[PATCH 0/4 V5] staging:iio: Add support for multiple buffers (testing required!)

[PATCH 0/4 V5] staging:iio: Add support for multiple buffers (testing required!)

[Jonathan Cameron]

In quick summary this is needed to do interrupt driven in kernel
clients as it adds the option to push to multiple 'buffer' interfaces.
Note that some of these may not actually do any buffering but rather
push directly into another subsytem (the example is input).

I would like to merge at least the first 3 patches early in this cycle.
What I need is some testing across a reasonable range of devices.  Review
is welcome of course as well!

The complexity in this set is entirely in the changes to industrialio-buffer.c
concerning how we go about adding and removing client buffers.  To do this
we need to work out which scan mask is appropriate given the requests of
all the given buffers (and whether we can satisfy it).  I've been testing
with the max1363 driver which probably has the most complex set of available
scan masks.  Thus when a new buffer is added or one is removed the whole
buffer set are torn down and built up again.  This may be undesirable for
some applications but should occur only rarely.

The example driver is for bridging to the input subsystem and still needs
some work, but that can occur later in this merge cycle whereas the changes
to the core really want to go in asap.

Changes since v3 

Rebased and added other drivers that have occured whilst this patch series
has been languishing in my local tree.

Changes since V2.

Improved handling of error conditions in the buffer insertion and
removal code.  (suggested by Lars-Peter).  I want to take another
look at these, but didn't want to keep people from testing this
in the meantime.

Also a number of minor fixes that came up during testing.

Thanks,

Jonathan

Jonathan Cameron (4):
  staging:iio: Add support for multiple buffers
  staging:iio:in kernel users: Add a data field for channel specific
    info.
  staging:iio: add a callback buffer for in kernel push interface
  staging:iio: Proof of concept input driver.

 drivers/iio/Kconfig                             |   6 +
 drivers/iio/Makefile                            |   1 +
 drivers/iio/accel/hid-sensor-accel-3d.c         |  15 +-
 drivers/iio/adc/ad7266.c                        |   3 +-
 drivers/iio/adc/ad7476.c                        |   2 +-
 drivers/iio/adc/ad_sigma_delta.c                |   2 +-
 drivers/iio/adc/at91_adc.c                      |   3 +-
 drivers/iio/buffer_cb.c                         | 113 +++++++
 drivers/iio/gyro/hid-sensor-gyro-3d.c           |  15 +-
 drivers/iio/industrialio-buffer.c               | 377 ++++++++++++++++--------
 drivers/iio/industrialio-core.c                 |   1 +
 drivers/iio/inkern.c                            |   1 +
 drivers/iio/light/adjd_s311.c                   |   3 +-
 drivers/iio/light/hid-sensor-als.c              |  15 +-
 drivers/iio/magnetometer/hid-sensor-magn-3d.c   |  15 +-
 drivers/staging/iio/Kconfig                     |  11 +
 drivers/staging/iio/Makefile                    |   1 +
 drivers/staging/iio/accel/adis16201_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16203_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16204_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16209_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16240_ring.c      |   2 +-
 drivers/staging/iio/accel/lis3l02dq_ring.c      |   2 +-
 drivers/staging/iio/adc/ad7298_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7606_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7887_ring.c           |   2 +-
 drivers/staging/iio/adc/ad799x_ring.c           |   2 +-
 drivers/staging/iio/adc/max1363_ring.c          |   2 +-
 drivers/staging/iio/gyro/adis16260_ring.c       |   2 +-
 drivers/staging/iio/iio_input.c                 | 225 ++++++++++++++
 drivers/staging/iio/iio_input.h                 |  23 ++
 drivers/staging/iio/iio_simple_dummy_buffer.c   |   5 +-
 drivers/staging/iio/impedance-analyzer/ad5933.c |   4 +-
 drivers/staging/iio/imu/adis16400_ring.c        |   5 +-
 drivers/staging/iio/meter/ade7758_ring.c        |   2 +-
 include/linux/iio/buffer.h                      |  24 +-
 include/linux/iio/consumer.h                    |  48 +++
 include/linux/iio/iio.h                         |   2 +
 include/linux/iio/machine.h                     |   2 +
 39 files changed, 740 insertions(+), 208 deletions(-)
 create mode 100644 drivers/iio/buffer_cb.c
 create mode 100644 drivers/staging/iio/iio_input.c
 create mode 100644 drivers/staging/iio/iio_input.h

-- 
1.7.12.2

[PATCH 1/4] staging:iio: Add support for multiple buffers

[Jonathan Cameron]

Route all buffer writes through the demux.
Addition or removal of a buffer results in tear down and
setup of all the buffers for a given device.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/accel/hid-sensor-accel-3d.c         |  15 +-
 drivers/iio/adc/ad7266.c                        |   3 +-
 drivers/iio/adc/ad7476.c                        |   2 +-
 drivers/iio/adc/ad_sigma_delta.c                |   2 +-
 drivers/iio/adc/at91_adc.c                      |   3 +-
 drivers/iio/gyro/hid-sensor-gyro-3d.c           |  15 +-
 drivers/iio/industrialio-buffer.c               | 377 ++++++++++++++++--------
 drivers/iio/industrialio-core.c                 |   1 +
 drivers/iio/light/adjd_s311.c                   |   3 +-
 drivers/iio/light/hid-sensor-als.c              |  15 +-
 drivers/iio/magnetometer/hid-sensor-magn-3d.c   |  15 +-
 drivers/staging/iio/accel/adis16201_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16203_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16204_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16209_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16240_ring.c      |   2 +-
 drivers/staging/iio/accel/lis3l02dq_ring.c      |   2 +-
 drivers/staging/iio/adc/ad7298_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7606_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7887_ring.c           |   2 +-
 drivers/staging/iio/adc/ad799x_ring.c           |   2 +-
 drivers/staging/iio/adc/max1363_ring.c          |   2 +-
 drivers/staging/iio/gyro/adis16260_ring.c       |   2 +-
 drivers/staging/iio/iio_simple_dummy_buffer.c   |   5 +-
 drivers/staging/iio/impedance-analyzer/ad5933.c |   4 +-
 drivers/staging/iio/imu/adis16400_ring.c        |   5 +-
 drivers/staging/iio/meter/ade7758_ring.c        |   2 +-
 include/linux/iio/buffer.h                      |  24 +-
 include/linux/iio/iio.h                         |   2 +
 29 files changed, 309 insertions(+), 208 deletions(-)

diff --git a/drivers/iio/accel/hid-sensor-accel-3d.c b/drivers/iio/accel/hid-sensor-accel-3d.c
index 314a405..a95cda0 100644
--- a/drivers/iio/accel/hid-sensor-accel-3d.c
+++ b/drivers/iio/accel/hid-sensor-accel-3d.c
@@ -197,21 +197,8 @@ static const struct iio_info accel_3d_info = {
 /* Function to push data to buffer */
 static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
 {
-	struct iio_buffer *buffer = indio_dev->buffer;
-	int datum_sz;
-
 	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	if (!buffer) {
-		dev_err(&indio_dev->dev, "Buffer == NULL\n");
-		return;
-	}
-	datum_sz = buffer->access->get_bytes_per_datum(buffer);
-	if (len > datum_sz) {
-		dev_err(&indio_dev->dev, "Datum size mismatch %d:%d\n", len,
-				datum_sz);
-		return;
-	}
-	iio_push_to_buffer(buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 }
 
 /* Callback handler to send event after all samples are received and captured */
diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
index b11f214..a6f4fc5 100644
--- a/drivers/iio/adc/ad7266.c
+++ b/drivers/iio/adc/ad7266.c
@@ -91,7 +91,6 @@ static irqreturn_t ad7266_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
-	struct iio_buffer *buffer = indio_dev->buffer;
 	struct ad7266_state *st = iio_priv(indio_dev);
 	int ret;
 
@@ -99,7 +98,7 @@ static irqreturn_t ad7266_trigger_handler(int irq, void *p)
 	if (ret == 0) {
 		if (indio_dev->scan_timestamp)
 			((s64 *)st->data)[1] = pf->timestamp;
-		iio_push_to_buffer(buffer, (u8 *)st->data);
+		iio_push_to_buffers(indio_dev, (u8 *)st->data);
 	}
 
 	iio_trigger_notify_done(indio_dev->trig);
diff --git a/drivers/iio/adc/ad7476.c b/drivers/iio/adc/ad7476.c
index 7f2f45a..330248b 100644
--- a/drivers/iio/adc/ad7476.c
+++ b/drivers/iio/adc/ad7476.c
@@ -76,7 +76,7 @@ static irqreturn_t ad7476_trigger_handler(int irq, void  *p)
 	if (indio_dev->scan_timestamp)
 		((s64 *)st->data)[1] = time_ns;
 
-	iio_push_to_buffer(indio_dev->buffer, st->data);
+	iio_push_to_buffers(indio_dev, st->data);
 done:
 	iio_trigger_notify_done(indio_dev->trig);
 
diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index 67baa13..afe6d78 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -391,7 +391,7 @@ static irqreturn_t ad_sd_trigger_handler(int irq, void *p)
 		break;
 	}
 
-	iio_push_to_buffer(indio_dev->buffer, (uint8_t *)data);
+	iio_push_to_buffers(indio_dev, (uint8_t *)data);
 
 	iio_trigger_notify_done(indio_dev->trig);
 	sigma_delta->irq_dis = false;
diff --git a/drivers/iio/adc/at91_adc.c b/drivers/iio/adc/at91_adc.c
index 3ed94bf..1f9e70e 100644
--- a/drivers/iio/adc/at91_adc.c
+++ b/drivers/iio/adc/at91_adc.c
@@ -66,7 +66,6 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *idev = pf->indio_dev;
 	struct at91_adc_state *st = iio_priv(idev);
-	struct iio_buffer *buffer = idev->buffer;
 	int i, j = 0;
 
 	for (i = 0; i < idev->masklength; i++) {
@@ -82,7 +81,7 @@ static irqreturn_t at91_adc_trigger_handler(int irq, void *p)
 		*timestamp = pf->timestamp;
 	}
 
-	buffer->access->store_to(buffer, (u8 *)st->buffer);
+	iio_push_to_buffers(indio_dev, (u8 *)st->buffer);
 
 	iio_trigger_notify_done(idev->trig);
 	st->irq_enabled = true;
diff --git a/drivers/iio/gyro/hid-sensor-gyro-3d.c b/drivers/iio/gyro/hid-sensor-gyro-3d.c
index 4c56ada..02ef989 100644
--- a/drivers/iio/gyro/hid-sensor-gyro-3d.c
+++ b/drivers/iio/gyro/hid-sensor-gyro-3d.c
@@ -197,21 +197,8 @@ static const struct iio_info gyro_3d_info = {
 /* Function to push data to buffer */
 static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
 {
-	struct iio_buffer *buffer = indio_dev->buffer;
-	int datum_sz;
-
 	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	if (!buffer) {
-		dev_err(&indio_dev->dev, "Buffer == NULL\n");
-		return;
-	}
-	datum_sz = buffer->access->get_bytes_per_datum(buffer);
-	if (len > datum_sz) {
-		dev_err(&indio_dev->dev, "Datum size mismatch %d:%d\n", len,
-				datum_sz);
-		return;
-	}
-	iio_push_to_buffer(buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 }
 
 /* Callback handler to send event after all samples are received and captured */
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index d4ad374..8caa0d7 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -31,6 +31,18 @@ static const char * const iio_endian_prefix[] = {
 	[IIO_LE] = "le",
 };
 
+static bool iio_buffer_is_active(struct iio_dev *indio_dev,
+				 struct iio_buffer *buf)
+{
+	struct list_head *p;
+
+	list_for_each(p, &indio_dev->buffer_list)
+		if (p == &buf->buffer_list)
+			return true;
+
+	return false;
+}
+
 /**
  * iio_buffer_read_first_n_outer() - chrdev read for buffer access
  *
@@ -134,7 +146,7 @@ static ssize_t iio_scan_el_store(struct device *dev,
 	if (ret < 0)
 		return ret;
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_enabled(indio_dev)) {
+	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
 		ret = -EBUSY;
 		goto error_ret;
 	}
@@ -180,12 +192,11 @@ static ssize_t iio_scan_el_ts_store(struct device *dev,
 		return ret;
 
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_enabled(indio_dev)) {
+	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
 		ret = -EBUSY;
 		goto error_ret;
 	}
 	indio_dev->buffer->scan_timestamp = state;
-	indio_dev->scan_timestamp = state;
 error_ret:
 	mutex_unlock(&indio_dev->mlock);
 
@@ -385,7 +396,7 @@ ssize_t iio_buffer_write_length(struct device *dev,
 			return len;
 
 	mutex_lock(&indio_dev->mlock);
-	if (iio_buffer_enabled(indio_dev)) {
+	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
 		ret = -EBUSY;
 	} else {
 		if (buffer->access->set_length)
@@ -398,102 +409,14 @@ ssize_t iio_buffer_write_length(struct device *dev,
 }
 EXPORT_SYMBOL(iio_buffer_write_length);
 
