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[83.31.10.81]) by smtp.gmail.com with ESMTPSA id s63sm19076896wme.17.2019.07.16.12.18.31 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 16 Jul 2019 12:18:32 -0700 (PDT) Subject: Re: [PATCH v5 2/2] documention: leds: Add multicolor class documentation To: Dan Murphy , pavel@ucw.cz Cc: linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org References: <20190701204634.10517-1-dmurphy@ti.com> <20190701204634.10517-3-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 emV3c2tpIDxqYWNlay5hbmFzemV3c2tpQGdtYWlsLmNvbT6JAj4EEwEIACgCGwMHCwkIBwMC AQYVCAIJCgsDFgIBAh4BAheABQJVo39tBQkJZgNMAAoJEL1qUBy3i3wmxLQQAK8QEQ0JqZEv 5hrxiwT+Qtkx1TULYriK9sYcY9zbi18YxbKB0C4Znh5iP5o7k26WnPGLM+w4qWvTAkHjuAI7 aBrvb4nGRvE5s14PQ9IHgL7iL3zAAHT1azIZng9dUCCSontB+vQZu1x/Un0lVlVCvsvO7QVt hAZUlT3iucNMO0jpCiS3raZkNfab8M+JWP/iplaV0Kn+O7LX3A/RdLmx5ZhuT+zvyHwl2c3K T56UHaQnjkuHB2Ytk8HtOjNXGNYnm4nLx3ok3jEN1nWDRV/DeiPn8zz4Zebsp686OH9vvX/0 R4dk2YEjUCY/S7CbJxXzUnLjboUAGmtTVOu/uJ7y11iS9XEoJ09HEzijQwWctJXLojcTXCFw rbYkgqOjDRE9NTC6b68iUUVUayEADWz80qChbDJ2R2/Spm5+eojI2NVnr3AVSc7ZCBkhSDei TtSjQmlPflKEAR8LH67XbzvwvDwX/Lmi+/1Yxws0rxeJNYMqfOBBW/xi3QEc9hMDTl99EZwl NqfEN7HHh2jzAGNtIYxhHHiPUw/UZeS1fxD8vRqVZHW3ENR6lOCEYED1ChU1w8Zzm/CiT4ea ZakZChzFeUWVO/yFEcAzTJSiJHqLooNfP/VyFppjAlLVPISLcLBVTy+Ue76Z0IrC12fI38cm lJJGVY6NUbNb883pu5B7qB8huQINBFWjfaEBEADDzcpgTaAlnNd1Oqjs7V6yCgVbCxmV6v8j mkdp+4BWxQAg9E1O17h9lHJ8LzUfrkBcEq0amhHM19leoiMtgiE1yoOWL4Ndsp9PYE5mn7qC MiqFNel7wt2mUENgZ9yztrET9I/zbjA/RpTt+6RwlUaSNgz8RRN/UzJtTy2x5wxvPpWapfna TcFsPHQ2kYMl8di3ueNgnEwU+dlQnnlg7andjMDq+C4qGJXxnwKpsHMLnAXUxAVMZJUGjkd1 WyUMep7SNqAzgZTRr451Q82XvokRHeZeNJfjo02olrwRl5L+jiPsMeUxT6fgTOgE1PulMxUU 1Fm4/i6lQPyTKmB0KdOGOB+RrY2xwmvGm0bwcCChL6cE8lmZX1z7afIEZTZsWJ+oEJU8hGQF qHV8BOwhPisTZ6u2zx3i760p/GyzSuvNj6Exq9GNNG4LmC38rxMLg2HpNf4fWEl7R2gkdwhI +C1NQeetRtY+xVWnmG1/WygQKMvxsQFvCeTtZ5psOxZ5Eh7sDv0A3tAjqDtEGettAn/SAVmB 1uJtjNsoeffNZVGojHDTNpD4LCRWJaBaNlxp+pVlPQa1oxKDQ4R2bRfsmjxLsI2aOsf9xNk7 txOSY9FaVXBPVNWav36rg2O/ZdkSZ+RDaIDrOfj4tBo1aRGEFVn5tD0wsTTzszsxkeEAdwTR bwARAQABiQIlBBgBCAAPBQJVo32hAhsMBQkJZgGAAAoJEL1qUBy3i3wmahsQAJVgVlb41OsY +9BsHp4IqmGcJltYvIH0uEzYm0E/ykatM5AZxMICsF0W1aFt/KWFbhmucfyQ0DCQ6ywCdMKw jkt18W0hwljpf5NmQ/TmsVHl6ujfjphk8362Lz1L1ktR8tOKvQA9XSGjDa7mUJr50X5DpNlA 53AyINNeuvzUx4mCNPR+ZqVhqR5/9mk+nZqVcLqDPf6x5RebOagAKPebWdEFtgbSHHhvf622 JS+e8GkjDxePWsL8C0F+UYVqBfJj0uS7Aa11yoZosyLJ+NLS24tkbVo8w1oGWIrappqoo3gp w7yEjeKif5wizuA44khrOfcOR0fpdJ8Hjw4TggOEWGaktXtgpcdVUpA1xaS93oGm3CLKiuwm emtta/JV1aaOEZzJULJl2U50ceEmoxb1+z60YP9NgvNdXy34dq+TuYn/LCkOgSipR6broqKn 4/8Pc9wdGkO9XuJ9czSQTtZHHc54pDywG6+4xoJAVF09ciYsKU30UK+ctlKNdiCbCsaIZzRV WLSvF/0ektHXij462VrwJJZYCD3B4zItlWvMsCk4/yYHKVDuSjfdOj3+8sGSEnuym3HP6pxN GIzz0qhTr6Hmbx3uhGQjFvfsWbGoqb5aqQckFVB51YNPSvWBb41AbAT3QvHn+mMIH0faOgJz 5sZdKDFCF5AgguXPfX8yWP5PiQKtBBgBCAAgFiEEvx38ClaPBfeVdXCQvWpQHLeLfCYFAlsK