[PATCH v2 0/3] iio: Add resource management kfifo alloc/free

[PATCH v2 0/3] iio: Add resource management kfifo alloc/free

[Karol Wrona]

Hello,

iio kfifo alloc took one argument struct iio_dev * indio_dev which was not used 
so it was removed in allocate function and in several drivers which used it.
Second patch adds devm_ alloc/free.

Karol

changes from RFC:
- rebased on next-20141219
- changes in clients
- add minor doc fix to iio core


Karol Wrona (3):
  iio: kfifo: Remove unused argument in iio_kfifo_allocate
  iio: kfifo: Add resource management devm_iio_kfifo_allocate/free
  iio: core: Get rid of misleading comment

 drivers/iio/adc/ti_am335x_adc.c                 |    2 +-
 drivers/iio/industrialio-core.c                 |    1 -
 drivers/iio/industrialio-triggered-buffer.c     |    2 +-
 drivers/iio/kfifo_buf.c                         |   60 ++++++++++++++++++++++-
 drivers/staging/iio/accel/lis3l02dq_ring.c      |    2 +-
 drivers/staging/iio/iio_simple_dummy_buffer.c   |    2 +-
 drivers/staging/iio/impedance-analyzer/ad5933.c |    2 +-
 drivers/staging/iio/meter/ade7758_ring.c        |    2 +-
 include/linux/iio/kfifo_buf.h                   |    5 +-
 9 files changed, 68 insertions(+), 10 deletions(-)

-- 
1.7.9.5

[PATCH v2 1/3] iio: kfifo: Remove unused argument in iio_kfifo_allocate

[Karol Wrona]

indio_dev was unused in function body plus some small style fix - add new
lines after "if(sth) return sth" and before the last return statement.

The argument was removed also in its client.

Signed-off-by: Karol Wrona <k.wrona@samsung.com>
---
 drivers/iio/adc/ti_am335x_adc.c                 |    2 +-
 drivers/iio/industrialio-triggered-buffer.c     |    2 +-
 drivers/iio/kfifo_buf.c                         |    6 ++++--
 drivers/staging/iio/accel/lis3l02dq_ring.c      |    2 +-
 drivers/staging/iio/iio_simple_dummy_buffer.c   |    2 +-
 drivers/staging/iio/impedance-analyzer/ad5933.c |    2 +-
 drivers/staging/iio/meter/ade7758_ring.c        |    2 +-
 include/linux/iio/kfifo_buf.h                   |    2 +-
 8 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index b730864..bf87993 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -250,7 +250,7 @@ static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
 	struct iio_buffer *buffer;
 	int ret;
 
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (!buffer)
 		return -ENOMEM;
 
diff --git a/drivers/iio/industrialio-triggered-buffer.c b/drivers/iio/industrialio-triggered-buffer.c
index d6f54930..6c6307a 100644
--- a/drivers/iio/industrialio-triggered-buffer.c
+++ b/drivers/iio/industrialio-triggered-buffer.c
@@ -49,7 +49,7 @@ int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
 	struct iio_buffer *buffer;
 	int ret;
 
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (!buffer) {
 		ret = -ENOMEM;
 		goto error_ret;
diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index 7134e8a..a383291 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -166,19 +166,21 @@ static const struct iio_buffer_access_funcs kfifo_access_funcs = {
 	.release = &iio_kfifo_buffer_release,
 };
 
-struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
+struct iio_buffer *iio_kfifo_allocate(void)
 {
 	struct iio_kfifo *kf;
 
