Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753323AbcCAViN (ORCPT ); Tue, 1 Mar 2016 16:38:13 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36096 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752052AbcCAVhH (ORCPT ); Tue, 1 Mar 2016 16:37:07 -0500 From: Heiner Kallweit Subject: [PATCH v5 4/4] leds: core: add support for RGB LED's To: Jacek Anaszewski Cc: linux-leds@vger.kernel.org, Benjamin Tissoires , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <56D60B4C.5000506@gmail.com> Date: Tue, 1 Mar 2016 22:36:12 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3136 Lines: 107 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 --- 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); + ret = led_classdev_next_name(led_cdev->name, name, sizeof(name)); if (ret < 0) return ret; diff --git a/drivers/leds/led-rgb-core.c b/drivers/leds/led-rgb-core.c index f6591f1..2b18d4c 100644 --- a/drivers/leds/led-rgb-core.c +++ b/drivers/leds/led-rgb-core.c @@ -38,3 +38,39 @@ enum led_brightness led_confine_brightness(struct led_classdev *led_cdev, return brightness | min(value & LED_BRIGHTNESS_MASK, led_cdev->max_brightness); } + +enum led_brightness led_hsv_to_rgb(enum led_brightness hsv) +{ + int h = min_t(int, (hsv >> 16) & 0xff, 251); + int s = (hsv >> 8) & 0xff; + int v = hsv & 0xff; + int f, p, q, t, r, g, b; + + if (!v) + return 0; + if (!s) + return (v << 16) + (v << 8) + v; + + f = DIV_ROUND_CLOSEST((h % 42) * 255, 42); + p = v - DIV_ROUND_CLOSEST(s * v, 255); + q = v - DIV_ROUND_CLOSEST(f * s * v, 255 * 255); + t = v - DIV_ROUND_CLOSEST((255 - f) * s * v, 255 * 255); + + switch (h / 42) { + case 0: + r = v; g = t; b = p; break; + case 1: + r = q; g = v; b = p; break; + case 2: + r = p; g = v; b = t; break; + case 3: + r = p; g = q; b = v; break; + case 4: + r = t; g = p; b = v; break; + case 5: + r = v; g = p; b = q; break; + } + + return (r << 16) + (g << 8) + b; +} +EXPORT_SYMBOL_GPL(led_hsv_to_rgb); diff --git a/include/linux/leds.h b/include/linux/leds.h index bbf24bb..82b3477 100644 --- a/include/linux/leds.h +++ b/include/linux/leds.h @@ -226,6 +226,14 @@ static inline bool led_sysfs_is_disabled(struct led_classdev *led_cdev) return led_cdev->flags & LED_SYSFS_DISABLE; } +/** + * led_hsv_to_rgb - convert a hsv color value to rgb color model + * @hsv: the hsv value to convert + * + * Returns: the resulting rgb value + */ +enum led_brightness led_hsv_to_rgb(enum led_brightness hsv); + /* * LED Triggers */ -- 2.7.1