diff mbox series

[v2,12/16] iio: adc: ad7768-1: Add GPIO controller support

Message ID 4067fc67ef617edbaea0de21241d59d6ff8eaf98.1737985435.git.Jonathan.Santos@analog.com (mailing list archive)
State Changes Requested
Headers show
Series Add features, improvements, and fixes | expand

Commit Message

Jonathan Santos Jan. 27, 2025, 3:13 p.m. UTC
From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>

The AD7768-1 has the ability to control other local hardware (such as gain
stages),to power down other blocks in the signal chain, or read local
status signals over the SPI interface.

This change exports the AD7768-1's four gpios and makes them accessible
at an upper layer.

Co-developed-by: Jonathan Santos <Jonathan.Santos@analog.com>
Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
---
v2 Changes:
* Replaced mutex for iio_device_claim_direct_mode().
* Use gpio-controller property to conditionally enable the
  GPIO support.
* OBS: when the GPIO is configured as output, we should read 
  the current state value from AD7768_REG_GPIO_WRITE.
---
 drivers/iio/adc/ad7768-1.c | 148 ++++++++++++++++++++++++++++++++++++-
 1 file changed, 146 insertions(+), 2 deletions(-)

Comments

David Lechner Jan. 27, 2025, 11:34 p.m. UTC | #1
On 1/27/25 9:13 AM, Jonathan Santos wrote:
> From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> 
> The AD7768-1 has the ability to control other local hardware (such as gain
> stages),to power down other blocks in the signal chain, or read local
> status signals over the SPI interface.
> 
> This change exports the AD7768-1's four gpios and makes them accessible
> at an upper layer.
> 
> Co-developed-by: Jonathan Santos <Jonathan.Santos@analog.com>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> ---
> v2 Changes:
> * Replaced mutex for iio_device_claim_direct_mode().
> * Use gpio-controller property to conditionally enable the
>   GPIO support.
> * OBS: when the GPIO is configured as output, we should read 
>   the current state value from AD7768_REG_GPIO_WRITE.
> ---
>  drivers/iio/adc/ad7768-1.c | 148 ++++++++++++++++++++++++++++++++++++-
>  1 file changed, 146 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> index c540583808c2..e3ea078e6ec4 100644
> --- a/drivers/iio/adc/ad7768-1.c
> +++ b/drivers/iio/adc/ad7768-1.c
> @@ -9,6 +9,8 @@
>  #include <linux/delay.h>
>  #include <linux/device.h>
>  #include <linux/err.h>
> +#include <linux/gpio.h>
> +#include <linux/gpio/driver.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> @@ -79,6 +81,19 @@
>  #define AD7768_CONV_MODE_MSK		GENMASK(2, 0)
>  #define AD7768_CONV_MODE(x)		FIELD_PREP(AD7768_CONV_MODE_MSK, x)
>  
> +/* AD7768_REG_GPIO_CONTROL */
> +#define AD7768_GPIO_UNIVERSAL_EN	BIT(7)
> +#define AD7768_GPIO_CONTROL_MSK		GENMASK(3, 0)
> +
> +/* AD7768_REG_GPIO_WRITE */
> +#define AD7768_GPIO_WRITE_MSK		GENMASK(3, 0)
> +
> +/* AD7768_REG_GPIO_READ */
> +#define AD7768_GPIO_READ_MSK		GENMASK(3, 0)
> +
> +#define AD7768_GPIO_INPUT(x)		0x00
> +#define AD7768_GPIO_OUTPUT(x)		BIT(x)
> +
>  #define AD7768_RD_FLAG_MSK(x)		(BIT(6) | ((x) & 0x3F))
>  #define AD7768_WR_FLAG_MSK(x)		((x) & 0x3F)
>  
> @@ -160,6 +175,8 @@ struct ad7768_state {
>  	struct regulator *vref;
>  	struct mutex lock;
>  	struct clk *mclk;
> +	struct gpio_chip gpiochip;
> +	unsigned int gpio_avail_map;
>  	unsigned int mclk_freq;
>  	unsigned int samp_freq;
>  	struct completion completion;
> @@ -309,6 +326,125 @@ static int ad7768_set_dig_fil(struct ad7768_state *st,
>  	return 0;
>  }
>  
> +static int ad7768_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;

Missing iio_device_release_direct_mode() here and in other functions.