-	kf = kzalloc(sizeof *kf, GFP_KERNEL);
+	kf = kzalloc(sizeof(*kf), GFP_KERNEL);
 	if (!kf)
 		return NULL;
+
 	kf->update_needed = true;
 	iio_buffer_init(&kf->buffer);
 	kf->buffer.attrs = &iio_kfifo_attribute_group;
 	kf->buffer.access = &kfifo_access_funcs;
 	kf->buffer.length = 2;
 	mutex_init(&kf->user_lock);
+
 	return &kf->buffer;
 }
 EXPORT_SYMBOL(iio_kfifo_allocate);
diff --git a/drivers/staging/iio/accel/lis3l02dq_ring.c b/drivers/staging/iio/accel/lis3l02dq_ring.c
index 9efc77b..1fd9009 100644
--- a/drivers/staging/iio/accel/lis3l02dq_ring.c
+++ b/drivers/staging/iio/accel/lis3l02dq_ring.c
@@ -393,7 +393,7 @@ int lis3l02dq_configure_buffer(struct iio_dev *indio_dev)
 	int ret;
 	struct iio_buffer *buffer;
 
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (!buffer)
 		return -ENOMEM;
 
diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c
index fd74f91..df765c9 100644
--- a/drivers/staging/iio/iio_simple_dummy_buffer.c
+++ b/drivers/staging/iio/iio_simple_dummy_buffer.c
@@ -122,7 +122,7 @@ int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev,
 	struct iio_buffer *buffer;
 
 	/* Allocate a buffer to use - here a kfifo */
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (buffer == NULL) {
 		ret = -ENOMEM;
 		goto error_ret;
diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index b6bd609..ace9ef8 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -626,7 +626,7 @@ static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
 {
 	struct iio_buffer *buffer;
 
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (!buffer)
 		return -ENOMEM;
 
diff --git a/drivers/staging/iio/meter/ade7758_ring.c b/drivers/staging/iio/meter/ade7758_ring.c
index 6e90064..31d2cf3 100644
--- a/drivers/staging/iio/meter/ade7758_ring.c
+++ b/drivers/staging/iio/meter/ade7758_ring.c
@@ -118,7 +118,7 @@ int ade7758_configure_ring(struct iio_dev *indio_dev)
 	struct iio_buffer *buffer;
 	int ret = 0;
 
-	buffer = iio_kfifo_allocate(indio_dev);
+	buffer = iio_kfifo_allocate();
 	if (!buffer) {
 		ret = -ENOMEM;
 		return ret;
diff --git a/include/linux/iio/kfifo_buf.h b/include/linux/iio/kfifo_buf.h
index 25eeac7..1a8d57a 100644
--- a/include/linux/iio/kfifo_buf.h
+++ b/include/linux/iio/kfifo_buf.h
@@ -5,7 +5,7 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/buffer.h>
 
-struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev);
+struct iio_buffer *iio_kfifo_allocate(void);
 void iio_kfifo_free(struct iio_buffer *r);
 
 #endif
-- 
1.7.9.5

[PATCH v2 2/3] iio: kfifo: Add resource management devm_iio_kfifo_allocate/free

[Karol Wrona]

iio kfifo allocate/free gained their devm_ wrappers.

Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Suggested-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/kfifo_buf.c       |   54 +++++++++++++++++++++++++++++++++++++++++
 include/linux/iio/kfifo_buf.h |    3 +++
 2 files changed, 57 insertions(+)

diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
index a383291..5d44099 100644
--- a/drivers/iio/kfifo_buf.c
+++ b/drivers/iio/kfifo_buf.c
@@ -191,4 +191,58 @@ void iio_kfifo_free(struct iio_buffer *r)
 }
 EXPORT_SYMBOL(iio_kfifo_free);
 
+static void devm_iio_kfifo_release(struct device *dev, void *res)
+{
+	iio_kfifo_free(*(struct iio_buffer **)res);
+}
+
+static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
+{
+	struct iio_buffer **r = res;
+
+	if (WARN_ON(!r || !*r))
+		return 0;
+
+	return *r == data;
+}
+
+/**
+ * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
+ * @dev:		Device to allocate kfifo buffer for
+ *
+ * RETURNS:
+ * Pointer to allocated iio_buffer on success, NULL on failure.
+ */
+struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
+{
+	struct iio_buffer **ptr, *r;
+
+	ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	r = iio_kfifo_allocate();
+	if (r) {
+		*ptr = r;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return r;
+}
+EXPORT_SYMBOL(devm_iio_kfifo_allocate);
+
+/**
+ * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
+ * @dev:		Device the buffer belongs to
+ * @r:			The buffer associated with the device
+ */
+void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
+{
+	WARN_ON(devres_release(dev, devm_iio_kfifo_release,
+			       devm_iio_kfifo_match, r));
+}
+EXPORT_SYMBOL(devm_iio_kfifo_free);
+
 MODULE_LICENSE("GPL");
diff --git a/include/linux/iio/kfifo_buf.h b/include/linux/iio/kfifo_buf.h
index 1a8d57a..1683bc7 100644
--- a/include/linux/iio/kfifo_buf.h
+++ b/include/linux/iio/kfifo_buf.h
@@ -8,4 +8,7 @@
 struct iio_buffer *iio_kfifo_allocate(void);
 void iio_kfifo_free(struct iio_buffer *r);
 
+struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev);
+void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r);
+
 #endif
-- 
1.7.9.5

[PATCH v2 3/3] iio: core: Get rid of misleading comment

[Karol Wrona]

This comment did not fit here.  It explains why devm_kmalloc
uses dr_alloc.  Generally is not needed at all.

Signed-off-by: Karol Wrona <k.wrona@samsung.com>
---
 drivers/iio/industrialio-core.c |    1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index af3e76d..1d030ae 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -1035,7 +1035,6 @@ struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
 	if (!ptr)
 		return NULL;
 
-	/* use raw alloc_dr for kmalloc caller tracing */
 	iio_dev = iio_device_alloc(sizeof_priv);
 	if (iio_dev) {
 		*ptr = iio_dev;
-- 
1.7.9.5

Re: [PATCH v2 1/3] iio: kfifo: Remove unused argument in iio_kfifo_allocate

[Jonathan Cameron]

On 19/12/14 17:39, Karol Wrona wrote:
> indio_dev was unused in function body plus some small style fix - add new
> lines after "if(sth) return sth" and before the last return statement.
> 
> The argument was removed also in its client.
> 
> Signed-off-by: Karol Wrona <k.wrona@samsung.com>
Good cleanup - some fuzz applying and required a bit of hand editting
in kfifo_buf.c for reasons I couldn't immediately spot.  Please sanity
check I haven't messed anything up.

