| Message ID | 1446133906-3076-1-git-send-email-p.zabel@pengutronix.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, 29 Oct 2015, Philipp Zabel wrote: > 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@pengutronix.de> > Reviewed-by: Christian Gmeiner <christian.gmeiner@gmail.com> > --- > Changes since v2: > - Leave GPIO configuration as is (GPIOD_ASIS) when requesting, > so we can actually check the initial state. > --- > drivers/video/backlight/pwm_bl.c | 25 ++++++++++++++++++++++++- > 1 file changed, 24 insertions(+), 1 deletion(-) > > diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c > index ae3c6b6..8e9c261 100644 > --- a/drivers/video/backlight/pwm_bl.c > +++ b/drivers/video/backlight/pwm_bl.c > @@ -199,6 +199,8 @@ 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; > + bool phandle; > int ret; > > if (!data) { > @@ -242,7 +244,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) > pb->enabled = false; > > pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", > - GPIOD_OUT_HIGH); > + GPIOD_ASIS); > if (IS_ERR(pb->enable_gpio)) { > ret = PTR_ERR(pb->enable_gpio); > goto err_alloc; > @@ -264,12 +266,32 @@ static int pwm_backlight_probe(struct platform_device *pdev) > pb->enable_gpio = gpio_to_desc(data->enable_gpio); > } > > + phandle = of_find_property(pdev->dev.of_node, "phandle", NULL) != NULL; This is a little ugly. If this is the only way to identify the probedness of a device then you probably want to neaten it up a little. I suggest something along the lines of: if (of_find_property(pdev->dev.of_node, "phandle", NULL)) already_probed = true; Also, do you also want to check for "linux,phandle", as this is always catered for in drivers/of/* > + 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 (phandle && > + 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)) { > ret = PTR_ERR(pb->power_supply); > goto err_alloc; > } > > + if (phandle && !regulator_is_enabled(pb->power_supply)) > + initial_blank = FB_BLANK_POWERDOWN; > + > pb->pwm = devm_pwm_get(&pdev->dev, NULL); > if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER > && !pdev->dev.of_node) { > @@ -320,6 +342,7 @@ 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);
Hi Lee, Am Freitag, den 30.10.2015, 18:21 +0000 schrieb Lee Jones: > > @@ -264,12 +266,32 @@ static int pwm_backlight_probe(struct platform_device *pdev) > > pb->enable_gpio = gpio_to_desc(data->enable_gpio); > > } > > > > + phandle = of_find_property(pdev->dev.of_node, "phandle", NULL) != NULL; > > This is a little ugly. > > If this is the only way to identify the probedness of a device then > you probably want to neaten it up a little. I suggest something along > the lines of: > > if (of_find_property(pdev->dev.of_node, "phandle", NULL)) > already_probed = true; > > Also, do you also want to check for "linux,phandle", as this is always > catered for in drivers/of/* Thanks for pointing this out. I suppose I should just check pdev->dev.of_node->phandle != 0 instead. That will already be initialized by unflatten_dt_node if either property was found. regards Philipp -- 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
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index ae3c6b6..8e9c261 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -199,6 +199,8 @@ 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; + bool phandle; int ret; if (!data) { @@ -242,7 +244,7 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enabled = false; pb->enable_gpio = devm_gpiod_get_optional(&pdev->dev, "enable", - GPIOD_OUT_HIGH); + GPIOD_ASIS); if (IS_ERR(pb->enable_gpio)) { ret = PTR_ERR(pb->enable_gpio); goto err_alloc; @@ -264,12 +266,32 @@ static int pwm_backlight_probe(struct platform_device *pdev) pb->enable_gpio = gpio_to_desc(data->enable_gpio); } + phandle = of_find_property(pdev->dev.of_node, "phandle", NULL) != NULL; + + 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 (phandle && + 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)) { ret = PTR_ERR(pb->power_supply); goto err_alloc; } + if (phandle && !regulator_is_enabled(pb->power_supply)) + initial_blank = FB_BLANK_POWERDOWN; + pb->pwm = devm_pwm_get(&pdev->dev, NULL); if (IS_ERR(pb->pwm) && PTR_ERR(pb->pwm) != -EPROBE_DEFER && !pdev->dev.of_node) { @@ -320,6 +342,7 @@ 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);