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[83.28.187.243]) by smtp.gmail.com with ESMTPSA id a2sm10499002wrt.45.2019.10.10.11.36.57 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 10 Oct 2019 11:36:58 -0700 (PDT) Subject: Re: [PATCH v11 04/16] leds: multicolor: Introduce a multicolor class definition To: Dan Murphy , pavel@ucw.cz Cc: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org References: <20191008204800.19870-1-dmurphy@ti.com> <20191008204800.19870-5-dmurphy@ti.com> From: Jacek Anaszewski Openpgp: preference=signencrypt Autocrypt: addr=jacek.anaszewski@gmail.com; prefer-encrypt=mutual; keydata= mQINBFWjfaEBEADd66EQbd6yd8YjG0kbEDT2QIkx8C7BqMXR8AdmA1OMApbfSvEZFT1D/ECR eWFBS8XtApKQx1xAs1j5z70k3zebk2eeNs5ahxi6vM4Qh89vBM46biSKeeX5fLcv7asmGb/a FnHPAfQaKFyG/Bj9V+//ef67hpjJWR3s74C6LZCFLcbZM0z/wTH+baA5Jwcnqr4h/ygosvhP X3gkRzJLSFYekmEv+WHieeKXLrJdsUPUvPJTZtvi3ELUxHNOZwX2oRJStWpmL2QGMwPokRNQ 29GvnueQdQrIl2ylhul6TSrClMrKZqOajDFng7TLgvNfyVZE8WQwmrkTrdzBLfu3kScjE14Q Volq8OtQpTsw5570D4plVKh2ahlhrwXdneSot0STk9Dh1grEB/Jfw8dknvqkdjALUrrM45eF FM4FSMxIlNV8WxueHDss9vXRbCUxzGw37Ck9JWYo0EpcpcvwPf33yntYCbnt+RQRjv7vy3w5 osVwRR4hpbL/fWt1AnZ+RvbP4kYSptOCPQ+Pp1tCw16BOaPjtlqSTcrlD2fo2IbaB5D21SUa IsdZ/XkD+V2S9jCrN1yyK2iKgxtDoUkWiqlfRgH2Ep1tZtb4NLF/S0oCr7rNLO7WbqLZQh1q ShfZR16h7YW//1/NFwnyCVaG1CP/L/io719dPWgEd/sVSKT2TwARAQABtC1KYWNlayBBbmFz emV3c2tpIDxqYWNlay5hbmFzemV3c2tpQGdtYWlsLmNvbT6JAlgEEwEIAEICGwMHCwkIBwMC AQYVCAIJCgsDFgIBAh4BAheABQkJZgNMFiEEvx38ClaPBfeVdXCQvWpQHLeLfCYFAl05/9sC GQEACgkQvWpQHLeLfCarMQ/9FN/WqJdN2tf6xkP0RFyS4ft0sT04zkOCFfOMxs8mZ+KZoMU+ X3a+fEppDL7xgRFpHyGaEel7lSi1eqtzsqZ5JiHbDS1Ht1G8TtATb8q8id68qeSeW2mfzaLQ 98NPELGfUXFoUqUQkG5z2p92UrGF4Muj1vOIW93pwvE4uDpNsl+jriwHomLtjIUoZtIRjGfZ RCyUQI0vi5LYzXCebuzAjGD7Jh2YAp7fDGrv3qTq8sX+DUJ4H/+I8PiL+jXKkEeppqIhlBJJ l4WcgggMu3c2uljYDuqRYghte33BXyCPAocfO2/sN+yJRUTVuRFlOxUk4srz/W8SQDwOAwtK V7TzdyF1/jOGBxWwS13EjMb4u3XwPMzcPlEQNdIqz76NFmJ99xYEvgkAmFmRioxuBTRv8Fs1 c1jQ00WWJ5vezqY6lccdDroPalXWeFzfPjIhKbV3LAYTlqv0It75GW9+0TBhPqdTM15DrCVX B7Ues7UnD5FBtWwewTnwr+cu8te449VDMzN2I+a9YKJ1s6uZmzh5HnuKn6tAfGyQh8MujSOM lZrNHrRsIsLXOjeGVa84Qk/watEcOoyQ7d+YaVosU0OCZl0GldvbGp1z2u8cd2N/HJ7dAgFh Q7dtGXmdXpt2WKQvTvQXhIrCWVQErNYbDZDD2V0TZtlPBaZP4fkUDkvH+Sy5Ag0EVaN9oQEQ AMPNymBNoCWc13U6qOztXrIKBVsLGZXq/yOaR2n7gFbFACD0TU7XuH2UcnwvNR+uQFwSrRqa EczX2V6iIy2CITXKg5Yvg12yn09gTmafuoIyKoU16XvC3aZQQ2Bn3LO2sRP0j/NuMD9GlO37 pHCVRpI2DPxFE39TMm1PLbHnDG8+lZql+dpNwWw8dDaRgyXx2Le542CcTBT52VCeeWDtqd2M wOr4LioYlfGfAqmwcwucBdTEBUxklQaOR3VbJQx6ntI2oDOBlNGvjnVDzZe+iREd5l40l+Oj TaiWvBGXkv6OI+wx5TFPp+BM6ATU+6UzFRTUWbj+LqVA/JMqYHQp04Y4H5GtjbHCa8abRvBw IKEvpwTyWZlfXPtp8gRlNmxYn6gQlTyEZAWodXwE7CE+KxNnq7bPHeLvrSn8bLNK682PoTGr 0Y00bguYLfyvEwuDYek1/h9YSXtHaCR3CEj4LU1B561G1j7FVaeYbX9bKBAoy/GxAW8J5O1n mmw7FnkSHuwO/QDe0COoO0QZ620Cf9IBWYHW4m2M2yh5981lUaiMcNM2kPgsJFYloFo2XGn6 lWU9BrWjEoNDhHZtF+yaPEuwjZo6x/3E2Tu3E5Jj0VpVcE9U1Zq/fquDY79l2RJn5ENogOs5 +Pi0GjVpEYQVWfm0PTCxNPOzOzGR4QB3BNFvABEBAAGJAiUEGAEIAA8FAlWjfaECGwwFCQlm AYAACgkQvWpQHLeLfCZqGxAAlWBWVvjU6xj70GwengiqYZwmW1i8gfS4TNibQT/KRq0zkBnE wgKwXRbVoW38pYVuGa5x/JDQMJDrLAJ0wrCOS3XxbSHCWOl/k2ZD9OaxUeXq6N+OmGTzfrYv PUvWS1Hy04q9AD1dIaMNruZQmvnRfkOk2UDncDIg0166/NTHiYI09H5mpWGpHn/2aT6dmpVw uoM9/rHlF5s5qAAo95tZ0QW2BtIceG9/rbYlL57waSMPF49awvwLQX5RhWoF8mPS5LsBrXXK