lkml.org 
[lkml]   [2011]   [Jan]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RESEND #2] [PATCH v2] LEDS: Add output invertion option to backlight trigger
    (Trying an alternate address for Richard, and adding Andrew to Cc..)

    On Thu, Dec 09, 2010 at 02:41:50PM +0100, Janusz Krzysztofik wrote:
    > This patch extends the LED backlight tirgger driver with an option that allows
    > for inverting the trigger output polarity.
    >
    > With the invertion option provided, I (ab)use the backlight trigger for
    > driving a LED that indicates LCD display blank condtition on my Amstrad Delta
    > videophone. Since the machine has no dedicated power LED, it was not possible
    > to distinguish if the display was blanked, or the machine was turned off,
    > without touching it.
    >
    > The invert sysfs control is patterned after a similiar function of the GPIO
    > trigger driver.
    >
    > Created and tested against linux-2.6.36-rc5 on Amstrad Delta.
    > Retested on linux-2.6.37-rc4.
    >
    > Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
    > Cc: Richard Purdie <rpurdie@rpsys.net>
    > ---
    >
    > Resent because I still can't see any response received, while yet another
    > merge window is going to pass away soon.
    >
    > Applies cleanly on top of 2.6.37-rc4, so no need for yet another refresh. Only
    > tried to clean up the commit message slightly - maybe my English is not good
    > enough to bother with, if not the code?
    >
    > v1 -> v2 changes:
    > - improve some conditional expressions to be more readable; thanks to Ralph
    > Corderoy (from e3-hacking) and Lars-Peter Clausen for their suggestions,
    > - refresh against linux-2.6.36-rc5.
    >
    > drivers/leds/ledtrig-backlight.c | 60
    > ++++++++++++++++++++++++++++++++++++---
    > 1 file changed, 56 insertions(+), 4 deletions(-)
    >
    > diff -upr linux-2.6.36-rc5.orig/drivers/leds/ledtrig-backlight.c linux-2.6.36-rc5/drivers/leds/ledtrig-backlight.c
    > --- linux-2.6.36-rc5.orig/drivers/leds/ledtrig-backlight.c 2010-09-24 15:35:13.000000000 +0200
    > +++ linux-2.6.36-rc5/drivers/leds/ledtrig-backlight.c 2010-10-03 15:59:49.000000000 +0200
    > @@ -26,6 +26,7 @@ struct bl_trig_notifier {
    > int brightness;
    > int old_status;
    > struct notifier_block notifier;
    > + unsigned invert;
    > };
    >
    > static int fb_notifier_callback(struct notifier_block *p,
    > @@ -36,23 +37,63 @@ static int fb_notifier_callback(struct n
    > struct led_classdev *led = n->led;
    > struct fb_event *fb_event = data;
    > int *blank = fb_event->data;
    > + int new_status = *blank ? BLANK : UNBLANK;
    >
    > switch (event) {
    > case FB_EVENT_BLANK :
    > - if (*blank && n->old_status == UNBLANK) {
    > + if (new_status == n->old_status)
    > + break;
    > +
    > + if ((n->old_status == UNBLANK) ^ n->invert) {
    > n->brightness = led->brightness;
    > led_set_brightness(led, LED_OFF);
    > - n->old_status = BLANK;
    > - } else if (!*blank && n->old_status == BLANK) {
    > + } else {
    > led_set_brightness(led, n->brightness);
    > - n->old_status = UNBLANK;
    > }
    > +
    > + n->old_status = new_status;
    > +
    > break;
    > }
    >
    > return 0;
    > }
    >
    > +static ssize_t bl_trig_invert_show(struct device *dev,
    > + struct device_attribute *attr, char *buf)
    > +{
    > + struct led_classdev *led = dev_get_drvdata(dev);
    > + struct bl_trig_notifier *n = led->trigger_data;
    > +
    > + return sprintf(buf, "%s\n", n->invert ? "yes" : "no");
    > +}
    > +
    > +static ssize_t bl_trig_invert_store(struct device *dev,
    > + struct device_attribute *attr, const char *buf, size_t num)
    > +{
    > + struct led_classdev *led = dev_get_drvdata(dev);
    > + struct bl_trig_notifier *n = led->trigger_data;
    > + unsigned invert;
    > + int ret;
    > +
    > + ret = sscanf(buf, "%u", &invert);
    > + if (ret < 1) {
    > + dev_err(dev, "invalid value\n");
    > + return -EINVAL;
    > + }
    > +
    > + n->invert = !!invert;
    > +
    > + /* After inverting, we need to update the LED. */
    > + if ((n->old_status == BLANK) ^ n->invert)
    > + led_set_brightness(led, LED_OFF);
    > + else
    > + led_set_brightness(led, n->brightness);
    > +
    > + return num;
    > +}
    > +static DEVICE_ATTR(invert, 0644, bl_trig_invert_show, bl_trig_invert_store);
    > +
    > static void bl_trig_activate(struct led_classdev *led)
    > {
    > int ret;
    > @@ -66,6 +107,10 @@ static void bl_trig_activate(struct led_
    > return;
    > }
    >
    > + ret = device_create_file(led->dev, &dev_attr_invert);
    > + if (ret)
    > + goto err_invert;
    > +
    > n->led = led;
    > n->brightness = led->brightness;
    > n->old_status = UNBLANK;
    > @@ -74,6 +119,12 @@ static void bl_trig_activate(struct led_
    > ret = fb_register_client(&n->notifier);
    > if (ret)
    > dev_err(led->dev, "unable to register backlight trigger\n");
    > +
    > + return;
    > +
    > +err_invert:
    > + led->trigger_data = NULL;
    > + kfree(n);
    > }
    >
    > static void bl_trig_deactivate(struct led_classdev *led)
    > @@ -82,6 +133,7 @@ static void bl_trig_deactivate(struct le
    > (struct bl_trig_notifier *) led->trigger_data;
    >
    > if (n) {
    > + device_remove_file(led->dev, &dev_attr_invert);
    > fb_unregister_client(&n->notifier);
    > kfree(n);
    > }
    > --
    > To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in
    > the body of a message to majordomo@vger.kernel.org
    > More majordomo info at http://vger.kernel.org/majordomo-info.html


    \
     
     \ /
      Last update: 2011-01-06 08:13    [W:0.066 / U:0.164 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site