Re: [PATCH 1/2] leds: add DT support for LEDs wired to supply and default brightness
From: Bryan Wu <hidden>
Date: 2014-03-27 22:28:32
Also in:
linux-arm-kernel, linux-leds
On Fri, Feb 28, 2014 at 1:25 PM, Russell King [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Some PWM outputs are wired such that the LED they're controlling is connected to supply rather than ground. Therefore, the duty cycle needs to be inverted to make the LED behave as it should do. We also provide a way to specify the default brightness when a trigger is not specified. Signed-off-by: Russell King <redacted> --- Documentation/devicetree/bindings/leds/leds-pwm.txt | 3 +++ drivers/leds/leds-pwm.c | 15 +++++++++++---- 2 files changed, 14 insertions(+), 4 deletions(-)diff --git a/Documentation/devicetree/bindings/leds/leds-pwm.txt b/Documentation/devicetree/bindings/leds/leds-pwm.txt index 7297107cf832..ffcb74ab61fd 100644 --- a/Documentation/devicetree/bindings/leds/leds-pwm.txt +++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt@@ -13,6 +13,9 @@ node's name represents the name of the corresponding LED. For the pwms and pwm-names property please refer to: Documentation/devicetree/bindings/pwm/pwm.txt - max-brightness : Maximum brightness possible for the LED +- default-brightness : (optional) Default brightness for the LED +- active-low : (optional) For PWMs where the LED is wired to supply + rather than ground. - label : (optional) see Documentation/devicetree/bindings/leds/common.txt - linux,default-trigger : (optional)
Why remove "max-brightness", "label" and "linux,default-trigger" here?
I believe you're still using them in your second patch like
+ front {
+ active-low;
+ default-brightness = <128>;
+ label = "imx6:red:front";
+ max-brightness = <248>;
+ pwms = <&pwm1 0 50000>;
+ };
Others are good to me.
Thierry, could you please review this patchset?
Thanks,
-Bryan
quoted hunk ↗ jump to hunk
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c index 605047428b5a..fe2cd849b593 100644 --- a/drivers/leds/leds-pwm.c +++ b/drivers/leds/leds-pwm.c@@ -70,6 +70,10 @@ static void led_pwm_set(struct led_classdev *led_cdev, duty *= brightness; do_div(duty, max); + + if (led_dat->active_low) + duty = led_dat->period - duty; + led_dat->duty = duty; if (led_dat->can_sleep)@@ -93,6 +97,10 @@ static int led_pwm_create_of(struct platform_device *pdev, for_each_child_of_node(pdev->dev.of_node, child) { struct led_pwm_data *led_dat = &priv->leds[priv->num_leds]; + led_dat->cdev.brightness_set = led_pwm_set; + led_dat->cdev.brightness = LED_OFF; + led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; + led_dat->cdev.name = of_get_property(child, "label", NULL) ? : child->name;@@ -110,10 +118,9 @@ static int led_pwm_create_of(struct platform_device *pdev, "linux,default-trigger", NULL); of_property_read_u32(child, "max-brightness", &led_dat->cdev.max_brightness); - - led_dat->cdev.brightness_set = led_pwm_set; - led_dat->cdev.brightness = LED_OFF; - led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; + of_property_read_u32(child, "default-brightness", + &led_dat->cdev.brightness); + led_dat->active_low = of_property_read_bool(child, "active-low"); led_dat->can_sleep = pwm_can_sleep(led_dat->pwm); if (led_dat->can_sleep) --1.8.3.1