Add support for adl8113 10MHz to 12GHz Low Noise Amplifier with
10MHz to 14GHz bypass switches.
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
---
no changes in v6.
drivers/iio/amplifiers/Kconfig | 12 ++
drivers/iio/amplifiers/Makefile | 1 +
drivers/iio/amplifiers/adl8113.c | 290 +++++++++++++++++++++++++++++++
3 files changed, 303 insertions(+)
create mode 100644 drivers/iio/amplifiers/adl8113.c
diff --git a/drivers/iio/amplifiers/Kconfig b/drivers/iio/amplifiers/Kconfig
index 55eb16b32f6c..a8a604863eed 100644
--- a/drivers/iio/amplifiers/Kconfig
+++ b/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
diff --git a/drivers/iio/amplifiers/Makefile b/drivers/iio/amplifiers/Makefile
index 2126331129cf..0a76443be1aa 100644
--- a/drivers/iio/amplifiers/Makefile
+++ b/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
diff --git a/drivers/iio/amplifiers/adl8113.c b/drivers/iio/amplifiers/adl8113.c
new file mode 100644
index 000000000000..eed5fe69280b
--- /dev/null
+++ b/drivers/iio/amplifiers/adl8113.c
@@ -0,0 +1,290 @@
+// 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/device.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/slab.h>
+#include <linux/sysfs.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;
+ int va;
+ int vb;
+};
+
+struct adl8113_state {
+ struct gpio_descs *gpios;
+ struct adl8113_gain_config *gain_configs;
+ 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;
+
+ bitmap_zero(values, 2);
+
+ /* Determine GPIO values based on signal path */
+ switch (path) {
+ case ADL8113_INTERNAL_AMP:
+ /* va=0, vb=0 - already zero */
+ break;
+ case ADL8113_INTERNAL_BYPASS:
+ /* va=1, vb=1 */
+ __set_bit(0, values);
+ __set_bit(1, values);
+ break;
+ case ADL8113_EXTERNAL_A:
+ /* va=0, vb=1 */
+ __set_bit(1, values);
+ break;
+ case ADL8113_EXTERNAL_B:
+ /* va=1, vb=0 */
+ __set_bit(0, values);
+ 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)
+{
+ 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);
+ 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, i = 0, j;
+
+ /*
+ * Allocate for all 4 possible paths:
+ * - Internal amp and bypass (always present)
+ * - External bypass A and B (optional, or INT_MIN for testing)
+ */
+ st->gain_configs = devm_kcalloc(dev, 4,
+ sizeof(*st->gain_configs), GFP_KERNEL);
+ if (!st->gain_configs)
+ return -ENOMEM;
+
+ /* Always include internal amplifier (14dB) */
+ st->gain_configs[i].path = ADL8113_INTERNAL_AMP;
+ st->gain_configs[i].gain_db = 14;
+ i++;
+
+ /* Always include internal bypass (-2dB insertion loss) */
+ st->gain_configs[i].path = ADL8113_INTERNAL_BYPASS;
+ st->gain_configs[i].gain_db = -2;
+ i++;
+
+ /* 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].path = ADL8113_EXTERNAL_A;
+ st->gain_configs[i].gain_db = external_a_gain;
+ i++;
+ }
+
+ /* 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].path = ADL8113_EXTERNAL_B;
+ st->gain_configs[i].gain_db = external_b_gain;
+ i++;
+ }
+
+ /*
+ * If there's a free external bypass path, add one with INT_MIN gain
+ * to represent "nothing connected" for testing purposes
+ */
+ if (!device_property_present(dev, "adi,external-bypass-a-gain-db")) {
+ st->gain_configs[i].path = ADL8113_EXTERNAL_A;
+ st->gain_configs[i].gain_db = INT_MIN;
+ i++;
+ } else if (!device_property_present(dev, "adi,external-bypass-b-gain-db")) {
+ st->gain_configs[i].path = ADL8113_EXTERNAL_B;
+ st->gain_configs[i].gain_db = INT_MIN;
+ i++;
+ }
+
+ st->num_gain_configs = i;
+
+ /* Check for duplicate gain values */
+ for (i = 0; i < st->num_gain_configs - 1; i++) {
+ for (j = i + 1; j < st->num_gain_configs; j++) {
+ if (st->gain_configs[i].gain_db == st->gain_configs[j].gain_db)
+ return dev_err_probe(dev, -EINVAL,
+ "Duplicate gain values not allowed: %d dB\n",
+ st->gain_configs[i].gain_db);
+ }
+ }
+
+ 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 %d\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 <antoniu.miclaus@analog.com>");
+MODULE_DESCRIPTION("Analog Devices ADL8113 Low Noise Amplifier");
+MODULE_LICENSE("GPL");
--
2.43.0On Fri, 5 Dec 2025 16:40:41 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
> Add support for adl8113 10MHz to 12GHz Low Noise Amplifier with
> 10MHz to 14GHz bypass switches.
