iio: amplifiers: adl8113: add driver support

Add support for adl8113 10MHz to 12GHz Low Noise Amplifier with
10MHz to 14GHz bypass switches.

Signed-off-by: Antoniu Miclaus <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>

Author: amiclaus

drivers/iio/amplifiers/Kconfig

@@ -36,6 +36,18 @@ config ADA4250
 	  To compile this driver as a module, choose M here: the
 	  module will be called ada4250.
 
+config ADL8113
+	tristate "Analog Devices ADL8113 Low Noise Amplifier"
+	depends on GPIOLIB
+	help
+	  Say yes here to build support for Analog Devices ADL8113 Low Noise
+	  Amplifier with integrated bypass switches. The device supports four
+	  operation modes controlled by GPIO pins: internal amplifier,
+	  internal bypass, and two external bypass modes.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called adl8113.
+
 config HMC425
 	tristate "Analog Devices HMC425A and similar GPIO Gain Amplifiers"
 	depends on GPIOLIB

drivers/iio/amplifiers/Makefile

@@ -6,4 +6,5 @@
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_AD8366) += ad8366.o
 obj-$(CONFIG_ADA4250) += ada4250.o
+obj-$(CONFIG_ADL8113) += adl8113.o
 obj-$(CONFIG_HMC425) += hmc425a.o