hmizIsn40tLbi2RtWjzDWgZYitqmmqijeCnDvISN4qJ/nCLO4DjiSGs59w5HR+l0nwePDhOC A4RYZqS1e2Clx1VSkDXFpL3egabcIsqK7CZ6a21r8lXVpo4RnMlQsmXZTnRx4SajFvX7PrRg /02C811fLfh2r5O5if8sKQ6BKKlHpuuioqfj/w9z3B0aQ71e4n1zNJBO1kcdznikPLAbr7jG gkBUXT1yJiwpTfRQr5y2Uo12IJsKxohnNFVYtK8X/R6S0deKPjrZWvAkllgIPcHjMi2Va8yw KTj/JgcpUO5KN906Pf7ywZISe7Kbcc/qnE0YjPPSqFOvoeZvHe6EZCMW9+xZsaipvlqpByQV UHnVg09K9YFvjUBsBPdC8ef6YwgfR9o6AnPmxl0oMUIXkCCC5c99fzJY/k+JAq0EGAEIACAW IQS/HfwKVo8F95V1cJC9alAct4t8JgUCWwqKhgIbAgCBCRC9alAct4t8JnYgBBkWCAAdFiEE FMMcSshOZf56bfAEYhBsURv0pdsFAlsKioYACgkQYhBsURv0pdvELgD/U+y3/hsz0bIjMQJY 0LLxM/rFY9Vz1L43+lQHXjL3MPsA/1lNm5sailsY7aFBVJxAzTa8ZAGWBdVaGo6KCvimDB8G 7joP/jx+oGOmdRogs7mG//H+w9DTnBfPpnfkeiiokGYo/+huWO5V0Ac9tTqZeFc//t/YuYJn wWvS0Rx+KL0fT3eh9BQo47uF4yDiZIiWLNh4Agpup1MUSVsz4MjD0lW6ghtnLcGlIgoVHW0v tPW1m9jATYyJSOG/MC1iDrcYcp9uVYn5tKfkEeQNspuG6iSfS0q3tajPKnT1nJxMTxVOD2RW EIGfaV9Scrou92VD/eC+/8INRsiWS93j3hOKIAV5XRNINFqtzkagPYAP8r6wksjSjh01fSTB p5zxjfsIwWDDzDrqgzwv83CvrLXRV3OlG1DNUDYA52qJr47paH5QMWmHW5TNuoBX8qb6RW/H M3DzPgT+l+r1pPjMPfvL1t7civZUoPuNzoyFpQRj6TvWi2bGGMQKryeYksXG2zi2+avMFnLe lOxGdUZ7jn1SJ6Abba5WL3VrXCP+TUE6bZLgfw8kYa8QSXP3ysyeMI0topHFntBZ8a0KXBNs qqFCBWmTHXfwsfW0VgBmRtPO7eXVBybjJ1VXKR2RZxwSq/GoNXh/yrRXQxbcpZ+QP3/Tttsb FdKciZ4u3ts+5UwYra0BRuvb51RiZR2wRNnUeBnXWagJVTlG7RHBO/2jJOE6wrcdCMjs0Iiw PNWmiVoZA930TvHA5UeGENxdGqo2MvMdRJ54YaIR Message-ID: <8ced5374-0e8a-34d0-a8c8-796de3f2f433@gmail.com> Date: Thu, 10 Oct 2019 20:36:56 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-leds-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org Dan, On 10/10/19 2:27 AM, Dan Murphy wrote: > Jacek > > On 10/9/19 4:47 PM, Jacek Anaszewski wrote: >> Dan, >> >> On 10/8/19 10:47 PM, Dan Murphy wrote: >>> Introduce a multicolor class that groups colored LEDs >>> within a LED node. >>> >>> The multi color class groups monochrome LEDs and allows controlling two >>> aspects of the final combined color: hue and lightness. The former is >>> controlled via _intensity files and the latter is controlled >>> via brightness file. >>> >>> Signed-off-by: Dan Murphy >>> --- >>>   .../ABI/testing/sysfs-class-led-multicolor    |  35 +++ >>>   Documentation/leds/index.rst                  |   1 + >>>   Documentation/leds/leds-class-multicolor.rst  |  96 +++++++ >>>   drivers/leds/Kconfig                          |  10 + >>>   drivers/leds/Makefile                         |   1 + >>>   drivers/leds/led-class-multicolor.c           | 271 ++++++++++++++++++ >>>   include/linux/led-class-multicolor.h          | 143 +++++++++ >>>   7 files changed, 557 insertions(+) >>>   create mode 100644 >>> Documentation/ABI/testing/sysfs-class-led-multicolor >>>   create mode 100644 Documentation/leds/leds-class-multicolor.rst >>>   create mode 100644 drivers/leds/led-class-multicolor.c >>>   create mode 100644 include/linux/led-class-multicolor.h >>> >>> diff --git a/Documentation/ABI/testing/sysfs-class-led-multicolor >>> b/Documentation/ABI/testing/sysfs-class-led-multicolor >>> new file mode 100644 >>> index 000000000000..65cb43de26e6 >>> --- /dev/null >>> +++ b/Documentation/ABI/testing/sysfs-class-led-multicolor >>> @@ -0,0 +1,35 @@ >>> +What:        /sys/class/leds//brightness >>> +Date:        Sept 2019 >>> +KernelVersion:    5.5 >>> +Contact:    Dan Murphy >>> +Description:    