-ssize_t iio_buffer_store_enable(struct device *dev,
-				struct device_attribute *attr,
-				const char *buf,
-				size_t len)
-{
-	int ret;
-	bool requested_state, current_state;
-	int previous_mode;
-	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	struct iio_buffer *buffer = indio_dev->buffer;
-
-	mutex_lock(&indio_dev->mlock);
-	previous_mode = indio_dev->currentmode;
-	requested_state = !(buf[0] == '0');
-	current_state = iio_buffer_enabled(indio_dev);
-	if (current_state == requested_state) {
-		printk(KERN_INFO "iio-buffer, current state requested again\n");
-		goto done;
-	}
-	if (requested_state) {
-		if (indio_dev->setup_ops->preenable) {
-			ret = indio_dev->setup_ops->preenable(indio_dev);
-			if (ret) {
-				printk(KERN_ERR
-				       "Buffer not started: "
-				       "buffer preenable failed\n");
-				goto error_ret;
-			}
-		}
-		if (buffer->access->request_update) {
-			ret = buffer->access->request_update(buffer);
-			if (ret) {
-				printk(KERN_INFO
-				       "Buffer not started: "
-				       "buffer parameter update failed\n");
-				goto error_ret;
-			}
-		}
-		/* Definitely possible for devices to support both of these. */
-		if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
-			if (!indio_dev->trig) {
-				printk(KERN_INFO
-				       "Buffer not started: no trigger\n");
-				ret = -EINVAL;
-				goto error_ret;
-			}
-			indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
-		} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
-			indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
-		else { /* should never be reached */
-			ret = -EINVAL;
-			goto error_ret;
-		}
-
-		if (indio_dev->setup_ops->postenable) {
-			ret = indio_dev->setup_ops->postenable(indio_dev);
-			if (ret) {
-				printk(KERN_INFO
-				       "Buffer not started: "
-				       "postenable failed\n");
-				indio_dev->currentmode = previous_mode;
-				if (indio_dev->setup_ops->postdisable)
-					indio_dev->setup_ops->
-						postdisable(indio_dev);
-				goto error_ret;
-			}
-		}
-	} else {
-		if (indio_dev->setup_ops->predisable) {
-			ret = indio_dev->setup_ops->predisable(indio_dev);
-			if (ret)
-				goto error_ret;
-		}
-		indio_dev->currentmode = INDIO_DIRECT_MODE;
-		if (indio_dev->setup_ops->postdisable) {
-			ret = indio_dev->setup_ops->postdisable(indio_dev);
-			if (ret)
-				goto error_ret;
-		}
-	}
-done:
-	mutex_unlock(&indio_dev->mlock);
-	return len;
-
-error_ret:
-	mutex_unlock(&indio_dev->mlock);
-	return ret;
-}
-EXPORT_SYMBOL(iio_buffer_store_enable);
-
 ssize_t iio_buffer_show_enable(struct device *dev,
 			       struct device_attribute *attr,
 			       char *buf)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
-	return sprintf(buf, "%d\n", iio_buffer_enabled(indio_dev));
+	return sprintf(buf, "%d\n",
+		       iio_buffer_is_active(indio_dev,
+					    indio_dev->buffer));
 }
 EXPORT_SYMBOL(iio_buffer_show_enable);
 
@@ -537,35 +460,217 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
 	return bytes;
 }
 
-int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
+int iio_update_buffers(struct iio_dev *indio_dev,
+		       struct iio_buffer *insert_buffer,
+		       struct iio_buffer *remove_buffer)
 {
-	struct iio_buffer *buffer = indio_dev->buffer;
-	dev_dbg(&indio_dev->dev, "%s\n", __func__);
+	int ret;
+	int success = 0;
+	struct iio_buffer *buffer;
+	unsigned long *compound_mask;
+	const unsigned long *old_mask;
 
-	/* How much space will the demuxed element take? */
-	indio_dev->scan_bytes =
-		iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
-				       buffer->scan_timestamp);
-	buffer->access->set_bytes_per_datum(buffer, indio_dev->scan_bytes);
+	/* Wind down existing buffers - iff there are any */
+	if (!list_empty(&indio_dev->buffer_list)) {
+		if (indio_dev->setup_ops->predisable) {
+			ret = indio_dev->setup_ops->predisable(indio_dev);
+			if (ret)
+				goto error_ret;
+		}
+		indio_dev->currentmode = INDIO_DIRECT_MODE;
+		if (indio_dev->setup_ops->postdisable) {
+			ret = indio_dev->setup_ops->postdisable(indio_dev);
+			if (ret)
+				goto error_ret;
+		}
+	}
+	/* Keep a copy of current setup to allow roll back */
+	old_mask = indio_dev->active_scan_mask;
+	if (!indio_dev->available_scan_masks)
+		indio_dev->active_scan_mask = NULL;
+
+	if (remove_buffer)
+		list_del(&remove_buffer->buffer_list);
+	if (insert_buffer)
+		list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
+
+	/* If no buffers in list, we are done */
+	if (list_empty(&indio_dev->buffer_list)) {
+		indio_dev->currentmode = INDIO_DIRECT_MODE;
+		return 0;
+	}
 
 	/* What scan mask do we actually have ?*/
-	if (indio_dev->available_scan_masks)
+	compound_mask = kzalloc(BITS_TO_LONGS(indio_dev->masklength)
+				*sizeof(long), GFP_KERNEL);
+	if (compound_mask == NULL)
+		return -ENOMEM;
+
+	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
+		bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
+			  indio_dev->masklength);
+		indio_dev->scan_timestamp |= buffer->scan_timestamp;
+	}
+	if (indio_dev->available_scan_masks) {
 		indio_dev->active_scan_mask =
 			iio_scan_mask_match(indio_dev->available_scan_masks,
 					    indio_dev->masklength,
-					    buffer->scan_mask);
-	else
-		indio_dev->active_scan_mask = buffer->scan_mask;
-
-	if (indio_dev->active_scan_mask == NULL)
-		return -EINVAL;
+					    compound_mask);
+		if (indio_dev->active_scan_mask == NULL) {
+			/*
+			 * Roll back.
+			 * Note can only occur when adding a buffer.
+			 */
+			list_del(&insert_buffer->buffer_list);
+			indio_dev->active_scan_mask = old_mask;
+			success = -EINVAL;
+		}
+	} else {
+		indio_dev->active_scan_mask = compound_mask;
+	}
 
 	iio_update_demux(indio_dev);
 
-	if (indio_dev->info->update_scan_mode)
-		return indio_dev->info
+	/* Wind up again */
+	if (indio_dev->setup_ops->preenable) {
+		ret = indio_dev->setup_ops->preenable(indio_dev);
+		if (ret) {
+			printk(KERN_ERR
+			       "Buffer not started:"
+			       "buffer preenable failed\n");
+			goto error_remove_inserted;
+		}
+	}
+	indio_dev->scan_bytes =
+		iio_compute_scan_bytes(indio_dev,
+				       indio_dev->active_scan_mask,
+				       indio_dev->scan_timestamp);
+	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
+		if (buffer->access->request_update) {
+			ret = buffer->access->request_update(buffer);
+			if (ret) {
+				printk(KERN_INFO
+				       "Buffer not started:"
+				       "buffer parameter update failed\n");
+				goto error_run_postdisable;
+			}
+		}
+	if (indio_dev->info->update_scan_mode) {
+		ret = indio_dev->info
 			->update_scan_mode(indio_dev,
 					   indio_dev->active_scan_mask);
+		if (ret < 0) {
+			printk(KERN_INFO "update scan mode failed\n");
+			goto error_run_postdisable;
+		}
+	}
+	/* Definitely possible for devices to support both of these.*/
+	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
+		if (!indio_dev->trig) {
+			printk(KERN_INFO "Buffer not started: no trigger\n");
+			ret = -EINVAL;
+			/* Can only occur on first buffer */
+			goto error_run_postdisable;
+		}
+		indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
+	} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
+		indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
+	} else { /* should never be reached */
+		ret = -EINVAL;
+		goto error_run_postdisable;
+	}
+
+	if (indio_dev->setup_ops->postenable) {
+		ret = indio_dev->setup_ops->postenable(indio_dev);
+		if (ret) {
+			printk(KERN_INFO
+			       "Buffer not started: postenable failed\n");
+			indio_dev->currentmode = INDIO_DIRECT_MODE;
+			if (indio_dev->setup_ops->postdisable)
+				indio_dev->setup_ops->postdisable(indio_dev);
+			goto error_disable_all_buffers;
+		}
+	}
+
+	if (indio_dev->available_scan_masks)
+		kfree(compound_mask);
+	else
+		kfree(old_mask);
+
+	return success;
+
+error_disable_all_buffers:
+	indio_dev->currentmode = INDIO_DIRECT_MODE;
+error_run_postdisable:
+	if (indio_dev->setup_ops->postdisable)
+		indio_dev->setup_ops->postdisable(indio_dev);
+error_remove_inserted:
+
+	if (insert_buffer)
+		list_del(&insert_buffer->buffer_list);
+	indio_dev->active_scan_mask = old_mask;
+	kfree(compound_mask);
+error_ret:
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(iio_update_buffers);
+
+ssize_t iio_buffer_store_enable(struct device *dev,
+				struct device_attribute *attr,
+				const char *buf,
+				size_t len)
+{
+	int ret;
+	bool requested_state;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct iio_buffer *pbuf = indio_dev->buffer;
+	bool inlist;
+
+	ret = strtobool(buf, &requested_state);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	/* Find out if it is in the list */
+	inlist = iio_buffer_is_active(indio_dev, pbuf);
+	/* Already enabled */
+	if (inlist && requested_state)
+		goto done;
+	/* Already disabled */
+	if (!inlist && !requested_state)
+		goto done;
+
+	if (requested_state)
+		ret = iio_update_buffers(indio_dev,
+					 indio_dev->buffer, NULL);
+	else
+		ret = iio_update_buffers(indio_dev,
+					 NULL, indio_dev->buffer);
+
+	if (ret < 0)
+		goto done;
+done:
+	mutex_unlock(&indio_dev->mlock);
+	return (ret < 0) ? ret : len;
+}
+EXPORT_SYMBOL(iio_buffer_store_enable);
+
+int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
+{
+	struct iio_buffer *buffer;
+	unsigned bytes;
+	dev_dbg(&indio_dev->dev, "%s\n", __func__);
+
+	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
+		if (buffer->access->set_bytes_per_datum) {
+			bytes = iio_compute_scan_bytes(indio_dev,
+						       buffer->scan_mask,
+						       buffer->scan_timestamp);
+
+			buffer->access->set_bytes_per_datum(buffer, bytes);
+		}
 	return 0;
 }
 EXPORT_SYMBOL(iio_sw_buffer_preenable);
@@ -599,7 +704,11 @@ static bool iio_validate_scan_mask(struct iio_dev *indio_dev,
  * iio_scan_mask_set() - set particular bit in the scan mask
  * @buffer: the buffer whose scan mask we are interested in
  * @bit: the bit to be set.
- **/
+ *
+ * Note that at this point we have no way of knowing what other
+ * buffers might request, hence this code only verifies that the
+ * individual buffers request is plausible.
+ */
 int iio_scan_mask_set(struct iio_dev *indio_dev,
 		      struct iio_buffer *buffer, int bit)
 {
@@ -682,13 +791,12 @@ static unsigned char *iio_demux(struct iio_buffer *buffer,
 	return buffer->demux_bounce;
 }
 
-int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data)
+static int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data)
 {
 	unsigned char *dataout = iio_demux(buffer, data);
 
 	return buffer->access->store_to(buffer, dataout);
 }
-EXPORT_SYMBOL_GPL(iio_push_to_buffer);
 
 static void iio_buffer_demux_free(struct iio_buffer *buffer)
 {
@@ -699,10 +807,26 @@ static void iio_buffer_demux_free(struct iio_buffer *buffer)
 	}
 }
 
-int iio_update_demux(struct iio_dev *indio_dev)
+
+int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data)
+{
+	int ret;
+	struct iio_buffer *buf;
+
+	list_for_each_entry(buf, &indio_dev->buffer_list, buffer_list) {
+		ret = iio_push_to_buffer(buf, data);
+		if (ret < 0)
+			return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iio_push_to_buffers);
+
+static int iio_buffer_update_demux(struct iio_dev *indio_dev,
+				   struct iio_buffer *buffer)
 {
 	const struct iio_chan_spec *ch;
-	struct iio_buffer *buffer = indio_dev->buffer;
 	int ret, in_ind = -1, out_ind, length;
 	unsigned in_loc = 0, out_loc = 0;
 	struct iio_demux_table *p;
@@ -787,4 +911,23 @@ error_clear_mux_table:
 
 	return ret;
 }
+
+int iio_update_demux(struct iio_dev *indio_dev)
+{
+	struct iio_buffer *buffer;
+	int ret;
+
+	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
+		ret = iio_buffer_update_demux(indio_dev, buffer);
+		if (ret < 0)
+			goto error_clear_mux_table;
+	}
+	return 0;
+
+error_clear_mux_table:
+	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
+		iio_buffer_demux_free(buffer);
+
+	return ret;
+}
 EXPORT_SYMBOL_GPL(iio_update_demux);
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 6eb24db..1bcaabf 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -851,6 +851,7 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
 			return NULL;
 		}
 		dev_set_name(&dev->dev, "iio:device%d", dev->id);
+		INIT_LIST_HEAD(&dev->buffer_list);
 	}
 
 	return dev;
diff --git a/drivers/iio/light/adjd_s311.c b/drivers/iio/light/adjd_s311.c
index 164b62b..36d210a 100644
--- a/drivers/iio/light/adjd_s311.c
+++ b/drivers/iio/light/adjd_s311.c
@@ -164,7 +164,6 @@ static irqreturn_t adjd_s311_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adjd_s311_data *data = iio_priv(indio_dev);
-	struct iio_buffer *buffer = indio_dev->buffer;
 	s64 time_ns = iio_get_time_ns();
 	int len = 0;
 	int i, j = 0;
@@ -187,7 +186,7 @@ static irqreturn_t adjd_s311_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*(s64 *)((u8 *)data->buffer + ALIGN(len, sizeof(s64)))
 			= time_ns;
-	iio_push_to_buffer(buffer, (u8 *)data->buffer);
+	iio_push_to_buffers(indio_dev, (u8 *)data->buffer);
 
 done:
 	iio_trigger_notify_done(indio_dev->trig);
diff --git a/drivers/iio/light/hid-sensor-als.c b/drivers/iio/light/hid-sensor-als.c
index 96e3691..8e1f698 100644
--- a/drivers/iio/light/hid-sensor-als.c
+++ b/drivers/iio/light/hid-sensor-als.c
@@ -176,21 +176,8 @@ static const struct iio_info als_info = {
 /* Function to push data to buffer */
 static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
 {
-	struct iio_buffer *buffer = indio_dev->buffer;
-	int datum_sz;
-
 	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	if (!buffer) {
-		dev_err(&indio_dev->dev, "Buffer == NULL\n");
-		return;
-	}
-	datum_sz = buffer->access->get_bytes_per_datum(buffer);
-	if (len > datum_sz) {
-		dev_err(&indio_dev->dev, "Datum size mismatch %d:%d\n", len,
-				datum_sz);
-		return;
-	}
-	iio_push_to_buffer(buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 }
 
