Hi, Am Freitag, den 12.06.2015, 18:26 +0200 schrieb Philipp Zabel: > If the driver is probed from the device tree, and there is a phandle > property set on it, and the enable GPIO is already configured as output, > and the backlight is currently disabled, keep it disabled. > If all these conditions are met, assume there will be some other driver > that can enable the backlight at the appropriate time. > > Signed-off-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > --- > I have seen the thread at https://lkml.org/lkml/2014/7/31/259, but I'm not > sure if it has come to a resolution. This is what I think could be useful > to keep the current default behaviour of enabling the backlight while at the > same time allowing to keep it disabled if we are absolutely certain that the > backlight is currently off, and we think there is some other driver that will > control it: do you have any comments on this? Would the conditions mentioned above be sufficient for your use cases? best regards Philipp > --- > drivers/video/backlight/pwm_bl.c | 19 +++++++++++++++++-- > 1 file changed, 17 insertions(+), 2 deletions(-) > > diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c > index 6897f1c..dcb6bfb 100644 > --- a/drivers/video/backlight/pwm_bl.c > +++ b/drivers/video/backlight/pwm_bl.c > @@ -199,6 +199,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) > struct backlight_properties props; > struct backlight_device *bl; > struct pwm_bl_data *pb; > + int initial_blank = FB_BLANK_UNBLANK; > int ret; > > if (!data) { > @@ -263,8 +264,21 @@ static int pwm_backlight_probe(struct platform_device *pdev) > pb->enable_gpio = gpio_to_desc(data->enable_gpio); > } > > - if (pb->enable_gpio) > - gpiod_direction_output(pb->enable_gpio, 1); > + if (pb->enable_gpio) { > + /* > + * If the driver is probed from the device tree and there is a > + * phandle link pointing to the backlight node, it is safe to > + * assume that another driver will enable the backlight at the > + * appropriate time. Therefore, if it is disabled, keep it so. > + */ > + if (of_find_property(pdev->dev.of_node, "phandle", NULL) && > + gpiod_get_direction(pb->enable_gpio) == GPIOF_DIR_OUT && > + gpiod_get_value(pb->enable_gpio) == 0) { > + initial_blank = FB_BLANK_POWERDOWN; > + } else { > + gpiod_direction_output(pb->enable_gpio, 1); > + } > + } > > pb->power_supply = devm_regulator_get(&pdev->dev, "power"); > if (IS_ERR(pb->power_supply)) { > @@ -323,6 +337,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) > } > > bl->props.brightness = data->dft_brightness; > + bl->props.power = initial_blank; > backlight_update_status(bl); > > platform_set_drvdata(pdev, bl); -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
