Hi Harald,
Am 22.04.2016 um 15:52 schrieb Harald Geyer:
> The hardware has two current sources ISRC0 and ISRC1 to allow measuring
> resistors without additional circuitry. This commit makes them available
> as regulators.
>
> Tested on an imx233-olinuxino board.
>
> Signed-off-by: Harald Geyer <harald@xxxxxxxxx>
> ---
> The current regulator API doesn't fit this type of device very well: Typically
> consumers will want to set a defined current, ie. min_uA == max_uA, but they
> can't without help from configuration data, because the valid values aren't
> reported by the API for current regulators. I have been thinking about
> extending the API, but currently AFAIK no such consumers exist and most
> users, like myself, will force the regulator to a defined value in
> devicetree anyway.
>
> .../bindings/staging/iio/adc/mxs-lradc.txt | 29 ++++
> drivers/iio/adc/Kconfig | 1 +
> drivers/iio/adc/mxs-lradc.c | 152 +++++++++++++++++++++
> 3 files changed, 182 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> index 555fb11..983952c 100644
> --- a/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> +++ b/Documentation/devicetree/bindings/staging/iio/adc/mxs-lradc.txt
> @@ -19,6 +19,15 @@ Optional properties:
> - fsl,settling: delay between plate switch to next sample. Allowed value is
> 1 ... 2047. It counts at 2 kHz and its default is
> 10 (= 5 ms)
> +- ISRC0: A node describing the regulator of internal current source 0
> +- ISRC1: A node describing the regulator of internal current source 1
> +
> +Required properties for the ISRCx sub-nodes:
> +- regulator-max-microamp: See standard regulator binding documentation.
> + Valid values are from 0 to 300 in steps of 20.
> +
> +Optional properties for the ISRCx sub-nodes:
> +Any standard regulator properties that apply to current regulators.
>
> Example for i.MX23 SoC:
>
> @@ -31,6 +40,16 @@ Example for i.MX23 SoC:
> fsl,ave-ctrl = <4>;
> fsl,ave-delay = <2>;
> fsl,settling = <10>;
> +
> + isrc_lradc0: ISRC0 {
> + regulator-max-microamp = <300>;
> + };
> +
> + isrc_lradc1: ISRC1 {
> + regulator-max-microamp = <120>;
> + regulator-min-microamp = <120>;
> + regulator-always-on;
> + };
IMHO the binding should represent the direct connection between the
current source and the physical channel. I think a node label isn't
enough. Unfortunately i don't have an idea to do it the "right way".
> };
>
> Example for i.MX28 SoC:
> @@ -44,4 +63,14 @@ Example for i.MX28 SoC:
> fsl,ave-ctrl = <4>;
> fsl,ave-delay = <2>;
> fsl,settling = <10>;
> +
> + isrc_lradc0: ISRC0 {
> + regulator-max-microamp = <300>;
> + };
> +
> + isrc_lradc6: ISRC1 {
> + regulator-max-microamp = <120>;
> + regulator-min-microamp = <120>;
> + regulator-always-on;
> + };
> };
> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
> index 5937030..1968d1c 100644
> --- a/drivers/iio/adc/Kconfig
> +++ b/drivers/iio/adc/Kconfig
> @@ -319,6 +319,7 @@ config MXS_LRADC
> tristate "Freescale i.MX23/i.MX28 LRADC"
> depends on (ARCH_MXS || COMPILE_TEST) && HAS_IOMEM
> depends on INPUT
> + depends on REGULATOR
Any chance to avoid this dependency for an optional feature?
Stefan
> select STMP_DEVICE
> select IIO_BUFFER
> select IIO_TRIGGERED_BUFFER
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