From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <54AC146C.9030502@imgtec.com> Date: Tue, 6 Jan 2015 13:59:24 -0300 From: Ezequiel Garcia MIME-Version: 1.0 To: Rob Herring CC: Jonathan Cameron , James Hartley , Andrew Bresticker , "Rob Herring" , Mark Rutland , , "linux-iio@vger.kernel.org" , "devicetree@vger.kernel.org" , Pawel Moll , Ian Campbell , "Kumar Gala" , Phani Movva , "Naidu Tellapati" Subject: Re: [PATCH v6 2/3] DT: iio: adc: Add CC_10001 binding documentation References: <1420558143-26276-1-git-send-email-ezequiel.garcia@imgtec.com> <1420558143-26276-3-git-send-email-ezequiel.garcia@imgtec.com> In-Reply-To: Content-Type: text/plain; charset="utf-8" List-ID: Hi Rob, Thanks a lot for the comments. On 01/06/2015 01:30 PM, Rob Herring wrote: > On Tue, Jan 6, 2015 at 9:29 AM, Ezequiel Garcia > wrote: >> From: Phani Movva >> >> Add the devicetree binding document for Cosmic Circuits 10001 ADC device. >> >> Signed-off-by: Phani Movva >> Signed-off-by: Naidu Tellapati >> [Ezequiel: minor style cleaning] >> Signed-off-by: Ezequiel Garcia >> --- >> .../devicetree/bindings/iio/adc/cc10001_adc.txt | 22 ++++++++++++++++++++++ >> 1 file changed, 22 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/iio/adc/cc10001_adc.txt >> >> diff --git a/Documentation/devicetree/bindings/iio/adc/cc10001_adc.txt b/Documentation/devicetree/bindings/iio/adc/cc10001_adc.txt >> new file mode 100644 >> index 0000000..b7ba558 >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/iio/adc/cc10001_adc.txt >> @@ -0,0 +1,22 @@ >> +* Cosmic Circuits - Analog to Digital Converter (CC-10001-ADC) >> + >> +Required properties: >> + - compatible: Should be "cosmic,10001-adc" >> + - reg: Should contain adc registers location and length. >> + - clock-names: Should contain "adc". >> + - clocks: Should contain a clock specifier for each entry in clock-names >> + - vref-supply: The regulator supply ADC reference voltage. >> + >> +Optional properties: >> + - cosmic,adc-reserved-channels: Bitmask of reserved channels, >> + i.e. channels that cannot be used by the OS. > > Seems like this could be pretty common for any ADC as well as having > the number of channels, so you can drop the vendor prefix. Do we have > any similar properties already in other drivers? Well, it seems the AT91 ADC has a similar property called adc-channels-used. Not sure if it means the same as here. We are not using it to model a hardware availability but the channels being reserved for another core or OS. See [1]. > I'd reverse the > polarity to be enabled channels, then the number of available channels > is the top set bit plus 1. You could count channels as is, but then > people have to remember to set the high bits on non-existent channels. Hm, isn't this too cumbersome? If we really need to pass the number of channels, shouldn't we have a separate property for that? Note that no driver currently needs it. > Absence of the property could still mean you know how many channels > and all are enabled. > This property was originally proposed to be "called cosmic,adc-available-channels". Andrew suggested to reverse the polarity, and be explicit about absence of property meaning no reserved channels (also in [1]). I'm fine either way. [1] http://www.spinics.net/lists/linux-iio/msg15578.html -- Ezequiel