From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andreas Klinger Subject: [PATCH v4 1/3] iio: hx711: add clock-frequency property in DT Date: Wed, 4 Jul 2018 14:36:38 +0200 Message-ID: <20180704123638.GA30535@arbeit> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: jic23@kernel.org, knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net, robh+dt@kernel.org, mark.rutland@arm.com, mchehab@kernel.org, davem@davemloft.net, gregkh@linuxfoundation.org, akpm@linux-foundation.org, linus.walleij@linaro.org, rdunlap@infradead.org, devicetree@vger.kernel.org, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org Add clock-frequency property for hx711 ADC This is the frequency of PD_SCK. It affects only the high value duration since low value duration is not relevant and we are not able to switch faster than the minimum duration specified. After PD_SCK goes high DOUT is read just before PD_SCK goes down again. This is necessary because of parasitic capacities on the wiring. Signed-off-by: Andreas Klinger --- Documentation/devicetree/bindings/iio/adc/avia-hx711.txt | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/Documentation/devicetree/bindings/iio/adc/avia-hx711.txt b/Documentation/devicetree/bindings/iio/adc/avia-hx711.txt index b3629405f568..4bee51d536e1 100644 --- a/Documentation/devicetree/bindings/iio/adc/avia-hx711.txt +++ b/Documentation/devicetree/bindings/iio/adc/avia-hx711.txt @@ -8,11 +8,21 @@ Required properties: See Documentation/devicetree/bindings/gpio/gpio.txt - avdd-supply: Definition of the regulator used as analog supply +Optional properties: + - clock-frequency: Frequency of PD_SCK + This setting affects the duration of the high value + phase of the clock (PD_SCK). The low value phase is + not affected since it is not relevant for the + measurement. + Minimum value allowed is 20 kHz because of maximum + high time of 50 microseconds. + Example: weight@0 { compatible = "avia,hx711"; sck-gpios = <&gpio3 10 GPIO_ACTIVE_HIGH>; dout-gpios = <&gpio0 7 GPIO_ACTIVE_HIGH>; avdd-suppy = <&avdd>; + clock-frequency = <100000>; }; -- 2.1.4