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([2600:8803:e7e4:500:4237:7c82:cb4f:1d6a]) by smtp.gmail.com with ESMTPSA id 5614622812f47-479a028cab5sm17487137b6e.16.2026.04.25.09.49.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 25 Apr 2026 09:49:37 -0700 (PDT) Message-ID: <46fd475f-8d54-4419-a195-d66c947fcc1b@baylibre.com> Date: Sat, 25 Apr 2026 11:49:35 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC] iio: light: tcs3472: implementing wait time TODO To: Aldo Conte , linux-iio@vger.kernel.org Cc: Jonathan Cameron , =?UTF-8?Q?Nuno_S=C3=A1?= , Andy Shevchenko , linux-kernel@vger.kernel.org References: <73d2183e-dffe-4ae4-9312-c544e0079f3a@gmail.com> Content-Language: en-US From: David Lechner In-Reply-To: <73d2183e-dffe-4ae4-9312-c544e0079f3a@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 4/25/26 11:28 AM, Aldo Conte wrote: > Hi all, > > I'd like to resolve the wait time TODO in tcs3472.c. Do you actually have this hardware to test it? What is the application that needs to make use of this feature? > > The TCS3472 has a WTIME register and WEN bit that insert a low-power What about WLONG? > wait state between RGBC cycles. The register is already defined in the driver but never used. > I noticed that tsl2772.c enables wait with a fixed default and no > userspace control. However, I think exposing the wait time to > userspace would be more useful to tune the power/responsiveness tradeoff. I assume this would affect the effective sample rate? > > My plan would be to expose it via an ext_info attribute in > microseconds, following the same convention as integration_time. > Does that sound acceptable, or would you prefer a simpler approach > with just a fixed default like tsl2772? So perhaps we could just use the standard sampling_frequency attribute? > > I also plan a following patch converting the driver to devm. Would be better to do this first before adding new features. > > Thanks, > Aldo >