Thanks,

Jonathan
> ---
>  drivers/iio/adc/ti_am335x_adc.c                 |    2 +-
>  drivers/iio/industrialio-triggered-buffer.c     |    2 +-
>  drivers/iio/kfifo_buf.c                         |    6 ++++--
>  drivers/staging/iio/accel/lis3l02dq_ring.c      |    2 +-
>  drivers/staging/iio/iio_simple_dummy_buffer.c   |    2 +-
>  drivers/staging/iio/impedance-analyzer/ad5933.c |    2 +-
>  drivers/staging/iio/meter/ade7758_ring.c        |    2 +-
>  include/linux/iio/kfifo_buf.h                   |    2 +-
>  8 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
> index b730864..bf87993 100644
> --- a/drivers/iio/adc/ti_am335x_adc.c
> +++ b/drivers/iio/adc/ti_am335x_adc.c
> @@ -250,7 +250,7 @@ static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev,
>  	struct iio_buffer *buffer;
>  	int ret;
>  
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (!buffer)
>  		return -ENOMEM;
>  
> diff --git a/drivers/iio/industrialio-triggered-buffer.c b/drivers/iio/industrialio-triggered-buffer.c
> index d6f54930..6c6307a 100644
> --- a/drivers/iio/industrialio-triggered-buffer.c
> +++ b/drivers/iio/industrialio-triggered-buffer.c
> @@ -49,7 +49,7 @@ int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
>  	struct iio_buffer *buffer;
>  	int ret;
>  
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (!buffer) {
>  		ret = -ENOMEM;
>  		goto error_ret;
> diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
> index 7134e8a..a383291 100644
> --- a/drivers/iio/kfifo_buf.c
> +++ b/drivers/iio/kfifo_buf.c
> @@ -166,19 +166,21 @@ static const struct iio_buffer_access_funcs kfifo_access_funcs = {
>  	.release = &iio_kfifo_buffer_release,
>  };
>  
> -struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev)
> +struct iio_buffer *iio_kfifo_allocate(void)
>  {
>  	struct iio_kfifo *kf;
>  
> -	kf = kzalloc(sizeof *kf, GFP_KERNEL);
> +	kf = kzalloc(sizeof(*kf), GFP_KERNEL);
>  	if (!kf)
>  		return NULL;
> +
>  	kf->update_needed = true;
>  	iio_buffer_init(&kf->buffer);
>  	kf->buffer.attrs = &iio_kfifo_attribute_group;
>  	kf->buffer.access = &kfifo_access_funcs;
>  	kf->buffer.length = 2;
>  	mutex_init(&kf->user_lock);
> +
>  	return &kf->buffer;
>  }
>  EXPORT_SYMBOL(iio_kfifo_allocate);
> diff --git a/drivers/staging/iio/accel/lis3l02dq_ring.c b/drivers/staging/iio/accel/lis3l02dq_ring.c
> index 9efc77b..1fd9009 100644
> --- a/drivers/staging/iio/accel/lis3l02dq_ring.c
> +++ b/drivers/staging/iio/accel/lis3l02dq_ring.c
> @@ -393,7 +393,7 @@ int lis3l02dq_configure_buffer(struct iio_dev *indio_dev)
>  	int ret;
>  	struct iio_buffer *buffer;
>  
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (!buffer)
>  		return -ENOMEM;
>  
> diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c
> index fd74f91..df765c9 100644
> --- a/drivers/staging/iio/iio_simple_dummy_buffer.c
> +++ b/drivers/staging/iio/iio_simple_dummy_buffer.c
> @@ -122,7 +122,7 @@ int iio_simple_dummy_configure_buffer(struct iio_dev *indio_dev,
>  	struct iio_buffer *buffer;
>  
>  	/* Allocate a buffer to use - here a kfifo */
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (buffer == NULL) {
>  		ret = -ENOMEM;
>  		goto error_ret;
> diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
> index b6bd609..ace9ef8 100644
> --- a/drivers/staging/iio/impedance-analyzer/ad5933.c
> +++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
> @@ -626,7 +626,7 @@ static int ad5933_register_ring_funcs_and_init(struct iio_dev *indio_dev)
>  {
>  	struct iio_buffer *buffer;
>  
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (!buffer)
>  		return -ENOMEM;
>  
> diff --git a/drivers/staging/iio/meter/ade7758_ring.c b/drivers/staging/iio/meter/ade7758_ring.c
> index 6e90064..31d2cf3 100644
> --- a/drivers/staging/iio/meter/ade7758_ring.c
> +++ b/drivers/staging/iio/meter/ade7758_ring.c
> @@ -118,7 +118,7 @@ int ade7758_configure_ring(struct iio_dev *indio_dev)
>  	struct iio_buffer *buffer;
>  	int ret = 0;
>  
> -	buffer = iio_kfifo_allocate(indio_dev);
> +	buffer = iio_kfifo_allocate();
>  	if (!buffer) {
>  		ret = -ENOMEM;
>  		return ret;
> diff --git a/include/linux/iio/kfifo_buf.h b/include/linux/iio/kfifo_buf.h
> index 25eeac7..1a8d57a 100644
> --- a/include/linux/iio/kfifo_buf.h
> +++ b/include/linux/iio/kfifo_buf.h
> @@ -5,7 +5,7 @@
>  #include <linux/iio/iio.h>
>  #include <linux/iio/buffer.h>
>  
> -struct iio_buffer *iio_kfifo_allocate(struct iio_dev *indio_dev);
> +struct iio_buffer *iio_kfifo_allocate(void);
>  void iio_kfifo_free(struct iio_buffer *r);
>  
>  #endif
> 

Re: [PATCH v2 2/3] iio: kfifo: Add resource management devm_iio_kfifo_allocate/free

[Jonathan Cameron]

On 19/12/14 17:39, Karol Wrona wrote:
> iio kfifo allocate/free gained their devm_ wrappers.
> 
> Signed-off-by: Karol Wrona <k.wrona@samsung.com>
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
Applied to the togreg branch of iio.git.