 /* Callback handler to send event after all samples are received and captured */
diff --git a/drivers/iio/magnetometer/hid-sensor-magn-3d.c b/drivers/iio/magnetometer/hid-sensor-magn-3d.c
index c4f0d27..d1b5fb7 100644
--- a/drivers/iio/magnetometer/hid-sensor-magn-3d.c
+++ b/drivers/iio/magnetometer/hid-sensor-magn-3d.c
@@ -198,21 +198,8 @@ static const struct iio_info magn_3d_info = {
 /* Function to push data to buffer */
 static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
 {
-	struct iio_buffer *buffer = indio_dev->buffer;
-	int datum_sz;
-
 	dev_dbg(&indio_dev->dev, "hid_sensor_push_data\n");
-	if (!buffer) {
-		dev_err(&indio_dev->dev, "Buffer == NULL\n");
-		return;
-	}
-	datum_sz = buffer->access->get_bytes_per_datum(buffer);
-	if (len > datum_sz) {
-		dev_err(&indio_dev->dev, "Datum size mismatch %d:%d\n", len,
-				datum_sz);
-		return;
-	}
-	iio_push_to_buffer(buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 }
 
 /* Callback handler to send event after all samples are received and captured */
diff --git a/drivers/staging/iio/accel/adis16201_ring.c b/drivers/staging/iio/accel/adis16201_ring.c
index 97c09f0..e14ca60 100644
--- a/drivers/staging/iio/accel/adis16201_ring.c
+++ b/drivers/staging/iio/accel/adis16201_ring.c
@@ -82,7 +82,7 @@ static irqreturn_t adis16201_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/accel/adis16203_ring.c b/drivers/staging/iio/accel/adis16203_ring.c
index 7507e1a..eba2e28 100644
--- a/drivers/staging/iio/accel/adis16203_ring.c
+++ b/drivers/staging/iio/accel/adis16203_ring.c
@@ -81,7 +81,7 @@ static irqreturn_t adis16203_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/accel/adis16204_ring.c b/drivers/staging/iio/accel/adis16204_ring.c
index 4c976be..3611a13 100644
--- a/drivers/staging/iio/accel/adis16204_ring.c
+++ b/drivers/staging/iio/accel/adis16204_ring.c
@@ -78,7 +78,7 @@ static irqreturn_t adis16204_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/accel/adis16209_ring.c b/drivers/staging/iio/accel/adis16209_ring.c
index f939e29..6af9a5d 100644
--- a/drivers/staging/iio/accel/adis16209_ring.c
+++ b/drivers/staging/iio/accel/adis16209_ring.c
@@ -78,7 +78,7 @@ static irqreturn_t adis16209_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/accel/adis16240_ring.c b/drivers/staging/iio/accel/adis16240_ring.c
index caff8e2..e2ac8a8 100644
--- a/drivers/staging/iio/accel/adis16240_ring.c
+++ b/drivers/staging/iio/accel/adis16240_ring.c
@@ -76,7 +76,7 @@ static irqreturn_t adis16240_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/accel/lis3l02dq_ring.c b/drivers/staging/iio/accel/lis3l02dq_ring.c
index fa4190d..d59abd3 100644
--- a/drivers/staging/iio/accel/lis3l02dq_ring.c
+++ b/drivers/staging/iio/accel/lis3l02dq_ring.c
@@ -154,7 +154,7 @@ static irqreturn_t lis3l02dq_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*(s64 *)((u8 *)data + ALIGN(len, sizeof(s64)))
 			= pf->timestamp;
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/adc/ad7298_ring.c b/drivers/staging/iio/adc/ad7298_ring.c
index c2906a8..b3dd514 100644
--- a/drivers/staging/iio/adc/ad7298_ring.c
+++ b/drivers/staging/iio/adc/ad7298_ring.c
@@ -93,7 +93,7 @@ static irqreturn_t ad7298_trigger_handler(int irq, void *p)
 						 indio_dev->masklength); i++)
 		buf[i] = be16_to_cpu(st->rx_buf[i]);
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)buf);
+	iio_push_to_buffers(indio_dev, (u8 *)buf);
 
 done:
 	iio_trigger_notify_done(indio_dev->trig);
diff --git a/drivers/staging/iio/adc/ad7606_ring.c b/drivers/staging/iio/adc/ad7606_ring.c
index ba04d0f..2b25cb0 100644
--- a/drivers/staging/iio/adc/ad7606_ring.c
+++ b/drivers/staging/iio/adc/ad7606_ring.c
@@ -83,7 +83,7 @@ static void ad7606_poll_bh_to_ring(struct work_struct *work_s)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(buf + indio_dev->scan_bytes - sizeof(s64))) = time_ns;
 
-	iio_push_to_buffer(indio_dev->buffer, buf);
+	iio_push_to_buffers(indio_dev, buf);
 done:
 	gpio_set_value(st->pdata->gpio_convst, 0);
 	iio_trigger_notify_done(indio_dev->trig);
diff --git a/drivers/staging/iio/adc/ad7887_ring.c b/drivers/staging/iio/adc/ad7887_ring.c
index b39923b..ccb8d4d 100644
--- a/drivers/staging/iio/adc/ad7887_ring.c
+++ b/drivers/staging/iio/adc/ad7887_ring.c
@@ -95,7 +95,7 @@ static irqreturn_t ad7887_trigger_handler(int irq, void *p)
 		memcpy(buf + indio_dev->scan_bytes - sizeof(s64),
 		       &time_ns, sizeof(time_ns));
 
-	iio_push_to_buffer(indio_dev->buffer, buf);
+	iio_push_to_buffers(indio_dev, buf);
 done:
 	kfree(buf);
 	iio_trigger_notify_done(indio_dev->trig);
diff --git a/drivers/staging/iio/adc/ad799x_ring.c b/drivers/staging/iio/adc/ad799x_ring.c
index 86026d9..2c5f384 100644
--- a/drivers/staging/iio/adc/ad799x_ring.c
+++ b/drivers/staging/iio/adc/ad799x_ring.c
@@ -77,7 +77,7 @@ static irqreturn_t ad799x_trigger_handler(int irq, void *p)
 		memcpy(rxbuf + indio_dev->scan_bytes - sizeof(s64),
 			&time_ns, sizeof(time_ns));
 
-	iio_push_to_buffer(indio_dev->buffer, rxbuf);
+	iio_push_to_buffers(indio_dev, rxbuf);
 done:
 	kfree(rxbuf);
 out:
diff --git a/drivers/staging/iio/adc/max1363_ring.c b/drivers/staging/iio/adc/max1363_ring.c
index 5f74f3b..688304b 100644
--- a/drivers/staging/iio/adc/max1363_ring.c
+++ b/drivers/staging/iio/adc/max1363_ring.c
@@ -80,7 +80,7 @@ static irqreturn_t max1363_trigger_handler(int irq, void *p)
 
 	if (indio_dev->scan_timestamp)
 		memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
-	iio_push_to_buffer(indio_dev->buffer, rxbuf);
+	iio_push_to_buffers(indio_dev, rxbuf);
 
 done_free:
 	kfree(rxbuf);
diff --git a/drivers/staging/iio/gyro/adis16260_ring.c b/drivers/staging/iio/gyro/adis16260_ring.c
index e294cb4..d6c48f8 100644
--- a/drivers/staging/iio/gyro/adis16260_ring.c
+++ b/drivers/staging/iio/gyro/adis16260_ring.c
@@ -81,7 +81,7 @@ static irqreturn_t adis16260_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 done:
diff --git a/drivers/staging/iio/iio_simple_dummy_buffer.c b/drivers/staging/iio/iio_simple_dummy_buffer.c
index 697d970..dee16f0 100644
--- a/drivers/staging/iio/iio_simple_dummy_buffer.c
+++ b/drivers/staging/iio/iio_simple_dummy_buffer.c
@@ -46,7 +46,6 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
-	struct iio_buffer *buffer = indio_dev->buffer;
 	int len = 0;
 	u16 *data;
 
@@ -76,7 +75,7 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
 		     i < bitmap_weight(indio_dev->active_scan_mask,
 				       indio_dev->masklength);
 		     i++, j++) {
-			j = find_next_bit(buffer->scan_mask,
+			j = find_next_bit(indio_dev->active_scan_mask,
 					  indio_dev->masklength, j);
 			/* random access read from the 'device' */
 			data[i] = fakedata[j];
@@ -87,7 +86,7 @@ static irqreturn_t iio_simple_dummy_trigger_h(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		*(s64 *)((u8 *)data + ALIGN(len, sizeof(s64)))
 			= iio_get_time_ns();
-	iio_push_to_buffer(buffer, (u8 *)data);
+	iio_push_to_buffers(indio_dev, (u8 *)data);
 
 	kfree(data);
 
diff --git a/drivers/staging/iio/impedance-analyzer/ad5933.c b/drivers/staging/iio/impedance-analyzer/ad5933.c
index de21d47..b1fef14 100644
--- a/drivers/staging/iio/impedance-analyzer/ad5933.c
+++ b/drivers/staging/iio/impedance-analyzer/ad5933.c
@@ -647,7 +647,6 @@ static void ad5933_work(struct work_struct *work)
 	struct ad5933_state *st = container_of(work,
 		struct ad5933_state, work.work);
 	struct iio_dev *indio_dev = i2c_get_clientdata(st->client);
-	struct iio_buffer *ring = indio_dev->buffer;
 	signed short buf[2];
 	unsigned char status;
 
@@ -677,8 +676,7 @@ static void ad5933_work(struct work_struct *work)
 		} else {
 			buf[0] = be16_to_cpu(buf[0]);
 		}
-		/* save datum to the ring */
-		iio_push_to_buffer(ring, (u8 *)buf);
+		iio_push_to_buffers(indio_dev, (u8 *)buf);
 	} else {
 		/* no data available - try again later */
 		schedule_delayed_work(&st->work, st->poll_time_jiffies);
diff --git a/drivers/staging/iio/imu/adis16400_ring.c b/drivers/staging/iio/imu/adis16400_ring.c
index 260bdd1..d46c1e3 100644
--- a/drivers/staging/iio/imu/adis16400_ring.c
+++ b/drivers/staging/iio/imu/adis16400_ring.c
@@ -114,7 +114,6 @@ static irqreturn_t adis16400_trigger_handler(int irq, void *p)
 	struct iio_poll_func *pf = p;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct adis16400_state *st = iio_priv(indio_dev);
-	struct iio_buffer *ring = indio_dev->buffer;
 	int i = 0, j, ret = 0;
 	s16 *data;
 
@@ -148,9 +147,9 @@ static irqreturn_t adis16400_trigger_handler(int irq, void *p)
 		}
 	}
 	/* Guaranteed to be aligned with 8 byte boundary */
-	if (ring->scan_timestamp)
+	if (indio_dev->scan_timestamp)
 		*((s64 *)(data + ((i + 3)/4)*4)) = pf->timestamp;
-	iio_push_to_buffer(ring, (u8 *) data);
+	iio_push_to_buffers(indio_dev, (u8 *) data);
 
 done:
 	kfree(data);
diff --git a/drivers/staging/iio/meter/ade7758_ring.c b/drivers/staging/iio/meter/ade7758_ring.c
index 9e49bac..4552a4c 100644
--- a/drivers/staging/iio/meter/ade7758_ring.c
+++ b/drivers/staging/iio/meter/ade7758_ring.c
@@ -73,7 +73,7 @@ static irqreturn_t ade7758_trigger_handler(int irq, void *p)
 	if (indio_dev->scan_timestamp)
 		dat64[1] = pf->timestamp;
 
-	iio_push_to_buffer(indio_dev->buffer, (u8 *)dat64);
+	iio_push_to_buffers(indio_dev, (u8 *)dat64);
 
 	iio_trigger_notify_done(indio_dev->trig);
 
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index c629b3a..0270405 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -66,7 +66,8 @@ struct iio_buffer_access_funcs {
  * @stufftoread:	[INTERN] flag to indicate new data.
  * @demux_list:		[INTERN] list of operations required to demux the scan.
  * @demux_bounce:	[INTERN] buffer for doing gather from incoming scan.
- **/
+ * @buffer_list:	[INTERN] entry in the devices list of current buffers.
+ */
 struct iio_buffer {
 	int					length;
 	int					bytes_per_datum;
@@ -81,9 +82,22 @@ struct iio_buffer {
 	const struct attribute_group *attrs;
 	struct list_head			demux_list;
 	unsigned char				*demux_bounce;
+	struct list_head			buffer_list;
 };
 
 /**
+ * iio_update_buffers() - add or remove buffer from active list
+ * @indio_dev:		device to add buffer to
+ * @insert_buffer:	buffer to insert
+ * @remove_buffer:	buffer_to_remove
+ *
+ * Note this will tear down the all buffering and build it up again
+ */
+int iio_update_buffers(struct iio_dev *indio_dev,
+		       struct iio_buffer *insert_buffer,
+		       struct iio_buffer *remove_buffer);
+
+/**
  * iio_buffer_init() - Initialize the buffer structure
  * @buffer:		buffer to be initialized
  **/
@@ -115,11 +129,11 @@ int iio_scan_mask_set(struct iio_dev *indio_dev,
 		      struct iio_buffer *buffer, int bit);
 