(And we are in the process of removing iio_device_claim_direct_scoped(), so
don't use that.)

> +
> +	return regmap_update_bits(st->regmap,
> +				  AD7768_REG_GPIO_CONTROL,
> +				  BIT(offset),
> +				  AD7768_GPIO_INPUT(offset));

Can be simplified to regmap_clear_bits(), then we can get rid of the odd
AD7768_GPIO_INPUT macro that ignores the argument.

> +}
> +
> +static int ad7768_gpio_direction_output(struct gpio_chip *chip,
> +					unsigned int offset, int value)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_update_bits(st->regmap,
> +				  AD7768_REG_GPIO_CONTROL,
> +				  BIT(offset),
> +				  AD7768_GPIO_OUTPUT(offset));

And regmap_set_bits() here.

> +}
> +
> +static int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (val & BIT(offset))
> +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_WRITE, &val);
> +	else
> +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_READ, &val);

Can we get a comment explaining why GPIO_READ doesn't work in output mode?

Or if it does work, we can simplify this function.


> +	if (ret < 0)
> +		return ret;
> +
> +	return !!(val & BIT(offset));
> +}
> +
> +static void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> +	if (ret < 0)
> +		return;
> +
> +	if (val & BIT(offset))
> +		regmap_update_bits(st->regmap,
> +				   AD7768_REG_GPIO_WRITE,
> +				   BIT(offset),
> +				   (value << offset));

Can remove extra ().

> +}
> +
> +static int ad7768_gpio_request(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +
> +	if (!(st->gpio_avail_map & BIT(offset)))
> +		return -ENODEV;
> +
> +	st->gpio_avail_map &= ~BIT(offset);

Is this really needed? It seems like GPIO core would be keeping track already.

Also would need a .free callback to undo this action.

It seems like most ADC's with GPIO controllers don't implement .request though.

> +
> +	return 0;
> +}
> +
Jonathan Cameron Feb. 1, 2025, 3:50 p.m. UTC | #2
On Mon, 27 Jan 2025 12:13:45 -0300
Jonathan Santos <Jonathan.Santos@analog.com> wrote:

> From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> 
> The AD7768-1 has the ability to control other local hardware (such as gain
> stages),to power down other blocks in the signal chain, or read local
> status signals over the SPI interface.
> 
> This change exports the AD7768-1's four gpios and makes them accessible
> at an upper layer.
> 
> Co-developed-by: Jonathan Santos <Jonathan.Santos@analog.com>
> Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
As David observed, the direct mode release calls are missing.

Also, there are a few places where you wrap lines much shorter than needed.

> +static int ad7768_gpio_direction_output(struct gpio_chip *chip,
> +					unsigned int offset, int value)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_update_bits(st->regmap,
> +				  AD7768_REG_GPIO_CONTROL,
> +				  BIT(offset),
> +				  AD7768_GPIO_OUTPUT(offset));
Again, wrap less.

> +}
> +
> +static int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
You aren't releasing it.  That should have deadlocked the second time
you called this.

> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (val & BIT(offset))
> +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_WRITE, &val);
> +	else
> +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_READ, &val);
> +	if (ret < 0)
> +		return ret;
> +
> +	return !!(val & BIT(offset));
> +}
> +
> +static void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> +{
> +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	unsigned int val;
> +	int ret;
> +
> +	ret = iio_device_claim_direct_mode(indio_dev);
As above, needs a matching release.  May mean you want to factor
out the guts of this as a helper function so you can still do
direct returns on error.