One addition - added to the list of devm functions in
Documentation/device-model/devres.txt


> ---
>  drivers/iio/kfifo_buf.c       |   54 +++++++++++++++++++++++++++++++++++++++++
>  include/linux/iio/kfifo_buf.h |    3 +++
>  2 files changed, 57 insertions(+)
> 
> diff --git a/drivers/iio/kfifo_buf.c b/drivers/iio/kfifo_buf.c
> index a383291..5d44099 100644
> --- a/drivers/iio/kfifo_buf.c
> +++ b/drivers/iio/kfifo_buf.c
> @@ -191,4 +191,58 @@ void iio_kfifo_free(struct iio_buffer *r)
>  }
>  EXPORT_SYMBOL(iio_kfifo_free);
>  
> +static void devm_iio_kfifo_release(struct device *dev, void *res)
> +{
> +	iio_kfifo_free(*(struct iio_buffer **)res);
> +}
> +
> +static int devm_iio_kfifo_match(struct device *dev, void *res, void *data)
> +{
> +	struct iio_buffer **r = res;
> +
> +	if (WARN_ON(!r || !*r))
> +		return 0;
> +
> +	return *r == data;
> +}
> +
> +/**
> + * devm_iio_fifo_allocate - Resource-managed iio_kfifo_allocate()
> + * @dev:		Device to allocate kfifo buffer for
> + *
> + * RETURNS:
> + * Pointer to allocated iio_buffer on success, NULL on failure.
> + */
> +struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
> +{
> +	struct iio_buffer **ptr, *r;
> +
> +	ptr = devres_alloc(devm_iio_kfifo_release, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr)
> +		return NULL;
> +
> +	r = iio_kfifo_allocate();
> +	if (r) {
> +		*ptr = r;
> +		devres_add(dev, ptr);
> +	} else {
> +		devres_free(ptr);
> +	}
> +
> +	return r;
> +}
> +EXPORT_SYMBOL(devm_iio_kfifo_allocate);
> +
> +/**
> + * devm_iio_fifo_free - Resource-managed iio_kfifo_free()
> + * @dev:		Device the buffer belongs to
> + * @r:			The buffer associated with the device
> + */
> +void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r)
> +{
> +	WARN_ON(devres_release(dev, devm_iio_kfifo_release,
> +			       devm_iio_kfifo_match, r));
> +}
> +EXPORT_SYMBOL(devm_iio_kfifo_free);
> +
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/iio/kfifo_buf.h b/include/linux/iio/kfifo_buf.h
> index 1a8d57a..1683bc7 100644
> --- a/include/linux/iio/kfifo_buf.h
> +++ b/include/linux/iio/kfifo_buf.h
> @@ -8,4 +8,7 @@
>  struct iio_buffer *iio_kfifo_allocate(void);
>  void iio_kfifo_free(struct iio_buffer *r);
>  
> +struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev);
> +void devm_iio_kfifo_free(struct device *dev, struct iio_buffer *r);
> +
>  #endif
> 

Re: [PATCH v2 3/3] iio: core: Get rid of misleading comment

[Jonathan Cameron]

On 19/12/14 17:39, Karol Wrona wrote:
> This comment did not fit here.  It explains why devm_kmalloc
> uses dr_alloc.  Generally is not needed at all.
> 
A classic bit of cut and paste I guess. Anyhow, applied.

Jonathan
> Signed-off-by: Karol Wrona <k.wrona@samsung.com>
> ---
>  drivers/iio/industrialio-core.c |    1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index af3e76d..1d030ae 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -1035,7 +1035,6 @@ struct iio_dev *devm_iio_device_alloc(struct device *dev, int sizeof_priv)
>  	if (!ptr)
>  		return NULL;
>  
> -	/* use raw alloc_dr for kmalloc caller tracing */
>  	iio_dev = iio_device_alloc(sizeof_priv);
>  	if (iio_dev) {
>  		*ptr = iio_dev;
>