On Wed, 2014-09-24 at 15:55 +0100, Mark Rutland wrote: > On Wed, Sep 24, 2014 at 02:58:23PM +0100, Ivan T. Ivanov wrote: > > The current ADC is peripheral of Qualcomm SPMI PMIC chips. It has > > 16 bits resolution and register space inside PMIC accessible across > > SPMI bus. > > > > The driver registers itself through IIO interface. > > > > Signed-off-by: Ivan T. Ivanov <iivanov@xxxxxxxxxx> > > --- > > Changes: > > - Fix Kconfig dependencies > > - Reword Kconfig help text > > - Replace IIO_CHAN_INFO_PROCESSED with IIO_CHAN_INFO_RAW and IIO_CHAN_INFO_SCALE, > > This enable client drivers to use microampers precission, instead miliamps. > > - Use const array for iio_schan_spec-fiers. > > - Fix spelling errors and adress review comments. > > > > Previous version: > > https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg728360.html > > > > .../devicetree/bindings/iio/adc/qcom,spmi-iadc.txt | 61 ++ > > drivers/iio/adc/Kconfig | 11 + > > drivers/iio/adc/Makefile | 1 + > > drivers/iio/adc/qcom-spmi-iadc.c | 691 +++++++++++++++++++++ > > 4 files changed, 764 insertions(+) > > create mode 100644 Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt > > create mode 100644 drivers/iio/adc/qcom-spmi-iadc.c > > > > diff --git a/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt > > new file mode 100644 > > index 0000000..06e58b6 > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/iio/adc/qcom,spmi-iadc.txt > > @@ -0,0 +1,61 @@ > > +Qualcomm's SPMI PMIC current ADC > > + > > +QPNP PMIC current ADC (IADC) provides interface to clients to read current. > > +A 16 bit ADC is used for current measurements. > > + > > +IADC node: > > + > > +- compatible: > > + Usage: required > > + Value type: <string> > > + Definition: Should contain "qcom,spmi-iadc". > > + > > +- reg: > > + Usage: required > > + Value type: <prop-encoded-array> > > + Definition: IADC base address and length in the SPMI PMIC register map. > > + TRIM_CNST_RDS register address and length(1) > > Are these two register regions? Please make the order explicit somehow > (either say first/second/third/etc, or use reg-names). Will make order explicit. > > Are they both part of the IADC, or is one part of an external/shared > component? I think that this is shared component. > > > + > > +- interrupts: > > + Usage: optional > > + Value type: <prop-encoded-array> > > + Definition: End of conversion interrupt number. If property is > > + missing driver will use polling to detect end of conversion > > + completion. > > Driver details shouldn't be in the binding. If the driver can poll, > that's good, but it should be dropped form this description. > Will remove driver details. > Is this the only interrupt? > Yes. > What do you mean be "End of conversion interrupt number"? Just describe > what the interrupt logically is from the PoV of the device -- interrupts > is a standard property so we don't need to be too explicit about the > type. Badly worded. Just, "End of conversion interrupt"? > > > + > > +- qcom,rsense: > > + Usage: optional > > + Value type: <u32> > > + Definition: External sense register value in Ohm. Defining this > > + propery will instruct ADC to use external ADC sense channel. > > + If property is not defined ADC will use internal sense channel. > > The latter two sentences sound like a driver description. > > What exactly is the difference between the internal and external > channels, and what exactly is the value in the sense register used for? Internal - when using chip build-in resistor External - when using off-chip resistor > > The binding should describe the logical properties of the device rather > than the specific programming model details. > > > + > > +- qcom,rds-trim: > > + Usage: optional > > + Value type: <u32> > > + Definition: Calculate internal sense resistor value based TRIM_CNST_RDS, > > + IADC RDS and manufacturer. > > + 0: Read the IADC and SMBB trim register and apply the default > > + RSENSE if conditions are met. > > + 1: Read the IADC, SMBB trim register and manufacturer type and > > + apply the default RSENSE if conditions are met. > > + 2: Read the IADC, SMBB trim register and apply the default RSENSE > > + if conditions are met. > > + If property is not defined driver will use qcom,rsense value if > > + defined or internal sense resistor value trimmed into register. > > Having read this a few times, I still don't understand which I would use > and when. > > Which conditions need to be met in each of these cases? > > When does the manufacturer need to be taken into account and what does > it even mean for that to be the case? That sounds very much like a > driver detail rather than a HW property. > > Cases 0 and 2 seem to be the same, just with s/, / and /. I cannot > figure out the intended difference between the two. > > The last sentence is very much a driver description. Sorry. I have tried to make it better. Now looking again DT files in codeaurora tree I see that 0 is used in pm8941, 1 is used in pm8110 and 2 is used for pm8226. So I will remove this property and handle this inside driver based on chip version. > > > + > > +Example: > > + /* IADC node */ > > + pmic_iadc: iadc@3600 { > > + compatible = "qcom,spmi-iadc"; > > + reg = <0x3600 0x100>, > > + <0x12f1 0x1>; > > + interrupts = <0x0 0x36 0x0 IRQ_TYPE_EDGE_RISING>; > > + qcom,rds-trim = <0>; > > + }; > > + > > + /* IIO client node */ > > + bat { > > + io-channels = <&pmic_iadc 0>; > > + io-channel-names = "iadc"; > > + }; > > Surely you need #iio-cells on the IADC node? Yes, I need to add it. > > Given the client seems to pass a specifier value, does this have > multiple channels, or only a single channel? Driver register only one IIO channel, so #io-channel-cells should be <0>. Thank you for the comments. Regards, Ivan -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