> +	if (ret)
> +		return;
> +
> +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> +	if (ret < 0)
> +		return;
> +
> +	if (val & BIT(offset))
> +		regmap_update_bits(st->regmap,
> +				   AD7768_REG_GPIO_WRITE,
> +				   BIT(offset),
> +				   (value << offset));
	Wrap a little less and drop the unnecessary brackets.

		regmap_update_bits(st->regmap, AD7768_REG_GPIO_WRITE,
				   BIT(offset), value << offset);
Also, check return value?

> +}
> +

> +
> +static int ad7768_gpio_init(struct iio_dev *indio_dev)
> +{
> +	struct ad7768_state *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = regmap_write(st->regmap, AD7768_REG_GPIO_CONTROL,
> +			   AD7768_GPIO_UNIVERSAL_EN);
> +	if (ret < 0)
> +		return ret;
> +
> +	st->gpio_avail_map = AD7768_GPIO_CONTROL_MSK;
> +	st->gpiochip.label = "ad7768_1_gpios";
> +	st->gpiochip.base = -1;
> +	st->gpiochip.ngpio = 4;
> +	st->gpiochip.parent = &st->spi->dev;
> +	st->gpiochip.can_sleep = true;
> +	st->gpiochip.direction_input = ad7768_gpio_direction_input;
> +	st->gpiochip.direction_output = ad7768_gpio_direction_output;
> +	st->gpiochip.get = ad7768_gpio_get;
> +	st->gpiochip.set = ad7768_gpio_set;
> +	st->gpiochip.request = ad7768_gpio_request;
> +	st->gpiochip.owner = THIS_MODULE;
Might not be worth it but I'd be tempted to do

	st->gpiochip = (struct gpio_chip) {
		.label = "ad7768_1_gpios",
		.base = -1,
		.ngpio = 4,
...
	};
perhaps.  This one is entirely up to your preference.
> +
> +	return gpiochip_add_data(&st->gpiochip, indio_dev);
> +}
> +
Jonathan Santos Feb. 3, 2025, 1:08 p.m. UTC | #3
On 01/27, David Lechner wrote:
> On 1/27/25 9:13 AM, Jonathan Santos wrote:
> > From: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> > 
> > The AD7768-1 has the ability to control other local hardware (such as gain
> > stages),to power down other blocks in the signal chain, or read local
> > status signals over the SPI interface.
> > 
> > This change exports the AD7768-1's four gpios and makes them accessible
> > at an upper layer.
> > 
> > Co-developed-by: Jonathan Santos <Jonathan.Santos@analog.com>
> > Signed-off-by: Jonathan Santos <Jonathan.Santos@analog.com>
> > Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
> > ---
> > v2 Changes:
> > * Replaced mutex for iio_device_claim_direct_mode().
> > * Use gpio-controller property to conditionally enable the
> >   GPIO support.
> > * OBS: when the GPIO is configured as output, we should read 
> >   the current state value from AD7768_REG_GPIO_WRITE.
> > ---
> >  drivers/iio/adc/ad7768-1.c | 148 ++++++++++++++++++++++++++++++++++++-
> >  1 file changed, 146 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
> > index c540583808c2..e3ea078e6ec4 100644
> > --- a/drivers/iio/adc/ad7768-1.c
> > +++ b/drivers/iio/adc/ad7768-1.c
> > @@ -9,6 +9,8 @@
> >  #include <linux/delay.h>
> >  #include <linux/device.h>
> >  #include <linux/err.h>
> > +#include <linux/gpio.h>
> > +#include <linux/gpio/driver.h>
> >  #include <linux/gpio/consumer.h>
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> > @@ -79,6 +81,19 @@
> >  #define AD7768_CONV_MODE_MSK		GENMASK(2, 0)
> >  #define AD7768_CONV_MODE(x)		FIELD_PREP(AD7768_CONV_MODE_MSK, x)
> >  
> > +/* AD7768_REG_GPIO_CONTROL */
> > +#define AD7768_GPIO_UNIVERSAL_EN	BIT(7)
> > +#define AD7768_GPIO_CONTROL_MSK		GENMASK(3, 0)
> > +
> > +/* AD7768_REG_GPIO_WRITE */
> > +#define AD7768_GPIO_WRITE_MSK		GENMASK(3, 0)
> > +
> > +/* AD7768_REG_GPIO_READ */
> > +#define AD7768_GPIO_READ_MSK		GENMASK(3, 0)
> > +
> > +#define AD7768_GPIO_INPUT(x)		0x00
> > +#define AD7768_GPIO_OUTPUT(x)		BIT(x)
> > +
> >  #define AD7768_RD_FLAG_MSK(x)		(BIT(6) | ((x) & 0x3F))
> >  #define AD7768_WR_FLAG_MSK(x)		((x) & 0x3F)
> >  
> > @@ -160,6 +175,8 @@ struct ad7768_state {
> >  	struct regulator *vref;
> >  	struct mutex lock;
> >  	struct clk *mclk;
> > +	struct gpio_chip gpiochip;
> > +	unsigned int gpio_avail_map;
> >  	unsigned int mclk_freq;
> >  	unsigned int samp_freq;
> >  	struct completion completion;
> > @@ -309,6 +326,125 @@ static int ad7768_set_dig_fil(struct ad7768_state *st,
> >  	return 0;
> >  }
> >  
> > +static int ad7768_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> > +	struct ad7768_state *st = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	ret = iio_device_claim_direct_mode(indio_dev);
> > +	if (ret)
> > +		return ret;
> 
> Missing iio_device_release_direct_mode() here and in other functions.
> 
> (And we are in the process of removing iio_device_claim_direct_scoped(), so
> don't use that.)
> 

