From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars-Peter Clausen Subject: Re: [PATCH v3 2/5] ARM: dts: add reference voltage property for MXS LRADC Date: Mon, 22 Jul 2013 20:34:47 +0200 Message-ID: <51ED7B47.2090104@metafoo.de> References: <1374501843-19651-1-git-send-email-hector.palacios@digi.com> <1374501843-19651-3-git-send-email-hector.palacios@digi.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1374501843-19651-3-git-send-email-hector.palacios-i7dp0qKlBMg@public.gmane.org> Sender: linux-iio-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Hector Palacios Cc: linux-iio-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org, jic23-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, fabio.estevam-KZfg59tc24xl57MIdRCFDg@public.gmane.org, marex-ynQEQJNshbs@public.gmane.org, Thomas Petazzoni List-Id: devicetree@vger.kernel.org On 07/22/2013 04:04 PM, Hector Palacios wrote: > Some LRADC channels have fixed pre-dividers so they can measure > different voltages at full scale. The reference voltage allows to > expose a scaling attribute through the IIO sysfs so that a user can > compute the real voltage out of a measured sample value. I've said before that I'm not convinced that this is the right way to implement this. And considering what Thomas said here http://www.mail-archive.com/devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org/msg36691.html I guess I'm not alone with that opinion. - Lars > > Signed-off-by: Hector Palacios > Acked-by: Marek Vasut > Acked-by: Alexandre Belloni > --- > Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt | 9 ++++++++- > arch/arm/boot/dts/imx23.dtsi | 4 ++++ > arch/arm/boot/dts/imx28.dtsi | 4 ++++ > 3 files changed, 16 insertions(+), 1 deletion(-) > > diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt > index 4688205..6ec485c 100644 > --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt > +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt > @@ -1,9 +1,12 @@ > * Freescale i.MX28 LRADC device driver > > Required properties: > -- compatible: Should be "fsl,imx28-lradc" > +- compatible: "fsl,imx28-lradc", "fsl,imx23-lradc" > - reg: Address and length of the register set for the device > - interrupts: Should contain the LRADC interrupts > +- fsl,vref: Reference voltage (in mV) for each LRADC channel. This is the > + maximum voltage that can be measured at full scale in each channel > + considering fixed pre-dividers. > > Optional properties: > - fsl,lradc-touchscreen-wires: Number of wires used to connect the touchscreen > @@ -18,4 +21,8 @@ Examples: > reg = <0x80050000 0x2000>; > interrupts = <10 14 15 16 17 18 19 > 20 21 22 23 24 25>; > + fsl,vref = <1850 1850 1850 1850 > + 1850 1850 1850 7400 > + 1850 1850 3700 1850 > + 3700 1850 1850 7400> > }; > diff --git a/arch/arm/boot/dts/imx23.dtsi b/arch/arm/boot/dts/imx23.dtsi > index 587ceef..e212902 100644 > --- a/arch/arm/boot/dts/imx23.dtsi > +++ b/arch/arm/boot/dts/imx23.dtsi > @@ -430,6 +430,10 @@ > compatible = "fsl,imx23-lradc"; > reg = <0x80050000 0x2000>; > interrupts = <36 37 38 39 40 41 42 43 44>; > + fsl,vref = <1850 1850 1850 1850 > + 1850 1850 3700 7400 > + 1850 1850 1850 1850 > + 1850 1850 1850 7400>; > status = "disabled"; > }; > > diff --git a/arch/arm/boot/dts/imx28.dtsi b/arch/arm/boot/dts/imx28.dtsi > index 6a8acb0..c1b3724 100644 > --- a/arch/arm/boot/dts/imx28.dtsi > +++ b/arch/arm/boot/dts/imx28.dtsi > @@ -865,6 +865,10 @@ > reg = <0x80050000 0x2000>; > interrupts = <10 14 15 16 17 18 19 > 20 21 22 23 24 25>; > + fsl,vref = <1850 1850 1850 1850 > + 1850 1850 1850 7400 > + 1850 1850 3700 1850 > + 3700 1850 1850 7400>; > status = "disabled"; > }; > > -- > To unsubscribe from this list: send the line "unsubscribe linux-iio" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >