[PATCH] staging: iio: adc: ad7816: remove obsolete driver

[PATCH] staging: iio: adc: ad7816: remove obsolete driver

[Joshua Crofts]

The AD7816 driver has been in staging for 16 years and hasn't seen any
significant improvements for it to mature out of staging.

Additionally, the AD7816/AD7817/AD7818 have been obsolete for ~11 years.

Remove the entire adc/ subdirectory and references to it as this is the
only driver in it.

Signed-off-by: Joshua Crofts <joshua.crofts1@gmail.com>
---
If people want to use the AD7816, Analog Devices have their own fork of
the kernel where the driver is present [1].

Also, I don't see a point in keeping the driver for newcomers to
practice on, as all mechanical changes (checkpatch, cocci) have been
applied.

[1] https://github.com/analogdevicesinc/linux/blob/main/drivers/staging/iio/adc/ad7816.c
---
 drivers/staging/iio/Kconfig      |   1 -
 drivers/staging/iio/Makefile     |   1 -
 drivers/staging/iio/adc/Kconfig  |  18 --
 drivers/staging/iio/adc/Makefile |   6 -
 drivers/staging/iio/adc/ad7816.c | 464 -------------------------------
 5 files changed, 490 deletions(-)
 delete mode 100644 drivers/staging/iio/adc/Kconfig
 delete mode 100644 drivers/staging/iio/adc/Makefile
 delete mode 100644 drivers/staging/iio/adc/ad7816.c

diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
index bf6addf2974f..58d6859e039a 100644
--- a/drivers/staging/iio/Kconfig
+++ b/drivers/staging/iio/Kconfig
@@ -5,7 +5,6 @@
 menu "IIO staging drivers"
 	depends on IIO
 
-source "drivers/staging/iio/adc/Kconfig"
 source "drivers/staging/iio/addac/Kconfig"
 source "drivers/staging/iio/frequency/Kconfig"
 source "drivers/staging/iio/impedance-analyzer/Kconfig"
diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
index 739e4cbf9a7a..7768c4a8d278 100644
--- a/drivers/staging/iio/Makefile
+++ b/drivers/staging/iio/Makefile
@@ -3,7 +3,6 @@
 # Makefile for the industrial I/O core.
 #
 
-obj-y += adc/
 obj-y += addac/
 obj-y += frequency/
 obj-y += impedance-analyzer/
diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
deleted file mode 100644
index 2f0d6cf048d2..000000000000
--- a/drivers/staging/iio/adc/Kconfig
+++ /dev/null
@@ -1,18 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-#
-# ADC drivers
-#
-menu "Analog to digital converters"
-
-config AD7816
-	tristate "Analog Devices AD7816/7/8 temperature sensor and ADC driver"
-	depends on SPI
-	depends on GPIOLIB || COMPILE_TEST
-	help
-	  Say yes here to build support for Analog Devices AD7816/7/8
-	  temperature sensors and ADC.
-
-	  To compile this driver as a module, choose M here: the
-	  module will be called ad7816.
-
-endmenu
diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
deleted file mode 100644
index 1e2a94c4db84..000000000000
--- a/drivers/staging/iio/adc/Makefile
+++ /dev/null
@@ -1,6 +0,0 @@
-# SPDX-License-Identifier: GPL-2.0
-#
-# Makefile for industrial I/O ADC drivers
-#
-
-obj-$(CONFIG_AD7816) += ad7816.o
diff --git a/drivers/staging/iio/adc/ad7816.c b/drivers/staging/iio/adc/ad7816.c
deleted file mode 100644
index 2a15d7598abb..000000000000
--- a/drivers/staging/iio/adc/ad7816.c
+++ /dev/null
@@ -1,464 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/*
- * AD7816 digital temperature sensor driver supporting AD7816/7/8
- *
- * Copyright 2010 Analog Devices Inc.
- */
-
-#include <linux/cleanup.h>
-#include <linux/device.h>
-#include <linux/gpio/consumer.h>
-#include <linux/interrupt.h>
-#include <linux/kernel.h>
-#include <linux/list.h>
-#include <linux/module.h>
-#include <linux/mutex.h>
-#include <linux/slab.h>
-#include <linux/spi/spi.h>
-#include <linux/sysfs.h>
-
-#include <linux/iio/events.h>
-#include <linux/iio/iio.h>
-#include <linux/iio/sysfs.h>
-
-/*
- * AD7816 config masks
- */
-#define AD7816_FULL			0x1
-#define AD7816_PD			0x2
-#define AD7816_CS_MASK			0x7
-#define AD7816_CS_MAX			0x4
-
-/*
- * AD7816 temperature masks
- */
-#define AD7816_VALUE_OFFSET		6
-#define AD7816_BOUND_VALUE_BASE		0x8
-#define AD7816_BOUND_VALUE_MIN		-95
-#define AD7816_BOUND_VALUE_MAX		152
-#define AD7816_TEMP_FLOAT_OFFSET	2
-#define AD7816_TEMP_FLOAT_MASK		0x3
-
-/*
- * struct ad7816_chip_info - chip specific information
- */
-
-struct ad7816_chip_info {
-	kernel_ulong_t id;
-	struct spi_device *spi_dev;
-	struct gpio_desc *rdwr_pin;
-	struct gpio_desc *convert_pin;
-	struct gpio_desc *busy_pin;
-	struct mutex lock; /* protect device state during SPI transfers */
-	u8  oti_data[AD7816_CS_MAX + 1];
-	u8  channel_id;	/* 0 always be temperature */
-	u8  mode;
-};
-
-enum ad7816_type {
-	ID_AD7816,
-	ID_AD7817,
-	ID_AD7818,
-};
-
-/*
- * ad7816 data access by SPI
- */
-static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
-{
-	struct spi_device *spi_dev = chip->spi_dev;
-	int ret;
-	__be16 buf;
-
-	guard(mutex)(&chip->lock);
-
-	gpiod_set_value(chip->rdwr_pin, 1);
-	gpiod_set_value(chip->rdwr_pin, 0);
-	ret = spi_write_then_read(spi_dev, &chip->channel_id, sizeof(chip->channel_id), NULL, 0);
-	if (ret < 0) {
-		dev_err(&spi_dev->dev, "SPI channel setting error\n");
-		return ret;
-	}
-	gpiod_set_value(chip->rdwr_pin, 1);
-
-	if (chip->mode == AD7816_PD) { /* operating mode 2 */
-		gpiod_set_value(chip->convert_pin, 1);
-		gpiod_set_value(chip->convert_pin, 0);
-	} else { /* operating mode 1 */
-		gpiod_set_value(chip->convert_pin, 0);
-		gpiod_set_value(chip->convert_pin, 1);
-	}
-
-	if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
-		while (gpiod_get_value(chip->busy_pin))
-			cpu_relax();
-	}
-
-	gpiod_set_value(chip->rdwr_pin, 0);
-	gpiod_set_value(chip->rdwr_pin, 1);
-	ret = spi_write_then_read(spi_dev, NULL, 0, &buf, sizeof(buf));
-	if (ret < 0) {
-		dev_err(&spi_dev->dev, "SPI data read error\n");
-		return ret;
-	}
-
-	*data = be16_to_cpu(buf);
-
-	return ret;
-}
-
-static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
-{
-	struct spi_device *spi_dev = chip->spi_dev;
-	int ret;
-
-	guard(mutex)(&chip->lock);
-
-	gpiod_set_value(chip->rdwr_pin, 1);
-	gpiod_set_value(chip->rdwr_pin, 0);
-	ret = spi_write_then_read(spi_dev, &data, sizeof(data), NULL, 0);
-	if (ret < 0)
-		dev_err(&spi_dev->dev, "SPI oti data write error\n");
-
-	return ret;
-}
-
-static ssize_t ad7816_show_mode(struct device *dev,
-				struct device_attribute *attr,
-				char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-
-	if (chip->mode)
-		return sysfs_emit(buf, "power-save\n");
-	return sysfs_emit(buf, "full\n");
-}
-
-static ssize_t ad7816_store_mode(struct device *dev,
-				 struct device_attribute *attr,
-				 const char *buf,
-				 size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-
-	guard(mutex)(&chip->lock);
-
-	if (strcmp(buf, "full") == 0) {
-		gpiod_set_value(chip->rdwr_pin, 1);
-		chip->mode = AD7816_FULL;
-	} else {
-		gpiod_set_value(chip->rdwr_pin, 0);
-		chip->mode = AD7816_PD;
-	}
-
-	return len;
-}
-
-static IIO_DEVICE_ATTR(mode, 0644,
-		ad7816_show_mode,
-		ad7816_store_mode,
-		0);
-
-static ssize_t ad7816_show_available_modes(struct device *dev,
-					   struct device_attribute *attr,
-					   char *buf)
-{
-	return sysfs_emit(buf, "full\npower-save\n");
-}
-
-static IIO_DEVICE_ATTR(available_modes, 0444, ad7816_show_available_modes,
-			NULL, 0);
-
-static ssize_t ad7816_show_channel(struct device *dev,
-				   struct device_attribute *attr,
-				   char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-
-	return sysfs_emit(buf, "%d\n", chip->channel_id);
-}
-
-static ssize_t ad7816_store_channel(struct device *dev,
-				    struct device_attribute *attr,
-				    const char *buf,
-				    size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-	unsigned long data;
-	int ret;
-
-	ret = kstrtoul(buf, 10, &data);
-	if (ret)
-		return ret;
-
-	if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
-		dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
-			data, indio_dev->name);
-		return -EINVAL;
-	} else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
-		dev_err(&chip->spi_dev->dev,
-			"Invalid channel id %lu for ad7818.\n", data);
-		return -EINVAL;
-	} else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
-		dev_err(&chip->spi_dev->dev,
-			"Invalid channel id %lu for ad7816.\n", data);
-		return -EINVAL;
-	}
-
-	guard(mutex)(&chip->lock);
-
-	chip->channel_id = data;
-
-	return len;
-}
-
-static IIO_DEVICE_ATTR(channel, 0644,
-		ad7816_show_channel,
-		ad7816_store_channel,
-		0);
-
-static ssize_t ad7816_show_value(struct device *dev,
-				 struct device_attribute *attr,
-				 char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-	u16 data;
-	s8 value;
-	int ret;
-
-	ret = ad7816_spi_read(chip, &data);
-	if (ret)
-		return -EIO;
-
-	data >>= AD7816_VALUE_OFFSET;
-
-	if (chip->channel_id == 0) {
-		value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
-		data &= AD7816_TEMP_FLOAT_MASK;
-		if (value < 0)
-			data = BIT(AD7816_TEMP_FLOAT_OFFSET) - data;
-		return sysfs_emit(buf, "%d.%.2d\n", value, data * 25);
-	}
-	return sysfs_emit(buf, "%u\n", data);
-}
-
-static IIO_DEVICE_ATTR(value, 0444, ad7816_show_value, NULL, 0);
-
-static struct attribute *ad7816_attributes[] = {
-	&iio_dev_attr_available_modes.dev_attr.attr,
-	&iio_dev_attr_mode.dev_attr.attr,
-	&iio_dev_attr_channel.dev_attr.attr,
-	&iio_dev_attr_value.dev_attr.attr,
-	NULL,
-};
-
-static const struct attribute_group ad7816_attribute_group = {
-	.attrs = ad7816_attributes,
-};
-
-/*
- * temperature bound events
- */
-
-#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP,	\
-						       0,		\
-						       IIO_EV_TYPE_THRESH, \
-						       IIO_EV_DIR_FALLING)
-
-static irqreturn_t ad7816_event_handler(int irq, void *private)
-{
-	iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI,
-		       iio_get_time_ns(private));
-	return IRQ_HANDLED;
-}
-
-static ssize_t ad7816_show_oti(struct device *dev,
-			       struct device_attribute *attr,
-			       char *buf)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-	int value;
-
-	if (chip->channel_id > AD7816_CS_MAX) {
-		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
-		return -EINVAL;
-	} else if (chip->channel_id == 0) {
-		value = AD7816_BOUND_VALUE_MIN +
-			(chip->oti_data[chip->channel_id] -
-			AD7816_BOUND_VALUE_BASE);
-		return sysfs_emit(buf, "%d\n", value);
-	}
-	return sysfs_emit(buf, "%u\n", chip->oti_data[chip->channel_id]);