Sure, my mistake. I am fixing this.

> > +
> > +	return regmap_update_bits(st->regmap,
> > +				  AD7768_REG_GPIO_CONTROL,
> > +				  BIT(offset),
> > +				  AD7768_GPIO_INPUT(offset));
> 
> Can be simplified to regmap_clear_bits(), then we can get rid of the odd
> AD7768_GPIO_INPUT macro that ignores the argument.
> 
> > +}
> > +
> > +static int ad7768_gpio_direction_output(struct gpio_chip *chip,
> > +					unsigned int offset, int value)
> > +{
> > +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> > +	struct ad7768_state *st = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	ret = iio_device_claim_direct_mode(indio_dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return regmap_update_bits(st->regmap,
> > +				  AD7768_REG_GPIO_CONTROL,
> > +				  BIT(offset),
> > +				  AD7768_GPIO_OUTPUT(offset));
> 
> And regmap_set_bits() here.
> 
> > +}
> > +
> > +static int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> > +	struct ad7768_state *st = iio_priv(indio_dev);
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	ret = iio_device_claim_direct_mode(indio_dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	if (val & BIT(offset))
> > +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_WRITE, &val);
> > +	else
> > +		ret = regmap_read(st->regmap, AD7768_REG_GPIO_READ, &val);
> 
> Can we get a comment explaining why GPIO_READ doesn't work in output mode?
> 
> Or if it does work, we can simplify this function.
> 
> 

The datasheet does not mention this; I reached this conclusion through testing.
It seems they separate the output state from the read register. Anyway, I will
add a comment.

> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return !!(val & BIT(offset));
> > +}
> > +
> > +static void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
> > +{
> > +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> > +	struct ad7768_state *st = iio_priv(indio_dev);
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	ret = iio_device_claim_direct_mode(indio_dev);
> > +	if (ret)
> > +		return;
> > +
> > +	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
> > +	if (ret < 0)
> > +		return;
> > +
> > +	if (val & BIT(offset))
> > +		regmap_update_bits(st->regmap,
> > +				   AD7768_REG_GPIO_WRITE,
> > +				   BIT(offset),
> > +				   (value << offset));
> 
> Can remove extra ().
> 
> > +}
> > +
> > +static int ad7768_gpio_request(struct gpio_chip *chip, unsigned int offset)
> > +{
> > +	struct iio_dev *indio_dev = gpiochip_get_data(chip);
> > +	struct ad7768_state *st = iio_priv(indio_dev);
> > +
> > +	if (!(st->gpio_avail_map & BIT(offset)))
> > +		return -ENODEV;
> > +
> > +	st->gpio_avail_map &= ~BIT(offset);
> 
> Is this really needed? It seems like GPIO core would be keeping track already.
> 
> Also would need a .free callback to undo this action.
> 
> It seems like most ADC's with GPIO controllers don't implement .request though.
> 