read/write >>> +        Writing to this file will update all LEDs within the group to a >>> +        calculated percentage of what each color LED intensity is set >>> +        to. The percentage is calculated via the equation below: >>> + >>> +        led_brightness = brightness * >>> _intensity/_max_intensity >> This equation alone incites questions on how it is supposed to work. >> >> It would be better to present the whole algorithm for calculating >> combined color here. > > I am not sure I follow.  Isn't that explained in the class document? I just think that this document should contain all necessary info for the reader to understand the effect of writing brightness. Looking once more it seems that slight modification of the last sentence above equation could suffice: s/is calculated/is calculated for each grouped LED/ >>> + >>> +        For additional details please refer to >>> +        Documentation/leds/leds-class-multicolor.rst. >>> + >>> +        The value of the color is from 0 to >>> +        /sys/class/leds//max_brightness. >>> + >>> +What:        /sys/class/leds//colors/_intensity >>> +Date:        Sept 2019 >>> +KernelVersion:    5.5 >>> +Contact:    Dan Murphy >>> +Description:    read/write >>> +        The _intensity file is created based on the color >>> +        defined by the registrar of the class. >>> +        There is one file per color presented. >>> + >>> +        The value of the color is from 0 to >>> +        /sys/class/leds//colors/_max_intensity. >>> + >>> +What:        /sys/class/leds//colors/_max_intensity >>> +Date:        Sept 2019 >>> +KernelVersion:    5.5 >>> +Contact:    Dan Murphy >>> +Description:    read only >>> +        Maximum intensity level for the LED color. >>> diff --git a/Documentation/leds/index.rst b/Documentation/leds/index.rst >>> index 060f4e485897..bc70c6aa7138 100644 >>> --- a/Documentation/leds/index.rst >>> +++ b/Documentation/leds/index.rst >>> @@ -9,6 +9,7 @@ LEDs >>>        leds-class >>>      leds-class-flash >>> +   leds-class-multicolor >>>      ledtrig-oneshot >>>      ledtrig-transient >>>      ledtrig-usbport >>> diff --git a/Documentation/leds/leds-class-multicolor.rst >>> b/Documentation/leds/leds-class-multicolor.rst >>> new file mode 100644 >>> index 000000000000..7a695a29377e >>> --- /dev/null >>> +++ b/Documentation/leds/leds-class-multicolor.rst >>> @@ -0,0 +1,96 @@ >>> +==================================== >>> +Multi Color LED handling under Linux >>> +==================================== >>> + >>> +Description >>> +=========== >>> +The multi color class groups monochrome LEDs and allows controlling two >>> +aspects of the final combined color: hue and lightness. The former is >>> +controlled via _intensity files and the latter is controlled >>> +via brightness file. >>> + >>> +For more details on hue and lightness notions please refer to >>> +https://en.wikipedia.org/wiki/CIECAM02. >>> + >>> +Note that intensity files only cache the written value and the actual >>> +change of hardware state occurs upon writing brightness file. This >>> +allows for changing many factors of the perceived color in a virtually >>> +unnoticeable way for the human observer. >>> + >>> +Multicolor Class Control >>> +======================== >>> +The multicolor class presents the LED groups under a directory >>> called "colors". >>> +This directory is a child under the LED parent node created by the >>> led_class >>> +framework.  