-}
-
-static inline ssize_t ad7816_set_oti(struct device *dev,
-				     struct device_attribute *attr,
-				     const char *buf,
-				     size_t len)
-{
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct ad7816_chip_info *chip = iio_priv(indio_dev);
-	long value;
-	u8 data;
-	int ret;
-
-	ret = kstrtol(buf, 10, &value);
-	if (ret)
-		return ret;
-
-	if (chip->channel_id > AD7816_CS_MAX) {
-		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
-		return -EINVAL;
-	} else if (chip->channel_id == 0) {
-		if (value < AD7816_BOUND_VALUE_MIN ||
-		    value > AD7816_BOUND_VALUE_MAX)
-			return -EINVAL;
-
-		data = (u8)(value - AD7816_BOUND_VALUE_MIN +
-			AD7816_BOUND_VALUE_BASE);
-	} else {
-		if (value < AD7816_BOUND_VALUE_BASE || value > 255)
-			return -EINVAL;
-
-		data = (u8)value;
-	}
-
-	ret = ad7816_spi_write(chip, data);
-	if (ret)
-		return -EIO;
-
-	chip->oti_data[chip->channel_id] = data;
-
-	return len;
-}
-
-static IIO_DEVICE_ATTR(oti, 0644,
-		       ad7816_show_oti, ad7816_set_oti, 0);
-
-static struct attribute *ad7816_event_attributes[] = {
-	&iio_dev_attr_oti.dev_attr.attr,
-	NULL,
-};
-
-static const struct attribute_group ad7816_event_attribute_group = {
-	.attrs = ad7816_event_attributes,
-	.name = "events",
-};
-
-static const struct iio_info ad7816_info = {
-	.attrs = &ad7816_attribute_group,
-	.event_attrs = &ad7816_event_attribute_group,
-};
-
-/*
- * device probe and remove
- */
-
-static int ad7816_probe(struct spi_device *spi_dev)
-{
-	struct ad7816_chip_info *chip;
-	struct iio_dev *indio_dev;
-	int i, ret;
-
-	indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
-	if (!indio_dev)
-		return -ENOMEM;
-	chip = iio_priv(indio_dev);
-
-	ret = devm_mutex_init(&spi_dev->dev, &chip->lock);
-	if (ret)
-		return ret;
-
-	chip->spi_dev = spi_dev;
-	for (i = 0; i <= AD7816_CS_MAX; i++)
-		chip->oti_data[i] = 203;
-
-	chip->id = spi_get_device_id(spi_dev)->driver_data;
-	chip->rdwr_pin = devm_gpiod_get(&spi_dev->dev, "rdwr", GPIOD_OUT_HIGH);
-	if (IS_ERR(chip->rdwr_pin)) {
-		ret = PTR_ERR(chip->rdwr_pin);
-		dev_err(&spi_dev->dev, "Failed to request rdwr GPIO: %d\n",
-			ret);
-		return ret;
-	}
-	chip->convert_pin = devm_gpiod_get(&spi_dev->dev, "convert",
-					   GPIOD_OUT_HIGH);
-	if (IS_ERR(chip->convert_pin)) {
-		ret = PTR_ERR(chip->convert_pin);
-		dev_err(&spi_dev->dev, "Failed to request convert GPIO: %d\n",
-			ret);
-		return ret;
-	}
-	if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
-		chip->busy_pin = devm_gpiod_get(&spi_dev->dev, "busy",
-						GPIOD_IN);
-		if (IS_ERR(chip->busy_pin)) {
-			ret = PTR_ERR(chip->busy_pin);
-			dev_err(&spi_dev->dev, "Failed to request busy GPIO: %d\n",
-				ret);
-			return ret;
-		}
-	}
-
-	indio_dev->name = spi_get_device_id(spi_dev)->name;
-	indio_dev->info = &ad7816_info;
-	indio_dev->modes = INDIO_DIRECT_MODE;
-
-	if (spi_dev->irq) {
-		/* Only low trigger is supported in ad7816/7/8 */
-		ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
-						NULL,
-						&ad7816_event_handler,
-						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
-						indio_dev->name,
-						indio_dev);
-		if (ret)
-			return ret;
-	}
-
-	ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
-	if (ret)
-		return ret;
-
-	dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
-		 indio_dev->name);
-
-	return 0;
-}
-
-static const struct of_device_id ad7816_of_match[] = {
-	{ .compatible = "adi,ad7816", },
-	{ .compatible = "adi,ad7817", },
-	{ .compatible = "adi,ad7818", },
-	{ }
-};
-MODULE_DEVICE_TABLE(of, ad7816_of_match);
-
-static const struct spi_device_id ad7816_id[] = {
-	{ .name = "ad7816", .driver_data = ID_AD7816 },
-	{ .name = "ad7817", .driver_data = ID_AD7817 },
-	{ .name = "ad7818", .driver_data = ID_AD7818 },
-	{ }
-};
-
-MODULE_DEVICE_TABLE(spi, ad7816_id);
-
-static struct spi_driver ad7816_driver = {
-	.driver = {
-		.name = "ad7816",
-		.of_match_table = ad7816_of_match,
-	},
-	.probe = ad7816_probe,
-	.id_table = ad7816_id,
-};
-module_spi_driver(ad7816_driver);
-
-MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
-MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
-MODULE_LICENSE("GPL v2");
-- 
2.47.3

