AD8366 Driver upstream update #3026

rodrigo455 · 2025-11-21T16:54:44Z

PR Description

This series modernizes the AD8366 amplifier/attenuator driver and adds support for additional device variants.

Adds support for HMC271 (legacy/obsolete part maintained in ADI tree)
Adds support for multiple digital step attenuators:
ADRF5720: 0.5 dB LSB, 6-Bit, Digital Attenuator, 9 kHz to 40 GHz
ADRF5730: 0.5 dB LSB, 6-Bit, Digital Attenuator, 100 MHz to 40 GHz
ADRF5731: 2 dB LSB, 4-Bit, Digital Attenuator, 100 MHz to 40 GHz
HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz
HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz

Device Tree Support:

Adds device tree binding documentation
Adds device tree compatible strings for all supported devices

PR Type

Bug fix (a change that fixes an issue)
New feature (a change that adds new functionality)
Breaking change (a change that affects other repos or cause CIs to fail)

PR Checklist

I have conducted a self-review of my own code changes
I have compiled my changes, including the documentation
I have tested the changes on the relevant hardware
I have updated the documentation outside this repo accordingly
I have provided links for the relevant upstream lore

This patch series modernizes the AD8366 amplifier/attenuator driver with several improvements and adds support for additional device variants. Device Support Expansion: - Adds support for HMC271 (legacy/obsolete part maintained in ADI tree) - Adds support for multiple digital step attenuators: - ADRF5720: 0.5 dB LSB, 6-Bit, Digital Attenuator, 9 kHz to 40 GHz - ADRF5730: 0.5 dB LSB, 6-Bit, Digital Attenuator, 100 MHz to 40 GHz - ADRF5731: 2 dB LSB, 4-Bit, Digital Attenuator, 100 MHz to 40 GHz - HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz - HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz Device Tree Support: - Adds device tree binding documentation - Adds device tree compatible strings for all supported devices # Describe the purpose of this series. The information you put here # will be used by the project maintainer to make a decision whether # your patches should be reviewed, and in what priority order. Please be # very detailed and link to any relevant discussions or sites that the # maintainer can review to better understand your proposed changes. If you # only have a single patch in your series, the contents of the cover # letter will be appended to the "under-the-cut" portion of the patch. # Lines starting with # will be removed from the cover letter. You can # use them to add notes or reminders to yourself. If you want to use # markdown headers in your cover letter, start the line with ">#". # You can add trailers to the cover letter. Any email addresses found in # these trailers will be added to the addresses specified/generated # during the b4 send stage. You can also run "b4 prep --auto-to-cc" to # auto-populate the To: and Cc: trailers based on the code being # modified. Signed-off-by: Rodrigo Alencar <[email protected]> --- b4-submit-tracking --- # This section is used internally by b4 prep for tracking purposes. { "series": { "revision": 1, "change-id": "20251121-iio-ad8366-update-56abac58bbca", "prefixes": [] } }

nunojsa

You should still add your sob tag for Michael's patches. If you actually change them in any meaningful way you should add co-authored-by tag. See git log for examples

nunojsa · 2025-11-24T12:45:38Z

drivers/iio/amplifiers/ad8366.c

 *   HMC1119 0.25 dB LSB, 7-Bit, Silicon Digital Attenuator
 *
- * Copyright 2012-2019 Analog Devices Inc.
+ * Copyright 2012-2021 Analog Devices Inc.


if we are changing this, better to update to the current year :)

a later commit performs the update. I haven't modified the commits I cherry-picked

nunojsa · 2025-11-24T13:01:43Z

drivers/iio/amplifiers/ad8366.c

 		}
+
+		st->enable_gpio = devm_gpiod_get(&spi->dev, "enable",
+			GPIOD_OUT_HIGH);


Is this really mandatory? Im also not seeing it being used anywhere so I kind of wonder why do we need it and how is it different from the reset gpio (I have not looked into the datasheet)

it is optional, will fix it. apparently only a few of those may have reset/enable pins, most of them do not.

nunojsa · 2025-11-24T13:04:44Z

drivers/iio/amplifiers/ad8366.c

 			break;
 		case ID_ADRF5731:
-			gain = -30000 + code * 500;
+			gain = -1 * code * 500;


This should be the first patch in the series. Fixes go first since we want to backport them and do not want to depend on additional patches

this one goes right after the support added to ADRF573x, no?
I cherry-picked Michael's commits, haven't changed them.

oh, if this is fixing a patch in this series, just squash it then. It does not make sense (from an upstream perspective,) to send a patch with a bug to then fix it in the same patch series.

nunojsa · 2025-11-24T13:07:49Z

Documentation/devicetree/bindings/iio/amplifiers/adi,ad8366.yaml

@@ -0,0 +1,98 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)


Comment on the commit subject. Don't mention "binding" in the subject. It is already obvious and the maintainers will complain it. See the git log for examples. Also, the binding should come before the driver changes.

