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[104.57.184.186]) by smtp.gmail.com with ESMTPSA id v15-20020a05683018cf00b0060603221251sm5158169ote.33.2022.05.04.07.50.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 May 2022 07:50:02 -0700 (PDT) Date: Wed, 4 May 2022 07:51:46 -0700 From: Bjorn Andersson To: Pavel Machek Cc: Thierry Reding , Uwe Kleine-K?nig , Lee Jones , Luca Weiss , Doug Anderson , Rob Herring , Jonathan Corbet , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-pwm@vger.kernel.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v14 2/2] leds: Add driver for Qualcomm LPG Message-ID: References: <20220303214300.59468-1-bjorn.andersson@linaro.org> <20220303214300.59468-2-bjorn.andersson@linaro.org> <20220504073009.GC8204@duo.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220504073009.GC8204@duo.ucw.cz> Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On Wed 04 May 00:30 PDT 2022, Pavel Machek wrote: > Hi! > > > +/sys/class/leds//hw_pattern > > +-------------------------------- > > + > > +Specify a hardware pattern for a Qualcomm LPG LED. > > + > > +The pattern is a series of brightness and hold-time pairs, with the hold-time > > +expressed in milliseconds. The hold time is a property of the pattern and must > > +therefor be identical for each element in the pattern (except for the pauses > > +described below). > > therefore? > Yes > > +Simple pattern:: > > + > > + "255 500 0 500" > > + > > + ^ > > + | > > + 255 +----+ +----+ > > + | | | | ... > > + 0 | +----+ +---- > > + +----------------------> > > + 0 5 10 15 time (100ms) > > + > > +The LPG supports specifying a longer hold-time for the first and last element > > +in the pattern, the so called "low pause" and "high pause". > > Please see > Documentation/devicetree/bindings/leds/leds-trigger-pattern.txt . This > should really be compatible. > Unfortunately the LPG hardware only supports fixed duration (except for the ability to hold/extend the first and last duration in the pattern) and it also does not support gradual transition between the brightness levels. As such the pattern sequence provided to hw_pattern looks to be the smae, but I don't see that it can be made compatible. > Can I get either patch to disable pattern infrastructure for now or to > get it compatible? > I'd be happy to get this updated to your liking, but this was one of the drivers we discussed when we introduced the pattern trigger and led to the conclusion that we need the ability to do hw-specific patterns. As such this document provides the hardware specific documentation, as we describe under "hw_pattern" in Documentation/ABI/testing/sysfs-class-led-trigger-pattern. Please advice on what you would like me to do. Regards, Bjorn