 /**
- * iio_push_to_buffer() - push to a registered buffer.
- * @buffer:		IIO buffer structure for device
- * @data:		the data to push to the buffer
+ * iio_push_to_buffers() - push to a registered buffer.
+ * @indio_dev:		iio_dev structure for device.
+ * @data:		Full scan.
  */
-int iio_push_to_buffer(struct iio_buffer *buffer, unsigned char *data);
+int iio_push_to_buffers(struct iio_dev *indio_dev, unsigned char *data);
 
 int iio_update_demux(struct iio_dev *indio_dev);
 
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index c0ae76a..0ff0e66 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -410,6 +410,7 @@ struct iio_buffer_setup_ops {
  *			and owner
  * @event_interface:	[INTERN] event chrdevs associated with interrupt lines
  * @buffer:		[DRIVER] any buffer present
+ * @buffer_list:	[INTERN] list of all buffers currently attached
  * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
  * @mlock:		[INTERN] lock used to prevent simultaneous device state
  *			changes
@@ -448,6 +449,7 @@ struct iio_dev {
 	struct iio_event_interface	*event_interface;
 
 	struct iio_buffer		*buffer;
+	struct list_head		buffer_list;
 	int				scan_bytes;
 	struct mutex			mlock;
 
-- 
1.7.12.2

Re: [PATCH 1/4] staging:iio: Add support for multiple buffers

[Lars-Peter Clausen]

On 10/13/2012 11:24 AM, Jonathan Cameron wrote:
> Route all buffer writes through the demux.
> Addition or removal of a buffer results in tear down and
> setup of all the buffers for a given device.
> 
> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
> ---
> [...]
>  /* Callback handler to send event after all samples are received and captured */
> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
> index d4ad374..8caa0d7 100644
> --- a/drivers/iio/industrialio-buffer.c
> +++ b/drivers/iio/industrialio-buffer.c
> @@ -31,6 +31,18 @@ static const char * const iio_endian_prefix[] = {
>  	[IIO_LE] = "le",
>  };
>  
> +static bool iio_buffer_is_active(struct iio_dev *indio_dev,
> +				 struct iio_buffer *buf)
> +{
> +	struct list_head *p;
> +
> +	list_for_each(p, &indio_dev->buffer_list)
> +		if (p == &buf->buffer_list)
> +			return true;
> +
> +	return false;
> +}
> +
>  /**
>   * iio_buffer_read_first_n_outer() - chrdev read for buffer access
>   *
> @@ -134,7 +146,7 @@ static ssize_t iio_scan_el_store(struct device *dev,
>  	if (ret < 0)
>  		return ret;
>  	mutex_lock(&indio_dev->mlock);
> -	if (iio_buffer_enabled(indio_dev)) {
> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>  		ret = -EBUSY;
>  		goto error_ret;
>  	}
> @@ -180,12 +192,11 @@ static ssize_t iio_scan_el_ts_store(struct device *dev,
>  		return ret;
>  
>  	mutex_lock(&indio_dev->mlock);
> -	if (iio_buffer_enabled(indio_dev)) {
> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>  		ret = -EBUSY;
>  		goto error_ret;
>  	}
>  	indio_dev->buffer->scan_timestamp = state;
> -	indio_dev->scan_timestamp = state;
>  error_ret:
>  	mutex_unlock(&indio_dev->mlock);
>  
> @@ -385,7 +396,7 @@ ssize_t iio_buffer_write_length(struct device *dev,
>  			return len;
>  
>  	mutex_lock(&indio_dev->mlock);
> -	if (iio_buffer_enabled(indio_dev)) {
> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>  		ret = -EBUSY;
>  	} else {
>  		if (buffer->access->set_length)
> @@ -398,102 +409,14 @@ ssize_t iio_buffer_write_length(struct device *dev,
>  }
>  EXPORT_SYMBOL(iio_buffer_write_length);
>  
> -ssize_t iio_buffer_store_enable(struct device *dev,
> -				struct device_attribute *attr,
> -				const char *buf,
> -				size_t len)
> -{
> -	int ret;
> -	bool requested_state, current_state;
> -	int previous_mode;
> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	struct iio_buffer *buffer = indio_dev->buffer;
> -
> -	mutex_lock(&indio_dev->mlock);
> -	previous_mode = indio_dev->currentmode;
> -	requested_state = !(buf[0] == '0');
> -	current_state = iio_buffer_enabled(indio_dev);
> -	if (current_state == requested_state) {
> -		printk(KERN_INFO "iio-buffer, current state requested again\n");
> -		goto done;
> -	}
> -	if (requested_state) {
> -		if (indio_dev->setup_ops->preenable) {
> -			ret = indio_dev->setup_ops->preenable(indio_dev);
> -			if (ret) {
> -				printk(KERN_ERR
> -				       "Buffer not started: "
> -				       "buffer preenable failed\n");
> -				goto error_ret;
> -			}
> -		}
> -		if (buffer->access->request_update) {
> -			ret = buffer->access->request_update(buffer);
> -			if (ret) {
> -				printk(KERN_INFO
> -				       "Buffer not started: "
> -				       "buffer parameter update failed\n");
> -				goto error_ret;
> -			}
> -		}
> -		/* Definitely possible for devices to support both of these. */
> -		if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
> -			if (!indio_dev->trig) {
> -				printk(KERN_INFO
> -				       "Buffer not started: no trigger\n");
> -				ret = -EINVAL;
> -				goto error_ret;
> -			}
> -			indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
> -		} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
> -			indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
> -		else { /* should never be reached */
> -			ret = -EINVAL;
> -			goto error_ret;
> -		}
> -
> -		if (indio_dev->setup_ops->postenable) {
> -			ret = indio_dev->setup_ops->postenable(indio_dev);
> -			if (ret) {
> -				printk(KERN_INFO
> -				       "Buffer not started: "
> -				       "postenable failed\n");
> -				indio_dev->currentmode = previous_mode;
> -				if (indio_dev->setup_ops->postdisable)
> -					indio_dev->setup_ops->
> -						postdisable(indio_dev);
> -				goto error_ret;
> -			}
> -		}
> -	} else {
> -		if (indio_dev->setup_ops->predisable) {
> -			ret = indio_dev->setup_ops->predisable(indio_dev);
> -			if (ret)
> -				goto error_ret;
> -		}
> -		indio_dev->currentmode = INDIO_DIRECT_MODE;
> -		if (indio_dev->setup_ops->postdisable) {
> -			ret = indio_dev->setup_ops->postdisable(indio_dev);
> -			if (ret)
> -				goto error_ret;
> -		}
> -	}
> -done:
> -	mutex_unlock(&indio_dev->mlock);
> -	return len;
> -
> -error_ret:
> -	mutex_unlock(&indio_dev->mlock);
> -	return ret;
> -}
> -EXPORT_SYMBOL(iio_buffer_store_enable);
> -
>  ssize_t iio_buffer_show_enable(struct device *dev,
>  			       struct device_attribute *attr,
>  			       char *buf)
>  {
>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> -	return sprintf(buf, "%d\n", iio_buffer_enabled(indio_dev));
> +	return sprintf(buf, "%d\n",
> +		       iio_buffer_is_active(indio_dev,
> +					    indio_dev->buffer));
>  }
>  EXPORT_SYMBOL(iio_buffer_show_enable);
>  
> @@ -537,35 +460,217 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
>  	return bytes;
>  }
>  
> -int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
> +int iio_update_buffers(struct iio_dev *indio_dev,
> +		       struct iio_buffer *insert_buffer,
> +		       struct iio_buffer *remove_buffer)
>  {
> -	struct iio_buffer *buffer = indio_dev->buffer;
> -	dev_dbg(&indio_dev->dev, "%s\n", __func__);
> +	int ret;
> +	int success = 0;
> +	struct iio_buffer *buffer;
> +	unsigned long *compound_mask;
> +	const unsigned long *old_mask;
>  
> -	/* How much space will the demuxed element take? */
> -	indio_dev->scan_bytes =
> -		iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
> -				       buffer->scan_timestamp);
> -	buffer->access->set_bytes_per_datum(buffer, indio_dev->scan_bytes);
> +	/* Wind down existing buffers - iff there are any */
> +	if (!list_empty(&indio_dev->buffer_list)) {
> +		if (indio_dev->setup_ops->predisable) {
> +			ret = indio_dev->setup_ops->predisable(indio_dev);
> +			if (ret)
> +				goto error_ret;
> +		}
> +		indio_dev->currentmode = INDIO_DIRECT_MODE;
> +		if (indio_dev->setup_ops->postdisable) {
> +			ret = indio_dev->setup_ops->postdisable(indio_dev);
> +			if (ret)
> +				goto error_ret;
> +		}
> +	}
> +	/* Keep a copy of current setup to allow roll back */
> +	old_mask = indio_dev->active_scan_mask;
> +	if (!indio_dev->available_scan_masks)
> +		indio_dev->active_scan_mask = NULL;
> +
> +	if (remove_buffer)
> +		list_del(&remove_buffer->buffer_list);
> +	if (insert_buffer)
> +		list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
> +
> +	/* If no buffers in list, we are done */
> +	if (list_empty(&indio_dev->buffer_list)) {
> +		indio_dev->currentmode = INDIO_DIRECT_MODE;
> +		return 0;

You leak old mask here, if indio_dev->available_scan_masks == NULL

> +	}
>  
>  	/* What scan mask do we actually have ?*/
> -	if (indio_dev->available_scan_masks)
> +	compound_mask = kzalloc(BITS_TO_LONGS(indio_dev->masklength)
> +				*sizeof(long), GFP_KERNEL);

kcalloc

> +	if (compound_mask == NULL)
> +		return -ENOMEM;

Also leaks oldmask

> +
> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
> +		bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
> +			  indio_dev->masklength);
> +		indio_dev->scan_timestamp |= buffer->scan_timestamp;

As far as I can see indio_dev->scan_timestamp is never set to 0, so once
enabled it stays enabled.

> +	}
> +	if (indio_dev->available_scan_masks) {
>  		indio_dev->active_scan_mask =
>  			iio_scan_mask_match(indio_dev->available_scan_masks,
>  					    indio_dev->masklength,
> -					    buffer->scan_mask);
> -	else
> -		indio_dev->active_scan_mask = buffer->scan_mask;
> -
> -	if (indio_dev->active_scan_mask == NULL)
> -		return -EINVAL;
> +					    compound_mask);
> +		if (indio_dev->active_scan_mask == NULL) {
> +			/*
> +			 * Roll back.
> +			 * Note can only occur when adding a buffer.
> +			 */
> +			list_del(&insert_buffer->buffer_list);

What if insert buffer is NULL? Is it possible that we end up in this path if
it is NULL?

> +			indio_dev->active_scan_mask = old_mask;
> +			success = -EINVAL;
> +		}
> +	} else {
> +		indio_dev->active_scan_mask = compound_mask;
> +	}
>  
>  	iio_update_demux(indio_dev);
>  
> -	if (indio_dev->info->update_scan_mode)
> -		return indio_dev->info
> +	/* Wind up again */
> +	if (indio_dev->setup_ops->preenable) {
> +		ret = indio_dev->setup_ops->preenable(indio_dev);
> +		if (ret) {
> +			printk(KERN_ERR
> +			       "Buffer not started:"
> +			       "buffer preenable failed\n");
> +			goto error_remove_inserted;
> +		}
> +	}
> +	indio_dev->scan_bytes =
> +		iio_compute_scan_bytes(indio_dev,
> +				       indio_dev->active_scan_mask,
> +				       indio_dev->scan_timestamp);
> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
> +		if (buffer->access->request_update) {
> +			ret = buffer->access->request_update(buffer);
> +			if (ret) {
> +				printk(KERN_INFO
> +				       "Buffer not started:"
> +				       "buffer parameter update failed\n");
> +				goto error_run_postdisable;
> +			}
> +		}
> +	if (indio_dev->info->update_scan_mode) {
> +		ret = indio_dev->info
>  			->update_scan_mode(indio_dev,
>  					   indio_dev->active_scan_mask);
> +		if (ret < 0) {
> +			printk(KERN_INFO "update scan mode failed\n");
> +			goto error_run_postdisable;
> +		}
> +	}
> +	/* Definitely possible for devices to support both of these.*/
> +	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
> +		if (!indio_dev->trig) {
> +			printk(KERN_INFO "Buffer not started: no trigger\n");
> +			ret = -EINVAL;
> +			/* Can only occur on first buffer */
> +			goto error_run_postdisable;
> +		}
> +		indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
> +	} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
> +		indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
> +	} else { /* should never be reached */
> +		ret = -EINVAL;
> +		goto error_run_postdisable;
> +	}
> +
> +	if (indio_dev->setup_ops->postenable) {
> +		ret = indio_dev->setup_ops->postenable(indio_dev);
> +		if (ret) {
> +			printk(KERN_INFO
> +			       "Buffer not started: postenable failed\n");
> +			indio_dev->currentmode = INDIO_DIRECT_MODE;
> +			if (indio_dev->setup_ops->postdisable)
> +				indio_dev->setup_ops->postdisable(indio_dev);
> +			goto error_disable_all_buffers;
> +		}
> +	}
> +
> +	if (indio_dev->available_scan_masks)
> +		kfree(compound_mask);
> +	else
> +		kfree(old_mask);
> +
> +	return success;
> +
> +error_disable_all_buffers:
> +	indio_dev->currentmode = INDIO_DIRECT_MODE;
> +error_run_postdisable:
> +	if (indio_dev->setup_ops->postdisable)
> +		indio_dev->setup_ops->postdisable(indio_dev);
> +error_remove_inserted:
> +
> +	if (insert_buffer)
> +		list_del(&insert_buffer->buffer_list);
> +	indio_dev->active_scan_mask = old_mask;
> +	kfree(compound_mask);
> +error_ret:
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(iio_update_buffers);
> +
> +ssize_t iio_buffer_store_enable(struct device *dev,
> +				struct device_attribute *attr,
> +				const char *buf,
> +				size_t len)
> +{
> +	int ret;
> +	bool requested_state;
> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);

dev_to_iio_dev

I don't think dev_get_drvdata works anymore

> +	struct iio_buffer *pbuf = indio_dev->buffer;
> +	bool inlist;
> +
> +	ret = strtobool(buf, &requested_state);
> +	if (ret < 0)
> +		return ret;
> +
> +	mutex_lock(&indio_dev->mlock);
> +
> +	/* Find out if it is in the list */
> +	inlist = iio_buffer_is_active(indio_dev, pbuf);
> +	/* Already enabled */
> +	if (inlist && requested_state)
> +		goto done;
> +	/* Already disabled */
> +	if (!inlist && !requested_state)
> +		goto done;

if (inlist == requested_state)
	goto done;

