Re: iio: adc: add exynos5 adc driver under iio framwork

[Guenter Roeck <linux@roeck-us.net>]

On Wed, Feb 13, 2013 at 06:46:01PM +0530, Naveen Krishna Ch wrote:
[ ... ]
> 
> Hello Guenter,
> 
> I've rebase my adc driver on top of your (OF for IIO patch)
> 
> My setup is like the below one. kindly, help me find the right device
> tree node params
> 
> One ADC controller with 8 channels,
>   4 NTC thermistors are connected to channel 3, 4, 5 and 6 of ADC respectively
> 
> ADC ch - 0
> ADC ch - 1
> ADC ch - 2
> ADC ch - 3 ------------------NTC
> ADC ch - 4 ------------------NTC
> ADC ch - 5 ------------------NTC
> ADC ch - 6 ------------------NTC
> ADC ch - 7
> 
> I've started off with something like this.
> 
>         adc0: adc@12D10000 {
>                 compatible = "samsung,exynos5250-adc";
>                 reg = <0x12D10000 0x100>;
>                 interrupts = <0 106 0>;
>                 #io-channel-cells = <1>;
>         };
> 
>         adc0: adc@12D10000 {
>                 vdd-supply = <&buck5_reg>;
> 
>                 ncp15wb473@0 {
>                         compatible = "ntc,ncp15wb473";
>                         io-channels = <&adc0 3>;
>                         io-channel-names = "adc3";
>                         pullup-uV = <1800000>;
>                         pullup-ohm = <47000>;
>                         pulldown-ohm = <0>;
>                         id = <3>;
>                 };
> 
>                 ncp15wb473@1 {
>                         compatible = "ntc,ncp15wb473";
>                         pullup-uV = <1800000>;
>                         pullup-ohm = <47000>;
>                         pulldown-ohm = <0>;
>                         io-channels = <&adc0 4>;
>                         io-channel-names = "adc4";
>                         id = <4>;
>                 };
>                 ncp15wb473@2 {
>                         compatible = "ntc,ncp15wb473";
>                         pullup-uV = <1800000>;
>                         pullup-ohm = <47000>;
>                         pulldown-ohm = <0>;
>                         io-channels = <&adc0 5>;
>                         io-channel-names = "adc5";
>                         id = <5>;
>                 };
>                 ncp15wb473@3 {
>                         compatible = "ntc,ncp15wb473";
>                         pullup-uV = <1800000>;
>                         pullup-ohm = <47000>;
>                         pulldown-ohm = <0>;
>                         io-channels = <&adc0 6>;
>                         io-channel-names = "adc6";
>                         id = <6>;
>                 };
>         };
> 
> ADC driver will use of_platform_populate() to populate the child nodes
> (ntc thermistors in my case)
> 
> I've modified the NTC driver to support DT. in probe
> chan = iio_channel_get(&pdev->dev, "adcX");
> and using "id" field to use respective ADC channel to do the raw_read()
> 
> Issue:
> 1. I get weird device names for thermistors starting from ncp15wb473.2
> to ncp15wb473.5

I noticed that device IDs and names created when OF is active are sometimes
not as one would expect. I never managed to get the device IDs I tried to
configure. Ultimately, it did not matter and I never bothered to track it down.

Guenter