Re: [PATCH 1/3] iio: mxs-lradc: Add regulators for current sources
From: Stefan Wahren <hidden>
Date: 2016-05-03 11:07:32
Also in:
linux-arm-kernel, linux-iio
Hi Harald, Am 22.04.2016 um 15:52 schrieb Harald Geyer:
quoted hunk
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 <redacted> --- 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".
quoted hunk
}; 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