = state; + + /* deactivate previous settings */ + del_timer_sync(&timer_data->timer); + + /* try to activate hardware acceleration, if any */ + if (!led_cdev->blink_set || + led_cdev->blink_set(led_cdev, + &timer_data->delay_on, &timer_data->delay_off)) { + /* no hardware acceleration, blink via timer */ + mod_timer(&timer_data->timer, jiffies + 1); + } + } ret = count; } @@ -143,6 +169,13 @@ static void timer_trig_activate(struct led_classdev *led_cdev) if (rc) goto err_out_delayon; + /* If there is hardware support for blinking, start one + * user friendly blink rate chosen by the driver. + */ + if (led_cdev->blink_set) + led_cdev->blink_set(led_cdev, + &timer_data->delay_on, &timer_data->delay_off); + return; err_out_delayon: |