> +
> +	if (requested_state)
> +		ret = iio_update_buffers(indio_dev,
> +					 indio_dev->buffer, NULL);
> +	else
> +		ret = iio_update_buffers(indio_dev,
> +					 NULL, indio_dev->buffer);
> +
> +	if (ret < 0)
> +		goto done;
> +done:
> +	mutex_unlock(&indio_dev->mlock);
> +	return (ret < 0) ? ret : len;
> +}
> +EXPORT_SYMBOL(iio_buffer_store_enable);
> +
> +int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
> +{
> +	struct iio_buffer *buffer;
> +	unsigned bytes;
> +	dev_dbg(&indio_dev->dev, "%s\n", __func__);
> +
> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
> +		if (buffer->access->set_bytes_per_datum) {
> +			bytes = iio_compute_scan_bytes(indio_dev,
> +						       buffer->scan_mask,
> +						       buffer->scan_timestamp);
> +
> +			buffer->access->set_bytes_per_datum(buffer, bytes);
> +		}
>  	return 0;
>  }
>  EXPORT_SYMBOL(iio_sw_buffer_preenable);
> [...]
>  
> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
> index c0ae76a..0ff0e66 100644
> --- a/include/linux/iio/iio.h
> +++ b/include/linux/iio/iio.h
> @@ -410,6 +410,7 @@ struct iio_buffer_setup_ops {
>   *			and owner
>   * @event_interface:	[INTERN] event chrdevs associated with interrupt lines
>   * @buffer:		[DRIVER] any buffer present
> + * @buffer_list:	[INTERN] list of all buffers currently attached
>   * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
>   * @mlock:		[INTERN] lock used to prevent simultaneous device state
>   *			changes
> @@ -448,6 +449,7 @@ struct iio_dev {
>  	struct iio_event_interface	*event_interface;
>  
>  	struct iio_buffer		*buffer;
> +	struct list_head		buffer_list;
>  	int				scan_bytes;
>  	struct mutex			mlock;
>  

Re: [PATCH 1/4] staging:iio: Add support for multiple buffers

[Jonathan Cameron]

On 10/17/2012 09:37 AM, Lars-Peter Clausen wrote:
> On 10/13/2012 11:24 AM, Jonathan Cameron wrote:
>> Route all buffer writes through the demux.
>> Addition or removal of a buffer results in tear down and
>> setup of all the buffers for a given device.
>>
Thanks Lars!

All fixed except the case commented below where unless something
really weird is going on it can't get there on removal.

Maybe it's safer to have the check anyway, but that might in turn
make people think it is possible when it shouldn't be!)

Jonathan
>> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
>> ---
>> [...]
>>  /* Callback handler to send event after all samples are received and captured */
>> diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
>> index d4ad374..8caa0d7 100644
>> --- a/drivers/iio/industrialio-buffer.c
>> +++ b/drivers/iio/industrialio-buffer.c
>> @@ -31,6 +31,18 @@ static const char * const iio_endian_prefix[] = {
>>  	[IIO_LE] = "le",
>>  };
>>
>> +static bool iio_buffer_is_active(struct iio_dev *indio_dev,
>> +				 struct iio_buffer *buf)
>> +{
>> +	struct list_head *p;
>> +
>> +	list_for_each(p, &indio_dev->buffer_list)
>> +		if (p == &buf->buffer_list)
>> +			return true;
>> +
>> +	return false;
>> +}
>> +
>>  /**
>>   * iio_buffer_read_first_n_outer() - chrdev read for buffer access
>>   *
>> @@ -134,7 +146,7 @@ static ssize_t iio_scan_el_store(struct device *dev,
>>  	if (ret < 0)
>>  		return ret;
>>  	mutex_lock(&indio_dev->mlock);
>> -	if (iio_buffer_enabled(indio_dev)) {
>> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>>  		ret = -EBUSY;
>>  		goto error_ret;
>>  	}
>> @@ -180,12 +192,11 @@ static ssize_t iio_scan_el_ts_store(struct device *dev,
>>  		return ret;
>>
>>  	mutex_lock(&indio_dev->mlock);
>> -	if (iio_buffer_enabled(indio_dev)) {
>> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>>  		ret = -EBUSY;
>>  		goto error_ret;
>>  	}
>>  	indio_dev->buffer->scan_timestamp = state;
>> -	indio_dev->scan_timestamp = state;
>>  error_ret:
>>  	mutex_unlock(&indio_dev->mlock);
>>
>> @@ -385,7 +396,7 @@ ssize_t iio_buffer_write_length(struct device *dev,
>>  			return len;
>>
>>  	mutex_lock(&indio_dev->mlock);
>> -	if (iio_buffer_enabled(indio_dev)) {
>> +	if (iio_buffer_is_active(indio_dev, indio_dev->buffer)) {
>>  		ret = -EBUSY;
>>  	} else {
>>  		if (buffer->access->set_length)
>> @@ -398,102 +409,14 @@ ssize_t iio_buffer_write_length(struct device *dev,
>>  }
>>  EXPORT_SYMBOL(iio_buffer_write_length);
>>
>> -ssize_t iio_buffer_store_enable(struct device *dev,
>> -				struct device_attribute *attr,
>> -				const char *buf,
>> -				size_t len)
>> -{
>> -	int ret;
>> -	bool requested_state, current_state;
>> -	int previous_mode;
>> -	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>> -	struct iio_buffer *buffer = indio_dev->buffer;
>> -
>> -	mutex_lock(&indio_dev->mlock);
>> -	previous_mode = indio_dev->currentmode;
>> -	requested_state = !(buf[0] == '0');
>> -	current_state = iio_buffer_enabled(indio_dev);
>> -	if (current_state == requested_state) {
>> -		printk(KERN_INFO "iio-buffer, current state requested again\n");
>> -		goto done;
>> -	}
>> -	if (requested_state) {
>> -		if (indio_dev->setup_ops->preenable) {
>> -			ret = indio_dev->setup_ops->preenable(indio_dev);
>> -			if (ret) {
>> -				printk(KERN_ERR
>> -				       "Buffer not started: "
>> -				       "buffer preenable failed\n");
>> -				goto error_ret;
>> -			}
>> -		}
>> -		if (buffer->access->request_update) {
>> -			ret = buffer->access->request_update(buffer);
>> -			if (ret) {
>> -				printk(KERN_INFO
>> -				       "Buffer not started: "
>> -				       "buffer parameter update failed\n");
>> -				goto error_ret;
>> -			}
>> -		}
>> -		/* Definitely possible for devices to support both of these. */
>> -		if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
>> -			if (!indio_dev->trig) {
>> -				printk(KERN_INFO
>> -				       "Buffer not started: no trigger\n");
>> -				ret = -EINVAL;
>> -				goto error_ret;
>> -			}
>> -			indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
>> -		} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE)
>> -			indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
>> -		else { /* should never be reached */
>> -			ret = -EINVAL;
>> -			goto error_ret;
>> -		}
>> -
>> -		if (indio_dev->setup_ops->postenable) {
>> -			ret = indio_dev->setup_ops->postenable(indio_dev);
>> -			if (ret) {
>> -				printk(KERN_INFO
>> -				       "Buffer not started: "
>> -				       "postenable failed\n");
>> -				indio_dev->currentmode = previous_mode;
>> -				if (indio_dev->setup_ops->postdisable)
>> -					indio_dev->setup_ops->
>> -						postdisable(indio_dev);
>> -				goto error_ret;
>> -			}
>> -		}
>> -	} else {
>> -		if (indio_dev->setup_ops->predisable) {
>> -			ret = indio_dev->setup_ops->predisable(indio_dev);
>> -			if (ret)
>> -				goto error_ret;
>> -		}
>> -		indio_dev->currentmode = INDIO_DIRECT_MODE;
>> -		if (indio_dev->setup_ops->postdisable) {
>> -			ret = indio_dev->setup_ops->postdisable(indio_dev);
>> -			if (ret)
>> -				goto error_ret;
>> -		}
>> -	}
>> -done:
>> -	mutex_unlock(&indio_dev->mlock);
>> -	return len;
>> -
>> -error_ret:
>> -	mutex_unlock(&indio_dev->mlock);
>> -	return ret;
>> -}
>> -EXPORT_SYMBOL(iio_buffer_store_enable);
>> -
>>  ssize_t iio_buffer_show_enable(struct device *dev,
>>  			       struct device_attribute *attr,
>>  			       char *buf)
>>  {
>>  	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
>> -	return sprintf(buf, "%d\n", iio_buffer_enabled(indio_dev));
>> +	return sprintf(buf, "%d\n",
>> +		       iio_buffer_is_active(indio_dev,
>> +					    indio_dev->buffer));
>>  }
>>  EXPORT_SYMBOL(iio_buffer_show_enable);
>>
>> @@ -537,35 +460,217 @@ static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
>>  	return bytes;
>>  }
>>
>> -int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
>> +int iio_update_buffers(struct iio_dev *indio_dev,
>> +		       struct iio_buffer *insert_buffer,
>> +		       struct iio_buffer *remove_buffer)
>>  {
>> -	struct iio_buffer *buffer = indio_dev->buffer;
>> -	dev_dbg(&indio_dev->dev, "%s\n", __func__);
>> +	int ret;
>> +	int success = 0;
>> +	struct iio_buffer *buffer;
>> +	unsigned long *compound_mask;
>> +	const unsigned long *old_mask;
>>
>> -	/* How much space will the demuxed element take? */
>> -	indio_dev->scan_bytes =
>> -		iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
>> -				       buffer->scan_timestamp);
>> -	buffer->access->set_bytes_per_datum(buffer, indio_dev->scan_bytes);
>> +	/* Wind down existing buffers - iff there are any */
>> +	if (!list_empty(&indio_dev->buffer_list)) {
>> +		if (indio_dev->setup_ops->predisable) {
>> +			ret = indio_dev->setup_ops->predisable(indio_dev);
>> +			if (ret)
>> +				goto error_ret;
>> +		}
>> +		indio_dev->currentmode = INDIO_DIRECT_MODE;
>> +		if (indio_dev->setup_ops->postdisable) {
>> +			ret = indio_dev->setup_ops->postdisable(indio_dev);
>> +			if (ret)
>> +				goto error_ret;
>> +		}
>> +	}
>> +	/* Keep a copy of current setup to allow roll back */
>> +	old_mask = indio_dev->active_scan_mask;
>> +	if (!indio_dev->available_scan_masks)
>> +		indio_dev->active_scan_mask = NULL;
>> +
>> +	if (remove_buffer)
>> +		list_del(&remove_buffer->buffer_list);
>> +	if (insert_buffer)
>> +		list_add(&insert_buffer->buffer_list, &indio_dev->buffer_list);
>> +
>> +	/* If no buffers in list, we are done */
>> +	if (list_empty(&indio_dev->buffer_list)) {
>> +		indio_dev->currentmode = INDIO_DIRECT_MODE;
>> +		return 0;
>
> You leak old mask here, if indio_dev->available_scan_masks == NULL
>
>> +	}
>>
>>  	/* What scan mask do we actually have ?*/
>> -	if (indio_dev->available_scan_masks)
>> +	compound_mask = kzalloc(BITS_TO_LONGS(indio_dev->masklength)
>> +				*sizeof(long), GFP_KERNEL);
>
> kcalloc
>
>> +	if (compound_mask == NULL)
>> +		return -ENOMEM;
>
> Also leaks oldmask
>
>> +
>> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list) {
>> +		bitmap_or(compound_mask, compound_mask, buffer->scan_mask,
>> +			  indio_dev->masklength);
>> +		indio_dev->scan_timestamp |= buffer->scan_timestamp;
>
> As far as I can see indio_dev->scan_timestamp is never set to 0, so once
> enabled it stays enabled.
>
>> +	}
>> +	if (indio_dev->available_scan_masks) {
>>  		indio_dev->active_scan_mask =
>>  			iio_scan_mask_match(indio_dev->available_scan_masks,
>>  					    indio_dev->masklength,
>> -					    buffer->scan_mask);
>> -	else
>> -		indio_dev->active_scan_mask = buffer->scan_mask;
>> -
>> -	if (indio_dev->active_scan_mask == NULL)
>> -		return -EINVAL;
>> +					    compound_mask);
>> +		if (indio_dev->active_scan_mask == NULL) {
>> +			/*
>> +			 * Roll back.
>> +			 * Note can only occur when adding a buffer.
>> +			 */
>> +			list_del(&insert_buffer->buffer_list);
>
> What if insert buffer is NULL? Is it possible that we end up in this path if
> it is NULL?
I don't think there is anyway we could go from a valid scan mask to there
not being one that exists (e.g. on removal of a buffer).  Afterall the
scan mask with the buffer there covers all desired channels so it still
will after the buffer is removed.