Re: [PATCH] staging: iio: adc: ad7816: remove obsolete driver

[Nuno Sá]

On Tue, Oct 06, 2026 at 11:51:19AM +0000, Joshua Crofts wrote:
> The AD7816 driver has been in staging for 16 years and hasn't seen any
> significant improvements for it to mature out of staging.
> 
> Additionally, the AD7816/AD7817/AD7818 have been obsolete for ~11 years.
> 
> Remove the entire adc/ subdirectory and references to it as this is the
> only driver in it.
> 
> Signed-off-by: Joshua Crofts <joshua.crofts1@gmail.com>
> ---
> If people want to use the AD7816, Analog Devices have their own fork of
> the kernel where the driver is present [1].

Just note that we do update the kernel so the removal will come to us
:). Anyways, the part is indeed marked as obsolete so I'm not expecting
any effort for updating the driver and remove it out of staging. So, fine
by me. If any customers shouts, we can add the driver back in our fork
(or add proper support for it) - but odds are low

So it is only fair to ack this:

Acked-by: Nuno Sá <nuno.sa@analog.com>

> 
> Also, I don't see a point in keeping the driver for newcomers to
> practice on, as all mechanical changes (checkpatch, cocci) have been
> applied.
> 
> [1] https://github.com/analogdevicesinc/linux/blob/main/drivers/staging/iio/adc/ad7816.c
> ---
>  drivers/staging/iio/Kconfig      |   1 -
>  drivers/staging/iio/Makefile     |   1 -
>  drivers/staging/iio/adc/Kconfig  |  18 --
>  drivers/staging/iio/adc/Makefile |   6 -
>  drivers/staging/iio/adc/ad7816.c | 464 -------------------------------
>  5 files changed, 490 deletions(-)
>  delete mode 100644 drivers/staging/iio/adc/Kconfig
>  delete mode 100644 drivers/staging/iio/adc/Makefile
>  delete mode 100644 drivers/staging/iio/adc/ad7816.c
> 
> diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
> index bf6addf2974f..58d6859e039a 100644
> --- a/drivers/staging/iio/Kconfig
> +++ b/drivers/staging/iio/Kconfig
> @@ -5,7 +5,6 @@
>  menu "IIO staging drivers"
>  	depends on IIO
>  
> -source "drivers/staging/iio/adc/Kconfig"
>  source "drivers/staging/iio/addac/Kconfig"
>  source "drivers/staging/iio/frequency/Kconfig"
>  source "drivers/staging/iio/impedance-analyzer/Kconfig"
> diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
> index 739e4cbf9a7a..7768c4a8d278 100644
> --- a/drivers/staging/iio/Makefile
> +++ b/drivers/staging/iio/Makefile
> @@ -3,7 +3,6 @@
>  # Makefile for the industrial I/O core.
>  #
>  
> -obj-y += adc/
>  obj-y += addac/
>  obj-y += frequency/
>  obj-y += impedance-analyzer/
> diff --git a/drivers/staging/iio/adc/Kconfig b/drivers/staging/iio/adc/Kconfig
> deleted file mode 100644
> index 2f0d6cf048d2..000000000000
> --- a/drivers/staging/iio/adc/Kconfig
> +++ /dev/null
> @@ -1,18 +0,0 @@
> -# SPDX-License-Identifier: GPL-2.0
> -#
> -# ADC drivers
> -#
> -menu "Analog to digital converters"
> -
> -config AD7816
> -	tristate "Analog Devices AD7816/7/8 temperature sensor and ADC driver"
> -	depends on SPI
> -	depends on GPIOLIB || COMPILE_TEST
> -	help
> -	  Say yes here to build support for Analog Devices AD7816/7/8
> -	  temperature sensors and ADC.
> -
> -	  To compile this driver as a module, choose M here: the
> -	  module will be called ad7816.
> -
> -endmenu
> diff --git a/drivers/staging/iio/adc/Makefile b/drivers/staging/iio/adc/Makefile
> deleted file mode 100644
> index 1e2a94c4db84..000000000000
> --- a/drivers/staging/iio/adc/Makefile
> +++ /dev/null
> @@ -1,6 +0,0 @@
> -# SPDX-License-Identifier: GPL-2.0
> -#
> -# Makefile for industrial I/O ADC drivers
> -#
> -
> -obj-$(CONFIG_AD7816) += ad7816.o
> diff --git a/drivers/staging/iio/adc/ad7816.c b/drivers/staging/iio/adc/ad7816.c
> deleted file mode 100644
> index 2a15d7598abb..000000000000
> --- a/drivers/staging/iio/adc/ad7816.c
> +++ /dev/null
> @@ -1,464 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0+
> -/*
> - * AD7816 digital temperature sensor driver supporting AD7816/7/8
> - *
> - * Copyright 2010 Analog Devices Inc.
> - */
> -
> -#include <linux/cleanup.h>
> -#include <linux/device.h>