Indeed, .request is optional and does not seem to make a pratical  
difference if the core handles that. If that is the case i can remove
this

> > +
> > +	return 0;
> > +}
> > +
diff mbox series

Patch

diff --git a/drivers/iio/adc/ad7768-1.c b/drivers/iio/adc/ad7768-1.c
index c540583808c2..e3ea078e6ec4 100644
--- a/drivers/iio/adc/ad7768-1.c
+++ b/drivers/iio/adc/ad7768-1.c
@@ -9,6 +9,8 @@ 
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/err.h>
+#include <linux/gpio.h>
+#include <linux/gpio/driver.h>
 #include <linux/gpio/consumer.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -79,6 +81,19 @@ 
 #define AD7768_CONV_MODE_MSK		GENMASK(2, 0)
 #define AD7768_CONV_MODE(x)		FIELD_PREP(AD7768_CONV_MODE_MSK, x)
 
+/* AD7768_REG_GPIO_CONTROL */
+#define AD7768_GPIO_UNIVERSAL_EN	BIT(7)
+#define AD7768_GPIO_CONTROL_MSK		GENMASK(3, 0)
+
+/* AD7768_REG_GPIO_WRITE */
+#define AD7768_GPIO_WRITE_MSK		GENMASK(3, 0)
+
+/* AD7768_REG_GPIO_READ */
+#define AD7768_GPIO_READ_MSK		GENMASK(3, 0)
+
+#define AD7768_GPIO_INPUT(x)		0x00
+#define AD7768_GPIO_OUTPUT(x)		BIT(x)
+
 #define AD7768_RD_FLAG_MSK(x)		(BIT(6) | ((x) & 0x3F))
 #define AD7768_WR_FLAG_MSK(x)		((x) & 0x3F)
 
@@ -160,6 +175,8 @@  struct ad7768_state {
 	struct regulator *vref;
 	struct mutex lock;
 	struct clk *mclk;
+	struct gpio_chip gpiochip;
+	unsigned int gpio_avail_map;
 	unsigned int mclk_freq;
 	unsigned int samp_freq;
 	struct completion completion;
@@ -309,6 +326,125 @@  static int ad7768_set_dig_fil(struct ad7768_state *st,
 	return 0;
 }
 