nunojsa · 2025-11-24T13:10:07Z

MAINTAINERS

 S:	Supported
 W:	https://ez.analog.com/linux-software-drivers
 F:	Documentation/devicetree/bindings/iio/amplifiers/adi,ad8366.yaml
+F:	drivers/iio/amplifiers/ad8366.c


This is a lot of changes for one patch. Do one logical change per patch if you really want to modernize it.

nunojsa · 2025-11-24T13:10:54Z

drivers/iio/amplifiers/ad8366.c

+		st->enable_gpio = devm_gpiod_get(&spi->dev, "enable", GPIOD_OUT_HIGH);
+		if (IS_ERR(st->enable_gpio))
+			return dev_err_probe(&spi->dev, PTR_ERR(st->enable_gpio),
+					     "Failed to get enable GPIO\n");


This needs to go into the patch adding this. Does not make sense to only fix it now

nunojsa · 2025-11-24T13:12:03Z

drivers/iio/amplifiers/ad8366.c

+	{ .compatible = "adi,hmc792a" },
+	{ .compatible = "adi,hmc1018a" },
+	{ .compatible = "adi,hmc1019a" },
+	{ .compatible = "adi,hmc1119" },


Since you are adding this, you might get asked to remove the enum (for the device ID) and have a struct per model. It is the preferred way in IIO

Add device tree binding documentation for amplifiers and digital attenuators. This covers different device variants with similar SPI control. Signed-off-by: Rodrigo Alencar <[email protected]>

This patch adds support for following digital step attenuators: * HMC271A: 1dB LSB 5-Bit Digital Attenuator SMT, 0.7 - 3.7 GHz * ADRF5720: 0.5 dB LSB, 6-Bit, Digital Attenuator, 9 kHz to 40 GHz * ADRF5730: 0.5 dB LSB, 6-Bit, Digital Attenuator, 100 MHz to 40 GHz * ADRF5731: 2 dB LSB, 4-Bit, Digital Attenuator, 100 MHz to 40 GHz * HMC1018A: 1.0 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz * HMC1019A: 0.5 dB LSB GaAs MMIC 5-BIT DIGITAL ATTENUATOR, 0.1 - 30 GHz Co-authored-by: Alexandru Ardelean <[email protected]> Co-authored-by: Michael Hennerich <[email protected]> Signed-off-by: Alexandru Ardelean <[email protected]> Signed-off-by: Michael Hennerich <[email protected]> Signed-off-by: Rodrigo Alencar <[email protected]>

use guard() from cleanup for mutex locking. replace mutex_init() for devm_mutex_init(). Signed-off-by: Rodrigo Alencar <[email protected]>

Device resource managed simplified with: - voltage regulator managed internally. - IIO device registration handled with devm_iio_device_register(). - removal of goto's from the probe function. - ad8366_remove() removed as it is not needed anymore. Also, dev_err_probe() is used to report probe errors. Signed-off-by: Rodrigo Alencar <[email protected]>

device-tree support achieved dropping the enum ID in favor of the chip info table. With this, switch cases on the device type were dropped. Signed-off-by: Rodrigo Alencar <[email protected]>

rodrigo455 requested review from CiprianRegus, amiclaus, btogorean, buha, chegbeli, danmois, dbogdan, machschmitt, mhennerich, nunojsa and rbolboac as code owners November 21, 2025 16:54

rodrigo455 marked this pull request as draft November 21, 2025 16:56

rodrigo455 force-pushed the staging/jic23_iio_ad8366-update branch from 378f2b8 to df90254 Compare November 21, 2025 17:08

github-actions bot force-pushed the mirror_ci/jic23/iio/testing branch 3 times, most recently from 573459b to 3982c2b Compare November 23, 2025 23:59

nunojsa reviewed Nov 24, 2025

View reviewed changes

rodrigo455 and others added 5 commits November 24, 2025 13:53

dt-bindings: iio: amplifiers: Add AD8366

16b1563

Add device tree binding documentation for amplifiers and digital attenuators. This covers different device variants with similar SPI control. Signed-off-by: Rodrigo Alencar <[email protected]>

iio: amplifiers: ad8366: use cleanup.h mutex guard

02cd171

use guard() from cleanup for mutex locking. replace mutex_init() for devm_mutex_init(). Signed-off-by: Rodrigo Alencar <[email protected]>

iio: amplifiers: ad8366: add device tree support

02e319f

device-tree support achieved dropping the enum ID in favor of the chip info table. With this, switch cases on the device type were dropped. Signed-off-by: Rodrigo Alencar <[email protected]>

rodrigo455 force-pushed the staging/jic23_iio_ad8366-update branch from df90254 to 02e319f Compare November 24, 2025 18:09

github-actions bot force-pushed the mirror_ci/jic23/iio/testing branch from 3982c2b to e333a0d Compare November 24, 2025 23:59

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AD8366 Driver upstream update #3026

AD8366 Driver upstream update #3026

rodrigo455 commented Nov 21, 2025 •

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		@@ -0,0 +1,98 @@
		# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)

AD8366 Driver upstream update #3026

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AD8366 Driver upstream update #3026

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rodrigo455 commented Nov 21, 2025 •

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