>
>> +			indio_dev->active_scan_mask = old_mask;
>> +			success = -EINVAL;
>> +		}
>> +	} else {
>> +		indio_dev->active_scan_mask = compound_mask;
>> +	}
>>
>>  	iio_update_demux(indio_dev);
>>
>> -	if (indio_dev->info->update_scan_mode)
>> -		return indio_dev->info
>> +	/* Wind up again */
>> +	if (indio_dev->setup_ops->preenable) {
>> +		ret = indio_dev->setup_ops->preenable(indio_dev);
>> +		if (ret) {
>> +			printk(KERN_ERR
>> +			       "Buffer not started:"
>> +			       "buffer preenable failed\n");
>> +			goto error_remove_inserted;
>> +		}
>> +	}
>> +	indio_dev->scan_bytes =
>> +		iio_compute_scan_bytes(indio_dev,
>> +				       indio_dev->active_scan_mask,
>> +				       indio_dev->scan_timestamp);
>> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
>> +		if (buffer->access->request_update) {
>> +			ret = buffer->access->request_update(buffer);
>> +			if (ret) {
>> +				printk(KERN_INFO
>> +				       "Buffer not started:"
>> +				       "buffer parameter update failed\n");
>> +				goto error_run_postdisable;
>> +			}
>> +		}
>> +	if (indio_dev->info->update_scan_mode) {
>> +		ret = indio_dev->info
>>  			->update_scan_mode(indio_dev,
>>  					   indio_dev->active_scan_mask);
>> +		if (ret < 0) {
>> +			printk(KERN_INFO "update scan mode failed\n");
>> +			goto error_run_postdisable;
>> +		}
>> +	}
>> +	/* Definitely possible for devices to support both of these.*/
>> +	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED) {
>> +		if (!indio_dev->trig) {
>> +			printk(KERN_INFO "Buffer not started: no trigger\n");
>> +			ret = -EINVAL;
>> +			/* Can only occur on first buffer */
>> +			goto error_run_postdisable;
>> +		}
>> +		indio_dev->currentmode = INDIO_BUFFER_TRIGGERED;
>> +	} else if (indio_dev->modes & INDIO_BUFFER_HARDWARE) {
>> +		indio_dev->currentmode = INDIO_BUFFER_HARDWARE;
>> +	} else { /* should never be reached */
>> +		ret = -EINVAL;
>> +		goto error_run_postdisable;
>> +	}
>> +
>> +	if (indio_dev->setup_ops->postenable) {
>> +		ret = indio_dev->setup_ops->postenable(indio_dev);
>> +		if (ret) {
>> +			printk(KERN_INFO
>> +			       "Buffer not started: postenable failed\n");
>> +			indio_dev->currentmode = INDIO_DIRECT_MODE;
>> +			if (indio_dev->setup_ops->postdisable)
>> +				indio_dev->setup_ops->postdisable(indio_dev);
>> +			goto error_disable_all_buffers;
>> +		}
>> +	}
>> +
>> +	if (indio_dev->available_scan_masks)
>> +		kfree(compound_mask);
>> +	else
>> +		kfree(old_mask);
>> +
>> +	return success;
>> +
>> +error_disable_all_buffers:
>> +	indio_dev->currentmode = INDIO_DIRECT_MODE;
>> +error_run_postdisable:
>> +	if (indio_dev->setup_ops->postdisable)
>> +		indio_dev->setup_ops->postdisable(indio_dev);
>> +error_remove_inserted:
>> +
>> +	if (insert_buffer)
>> +		list_del(&insert_buffer->buffer_list);
>> +	indio_dev->active_scan_mask = old_mask;
>> +	kfree(compound_mask);
>> +error_ret:
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(iio_update_buffers);
>> +
>> +ssize_t iio_buffer_store_enable(struct device *dev,
>> +				struct device_attribute *attr,
>> +				const char *buf,
>> +				size_t len)
>> +{
>> +	int ret;
>> +	bool requested_state;
>> +	struct iio_dev *indio_dev = dev_get_drvdata(dev);
>
> dev_to_iio_dev
>
> I don't think dev_get_drvdata works anymore
oops.. :)
>
>> +	struct iio_buffer *pbuf = indio_dev->buffer;
>> +	bool inlist;
>> +
>> +	ret = strtobool(buf, &requested_state);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	mutex_lock(&indio_dev->mlock);
>> +
>> +	/* Find out if it is in the list */
>> +	inlist = iio_buffer_is_active(indio_dev, pbuf);
>> +	/* Already enabled */
>> +	if (inlist && requested_state)
>> +		goto done;
>> +	/* Already disabled */
>> +	if (!inlist && !requested_state)
>> +		goto done;
>
> if (inlist == requested_state)
> 	goto done;
oops again.  I like to think it evolved to this state, but
maybe I was just being an idiot ;)
>
>> +
>> +	if (requested_state)
>> +		ret = iio_update_buffers(indio_dev,
>> +					 indio_dev->buffer, NULL);
>> +	else
>> +		ret = iio_update_buffers(indio_dev,
>> +					 NULL, indio_dev->buffer);
>> +
>> +	if (ret < 0)
>> +		goto done;
>> +done:
>> +	mutex_unlock(&indio_dev->mlock);
>> +	return (ret < 0) ? ret : len;
>> +}
>> +EXPORT_SYMBOL(iio_buffer_store_enable);
>> +
>> +int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
>> +{
>> +	struct iio_buffer *buffer;
>> +	unsigned bytes;
>> +	dev_dbg(&indio_dev->dev, "%s\n", __func__);
>> +
>> +	list_for_each_entry(buffer, &indio_dev->buffer_list, buffer_list)
>> +		if (buffer->access->set_bytes_per_datum) {
>> +			bytes = iio_compute_scan_bytes(indio_dev,
>> +						       buffer->scan_mask,
>> +						       buffer->scan_timestamp);
>> +
>> +			buffer->access->set_bytes_per_datum(buffer, bytes);
>> +		}
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL(iio_sw_buffer_preenable);
>> [...]
>>
>> diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
>> index c0ae76a..0ff0e66 100644
>> --- a/include/linux/iio/iio.h
>> +++ b/include/linux/iio/iio.h
>> @@ -410,6 +410,7 @@ struct iio_buffer_setup_ops {
>>   *			and owner
>>   * @event_interface:	[INTERN] event chrdevs associated with interrupt lines
>>   * @buffer:		[DRIVER] any buffer present
>> + * @buffer_list:	[INTERN] list of all buffers currently attached
>>   * @scan_bytes:		[INTERN] num bytes captured to be fed to buffer demux
>>   * @mlock:		[INTERN] lock used to prevent simultaneous device state
>>   *			changes
>> @@ -448,6 +449,7 @@ struct iio_dev {
>>  	struct iio_event_interface	*event_interface;
>>
>>  	struct iio_buffer		*buffer;
>> +	struct list_head		buffer_list;
>>  	int				scan_bytes;
>>  	struct mutex			mlock;
>>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

[PATCH 2/4] staging:iio:in kernel users: Add a data field for channel specific info.

[Jonathan Cameron]

Used to allow information about a given channel mapping to be passed
through from board files to the consumer drivers.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/inkern.c         | 1 +
 include/linux/iio/consumer.h | 2 ++
 include/linux/iio/machine.h  | 2 ++
 3 files changed, 5 insertions(+)

diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index f2b78d4..4113105 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -203,6 +203,7 @@ struct iio_channel *iio_channel_get_all(const char *name)
 		if (name && strcmp(name, c->map->consumer_dev_name) != 0)
 			continue;
 		chans[mapind].indio_dev = c->indio_dev;
+		chans[mapind].data = c->map->consumer_data;
 		chans[mapind].channel =
 			iio_chan_spec_from_name(chans[mapind].indio_dev,
 						c->map->adc_channel_label);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index e875bcf..57efee6 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -18,10 +18,12 @@ struct iio_chan_spec;
  * struct iio_channel - everything needed for a consumer to use a channel
  * @indio_dev:		Device on which the channel exists.
  * @channel:		Full description of the channel.
+ * @data:		Data about the channel used by consumer.
  */
 struct iio_channel {
 	struct iio_dev *indio_dev;
 	const struct iio_chan_spec *channel;
+	void *data;
 };
 
 /**
diff --git a/include/linux/iio/machine.h b/include/linux/iio/machine.h
index 809a3f0..1601a2a 100644
--- a/include/linux/iio/machine.h
+++ b/include/linux/iio/machine.h
@@ -19,11 +19,13 @@
  * @consumer_dev_name:	Name to uniquely identify the consumer device.
  * @consumer_channel:	Unique name used to identify the channel on the
  *			consumer side.
+ * @consumer_data:	Data about the channel for use by the consumer driver.
  */
 struct iio_map {
 	const char *adc_channel_label;
 	const char *consumer_dev_name;
 	const char *consumer_channel;
+	void *consumer_data;
 };
 
 #endif
-- 
1.7.12.2

[PATCH 3/4] staging:iio: add a callback buffer for in kernel push interface

[Jonathan Cameron]

This callback buffer is meant to be opaque to users, but basically
adds a very simple pass through buffer to which data may be
pushed when it is inserted into the buffer list.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/iio/Kconfig          |   6 +++
 drivers/iio/Makefile         |   1 +
 drivers/iio/buffer_cb.c      | 113 +++++++++++++++++++++++++++++++++++++++++++
 include/linux/iio/consumer.h |  46 ++++++++++++++++++
 4 files changed, 166 insertions(+)

diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 6e3f143..0aad08a 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -20,6 +20,12 @@ config IIO_BUFFER
 
 if IIO_BUFFER
 
+config IIO_BUFFER_CB
+       boolean "IIO callback buffer used for push in kernel interfaces"
+       help
+         Should be selected by any drivers that do inkernel push
+	 usage.  That is, those where the data is pushed to the consumer.
+
 config IIO_KFIFO_BUF
 	select IIO_TRIGGER
 	tristate "Industrial I/O buffering based on kfifo"
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index f7fa3c0..a27ec1c 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -6,6 +6,7 @@ obj-$(CONFIG_IIO) += industrialio.o
 industrialio-y := industrialio-core.o industrialio-event.o inkern.o
 industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
 industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
+industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o
 
 obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
 obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
diff --git a/drivers/iio/buffer_cb.c b/drivers/iio/buffer_cb.c
new file mode 100644
index 0000000..d1e4881
--- /dev/null
+++ b/drivers/iio/buffer_cb.c
@@ -0,0 +1,113 @@
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/consumer.h>
+
+struct iio_cb_buffer {
+	struct iio_buffer buffer;
+	int (*cb)(u8 *data, void *private);
+	void *private;
+	struct iio_channel *channels;
+};
+
+static int iio_buffer_cb_store_to(struct iio_buffer *buffer, u8 *data)
+{
+	struct iio_cb_buffer *cb_buff = container_of(buffer,
+						     struct iio_cb_buffer,
+						     buffer);
+
+	return cb_buff->cb(data, cb_buff->private);
+}
+
+static struct iio_buffer_access_funcs iio_cb_access = {
+	.store_to = &iio_buffer_cb_store_to,
+};
+
+struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
+					     int (*cb)(u8 *data,
+						       void *private),
+					     void *private)
+{
+	int ret;
+	struct iio_cb_buffer *cb_buff;
+	struct iio_dev *indio_dev;
+	struct iio_channel *chan;
+
+	cb_buff = kzalloc(sizeof *cb_buff, GFP_KERNEL);
+	if (cb_buff == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	cb_buff->private = private;
+	cb_buff->cb = cb;
+	cb_buff->buffer.access = &iio_cb_access;
+	INIT_LIST_HEAD(&cb_buff->buffer.demux_list);
+
+	cb_buff->channels = iio_channel_get_all(name);
+	if (IS_ERR(cb_buff->channels)) {
+		ret = PTR_ERR(cb_buff->channels);
+		goto error_free_cb_buff;
+	}
+
+	indio_dev = cb_buff->channels[0].indio_dev;
+	cb_buff->buffer.scan_mask
+		= kzalloc(sizeof(long)*BITS_TO_LONGS(indio_dev->masklength),
+			  GFP_KERNEL);
+	if (cb_buff->buffer.scan_mask == NULL) {
+		ret = -ENOMEM;
+		goto error_release_channels;
+	}
+	chan = &cb_buff->channels[0];
+	while (chan->indio_dev) {
+		if (chan->indio_dev != indio_dev) {
+			ret = -EINVAL;
+			goto error_release_channels;
+		}
+		set_bit(chan->channel->scan_index,
+			cb_buff->buffer.scan_mask);
+		chan++;
+	}
+
+	return cb_buff;
+
+error_release_channels:
+	iio_channel_release_all(cb_buff->channels);
+error_free_cb_buff:
+	kfree(cb_buff);
+error_ret:
+	return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
+
+int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	return iio_update_buffers(cb_buff->channels[0].indio_dev,
+				  &cb_buff->buffer,
+				  NULL);
+}
+EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
+
+void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	iio_update_buffers(cb_buff->channels[0].indio_dev,
+			   NULL,
+			   &cb_buff->buffer);
+}
+EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
+
+void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
+{
+	iio_channel_release_all(cb_buff->channels);
+	kfree(cb_buff);
+}
+EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
+
+struct iio_channel
+*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
+{
+	return cb_buffer->channels;
+}
+EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
index 57efee6..caf103b 100644
--- a/include/linux/iio/consumer.h
+++ b/include/linux/iio/consumer.h
@@ -61,6 +61,52 @@ struct iio_channel *iio_channel_get_all(const char *name);
  */
 void iio_channel_release_all(struct iio_channel *chan);
 
+struct iio_cb_buffer;
+/**
+ * iio_channel_get_all_cb() - register callback for triggered capture
+ * @name:		Name of client device.
+ * @cb:			Callback function.
+ * @private:		Private data passed to callback.
+ *
+ * NB right now we have no ability to mux data from multiple devices.
+ * So if the channels requested come from different devices this will
+ * fail.
+ */
+struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
+					     int (*cb)(u8 *data,
+						       void *private),
+					     void *private);
+/**
+ * iio_channel_release_all_cb() - release and unregister the callback.
+ * @cb_buffer:		The callback buffer that was allocated.
+ */
+void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
+
+/**
+ * iio_channel_start_all_cb() - start the flow of data through callback.
+ * @cb_buff:		The callback buffer we are starting.
+ */
+int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
+
+/**
+ * iio_channel_stop_all_cb() - stop the flow of data through the callback.
+ * @cb_buff:		The callback buffer we are stopping.
+ */
+void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
+
+/**
+ * iio_channel_cb_get_channels() - get access to the underlying channels.
+ * @cb_buff:		The callback buffers from whom we want the channel
+ *			information.
+ *
+ * This function allows one to obtain information about the channels.
+ * Whilst this may allow direct reading if all buffers are disabled, the
+ * primary aim is to allow drivers that are consuming a channel to query
+ * things like scaling of the channel.
+ */
+struct iio_channel
+*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
+
 /**
  * iio_read_channel_raw() - read from a given channel
  * @chan:		The channel being queried.
-- 
1.7.12.2

Re: [PATCH 3/4] staging:iio: add a callback buffer for in kernel push interface

[Lars-Peter Clausen]

On 10/13/2012 11:24 AM, Jonathan Cameron wrote:
> This callback buffer is meant to be opaque to users, but basically
> adds a very simple pass through buffer to which data may be
> pushed when it is inserted into the buffer list.
> 
> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  drivers/iio/Kconfig          |   6 +++
>  drivers/iio/Makefile         |   1 +
>  drivers/iio/buffer_cb.c      | 113 +++++++++++++++++++++++++++++++++++++++++++
>  include/linux/iio/consumer.h |  46 ++++++++++++++++++
>  4 files changed, 166 insertions(+)
> 
> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 6e3f143..0aad08a 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -20,6 +20,12 @@ config IIO_BUFFER
>  
>  if IIO_BUFFER
>  
> +config IIO_BUFFER_CB
> +       boolean "IIO callback buffer used for push in kernel interfaces"

Any specific reason why this has to be bool?