> -#include <linux/gpio/consumer.h>
> -#include <linux/interrupt.h>
> -#include <linux/kernel.h>
> -#include <linux/list.h>
> -#include <linux/module.h>
> -#include <linux/mutex.h>
> -#include <linux/slab.h>
> -#include <linux/spi/spi.h>
> -#include <linux/sysfs.h>
> -
> -#include <linux/iio/events.h>
> -#include <linux/iio/iio.h>
> -#include <linux/iio/sysfs.h>
> -
> -/*
> - * AD7816 config masks
> - */
> -#define AD7816_FULL			0x1
> -#define AD7816_PD			0x2
> -#define AD7816_CS_MASK			0x7
> -#define AD7816_CS_MAX			0x4
> -
> -/*
> - * AD7816 temperature masks
> - */
> -#define AD7816_VALUE_OFFSET		6
> -#define AD7816_BOUND_VALUE_BASE		0x8
> -#define AD7816_BOUND_VALUE_MIN		-95
> -#define AD7816_BOUND_VALUE_MAX		152
> -#define AD7816_TEMP_FLOAT_OFFSET	2
> -#define AD7816_TEMP_FLOAT_MASK		0x3
> -
> -/*
> - * struct ad7816_chip_info - chip specific information
> - */
> -
> -struct ad7816_chip_info {
> -	kernel_ulong_t id;
> -	struct spi_device *spi_dev;
> -	struct gpio_desc *rdwr_pin;
> -	struct gpio_desc *convert_pin;
> -	struct gpio_desc *busy_pin;
> -	struct mutex lock; /* protect device state during SPI transfers */
> -	u8  oti_data[AD7816_CS_MAX + 1];
> -	u8  channel_id;	/* 0 always be temperature */
> -	u8  mode;
> -};
> -
> -enum ad7816_type {
> -	ID_AD7816,
> -	ID_AD7817,
> -	ID_AD7818,
> -};
> -
> -/*
> - * ad7816 data access by SPI
> - */
> -static int ad7816_spi_read(struct ad7816_chip_info *chip, u16 *data)
> -{
> -	struct spi_device *spi_dev = chip->spi_dev;
> -	int ret;
> -	__be16 buf;
> -
> -	guard(mutex)(&chip->lock);
> -
> -	gpiod_set_value(chip->rdwr_pin, 1);
> -	gpiod_set_value(chip->rdwr_pin, 0);
> -	ret = spi_write_then_read(spi_dev, &chip->channel_id, sizeof(chip->channel_id), NULL, 0);
> -	if (ret < 0) {
> -		dev_err(&spi_dev->dev, "SPI channel setting error\n");
> -		return ret;
> -	}
> -	gpiod_set_value(chip->rdwr_pin, 1);
> -
> -	if (chip->mode == AD7816_PD) { /* operating mode 2 */
> -		gpiod_set_value(chip->convert_pin, 1);
> -		gpiod_set_value(chip->convert_pin, 0);
> -	} else { /* operating mode 1 */
> -		gpiod_set_value(chip->convert_pin, 0);
> -		gpiod_set_value(chip->convert_pin, 1);
> -	}
> -
> -	if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
> -		while (gpiod_get_value(chip->busy_pin))
> -			cpu_relax();
> -	}
> -
> -	gpiod_set_value(chip->rdwr_pin, 0);
> -	gpiod_set_value(chip->rdwr_pin, 1);
> -	ret = spi_write_then_read(spi_dev, NULL, 0, &buf, sizeof(buf));
> -	if (ret < 0) {
> -		dev_err(&spi_dev->dev, "SPI data read error\n");
> -		return ret;
> -	}
> -
> -	*data = be16_to_cpu(buf);
> -
> -	return ret;
> -}
> -
> -static int ad7816_spi_write(struct ad7816_chip_info *chip, u8 data)
> -{
> -	struct spi_device *spi_dev = chip->spi_dev;
> -	int ret;
> -
> -	guard(mutex)(&chip->lock);
> -
> -	gpiod_set_value(chip->rdwr_pin, 1);
> -	gpiod_set_value(chip->rdwr_pin, 0);
> -	ret = spi_write_then_read(spi_dev, &data, sizeof(data), NULL, 0);
> -	if (ret < 0)
> -		dev_err(&spi_dev->dev, "SPI oti data write error\n");
> -
> -	return ret;
> -}
> -
> -static ssize_t ad7816_show_mode(struct device *dev,
> -				struct device_attribute *attr,
> -				char *buf)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -
> -	if (chip->mode)
> -		return sysfs_emit(buf, "power-save\n");
> -	return sysfs_emit(buf, "full\n");
> -}
> -
> -static ssize_t ad7816_store_mode(struct device *dev,
> -				 struct device_attribute *attr,
> -				 const char *buf,
> -				 size_t len)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -
> -	guard(mutex)(&chip->lock);
> -
> -	if (strcmp(buf, "full") == 0) {
> -		gpiod_set_value(chip->rdwr_pin, 1);
> -		chip->mode = AD7816_FULL;
> -	} else {
> -		gpiod_set_value(chip->rdwr_pin, 0);
> -		chip->mode = AD7816_PD;
> -	}
> -
> -	return len;
> -}
> -
> -static IIO_DEVICE_ATTR(mode, 0644,
> -		ad7816_show_mode,
> -		ad7816_store_mode,
> -		0);
> -
> -static ssize_t ad7816_show_available_modes(struct device *dev,
> -					   struct device_attribute *attr,
> -					   char *buf)
> -{
> -	return sysfs_emit(buf, "full\npower-save\n");
