Hi Stefan!
On 03.05.2016 13:07, Stefan Wahren wrote:
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".
I strictly followed the names of the data sheet here: imx23 and imx28
reference manuals both call the current sources ISRC0 and ISRC1 even
if they are attached to different channels of the ADC. I think
inventing some ISRC6 for imx28 would do more harm then good.
};
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?
I haven't looked into it yet, but I expect that that the mfd
conversion will avoid this neatly.
Thanks,
Harald
Stefan
select STMP_DEVICE
select IIO_BUFFER
select IIO_TRIGGERED_BUFFER
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