On Fri, 23 Feb 2024, Lee Jones wrote:
> On Mon, 09 Jan 2023, Uwe Kleine-König wrote:
>
> > Hello Jürgen,
> >
> > On Mon, May 03, 2021 at 11:25:42AM +0200, Juergen Borleis wrote:
> > > Using led_set_brightness_sync() only works for LEDs which are connected
> > > via some kind of external bus like I²C or SPI. But it doesn't work for
> > > the simple use case of directly connected LEDs via GPIOs.
> > > Because this function only honors the led_classdev::brightness_set_blocking
> > > callback. But the LED-GPIO driver registers the
> > > led_classdev::brightness_set member if the GPIO can be modified directly
> > > and thus, TTY triggers fail silently with -ENOTSUPP.
> > >
> > > With the previously used led_set_brightness() it works for both use cases.
> > > This function first checks for the simple case where the GPIO can be changed
> > > without additional overhead, and if it fails, does the modification via a
> > > workqueue.
> > >
> > > Signed-off-by: Juergen Borleis <jbe@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/leds/trigger/ledtrig-tty.c | 4 ++--
> > > 1 file changed, 2 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c
> > > index f62db7e..af61281 100644
> > > --- a/drivers/leds/trigger/ledtrig-tty.c
> > > +++ b/drivers/leds/trigger/ledtrig-tty.c
> > > @@ -122,12 +122,12 @@ static void ledtrig_tty_work(struct work_struct *work)
> > >
> > > if (icount.rx != trigger_data->rx ||
> > > icount.tx != trigger_data->tx) {
> > > - led_set_brightness_sync(trigger_data->led_cdev, LED_ON);
> > > + led_set_brightness(trigger_data->led_cdev, LED_ON);
> > >
> > > trigger_data->rx = icount.rx;
> > > trigger_data->tx = icount.tx;
> > > } else {
> > > - led_set_brightness_sync(trigger_data->led_cdev, LED_OFF);
> > > + led_set_brightness(trigger_data->led_cdev, LED_OFF);
> > > }
> >
> > This problem still exists, right?
> >
> > I think the right thing here is to call led_set_brightness_nosleep()
> > however.
> >
> > Having said that, I think there are too many variants of
> > led_set_brightness which makes it difficult to pick the right one.
> >
> > (I'm aware of
> > - led_set_brightness_nosleep
> > - led_set_brightness_nopm
> > - led_set_brightness_sync
> > - led_set_brightness
> >
> > and there are a few more static variants in led-core.c
> > (__led_set_brightness, __led_set_brightness_blocking,
> > set_brightness_delayed).)
>
> This patch (and this response) was never sent to me.
>
> Not a great deal I can do if I'm not aware of it.
Starting to think I've gone too far back in the LEDs ML's history? =;-)
--
Lee Jones [李琼斯]