> +       help
> +         Should be selected by any drivers that do inkernel push
> +	 usage.  That is, those where the data is pushed to the consumer.
> +
>  config IIO_KFIFO_BUF
>  	select IIO_TRIGGER
>  	tristate "Industrial I/O buffering based on kfifo"
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index f7fa3c0..a27ec1c 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -6,6 +6,7 @@ obj-$(CONFIG_IIO) += industrialio.o
>  industrialio-y := industrialio-core.o industrialio-event.o inkern.o
>  industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
>  industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
> +industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o
>  
>  obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
>  obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
> diff --git a/drivers/iio/buffer_cb.c b/drivers/iio/buffer_cb.c
> new file mode 100644
> index 0000000..d1e4881
> --- /dev/null
> +++ b/drivers/iio/buffer_cb.c
> @@ -0,0 +1,113 @@
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/err.h>
> +#include <linux/export.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/consumer.h>
> +
> +struct iio_cb_buffer {
> +	struct iio_buffer buffer;
> +	int (*cb)(u8 *data, void *private);
> +	void *private;
> +	struct iio_channel *channels;
> +};
> +
> +static int iio_buffer_cb_store_to(struct iio_buffer *buffer, u8 *data)
> +{
> +	struct iio_cb_buffer *cb_buff = container_of(buffer,
> +						     struct iio_cb_buffer,
> +						     buffer);
> +
> +	return cb_buff->cb(data, cb_buff->private);
> +}
> +
> +static struct iio_buffer_access_funcs iio_cb_access = {
> +	.store_to = &iio_buffer_cb_store_to,
> +};
> +
> +struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
> +					     int (*cb)(u8 *data,
> +						       void *private),
> +					     void *private)
> +{
> +	int ret;
> +	struct iio_cb_buffer *cb_buff;
> +	struct iio_dev *indio_dev;
> +	struct iio_channel *chan;
> +
> +	cb_buff = kzalloc(sizeof *cb_buff, GFP_KERNEL);

sizeof(*cb_buff)

> +	if (cb_buff == NULL) {
> +		ret = -ENOMEM;
> +		goto error_ret;
> +	}
> +
> +	cb_buff->private = private;
> +	cb_buff->cb = cb;
> +	cb_buff->buffer.access = &iio_cb_access;
> +	INIT_LIST_HEAD(&cb_buff->buffer.demux_list);

It probably makes sense to have some kind of iio_buffer_init(...) for this

> +
> +	cb_buff->channels = iio_channel_get_all(name);
> +	if (IS_ERR(cb_buff->channels)) {
> +		ret = PTR_ERR(cb_buff->channels);
> +		goto error_free_cb_buff;
> +	}
> +
> +	indio_dev = cb_buff->channels[0].indio_dev;
> +	cb_buff->buffer.scan_mask
> +		= kzalloc(sizeof(long)*BITS_TO_LONGS(indio_dev->masklength),
> +			  GFP_KERNEL);

kcalloc

> +	if (cb_buff->buffer.scan_mask == NULL) {
> +		ret = -ENOMEM;
> +		goto error_release_channels;
> +	}
> +	chan = &cb_buff->channels[0];
> +	while (chan->indio_dev) {
> +		if (chan->indio_dev != indio_dev) {
> +			ret = -EINVAL;
> +			goto error_release_channels;
> +		}
> +		set_bit(chan->channel->scan_index,
> +			cb_buff->buffer.scan_mask);
> +		chan++;
> +	}
> +
> +	return cb_buff;
> +
> +error_release_channels:
> +	iio_channel_release_all(cb_buff->channels);
> +error_free_cb_buff:
> +	kfree(cb_buff);
> +error_ret:
> +	return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
> +
> +int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
> +{
> +	return iio_update_buffers(cb_buff->channels[0].indio_dev,
> +				  &cb_buff->buffer,
> +				  NULL);
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
> +
> +void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
> +{
> +	iio_update_buffers(cb_buff->channels[0].indio_dev,
> +			   NULL,
> +			   &cb_buff->buffer);
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
> +
> +void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
> +{
> +	iio_channel_release_all(cb_buff->channels);
> +	kfree(cb_buff);
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
> +
> +struct iio_channel
> +*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
> +{
> +	return cb_buffer->channels;
> +}
> +EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
> index 57efee6..caf103b 100644
> --- a/include/linux/iio/consumer.h
> +++ b/include/linux/iio/consumer.h
> @@ -61,6 +61,52 @@ struct iio_channel *iio_channel_get_all(const char *name);
>   */
>  void iio_channel_release_all(struct iio_channel *chan);
>  
> +struct iio_cb_buffer;
> +/**
> + * iio_channel_get_all_cb() - register callback for triggered capture
> + * @name:		Name of client device.
> + * @cb:			Callback function.
> + * @private:		Private data passed to callback.
> + *
> + * NB right now we have no ability to mux data from multiple devices.
> + * So if the channels requested come from different devices this will
> + * fail.
> + */
> +struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
> +					     int (*cb)(u8 *data,
> +						       void *private),
> +					     void *private);
> +/**
> + * iio_channel_release_all_cb() - release and unregister the callback.
> + * @cb_buffer:		The callback buffer that was allocated.
> + */
> +void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
> +
> +/**
> + * iio_channel_start_all_cb() - start the flow of data through callback.
> + * @cb_buff:		The callback buffer we are starting.
> + */
> +int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
> +
> +/**
> + * iio_channel_stop_all_cb() - stop the flow of data through the callback.
> + * @cb_buff:		The callback buffer we are stopping.
> + */
> +void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
> +
> +/**
> + * iio_channel_cb_get_channels() - get access to the underlying channels.
> + * @cb_buff:		The callback buffers from whom we want the channel
> + *			information.
> + *
> + * This function allows one to obtain information about the channels.
> + * Whilst this may allow direct reading if all buffers are disabled, the
> + * primary aim is to allow drivers that are consuming a channel to query
> + * things like scaling of the channel.
> + */
> +struct iio_channel
> +*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
> +
>  /**
>   * iio_read_channel_raw() - read from a given channel
>   * @chan:		The channel being queried.

Re: [PATCH 3/4] staging:iio: add a callback buffer for in kernel push interface

[Jonathan Cameron]

On 17/10/12 09:50, Lars-Peter Clausen wrote:
> On 10/13/2012 11:24 AM, Jonathan Cameron wrote:
>> This callback buffer is meant to be opaque to users, but basically
>> adds a very simple pass through buffer to which data may be
>> pushed when it is inserted into the buffer list.
>>
>> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
>> ---
>>   drivers/iio/Kconfig          |   6 +++
>>   drivers/iio/Makefile         |   1 +
>>   drivers/iio/buffer_cb.c      | 113 +++++++++++++++++++++++++++++++++++++++++++
>>   include/linux/iio/consumer.h |  46 ++++++++++++++++++
>>   4 files changed, 166 insertions(+)
>>
>> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
>> index 6e3f143..0aad08a 100644
>> --- a/drivers/iio/Kconfig
>> +++ b/drivers/iio/Kconfig
>> @@ -20,6 +20,12 @@ config IIO_BUFFER
>>
>>   if IIO_BUFFER
>>
>> +config IIO_BUFFER_CB
>> +       boolean "IIO callback buffer used for push in kernel interfaces"
>
> Any specific reason why this has to be bool?
Doesn't have it's own module as it's so small. Gets built in to the core.

Agreed to all the rest. Thanks for looking at these.
>
>> +       help
>> +         Should be selected by any drivers that do inkernel push
>> +	 usage.  That is, those where the data is pushed to the consumer.
>> +
>>   config IIO_KFIFO_BUF
>>   	select IIO_TRIGGER
>>   	tristate "Industrial I/O buffering based on kfifo"
>> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
>> index f7fa3c0..a27ec1c 100644
>> --- a/drivers/iio/Makefile
>> +++ b/drivers/iio/Makefile
>> @@ -6,6 +6,7 @@ obj-$(CONFIG_IIO) += industrialio.o
>>   industrialio-y := industrialio-core.o industrialio-event.o inkern.o
>>   industrialio-$(CONFIG_IIO_BUFFER) += industrialio-buffer.o
>>   industrialio-$(CONFIG_IIO_TRIGGER) += industrialio-trigger.o
>> +industrialio-$(CONFIG_IIO_BUFFER_CB) += buffer_cb.o
>>
>>   obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o
>>   obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
>> diff --git a/drivers/iio/buffer_cb.c b/drivers/iio/buffer_cb.c
>> new file mode 100644
>> index 0000000..d1e4881
>> --- /dev/null
>> +++ b/drivers/iio/buffer_cb.c
>> @@ -0,0 +1,113 @@
>> +#include <linux/kernel.h>
>> +#include <linux/slab.h>
>> +#include <linux/err.h>
>> +#include <linux/export.h>
>> +#include <linux/iio/buffer.h>
>> +#include <linux/iio/consumer.h>
>> +
>> +struct iio_cb_buffer {
>> +	struct iio_buffer buffer;
>> +	int (*cb)(u8 *data, void *private);
>> +	void *private;
>> +	struct iio_channel *channels;
>> +};
>> +
>> +static int iio_buffer_cb_store_to(struct iio_buffer *buffer, u8 *data)
>> +{
>> +	struct iio_cb_buffer *cb_buff = container_of(buffer,
>> +						     struct iio_cb_buffer,
>> +						     buffer);
>> +
>> +	return cb_buff->cb(data, cb_buff->private);
>> +}
>> +
>> +static struct iio_buffer_access_funcs iio_cb_access = {
>> +	.store_to = &iio_buffer_cb_store_to,
>> +};
>> +
>> +struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
>> +					     int (*cb)(u8 *data,
>> +						       void *private),
>> +					     void *private)
>> +{
>> +	int ret;
>> +	struct iio_cb_buffer *cb_buff;
>> +	struct iio_dev *indio_dev;
>> +	struct iio_channel *chan;
>> +
>> +	cb_buff = kzalloc(sizeof *cb_buff, GFP_KERNEL);
>
> sizeof(*cb_buff)
>
>> +	if (cb_buff == NULL) {
>> +		ret = -ENOMEM;
>> +		goto error_ret;
>> +	}
>> +
>> +	cb_buff->private = private;
>> +	cb_buff->cb = cb;
>> +	cb_buff->buffer.access = &iio_cb_access;
>> +	INIT_LIST_HEAD(&cb_buff->buffer.demux_list);
>
> It probably makes sense to have some kind of iio_buffer_init(...) for this
>
>> +
>> +	cb_buff->channels = iio_channel_get_all(name);
>> +	if (IS_ERR(cb_buff->channels)) {
>> +		ret = PTR_ERR(cb_buff->channels);
>> +		goto error_free_cb_buff;
>> +	}
>> +
>> +	indio_dev = cb_buff->channels[0].indio_dev;
>> +	cb_buff->buffer.scan_mask
>> +		= kzalloc(sizeof(long)*BITS_TO_LONGS(indio_dev->masklength),
>> +			  GFP_KERNEL);
>
> kcalloc
>
>> +	if (cb_buff->buffer.scan_mask == NULL) {
>> +		ret = -ENOMEM;
>> +		goto error_release_channels;
>> +	}
>> +	chan = &cb_buff->channels[0];
>> +	while (chan->indio_dev) {
>> +		if (chan->indio_dev != indio_dev) {
>> +			ret = -EINVAL;
>> +			goto error_release_channels;
>> +		}
>> +		set_bit(chan->channel->scan_index,
>> +			cb_buff->buffer.scan_mask);
>> +		chan++;
>> +	}
>> +
>> +	return cb_buff;
>> +
>> +error_release_channels:
>> +	iio_channel_release_all(cb_buff->channels);
>> +error_free_cb_buff:
>> +	kfree(cb_buff);
>> +error_ret:
>> +	return ERR_PTR(ret);
>> +}
>> +EXPORT_SYMBOL_GPL(iio_channel_get_all_cb);
>> +
>> +int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff)
>> +{
>> +	return iio_update_buffers(cb_buff->channels[0].indio_dev,
>> +				  &cb_buff->buffer,
>> +				  NULL);
>> +}
>> +EXPORT_SYMBOL_GPL(iio_channel_start_all_cb);
>> +
>> +void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff)
>> +{
>> +	iio_update_buffers(cb_buff->channels[0].indio_dev,
>> +			   NULL,
>> +			   &cb_buff->buffer);
>> +}
>> +EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb);
>> +
>> +void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff)
>> +{
>> +	iio_channel_release_all(cb_buff->channels);
>> +	kfree(cb_buff);
>> +}
>> +EXPORT_SYMBOL_GPL(iio_channel_release_all_cb);
>> +
>> +struct iio_channel
>> +*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer)
>> +{
>> +	return cb_buffer->channels;
>> +}
>> +EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels);
>> diff --git a/include/linux/iio/consumer.h b/include/linux/iio/consumer.h
>> index 57efee6..caf103b 100644
>> --- a/include/linux/iio/consumer.h
>> +++ b/include/linux/iio/consumer.h
>> @@ -61,6 +61,52 @@ struct iio_channel *iio_channel_get_all(const char *name);
>>    */
>>   void iio_channel_release_all(struct iio_channel *chan);
>>
>> +struct iio_cb_buffer;
>> +/**
>> + * iio_channel_get_all_cb() - register callback for triggered capture
>> + * @name:		Name of client device.
>> + * @cb:			Callback function.
>> + * @private:		Private data passed to callback.
>> + *
>> + * NB right now we have no ability to mux data from multiple devices.
>> + * So if the channels requested come from different devices this will
>> + * fail.
>> + */
>> +struct iio_cb_buffer *iio_channel_get_all_cb(const char *name,
>> +					     int (*cb)(u8 *data,
>> +						       void *private),
>> +					     void *private);
>> +/**
>> + * iio_channel_release_all_cb() - release and unregister the callback.
>> + * @cb_buffer:		The callback buffer that was allocated.
>> + */
>> +void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buffer);
>> +
>> +/**
>> + * iio_channel_start_all_cb() - start the flow of data through callback.
>> + * @cb_buff:		The callback buffer we are starting.
>> + */
>> +int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff);
>> +
>> +/**
>> + * iio_channel_stop_all_cb() - stop the flow of data through the callback.
>> + * @cb_buff:		The callback buffer we are stopping.
>> + */
>> +void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff);
>> +
>> +/**
>> + * iio_channel_cb_get_channels() - get access to the underlying channels.
>> + * @cb_buff:		The callback buffers from whom we want the channel
>> + *			information.
>> + *
>> + * This function allows one to obtain information about the channels.
>> + * Whilst this may allow direct reading if all buffers are disabled, the
>> + * primary aim is to allow drivers that are consuming a channel to query
>> + * things like scaling of the channel.
>> + */
>> +struct iio_channel
>> +*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer);
>> +
>>   /**
>>    * iio_read_channel_raw() - read from a given channel
>>    * @chan:		The channel being queried.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