>
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
Hi Antoniu,
> no changes in v6.
Given I assume you just missed Andy's prior review I'll take
a look at this version with assumption both sets of comments will be
sorted for v7.
A few things inline.
> diff --git a/drivers/iio/amplifiers/adl8113.c b/drivers/iio/amplifiers/adl8113.c
> new file mode 100644
> index 000000000000..eed5fe69280b
> --- /dev/null
> +++ b/drivers/iio/amplifiers/adl8113.c
> +struct adl8113_gain_config {
> + enum adl8113_signal_path path;
> + int gain_db;
> + int va;
> + int vb;
What are va and vb for? Currently seem unused because you derive
them from path at use point.
> +};
> +
> +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, i = 0, j;
Preference for not hiding initializations in a list where only one is initialized.
int external_a_gain, external_b_gain, j;
int i = 0;
makes it easier to spot.
> +
> + /*
> + * Allocate for all 4 possible paths:
> + * - Internal amp and bypass (always present)
> + * - External bypass A and B (optional, or INT_MIN for testing)
> + */
> + st->gain_configs = devm_kcalloc(dev, 4,
> + sizeof(*st->gain_configs), GFP_KERNEL);
Slightly odd wrap. I'd move the sizeof() up a line.
> + if (!st->gain_configs)
> + return -ENOMEM;
> +
> + /* Always include internal amplifier (14dB) */
> + st->gain_configs[i].path = ADL8113_INTERNAL_AMP;
> + st->gain_configs[i].gain_db = 14;
Could do this as something like:
st->gain_configs[i++] = (struct adl8113_gain_config) {
.path = ADL8113_INTERNAL_AMP,
.gain_db = 14,
};
st->gain_configs[i++] = (struct adl8113_gain_config) {
.path = ADL8113_INTERNAL_BYPASS,
.gain_db = -2,
};
etc.
> + i++;
> +
> + /* Always include internal bypass (-2dB insertion loss) */
> + st->gain_configs[i].path = ADL8113_INTERNAL_BYPASS;
> + st->gain_configs[i].gain_db = -2;
> + i++;
> +
> + /* 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].path = ADL8113_EXTERNAL_A;
> + st->gain_configs[i].gain_db = external_a_gain;
> + i++;
> + }
> +
> + /* 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].path = ADL8113_EXTERNAL_B;
> + st->gain_configs[i].gain_db = external_b_gain;
> + i++;
> + }
> +
> + /*
> + * If there's a free external bypass path, add one with INT_MIN gain
> + * to represent "nothing connected" for testing purposes
I don't follow this one. What sort of testing purpose? Something we want
in a real system?
