Messages in this thread | | | Date | Wed, 30 Mar 2016 10:00:07 +0200 | From | Jacek Anaszewski <> | Subject | Re: [PATCH v5 4/4] leds: core: add support for RGB LED's |
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On 03/29/2016 10:42 PM, Heiner Kallweit wrote: > Am 29.03.2016 um 12:05 schrieb Pavel Machek: >> On Tue 2016-03-01 22:36:12, Heiner Kallweit wrote: >>> Export a function to convert HSV color values to RGB. >>> It's intended to be called by drivers for RGB LEDs. >>> >>> Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> >>> --- >>> v2: >>> - move hsv -> rgb conversion to separate file >>> - remove flag LED_DEV_CAP_RGB >>> v3: >>> - call led_hsv_to_rgb only if LED_DEV_CAP_HSV is set >>> This is needed in cases when we have monochrome and color LEDs >>> as well in a system. >>> v4: >>> - Export led_hsv_to_rgb and let the device driver call it instead >>> of doing the conversion in the core >>> v5: >>> - don't ignore led_cdev->brightness_get silently if LED_DEV_CAP_RGB >>> is set but warn >>> --- >>> drivers/leds/led-class.c | 7 +++++++ >>> drivers/leds/led-rgb-core.c | 36 ++++++++++++++++++++++++++++++++++++ >>> include/linux/leds.h | 8 ++++++++ >>> 3 files changed, 51 insertions(+) >>> >>> diff --git a/drivers/leds/led-class.c b/drivers/leds/led-class.c >>> index 8a3748a..a4b144e 100644 >>> --- a/drivers/leds/led-class.c >>> +++ b/drivers/leds/led-class.c >>> @@ -193,6 +193,13 @@ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) >>> char name[64]; >>> int ret; >>> >>> + /* >>> + * for now reading back the color is not supported as multiple >>> + * HSV -> RGB -> HSV conversions may distort the color due to >>> + * rounding issues in the conversion algorithm >>> + */ >>> + WARN_ON(led_cdev->flags & LED_DEV_CAP_RGB && led_cdev->brightness_get); >>> + >> >> Backtrace is useless here, you may want to add some ()s and you don't >> really want user to be causing messages in syslog this easily. >> > I agree that the backtrace doesn't provide a benefit here.
I requested it to provide a verbose notification for a LED RGB class driver developer, in case they try to implement a brightness_get op, which would be harmful in case of HSV interface for RGB LEDs.
> However I don't see how a user could create syslog entries. > The warn condition can be true only for drivers implementing the RGB extension > in a not supported way (by setting flag LED_DEV_CAP_RGB and implementing > brightness_get). > > Pavel >> > > >
-- Best regards, Jacek Anaszewski
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