Re: [PATCH 5/5] dt-bindings: iio: Add adis16475 documentation

Sa, Nuno
2020-03-03T09:44:10Z

On Mon, 2020-03-02 at 16:22 -0600, Rob Herring wrote:
> On Tue, Feb 25, 2020 at 01:41:52PM +0100, Nuno Sá wrote:
> > Document the ADIS16475 device devicetree bindings.
> >
> > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > ---
> > .../bindings/iio/imu/adi,adis16475.yaml | 130
> > ++++++++++++++++++
> > MAINTAINERS | 1 +
> > 2 files changed, 131 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
> > b/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
> > new file mode 100644
> > index 000000000000..c0f2146e000c
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
> > @@ -0,0 +1,130 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/imu/adi,adis16475.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Analog Devices ADIS16475 and similar IMUs
> > +
> > +maintainers:
> > + - Nuno Sá <nuno.sa@analog.com>
> > +
> > +description: |
> > + Analog Devices ADIS16475 and similar IMUs
> > +
> > https://www.analog.com/media/en/technical-documentation/data-sheets/ADIS16475.pdf
> > +
> > +properties:
> > + compatible:
> > + enum:
> > + - adi,adis16475-1
> > + - adi,adis16475-2
> > + - adi,adis16475-3
> > + - adi,adis16477-1
> > + - adi,adis16477-2
> > + - adi,adis16477-3
> > + - adi,adis16470
> > + - adi,adis16465-1
> > + - adi,adis16465-2
> > + - adi,adis16465-3
> > + - adi,adis16467-1
> > + - adi,adis16467-2
> > + - adi,adis16467-3
> > + - adi,adis16500
> > + - adi,adis16505-1
> > + - adi,adis16505-2
> > + - adi,adis16505-3
> > + - adi,adis16507-1
> > + - adi,adis16507-2
> > + - adi,adis16507-3
> > +
> > + reg:
> > + maxItems: 1
> > +
> > + spi-cpha: true
> > +
> > + spi-cpol: true
> > +
> > + spi-max-frequency:
> > + maximum: 2000000
> > +
> > + interrupts:
> > + maxItems: 1
> > +
> > + clocks:
> > + maxItems: 1
> > +
> > + clock-names:
> > + oneOf:
> > + - const: sync
> > + - const: direct-sync
> > + - const: pulse-sync
> > + - const: scaled-sync
>
> According to the datasheet I looked at, the input is called 'sync'.
> It
> looks like you are mixing operating mode and clock connection.

The sync pin is where the external clock should be connected (when
available). I'm kinda of using the clock-name property as a way of
selecting the mode the user wants to use as done in other devices (
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/iio/imu/adi,adis16480.txt
). In the end, what we should have in the sync pin is an external clock
with the exception of the `sync` mode. I guess this one could be called
output-sync and, in this case, the sync pin is actually an output pin
pulsing when the internal processor collects data.

I'm ok in changing it if there's a better way of doing it... Do you
have any suggestion?

-Nuno Sá
> > +
> > + reset-gpios:
> > + description:
> > + Must be the device tree identifier of the RESET pin. If
> > specified,
> > + it will be asserted during driver probe. As the line is
> > active low,
> > + it should be marked GPIO_ACTIVE_LOW.
> > + maxItems: 1
> > +
> > + adi,scaled-output-hz:
> > + description:
> > + This property must be present if the clock mode is scaled-
> > sync through
> > + clock-names property. In this mode, the input clock can have
> > a range
> > + of 1Hz to 128HZ which must be scaled to originate an
> > allowable sample
> > + rate. This property specifies that rate.
> > + minimum: 1900
> > + maximum: 2100
> > +
> > +required:
> > + - compatible
> > + - reg
> > + - interrupts
> > + - spi-cpha
> > + - spi-cpol
> > +
> > +if:
> > + properties:
> > + compatible:
> > + contains:
> > + enum:
> > + - adi,adis16500
> > + - adi,adis16505-1
> > + - adi,adis16505-2
> > + - adi,adis16505-3
> > + - adi,adis16507-1
> > + - adi,adis16507-2
> > + - adi,adis16507-3
> > +
> > +then:
> > + properties:
> > + clock-names:
> > + oneOf:
> > + - const: sync
> > + - const: direct-sync
> > + - const: scaled-sync
> > +
> > + adi,burst32-enable:
> > + description:
> > + Enable burst32 mode. In this mode, a burst reading
> > contains calibrated
> > + gyroscope and accelerometer data in 32-bit format.
> > + type: boolean
> > +
> > +examples:
> > + - |
> > + #include <dt-bindings/interrupt-controller/irq.h>
> > + spi {
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > +
> > + adis16475: adis16475-3@0 {
> > + compatible = "adi,adis16475-3";
> > + reg = <0>;
> > + spi-cpha;
> > + spi-cpol;
> > + spi-max-frequency = <2000000>;
> > + interrupts = <4 IRQ_TYPE_EDGE_RISING>;
> > + interrupt-parent = <&gpio>;
> > + };
> > + };
> > +...
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index f11262f1f3bb..f8ccc92ab378 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -1015,6 +1015,7 @@ W:
> > http://ez.analog.com/community/linux-device-drivers
> > S: Supported
> > F: drivers/iio/imu/adis16475.c
> > F: Documentation/ABI/testing/sysfs-bus-iio-imu-adis16475
> > +F: Documentation/devicetree/bindings/iio/imu/adi,adis16475.yaml
> >
> > ANALOG DEVICES INC ADM1177 DRIVER
> > M: Beniamin Bia <beniamin.bia@analog.com>
> > --
> > 2.25.1