> -}
> -
> -static IIO_DEVICE_ATTR(available_modes, 0444, ad7816_show_available_modes,
> -			NULL, 0);
> -
> -static ssize_t ad7816_show_channel(struct device *dev,
> -				   struct device_attribute *attr,
> -				   char *buf)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -
> -	return sysfs_emit(buf, "%d\n", chip->channel_id);
> -}
> -
> -static ssize_t ad7816_store_channel(struct device *dev,
> -				    struct device_attribute *attr,
> -				    const char *buf,
> -				    size_t len)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -	unsigned long data;
> -	int ret;
> -
> -	ret = kstrtoul(buf, 10, &data);
> -	if (ret)
> -		return ret;
> -
> -	if (data > AD7816_CS_MAX && data != AD7816_CS_MASK) {
> -		dev_err(&chip->spi_dev->dev, "Invalid channel id %lu for %s.\n",
> -			data, indio_dev->name);
> -		return -EINVAL;
> -	} else if (strcmp(indio_dev->name, "ad7818") == 0 && data > 1) {
> -		dev_err(&chip->spi_dev->dev,
> -			"Invalid channel id %lu for ad7818.\n", data);
> -		return -EINVAL;
> -	} else if (strcmp(indio_dev->name, "ad7816") == 0 && data > 0) {
> -		dev_err(&chip->spi_dev->dev,
> -			"Invalid channel id %lu for ad7816.\n", data);
> -		return -EINVAL;
> -	}
> -
> -	guard(mutex)(&chip->lock);
> -
> -	chip->channel_id = data;
> -
> -	return len;
> -}
> -
> -static IIO_DEVICE_ATTR(channel, 0644,
> -		ad7816_show_channel,
> -		ad7816_store_channel,
> -		0);
> -
> -static ssize_t ad7816_show_value(struct device *dev,
> -				 struct device_attribute *attr,
> -				 char *buf)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -	u16 data;
> -	s8 value;
> -	int ret;
> -
> -	ret = ad7816_spi_read(chip, &data);
> -	if (ret)
> -		return -EIO;
> -
> -	data >>= AD7816_VALUE_OFFSET;
> -
> -	if (chip->channel_id == 0) {
> -		value = (s8)((data >> AD7816_TEMP_FLOAT_OFFSET) - 103);
> -		data &= AD7816_TEMP_FLOAT_MASK;
> -		if (value < 0)
> -			data = BIT(AD7816_TEMP_FLOAT_OFFSET) - data;
> -		return sysfs_emit(buf, "%d.%.2d\n", value, data * 25);
> -	}
> -	return sysfs_emit(buf, "%u\n", data);
> -}
> -
> -static IIO_DEVICE_ATTR(value, 0444, ad7816_show_value, NULL, 0);
> -
> -static struct attribute *ad7816_attributes[] = {
> -	&iio_dev_attr_available_modes.dev_attr.attr,
> -	&iio_dev_attr_mode.dev_attr.attr,
> -	&iio_dev_attr_channel.dev_attr.attr,
> -	&iio_dev_attr_value.dev_attr.attr,
> -	NULL,
> -};
> -
> -static const struct attribute_group ad7816_attribute_group = {
> -	.attrs = ad7816_attributes,
> -};
> -
> -/*
> - * temperature bound events
> - */
> -
> -#define IIO_EVENT_CODE_AD7816_OTI IIO_UNMOD_EVENT_CODE(IIO_TEMP,	\
> -						       0,		\
> -						       IIO_EV_TYPE_THRESH, \
> -						       IIO_EV_DIR_FALLING)
> -
> -static irqreturn_t ad7816_event_handler(int irq, void *private)
> -{
> -	iio_push_event(private, IIO_EVENT_CODE_AD7816_OTI,
> -		       iio_get_time_ns(private));
> -	return IRQ_HANDLED;
> -}
> -
> -static ssize_t ad7816_show_oti(struct device *dev,
> -			       struct device_attribute *attr,
> -			       char *buf)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -	int value;
> -
> -	if (chip->channel_id > AD7816_CS_MAX) {
> -		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
> -		return -EINVAL;
> -	} else if (chip->channel_id == 0) {
> -		value = AD7816_BOUND_VALUE_MIN +
> -			(chip->oti_data[chip->channel_id] -
> -			AD7816_BOUND_VALUE_BASE);
> -		return sysfs_emit(buf, "%d\n", value);
> -	}
> -	return sysfs_emit(buf, "%u\n", chip->oti_data[chip->channel_id]);
> -}
> -
> -static inline ssize_t ad7816_set_oti(struct device *dev,
> -				     struct device_attribute *attr,
> -				     const char *buf,
> -				     size_t len)
> -{
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct ad7816_chip_info *chip = iio_priv(indio_dev);
> -	long value;
> -	u8 data;
> -	int ret;
> -
> -	ret = kstrtol(buf, 10, &value);
> -	if (ret)
> -		return ret;
> -
> -	if (chip->channel_id > AD7816_CS_MAX) {
> -		dev_err(dev, "Invalid oti channel id %d.\n", chip->channel_id);
> -		return -EINVAL;
> -	} else if (chip->channel_id == 0) {