drivers/iio/amplifiers/adl8113.c

@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ADL8113 Low Noise Amplifier with integrated bypass switches
+ *
+ * Copyright 2025 Analog Devices Inc.
+ */
+
+#include <linux/array_size.h>
+#include <linux/bitmap.h>
+#include <linux/device/driver.h>
+#include <linux/dev_printk.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/iio.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regulator/consumer.h>
+#include <linux/types.h>
+
+enum adl8113_signal_path {
+	ADL8113_INTERNAL_AMP,
+	ADL8113_INTERNAL_BYPASS,
+	ADL8113_EXTERNAL_A,
+	ADL8113_EXTERNAL_B,
+};
+
+struct adl8113_gain_config {
+	enum adl8113_signal_path path;
+	int gain_db;
+};
+
+struct adl8113_state {
+	struct gpio_descs *gpios;
+	struct adl8113_gain_config *gain_configs;
+	unsigned int num_gain_configs;
+	enum adl8113_signal_path current_path;
+};
+
+static const char * const adl8113_supply_names[] = {
+	"vdd1",
+	"vss2",
+	"vdd2",
+};
+
+static int adl8113_set_path(struct adl8113_state *st,
+			    enum adl8113_signal_path path)
+{
+	DECLARE_BITMAP(values, 2);
+	int ret;
+
+	/*
+	 * Determine GPIO values based on signal path.
+	 * Va: bit 0, Vb: bit 1.
+	 */
+	switch (path) {
+	case ADL8113_INTERNAL_AMP:
+		bitmap_write(values, 0x00, 0, 2);
+		break;
+	case ADL8113_INTERNAL_BYPASS:
+		bitmap_write(values, 0x03, 0, 2);
+		break;
+	case ADL8113_EXTERNAL_A:
+		bitmap_write(values, 0x02, 0, 2);
+		break;
+	case ADL8113_EXTERNAL_B:
+		bitmap_write(values, 0x01, 0, 2);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	ret = gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc,
+					     st->gpios->info, values);
+	if (ret)
+		return ret;
+
+	st->current_path = path;
+	return 0;
+}
+
+static int adl8113_find_gain_config(struct adl8113_state *st, int gain_db)
+{
+	unsigned int i;
+
+	for (i = 0; i < st->num_gain_configs; i++) {
+		if (st->gain_configs[i].gain_db == gain_db)
+			return i;
+	}
+	return -EINVAL;
+}
+
+static const struct iio_chan_spec adl8113_channels[] = {
+	{
+		.type = IIO_VOLTAGE,
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN),
+	},
+};
+
+static int adl8113_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct adl8113_state *st = iio_priv(indio_dev);
+	unsigned int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		/* Find current gain configuration */
+		for (i = 0; i < st->num_gain_configs; i++) {
+			if (st->gain_configs[i].path == st->current_path) {
+				*val = st->gain_configs[i].gain_db;
+				*val2 = 0;
+				return IIO_VAL_INT_PLUS_MICRO_DB;
+			}
+		}
+		return -EINVAL;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int adl8113_write_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int val, int val2, long mask)
+{
+	struct adl8113_state *st = iio_priv(indio_dev);
+	int config_idx;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_HARDWAREGAIN:
+		if (val2 != 0)
+			return -EINVAL;
+
+		config_idx = adl8113_find_gain_config(st, val);
+		if (config_idx < 0)
+			return config_idx;
+
+		return adl8113_set_path(st, st->gain_configs[config_idx].path);
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_info adl8113_info = {
+	.read_raw = adl8113_read_raw,
+	.write_raw = adl8113_write_raw,
+};
+
+static int adl8113_init_gain_configs(struct device *dev, struct adl8113_state *st)
+{
+	int external_a_gain, external_b_gain;
+	unsigned int i;
+
+	/*
+	 * Allocate for all 4 possible paths:
+	 * - Internal amp and bypass (always present)
+	 * - External bypass A and B (optional if configured)
+	 */
+	st->gain_configs = devm_kcalloc(dev, 4, sizeof(*st->gain_configs),
+					GFP_KERNEL);
+	if (!st->gain_configs)
+		return -ENOMEM;
+
+	/* Start filling the gain configurations with data */
+	i = 0;
+
+	/* Always include internal amplifier (14dB) */
+	st->gain_configs[i++] = (struct adl8113_gain_config) {
+		.path = ADL8113_INTERNAL_AMP,
+		.gain_db = 14,
+	};
+
+	/* Always include internal bypass (-2dB insertion loss) */
+	st->gain_configs[i++] = (struct adl8113_gain_config) {
+		.path = ADL8113_INTERNAL_BYPASS,
+		.gain_db = -2,
+	};
+
+	/* Add external bypass A if configured */
+	if (!device_property_read_u32(dev, "adi,external-bypass-a-gain-db",
+				      &external_a_gain)) {
+		st->gain_configs[i++] = (struct adl8113_gain_config) {
+			.path = ADL8113_EXTERNAL_A,
+			.gain_db = external_a_gain,
+		};
+	}
+
+	/* Add external bypass B if configured */
+	if (!device_property_read_u32(dev, "adi,external-bypass-b-gain-db",
+				      &external_b_gain)) {
+		st->gain_configs[i++] = (struct adl8113_gain_config) {
+			.path = ADL8113_EXTERNAL_B,
+			.gain_db = external_b_gain,
+		};
+	}
+
+	st->num_gain_configs = i;
+
+	return 0;
+}
+
+static int adl8113_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct adl8113_state *st;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->gpios = devm_gpiod_get_array(dev, "ctrl", GPIOD_OUT_LOW);
+	if (IS_ERR(st->gpios))
+		return dev_err_probe(dev, PTR_ERR(st->gpios),
+				     "failed to get control GPIOs\n");
+
+	if (st->gpios->ndescs != 2)
+		return dev_err_probe(dev, -EINVAL,
+				     "expected 2 control GPIOs, got %u\n",
+				     st->gpios->ndescs);
+
+	ret = devm_regulator_bulk_get_enable(dev,
+					     ARRAY_SIZE(adl8113_supply_names),
+					     adl8113_supply_names);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "failed to get and enable supplies\n");
+
+	/* Initialize gain configurations from devicetree */
+	ret = adl8113_init_gain_configs(dev, st);
+	if (ret)
+		return ret;
+
+	/* Initialize to internal amplifier path (14dB) */
+	ret = adl8113_set_path(st, ADL8113_INTERNAL_AMP);
+	if (ret)
+		return ret;
+
+	indio_dev->info = &adl8113_info;
+	indio_dev->name = "adl8113";
+	indio_dev->channels = adl8113_channels;
+	indio_dev->num_channels = ARRAY_SIZE(adl8113_channels);
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct of_device_id adl8113_of_match[] = {
+	{ .compatible = "adi,adl8113" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, adl8113_of_match);
+
+static struct platform_driver adl8113_driver = {
+	.driver = {
+		.name = "adl8113",
+		.of_match_table = adl8113_of_match,
+	},
+	.probe = adl8113_probe,
+};
+module_platform_driver(adl8113_driver);
+
+MODULE_AUTHOR("Antoniu Miclaus <[email protected]>");
+MODULE_DESCRIPTION("Analog Devices ADL8113 Low Noise Amplifier");
+MODULE_LICENSE("GPL");