Re: [PATCH] dt-bindings: iio: adc: add adi,ad7780.yaml binding
From: Renato Lui Geh
Date: Fri May 24 2019 - 20:31:18 EST
Hi Jonathan, Alex,
Thanks for the review. Some comments inline.
Thanks,
Renato
On 05/20, Ardelean, Alexandru wrote:
On Sun, 2019-05-19 at 12:32 +0100, Jonathan Cameron wrote:
[External]
On Sat, 18 May 2019 19:41:12 -0300
Renato Lui Geh <renatogeh@xxxxxxxxx> wrote:
> This patch adds a YAML binding for the Analog Devices AD7780/1 and
> AD7170/1 analog-to-digital converters.
>
> Signed-off-by: Renato Lui Geh <renatogeh@xxxxxxxxx>
One comment inline. I'll also be needing an ack from Analog on this,
preferably Michael's.
Thanks,
Jonathan
> ---
> .../bindings/iio/adc/adi,ad7780.txt | 48 -----------
> .../bindings/iio/adc/adi,ad7780.yaml | 85 +++++++++++++++++++
You should also update the MAINTAINERS file.
Maybe in a following patch.
It looks like there is not entry in there, so maybe you need to add a new
one.
Something like:
ANALOG DEVICES INC AD7780 DRIVER
M: Michael Hennerich <Michael.Hennerich@xxxxxxxxxx>
M: Renato Lui Geh <renatogeh@xxxxxxxxx>
L: linux-iio@xxxxxxxxxxxxxxx
W: http://ez.analog.com/community/linux-device-drivers
S: Supported
F: drivers/iio/adc/ad7780.c
F: Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
This should be after this block
ANALOG DEVICES INC AD7768-1 DRIVER
Note that I added you as a co-maintainer.
If you want, you do not need to add that line.
> 2 files changed, 85 insertions(+), 48 deletions(-)
> delete mode 100644
> Documentation/devicetree/bindings/iio/adc/adi,ad7780.txt
> create mode 100644
> Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
>
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7780.txt
> b/Documentation/devicetree/bindings/iio/adc/adi,ad7780.txt
> deleted file mode 100644
> index 440e52555349..000000000000
> --- a/Documentation/devicetree/bindings/iio/adc/adi,ad7780.txt
> +++ /dev/null
> @@ -1,48 +0,0 @@
> -* Analog Devices AD7170/AD7171/AD7780/AD7781
> -
> -Data sheets:
> -
> -- AD7170:
> - *
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7170.pdf
> -- AD7171:
> - *
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7171.pdf
> -- AD7780:
> - *
> https://www.analog.com/media/en/technical-documentation/data-sheets/ad7780.pdf
> -- AD7781:
> - *
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7781.pdf
> -
> -Required properties:
> -
> -- compatible: should be one of
> - * "adi,ad7170"
> - * "adi,ad7171"
> - * "adi,ad7780"
> - * "adi,ad7781"
> -- reg: spi chip select number for the device
> -- vref-supply: the regulator supply for the ADC reference voltage
> -
> -Optional properties:
> -
> -- powerdown-gpios: must be the device tree identifier of the PDRST
> pin. If
> - specified, it will be asserted during driver probe.
> As the
> - line is active high, it should be marked
> GPIO_ACTIVE_HIGH.
> -- adi,gain-gpios: must be the device tree identifier of the GAIN
> pin. Only for
> - the ad778x chips. If specified, it will be asserted
> during
> - driver probe. As the line is active low, it should be
> marked
> - GPIO_ACTIVE_LOW.
> -- adi,filter-gpios: must be the device tree identifier of the FILTER
> pin. Only
> - for the ad778x chips. If specified, it will be
> asserted
> - during driver probe. As the line is active low, it
> should be
> - marked GPIO_ACTIVE_LOW.