> + */
> + if (!device_property_present(dev, "adi,external-bypass-a-gain-db")) {
> + st->gain_configs[i].path = ADL8113_EXTERNAL_A;
> + st->gain_configs[i].gain_db = INT_MIN;
> + i++;
> + } else if (!device_property_present(dev, "adi,external-bypass-b-gain-db")) {
> + st->gain_configs[i].path = ADL8113_EXTERNAL_B;
> + st->gain_configs[i].gain_db = INT_MIN;
> + i++;
> + }
> +
> + st->num_gain_configs = i;
> +
> + /* Check for duplicate gain values */
> + for (i = 0; i < st->num_gain_configs - 1; i++) {
> + for (j = i + 1; j < st->num_gain_configs; j++) {
> + if (st->gain_configs[i].gain_db == st->gain_configs[j].gain_db)
> + return dev_err_probe(dev, -EINVAL,
> + "Duplicate gain values not allowed: %d dB\n",
> + st->gain_configs[i].gain_db);
What happens if we just don't bother enforcing this? I assume the second of the duplicates
can't be selected? Do we care beyond it being silly?
> + }
> + }
> +
> + return 0;
> +}
On Sat, Dec 06, 2025 at 07:03:32PM +0000, Jonathan Cameron wrote:
> On Fri, 5 Dec 2025 16:40:41 +0200
> Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
...
> > + /* Always include internal amplifier (14dB) */
> > + st->gain_configs[i].path = ADL8113_INTERNAL_AMP;
> > + st->gain_configs[i].gain_db = 14;
>
> Could do this as something like:
I remember a discussion where it was against this approach due to compiler
warnings or so. However, IIRC, there was slightly different pattern, i.e.
foo[i].bar = ...
foo[i++].baz = ...
That said, I have no objection to your proposal, but we need to use it with
a good compile test coverage (clang with `make W=1` for a starter.
OTOH, the original code is robust enough...
> st->gain_configs[i++] = (struct adl8113_gain_config) {
> .path = ADL8113_INTERNAL_AMP,
> .gain_db = 14,
> };
...and doesn't require a good understanding of differences between designated
initialisers and compound literals.
> st->gain_configs[i++] = (struct adl8113_gain_config) {
> .path = ADL8113_INTERNAL_BYPASS,
> .gain_db = -2,
> };
--
With Best Regards,
Andy Shevchenko
On Sat, 6 Dec 2025 22:48:19 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:
> On Sat, Dec 06, 2025 at 07:03:32PM +0000, Jonathan Cameron wrote:
> > On Fri, 5 Dec 2025 16:40:41 +0200
> > Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:
>
> ...
>
> > > + /* Always include internal amplifier (14dB) */
> > > + st->gain_configs[i].path = ADL8113_INTERNAL_AMP;
> > > + st->gain_configs[i].gain_db = 14;
> >
> > Could do this as something like:
>
> I remember a discussion where it was against this approach due to compiler
> warnings or so. However, IIRC, there was slightly different pattern, i.e.
>
> foo[i].bar = ...
> foo[i++].baz = ...
>
> That said, I have no objection to your proposal, but we need to use it with
> a good compile test coverage (clang with `make W=1` for a starter.
That's my standard 1st build choice now because it seems to be fussiest ;)
I haven't tried this one however.
Googling came up with a link saying GCC gives warnings on cases where
not all structure elements are set. I think they always should be here
though which may make this fine (and act as a correct warning if they aren't).
That only works if the two uninitialized structure elements are dropped
obviously!
>
> OTOH, the original code is robust enough...
>
> > st->gain_configs[i++] = (struct adl8113_gain_config) {
> > .path = ADL8113_INTERNAL_AMP,
> > .gain_db = 14,
> > };
>
> ...and doesn't require a good understanding of differences between designated
> initialisers and compound literals.
Fair enough. Original is better than the i++ in only the second in my view.
Jonathan
>
> > st->gain_configs[i++] = (struct adl8113_gain_config) {
> > .path = ADL8113_INTERNAL_BYPASS,
> > .gain_db = -2,
> > };
>
>
On Fri, Dec 05, 2025 at 04:40:41PM +0200, Antoniu Miclaus wrote: > Add support for adl8113 10MHz to 12GHz Low Noise Amplifier with > 10MHz to 14GHz bypass switches. ... > no changes in v6. This is surprisingly interesting. https://lore.kernel.org/linux-iio/CAHp75VcxYGskVpQ5HKiFUUnNSj-9qpdXeBjz9-oEHc9eumE0fg@mail.gmail.com/ -- With Best Regards, Andy Shevchenko
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