+static int ad7768_gpio_direction_input(struct gpio_chip *chip, unsigned int offset)
+{
+	struct iio_dev *indio_dev = gpiochip_get_data(chip);
+	struct ad7768_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(st->regmap,
+				  AD7768_REG_GPIO_CONTROL,
+				  BIT(offset),
+				  AD7768_GPIO_INPUT(offset));
+}
+
+static int ad7768_gpio_direction_output(struct gpio_chip *chip,
+					unsigned int offset, int value)
+{
+	struct iio_dev *indio_dev = gpiochip_get_data(chip);
+	struct ad7768_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	return regmap_update_bits(st->regmap,
+				  AD7768_REG_GPIO_CONTROL,
+				  BIT(offset),
+				  AD7768_GPIO_OUTPUT(offset));
+}
+
+static int ad7768_gpio_get(struct gpio_chip *chip, unsigned int offset)
+{
+	struct iio_dev *indio_dev = gpiochip_get_data(chip);
+	struct ad7768_state *st = iio_priv(indio_dev);
+	unsigned int val;
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val & BIT(offset))
+		ret = regmap_read(st->regmap, AD7768_REG_GPIO_WRITE, &val);
+	else
+		ret = regmap_read(st->regmap, AD7768_REG_GPIO_READ, &val);
+	if (ret < 0)
+		return ret;
+
+	return !!(val & BIT(offset));
+}
+
+static void ad7768_gpio_set(struct gpio_chip *chip, unsigned int offset, int value)
+{
+	struct iio_dev *indio_dev = gpiochip_get_data(chip);
+	struct ad7768_state *st = iio_priv(indio_dev);
+	unsigned int val;
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return;
+
+	ret = regmap_read(st->regmap, AD7768_REG_GPIO_CONTROL, &val);
+	if (ret < 0)
+		return;
+
+	if (val & BIT(offset))
+		regmap_update_bits(st->regmap,
+				   AD7768_REG_GPIO_WRITE,
+				   BIT(offset),
+				   (value << offset));
+}
+
+static int ad7768_gpio_request(struct gpio_chip *chip, unsigned int offset)
+{
+	struct iio_dev *indio_dev = gpiochip_get_data(chip);
+	struct ad7768_state *st = iio_priv(indio_dev);
+
+	if (!(st->gpio_avail_map & BIT(offset)))
+		return -ENODEV;
+
+	st->gpio_avail_map &= ~BIT(offset);
+
+	return 0;
+}
+
+static int ad7768_gpio_init(struct iio_dev *indio_dev)
+{
+	struct ad7768_state *st = iio_priv(indio_dev);
+	int ret;
+
+	ret = regmap_write(st->regmap, AD7768_REG_GPIO_CONTROL,
+			   AD7768_GPIO_UNIVERSAL_EN);
+	if (ret < 0)
+		return ret;
+
+	st->gpio_avail_map = AD7768_GPIO_CONTROL_MSK;
+	st->gpiochip.label = "ad7768_1_gpios";
+	st->gpiochip.base = -1;
+	st->gpiochip.ngpio = 4;
+	st->gpiochip.parent = &st->spi->dev;
+	st->gpiochip.can_sleep = true;
+	st->gpiochip.direction_input = ad7768_gpio_direction_input;
+	st->gpiochip.direction_output = ad7768_gpio_direction_output;
+	st->gpiochip.get = ad7768_gpio_get;
+	st->gpiochip.set = ad7768_gpio_set;
+	st->gpiochip.request = ad7768_gpio_request;
+	st->gpiochip.owner = THIS_MODULE;
+
+	return gpiochip_add_data(&st->gpiochip, indio_dev);
+}
+
 static int ad7768_set_freq(struct ad7768_state *st,
 			   unsigned int freq)
 {
@@ -457,8 +593,9 @@  static const struct iio_info ad7768_info = {
 	.debugfs_reg_access = &ad7768_reg_access,
 };
 
-static int ad7768_setup(struct ad7768_state *st)
+static int ad7768_setup(struct iio_dev *indio_dev)
 {
+	struct ad7768_state *st = iio_priv(indio_dev);
 	int ret;
 
 	st->gpio_reset = devm_gpiod_get_optional(&st->spi->dev, "reset",
@@ -491,6 +628,13 @@  static int ad7768_setup(struct ad7768_state *st)
 	if (IS_ERR(st->gpio_sync_in))
 		return PTR_ERR(st->gpio_sync_in);
 
+	/* Only create a Chip GPIO if flagged for it */
+	if (device_property_read_bool(&st->spi->dev, "gpio-controller")) {
+		ret = ad7768_gpio_init(indio_dev);
+		if (ret < 0)
+			return ret;
+	}
+
 	/* Set the default sampling frequency to 32000 kSPS */
 	return ad7768_set_freq(st, 32000);
 }
@@ -708,7 +852,7 @@  static int ad7768_probe(struct spi_device *spi)
 			return ret;
 	}
 
-	ret = ad7768_setup(st);
+	ret = ad7768_setup(indio_dev);
 	if (ret < 0) {
 		dev_err(&spi->dev, "AD7768 setup failed\n");
 		return ret;