The led_class framework is documented in led-class.rst >>> within this >>> +documentation directory. >>> + >>> +Each colored LED will have two files created under the colors directory >>> +_intensity and _max_intensity. These files will contain >>> +one of LED_COLOR_ID_* definitions from the header >>> +include/dt-bindings/leds/common.h. >>> + >>> +Directory Layout Example >>> +======================== >>> +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/ >>> +-rw-r--r--    1 root     root          4096 Jul  7 03:10 blue_intensity >>> +-r--r--r--    1 root     root          4096 Jul  7 03:10 >>> blue_max_intensity >>> +-rw-r--r--    1 root     root          4096 Jul  7 03:10 >>> green_intensity >>> +-r--r--r--    1 root     root          4096 Jul  7 03:10 >>> green_max_intensity >>> +-rw-r--r--    1 root     root          4096 Jul  7 03:10 red_intensity >>> +-r--r--r--    1 root     root          4096 Jul  7 03:10 >>> red_max_intensity >>> + >>> +Multicolor Class Brightness Control >>> +=================================== >>> +The multiclor class framework will calculate each monochrome LEDs >>> intensity. >>> + >>> +The brightness level for each LED is calculated based on the color LED >>> +intensity setting divided by the color LED max intensity setting >>> multiplied by >>> +the requested brightness. >>> + >>> +led_brightness = brightness * _intensity/_max_intensity >>> + >>> +Example: >>> +Three LEDs are present in the group as defined in "Directory Layout >>> Example" >>> +within this document. >>> + >>> +A user first writes the color LED brightness file with the >>> brightness level that >>> +is necessary to achieve a blueish violet output from the RGB LED group. >>> + >>> +echo 138 > /sys/class/leds/rgb:grouped_leds/red_intensity >>> +echo 43 > /sys/class/leds/rgb:grouped_leds/green_intensity >>> +echo 226 > /sys/class/leds/rgb:grouped_leds/blue_intensity >>> + >>> +red - >>> +    intensity = 138 >>> +    max_intensity = 255 >>> +green - >>> +    intensity = 43 >>> +    max_intensity = 255 >>> +blue - >>> +    intensity = 226 >>> +    max_intensity = 255 >>> + >>> +The user can control the brightness of that RGB group by writing the >>> parent >>> +'brightness' control.  Assuming a parent max_brightness of 255 the >>> user may want >>> +to dim the LED color group to half.  The user would write a value of >>> 128 to the >>> +parent brightness file then the values written to each LED will be >>> adjusted >>> +base on this value >>> + >>> +cat /sys/class/leds/rgb:grouped_leds/max_brightness >>> +255 >>> +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness >>> + >>> +adjusted_red_value = 128 * 138/255 = 69 >>> +adjusted_green_value = 128 * 43/255 = 21 >>> +adjusted_blue_value = 128 * 226/255 = 113 >>> + >>> +Reading the parent brightness file will return the current >>> brightness value of >>> +the color LED group. >>> + >>> +cat /sys/class/leds/rgb:grouped_leds/max_brightness >>> +255 >>> + >>> +echo 128 > /sys/class/leds/rgb:grouped_leds/brightness >>> + >>> +cat /sys/class/leds/rgb:grouped_leds/brightness >>> +128 >>> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig >>> index 4b68520ac251..a1ede89afc9e 100644 >>> --- a/drivers/leds/Kconfig >>> +++ b/drivers/leds/Kconfig >>> @@ -30,6 +30,16 @@ config LEDS_CLASS_FLASH >>>         for the flash related features of a LED device. It can be built >>>         as a module. >>>   +config LEDS_CLASS_MULTI_COLOR >>> +    tristate "LED Mulit Color LED Class Support" >>> +    depends on LEDS_CLASS >>> +    help >>> +      This option enables the multicolor LED sysfs class in >>> /sys/class/leds. >>> +      It wraps LED class and adds multicolor LED specific sysfs >>> attributes >>> +      and kernel internal API to it. You'll need this to provide >>> support >>> +      for multicolor LEDs that are grouped together. This class is not >>> +      intended for single color LEDs. It can be built as a module. >>> + >>>   config LEDS_BRIGHTNESS_HW_CHANGED >>>       bool "LED Class brightness_hw_changed attribute support" >>>       depends on LEDS_CLASS >>> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile >>> index 2da39e896ce8..841038cfe35b 100644 >>> --- a/drivers/leds/Makefile >>> +++ b/drivers/leds/Makefile >>> @@ -4,6 +4,7 @@ >>>   obj-$(CONFIG_NEW_LEDS)            += led-core.o >>>   obj-$(CONFIG_LEDS_CLASS)        += led-class.o >>>   obj-$(CONFIG_LEDS_CLASS_FLASH)        += led-class-flash.o >>> +obj-$(CONFIG_LEDS_CLASS_MULTI_COLOR)    += led-class-multicolor.o >>>   obj-$(CONFIG_LEDS_TRIGGERS)        += led-triggers.o >>>     # LED Platform Drivers >>> diff --git a/drivers/leds/led-class-multicolor.c >>> b/drivers/leds/led-class-multicolor.c >>> new file mode 100644 >>> index 000000000000..89f4bc9e057c >>> --- /dev/null >>> +++ b/drivers/leds/led-class-multicolor.c >>> @@ -0,0 +1,271 @@ >>> +// SPDX-License-Identifier: GPL-2.0 >>> +// LED Multi Color class interface >>> +// Copyright (C) 2019 Texas Instruments Incorporated - >>> http://www.ti.com/ >>> + >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> +#include >>> + >>> +#include "leds.h" >>> + >>> +#define INTENSITY_NAME        "_intensity" >>> +#define MAX_INTENSITY_NAME    "_max_intensity" >>> + >>> +int led_mc_calc_brightness(struct led_classdev_mc *mcled_cdev, >>> +                enum led_brightness brightness, >>> +                struct led_mc_color_conversion color_component[]) >> Now the function name doesn't match with the output array name. >> >> How about: >> >> - led_mc_brightness_to_color_components >> - led_mc_calc_color_components >> >> Other suggestions? > > led_mc_calc_color_components is fine the first one is to long Agreed. [...] >>> +static inline int devm_led_classdev_multicolor_register(struct >>> device *parent, >>> +                     struct led_classdev_mc *mcled_cdev) >>> +{ >>> +    return -EINVAL; >>> +} >> Do you have use case for which these no-ops would be useful? >> We don't have no-ops for any of current LED API beside triggers, >> which are indeed useful. > > Absolutely this was the solution for the kbuild test.  This MC framework > is optional for drivers where as the LED class and flash are not. > > The LP55xx does not have a dependency on the CONFIG_MULTICOLOR_CLASS > flag and it does not need a hard dependency.  Without that flag defined > in the defconfig Ack. -- Best regards, Jacek Anaszewski