ioYCGwIAgQkQvWpQHLeLfCZ2IAQZFggAHRYhBBTDHErITmX+em3wBGIQbFEb9KXbBQJbCoqG AAoJEGIQbFEb9KXbxC4A/1Pst/4bM9GyIzECWNCy8TP6xWPVc9S+N/pUB14y9zD7AP9ZTZub GopbGO2hQVScQM02vGQBlgXVWhqOigr4pgwfBu46D/48fqBjpnUaILO5hv/x/sPQ05wXz6Z3 5HooqJBmKP/obljuVdAHPbU6mXhXP/7f2LmCZ8Fr0tEcfii9H093ofQUKOO7heMg4mSIlizY eAIKbqdTFElbM+DIw9JVuoIbZy3BpSIKFR1tL7T1tZvYwE2MiUjhvzAtYg63GHKfblWJ+bSn 5BHkDbKbhuokn0tKt7Wozyp09ZycTE8VTg9kVhCBn2lfUnK6LvdlQ/3gvv/CDUbIlkvd494T iiAFeV0TSDRarc5GoD2AD/K+sJLI0o4dNX0kwaec8Y37CMFgw8w66oM8L/Nwr6y10VdzpRtQ zVA2AOdqia+O6Wh+UDFph1uUzbqAV/Km+kVvxzNw8z4E/pfq9aT4zD37y9be3Ir2VKD7jc6M haUEY+k71otmxhjECq8nmJLFxts4tvmrzBZy3pTsRnVGe459UiegG22uVi91a1wj/k1BOm2S 4H8PJGGvEElz98rMnjCNLaKRxZ7QWfGtClwTbKqhQgVpkx138LH1tFYAZkbTzu3l1Qcm4ydV VykdkWccEqvxqDV4f8q0V0MW3KWfkD9/07bbGxXSnImeLt7bPuVMGK2tAUbr2+dUYmUdsETZ 1HgZ11moCVU5Ru0RwTv9oyThOsK3HQjI7NCIsDzVpolaGQPd9E7xwOVHhhDcXRqqNjLzHUSe eGGiEQ== Message-ID: <1049968b-6084-ed21-67bf-ef074c591f0a@gmail.com> Date: Tue, 16 Jul 2019 21:18:30 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190701204634.10517-3-dmurphy@ti.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Dan, Thanks for the update. I have some nits below, please take a look. On 7/1/19 10:46 PM, Dan Murphy wrote: > Add the support documentation on the multicolor LED framework. > This document defines the directores and file generated by the > multicolor framework. It also documents usage. > > Signed-off-by: Dan Murphy > --- > Documentation/leds/leds-class-multicolor.txt | 152 +++++++++++++++++++ > 1 file changed, 152 insertions(+) > create mode 100644 Documentation/leds/leds-class-multicolor.txt > > diff --git a/Documentation/leds/leds-class-multicolor.txt b/Documentation/leds/leds-class-multicolor.txt > new file mode 100644 > index 000000000000..01175288502e > --- /dev/null > +++ b/Documentation/leds/leds-class-multicolor.txt > @@ -0,0 +1,152 @@ > + > +Multi Color LED handling under Linux > +================================================= > + > +Author: Dan Murphy > + > +Description > +----------- > +There are varying monochrome LED colors available for application. These > +LEDs can be used as a single use case LED or can be mixed with other color > +LEDs to produce the full spectrum of color. Color LEDs that are grouped > +can be presented under a single LED node with individual color control. > +The multicolor class groups these LEDs and allows dynamically setting the value > +of a single LED or setting the intensity values of the LEDs in the group and > +updating the LEDs virtually simultaneously. > + > +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.txt within this > +documentation directory. > + > +Each colored LED is given its own directory. These directories can be, but not > +limited to red, green, blue, white, amber, yellow and violet. Under these > +directories the intensity and max_intensity files are presented for each LED. > + > + > +Directory Layout Example > +------------------------ > +root:/sys/class/leds/rgb:grouped_leds# ls -lR colors/ > +colors/: > +drwxr-xr-x 2 root root 0 Jun 28 20:21 blue > +drwxr-xr-x 2 root root 0 Jun 28 20:21 green > +drwxr-xr-x 2 root root 0 Jun 28 20:21 red > +-rw------- 1 root root 4096 Jun 28 20:21 color_mix > + > +colors/blue: > +-rw------- 1 root root 4096 Jun 28 20:21 intensity > +-r-------- 1 root root 4096 Jun 28 20:27 max_intensity > +-r-------- 1 root root 4096 Jun 28 20:21 color_id > + > +colors/green: > +-rw------- 1 root root 4096 Jun 28 20:22 intensity > +-r-------- 1 root root 4096 Jun 28 20:27 max_intensity > +-r-------- 1 root root 4096 Jun 28 20:21 color_id > + > +colors/red: > +-rw------- 1 root root 4096 Jun 28 20:21 intensity > +-r-------- 1 root root 4096 Jun 28 20:27 max_intensity > +-r-------- 1 root root 4096 Jun 28 20:21 color_id > + > +Multicolor Color Mixing > +----------------------- > +Multicolor monochrome LEDs intensity can be modified and mixed to produce a > +varying array of colors. The color_mix file gives the user the ability to write > +all the monochrome LEDs registered in the directory with a single call. > +To create a specific color from monochrome LEDs the color_mix file needs to be > +written with each color's intensity. The order in which the monochrome LEDs > +should be written is based on the colors color_id. > + > +For example: > +cat /sys/class/leds/rgb:grouped_leds/red/color_id > +0 > +cat /sys/class/leds/rgb:grouped_leds/green/color_id > +1 > +cat /sys/class/leds/rgb:grouped_leds/blue/color_id > +2 > + > +red - color_id = 0 > +green - color_id = 1 > +blue - color_id = 2 > + > +These id's are the order in which to write the color_mix file. > + > +echo " " > color_mix > + > +echo "0x80 0x00 0x80" > color_mix > + > +The order of the monochrome LEDs are determined during multicolor class > +registration and will not change unless unregistered and re-registered. > + > +Other example with amber monochrome LED: > +blue - color_id = 0 > +amber - color_id = 1 > + > +In this exampe blue is at ID 0 and amber ID is 1 so the user would write > +echo " " > color_mix > + > +echo "0x38 0x80" > color_mix > + > +If a single monochrome LED needs to be modified then the user would write the > +colors//intensity file. > + > + > +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 value. > + > +led_brightness = requested_value*(led_color_intensity/led_color_max_intensity) Please drop parentheses here as pointed out before in the code review. > + > +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 neccesary 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 We probably need to state here that any amendment to color intensity values resets brightness to its max 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 Drop parentheses. > + > +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/max_brightness > +128 > + > + > -- Best regards, Jacek Anaszewski