> -
> -Example:
> -
> -adc@0 {
> - compatible = "adi,ad7780";
> - reg = <0>;
> - vref-supply = <&vdd_supply>
> -
> - powerdown-gpios = <&gpio 12 GPIO_ACTIVE_HIGH>;
> - adi,gain-gpios = <&gpio 5 GPIO_ACTIVE_LOW>;
> - adi,filter-gpios = <&gpio 15 GPIO_ACTIVE_LOW>;
> -};
> diff --git a/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
> b/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
> new file mode 100644
> index 000000000000..931bc4f8ec04
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/adc/adi,ad7780.yaml
> @@ -0,0 +1,85 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/adc/adi,ad7780.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices AD7170/AD7171/AD7780/AD7781 analog to digital
> converters
> +
> +maintainers:
> + - Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> +
> +description: |
> + The ad7780 is a sigma-delta analog to digital converter. This driver
> provides
> + reading voltage values and status bits from both the ad778x and
> ad717x series.
> + Its interface also allows writing on the FILTER and GAIN GPIO pins
> on the
> + ad778x.
> +
> + Specifications on the converters can be found at:
> + AD7170:
> +
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7170.pdf
> + AD7171:
> +
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7171.pdf
> + AD7780:
> +
> https://www.analog.com/media/en/technical-documentation/data-sheets/ad7780.pdf
> + AD7781:
> +
> https://www.analog.com/media/en/technical-documentation/data-sheets/AD7781.pdf
> +
> +properties:
> + compatible:
> + enum:
> + - adi,ad7170
> + - adi,ad7171
> + - adi,ad7780
> + - adi,ad7781
> +
> + reg:
> + description:
> + Chip select number for the device
No need to add a description.
This is pretty standard.
> + maxItems: 1
> +
> + vref-supply:
> + description:
> + The regulator supply for the ADC reference voltage
> + maxItems: 1
> +
As I see in the driver, it's not vref-supply, it's avdd-supply.
You're absolutely right. Shouldn't have mindlessly copied
from the txt, even though the txt's was also my fault.
By the way, a quick look at ad7170 and ad7780's datasheets
shows that the 7170 uses VDD, and the 7780, AVDD. Are they
equivalent?
> + powerdown-gpios:
> + description:
> + Must be the device tree identifier of the PDRST pin. If
> + specified, it will be asserted during driver probe. As the
> + line is active high, it should be marked GPIO_ACTIVE_HIGH.
> + maxItems: 1
> +
> + adi,gain-gpios:
> + description:
> + Must be the device tree identifier of the GAIN pin. Only for
> + the ad778x chips. 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,filter-gpios:
> + description:
> + Must be the device tree identifier of the FILTER pin. Only
> + for the ad778x chips. If specified, it will be asserted
> + during driver probe. As the line is active low, it should be
> + marked GPIO_ACTIVE_LOW.
> + maxItems: 1
> +
> +required:
> + - compatible
> + - reg
> + - vref-supply
Is that actually true? I'd imagine it'll use a stub regulator if
it isn't supplied.
Hmm, I also think this can be omitted as required.
devm_regulator_get() is used.
devm_regulator_get_exclusive() would be needed to make this required.
I see. So the difference between devm_regulator_get and
devm_regulator_get_optional is that the former uses a stub
when the requested reg isn't supplied, and the latter
doesn't?
> +
> +examples:
> + - |
> + #include <dt-bindings/gpio/gpio.h>
> + adc@0 {
The adc@0 block should be included in a spi block.
So, something like
spi0 {
adc@0 {
compatible = "adi,ad7780";
reg = <0>;
avdd-supply = <&vdd_supply>
powerdown-gpios = <&gpio 12 GPIO_ACTIVE_HIGH>;
adi,gain-gpios = <&gpio 5 GPIO_ACTIVE_LOW>;
adi,filter-gpios = <&gpio 15 GPIO_ACTIVE_LOW>;
};
};
I know this wasn't the case before, but it should be (from what I recall).
> + compatible = "adi,ad7780";
> + reg = <0>;
> + vref-supply = <&vdd_supply>;
> +
> + powerdown-gpios = <&gpio0 12 GPIO_ACTIVE_HIGH>;
> + adi,gain-gpios = <&gpio1 5 GPIO_ACTIVE_LOW>;
> + adi,filter-gpios = <&gpio2 15 GPIO_ACTIVE_LOW>;
Rest looks good.
Thanks
Alex
> + };