> -		if (value < AD7816_BOUND_VALUE_MIN ||
> -		    value > AD7816_BOUND_VALUE_MAX)
> -			return -EINVAL;
> -
> -		data = (u8)(value - AD7816_BOUND_VALUE_MIN +
> -			AD7816_BOUND_VALUE_BASE);
> -	} else {
> -		if (value < AD7816_BOUND_VALUE_BASE || value > 255)
> -			return -EINVAL;
> -
> -		data = (u8)value;
> -	}
> -
> -	ret = ad7816_spi_write(chip, data);
> -	if (ret)
> -		return -EIO;
> -
> -	chip->oti_data[chip->channel_id] = data;
> -
> -	return len;
> -}
> -
> -static IIO_DEVICE_ATTR(oti, 0644,
> -		       ad7816_show_oti, ad7816_set_oti, 0);
> -
> -static struct attribute *ad7816_event_attributes[] = {
> -	&iio_dev_attr_oti.dev_attr.attr,
> -	NULL,
> -};
> -
> -static const struct attribute_group ad7816_event_attribute_group = {
> -	.attrs = ad7816_event_attributes,
> -	.name = "events",
> -};
> -
> -static const struct iio_info ad7816_info = {
> -	.attrs = &ad7816_attribute_group,
> -	.event_attrs = &ad7816_event_attribute_group,
> -};
> -
> -/*
> - * device probe and remove
> - */
> -
> -static int ad7816_probe(struct spi_device *spi_dev)
> -{
> -	struct ad7816_chip_info *chip;
> -	struct iio_dev *indio_dev;
> -	int i, ret;
> -
> -	indio_dev = devm_iio_device_alloc(&spi_dev->dev, sizeof(*chip));
> -	if (!indio_dev)
> -		return -ENOMEM;
> -	chip = iio_priv(indio_dev);
> -
> -	ret = devm_mutex_init(&spi_dev->dev, &chip->lock);
> -	if (ret)
> -		return ret;
> -
> -	chip->spi_dev = spi_dev;
> -	for (i = 0; i <= AD7816_CS_MAX; i++)
> -		chip->oti_data[i] = 203;
> -
> -	chip->id = spi_get_device_id(spi_dev)->driver_data;
> -	chip->rdwr_pin = devm_gpiod_get(&spi_dev->dev, "rdwr", GPIOD_OUT_HIGH);
> -	if (IS_ERR(chip->rdwr_pin)) {
> -		ret = PTR_ERR(chip->rdwr_pin);
> -		dev_err(&spi_dev->dev, "Failed to request rdwr GPIO: %d\n",
> -			ret);
> -		return ret;
> -	}
> -	chip->convert_pin = devm_gpiod_get(&spi_dev->dev, "convert",
> -					   GPIOD_OUT_HIGH);
> -	if (IS_ERR(chip->convert_pin)) {
> -		ret = PTR_ERR(chip->convert_pin);
> -		dev_err(&spi_dev->dev, "Failed to request convert GPIO: %d\n",
> -			ret);
> -		return ret;
> -	}
> -	if (chip->id == ID_AD7816 || chip->id == ID_AD7817) {
> -		chip->busy_pin = devm_gpiod_get(&spi_dev->dev, "busy",
> -						GPIOD_IN);
> -		if (IS_ERR(chip->busy_pin)) {
> -			ret = PTR_ERR(chip->busy_pin);
> -			dev_err(&spi_dev->dev, "Failed to request busy GPIO: %d\n",
> -				ret);
> -			return ret;
> -		}
> -	}
> -
> -	indio_dev->name = spi_get_device_id(spi_dev)->name;
> -	indio_dev->info = &ad7816_info;
> -	indio_dev->modes = INDIO_DIRECT_MODE;
> -
> -	if (spi_dev->irq) {
> -		/* Only low trigger is supported in ad7816/7/8 */
> -		ret = devm_request_threaded_irq(&spi_dev->dev, spi_dev->irq,
> -						NULL,
> -						&ad7816_event_handler,
> -						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> -						indio_dev->name,
> -						indio_dev);
> -		if (ret)
> -			return ret;
> -	}
> -
> -	ret = devm_iio_device_register(&spi_dev->dev, indio_dev);
> -	if (ret)
> -		return ret;
> -
> -	dev_info(&spi_dev->dev, "%s temperature sensor and ADC registered.\n",
> -		 indio_dev->name);
> -
> -	return 0;
> -}
> -
> -static const struct of_device_id ad7816_of_match[] = {
> -	{ .compatible = "adi,ad7816", },
> -	{ .compatible = "adi,ad7817", },
> -	{ .compatible = "adi,ad7818", },
> -	{ }
> -};
> -MODULE_DEVICE_TABLE(of, ad7816_of_match);
> -
> -static const struct spi_device_id ad7816_id[] = {
> -	{ .name = "ad7816", .driver_data = ID_AD7816 },
> -	{ .name = "ad7817", .driver_data = ID_AD7817 },
> -	{ .name = "ad7818", .driver_data = ID_AD7818 },
> -	{ }
> -};
> -
> -MODULE_DEVICE_TABLE(spi, ad7816_id);
> -
> -static struct spi_driver ad7816_driver = {
> -	.driver = {
> -		.name = "ad7816",
> -		.of_match_table = ad7816_of_match,
> -	},
> -	.probe = ad7816_probe,
> -	.id_table = ad7816_id,
> -};
> -module_spi_driver(ad7816_driver);
> -
> -MODULE_AUTHOR("Sonic Zhang <sonic.zhang@analog.com>");
> -MODULE_DESCRIPTION("Analog Devices AD7816/7/8 digital temperature sensor driver");
> -MODULE_LICENSE("GPL v2");
> -- 
> 2.47.3
>