[PATCH 4/4] staging:iio: Proof of concept input driver.

[Jonathan Cameron]

From: Jonathan Cameron <jic23@cam.ac.uk>

This is no where near ready to merge.  Lots of stuff missing.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/staging/iio/Kconfig     |  11 ++
 drivers/staging/iio/Makefile    |   1 +
 drivers/staging/iio/iio_input.c | 225 ++++++++++++++++++++++++++++++++++++++++
 drivers/staging/iio/iio_input.h |  23 ++++
 4 files changed, 260 insertions(+)

diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
index ca56c75..3d21f6d 100644
--- a/drivers/staging/iio/Kconfig
+++ b/drivers/staging/iio/Kconfig
@@ -4,6 +4,17 @@
 menu "IIO staging drivers"
 	depends on IIO
 
+config IIO_ST_INPUT
+	tristate "Input driver that uses channels specified via iio maps"
+	depends on INPUT
+	depends on IIO_BUFFER
+	select IIO_BUFFER_CB
+	help
+	  Client driver for IIO via the push interfaces.  Used to provide
+	  and input interface for IIO devices that can feed a buffer on
+	  a trigger interrupt.  Note that all channels must come from a
+	  single IIO supported device.
+
 config IIO_ST_HWMON
 	tristate "Hwmon driver that uses channels specified via iio maps"
 	depends on HWMON
diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
index fa6937d..9e71498 100644
--- a/drivers/staging/iio/Makefile
+++ b/drivers/staging/iio/Makefile
@@ -12,6 +12,7 @@ iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
 obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
 
 obj-$(CONFIG_IIO_ST_HWMON) += iio_hwmon.o
+obj-$(CONFIG_IIO_ST_INPUT) += iio_input.o
 
 obj-y += accel/
 obj-y += adc/
diff --git a/drivers/staging/iio/iio_input.c b/drivers/staging/iio/iio_input.c
new file mode 100644
index 0000000..c34b325
--- /dev/null
+++ b/drivers/staging/iio/iio_input.c
@@ -0,0 +1,225 @@
+/*
+ * The industrial I/O input client driver
+ *
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/err.h>
+#include <linux/platform_device.h>
+#include <linux/input.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/consumer.h>
+#include "iio_input.h"
+
+struct iio_input_state {
+	struct iio_cb_buffer *buff;
+	struct input_dev *idev;
+};
+
+static int iio_channel_value(u8 *data,
+			     const struct iio_chan_spec *chan,
+			     s32 *val)
+{
+	u32 value = 0;
+
+	if (chan->scan_type.sign == 's') {
+		switch (chan->scan_type.storagebits) {
+		case 8:
+			value = *(s8 *)(data);
+			break;
+		case 16:
+			switch (chan->scan_type.endianness) {
+			case IIO_CPU:
+				value = *(s16 *)(data);
+				break;
+			case IIO_BE:
+				value = be16_to_cpu(*(__be16 *)data);
+				break;
+			case IIO_LE:
+				value = le16_to_cpu(*(__le16 *)data);
+				break;
+			}
+			break;
+		case 32:
+			switch (chan->scan_type.endianness) {
+			case IIO_CPU:
+				value = *(s32 *)(data);
+				break;
+			case IIO_BE:
+				value = be32_to_cpu(*(__be32 *)data);
+				break;
+			case IIO_LE:
+				value = le32_to_cpu(*(__le32  *)data);
+				break;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+		*val = sign_extend32(value, chan->scan_type.storagebits);
+	} else {
+		switch (chan->scan_type.storagebits) {
+		case 8:
+			value = *(u8 *)(data);
+			break;
+		case 16:
+			switch (chan->scan_type.endianness) {
+			case IIO_CPU:
+				value = *(u16 *)(data);
+				break;
+			case IIO_BE:
+				value = be16_to_cpu(*(__be16 *)data);
+				break;
+			case IIO_LE:
+				value = le16_to_cpu(*(__le16 *)data);
+				break;
+			}
+			break;
+		case 32:
+			switch (chan->scan_type.endianness) {
+			case IIO_CPU:
+				value = *(u32 *)(data);
+				break;
+			case IIO_BE:
+				value = be32_to_cpu(*(__be32 *)data);
+				break;
+			case IIO_LE:
+				value = le32_to_cpu(*(__le32 *)data);
+				break;
+			}
+			break;
+		default:
+			return -EINVAL;
+		}
+		value >>= chan->scan_type.shift;
+		value &= (1 << chan->scan_type.realbits) - 1;
+		*val = value;
+	}
+
+	return 0;
+}
+
+static int iio_input_store_to(u8 *data, void *private)
+{
+	struct iio_input_state *st = private;
+	struct iio_channel *channel;
+	struct iio_input_channel_data *input_data;
+	int offset = 0;
+	s32 value;
+	int ret;
+
+	channel = iio_channel_cb_get_channels(st->buff);
+	while (channel->indio_dev) {
+		input_data = channel->data;
+		offset = ALIGN(offset,
+			       channel->channel->scan_type.storagebits/8);
+		ret = iio_channel_value(&data[offset],
+					channel->channel,
+					&value);
+		if (ret < 0)
+			return ret;
+		offset += channel->channel->scan_type.storagebits/8;
+
+		input_report_abs(st->idev, input_data->code, value);
+		channel++;
+	}
+	input_sync(st->idev);
+
+	return 0;
+}
+
+static int __devinit iio_input_probe(struct platform_device *pdev)
+{
+	struct iio_input_state *st;
+	int ret;
+	bool registered;
+	struct iio_channel *channel;
+	struct iio_input_channel_data *input_data;
+
+	registered = false;
+	st = kzalloc(sizeof(*st), GFP_KERNEL);
+	if (st == NULL)
+		return -ENOMEM;
+	platform_set_drvdata(pdev, st);
+	st->buff = iio_channel_get_all_cb(dev_name(&pdev->dev),
+					  &iio_input_store_to,
+					  st);
+	if (IS_ERR(st->buff)) {
+		ret = PTR_ERR(st->buff);
+		goto error_free_state;
+	}
+
+	st->idev = input_allocate_device();
+	if (!st->idev) {
+		ret = -ENOMEM;
+		goto error_channels_release_all;
+	}
+
+	__set_bit(EV_ABS, st->idev->evbit);
+	channel = iio_channel_cb_get_channels(st->buff);
+	while (channel->indio_dev) {
+		input_data = channel->data;
+		input_set_abs_params(st->idev, input_data->code,
+				     input_data->min,
+				     input_data->max,
+				     input_data->fuzz,
+				     input_data->flat);
+		channel++;
+	}
+
+	ret = input_register_device(st->idev);
+	if (ret < 0)
+		goto error_free_idev;
+	registered = true;
+	/* NORMALLY IN THE OPEN */
+	ret = iio_channel_start_all_cb(st->buff);
+	if (ret < 0)
+		goto error_unregister_input;
+
+	return 0;
+error_unregister_input:
+	if (registered)
+		input_unregister_device(st->idev);
+error_free_idev:
+	if (!registered)
+		input_free_device(st->idev);
+error_channels_release_all:
+	iio_channel_release_all_cb(st->buff);
+error_free_state:
+	kfree(st);
+	return ret;
+}
+
+static int __devexit iio_input_remove(struct platform_device *pdev)
+{
+	struct iio_input_state *st = platform_get_drvdata(pdev);
+	/* NORMALLY IN THE CLOSE */
+	iio_channel_stop_all_cb(st->buff);
+	input_unregister_device(st->idev);
+	iio_channel_release_all_cb(st->buff);
+
+	kfree(st);
+	return 0;
+}
+
+static struct platform_driver iio_input_driver = {
+	.driver = {
+		.name = "iio_input_bridge",
+		.owner = THIS_MODULE,
+	},
+	.probe = iio_input_probe,
+	.remove = __devexit_p(iio_input_remove),
+};
+
+module_platform_driver(iio_input_driver);
+
+MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
+MODULE_DESCRIPTION("IIO input buffer driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/staging/iio/iio_input.h b/drivers/staging/iio/iio_input.h
new file mode 100644
index 0000000..cfd1d34
--- /dev/null
+++ b/drivers/staging/iio/iio_input.h
@@ -0,0 +1,23 @@
+/*
+ * The industrial I/O input client driver
+ *
+ * Copyright (c) 2011 Jonathan Cameron
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published by
+ * the Free Software Foundation.
+ */
+
+/**
+ * iio_input_channel_data - description of the channel for input subsystem
+ * @code:	Absolute axis.
+ * @min:	Minimum value.
+ * @max:	Maximum value.
+ * @fuzz:	Used to filter noise from the event stream.
+ * @flat:	Values within this value will be discarded by joydev
+ *		and reported as 0 instead.
+ */
+struct iio_input_channel_data {
+	unsigned int code;
+	int min, max, fuzz, flat;
+};
-- 
1.7.12.2

Re: [PATCH 4/4] staging:iio: Proof of concept input driver.

[Jonathan Cameron]

On 10/13/2012 10:24 AM, Jonathan Cameron wrote:
> From: Jonathan Cameron <jic23@cam.ac.uk>
> 
> This is no where near ready to merge.  Lots of stuff missing.
It also contains an issue with using the input dev after freeing that
has already been reported. Naughty me - I forgot about that one.

Doesn't effect the usefulness of this as a test tool though!

> 
> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  drivers/staging/iio/Kconfig     |  11 ++
>  drivers/staging/iio/Makefile    |   1 +
>  drivers/staging/iio/iio_input.c | 225 ++++++++++++++++++++++++++++++++++++++++
>  drivers/staging/iio/iio_input.h |  23 ++++
>  4 files changed, 260 insertions(+)
> 
> diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
> index ca56c75..3d21f6d 100644
> --- a/drivers/staging/iio/Kconfig
> +++ b/drivers/staging/iio/Kconfig
> @@ -4,6 +4,17 @@
>  menu "IIO staging drivers"
>  	depends on IIO
>  
> +config IIO_ST_INPUT
> +	tristate "Input driver that uses channels specified via iio maps"
> +	depends on INPUT
> +	depends on IIO_BUFFER
> +	select IIO_BUFFER_CB
> +	help
> +	  Client driver for IIO via the push interfaces.  Used to provide
> +	  and input interface for IIO devices that can feed a buffer on
> +	  a trigger interrupt.  Note that all channels must come from a
> +	  single IIO supported device.
> +
>  config IIO_ST_HWMON
>  	tristate "Hwmon driver that uses channels specified via iio maps"
>  	depends on HWMON
> diff --git a/drivers/staging/iio/Makefile b/drivers/staging/iio/Makefile
> index fa6937d..9e71498 100644
> --- a/drivers/staging/iio/Makefile
> +++ b/drivers/staging/iio/Makefile
> @@ -12,6 +12,7 @@ iio_dummy-$(CONFIG_IIO_SIMPLE_DUMMY_BUFFER) += iio_simple_dummy_buffer.o
>  obj-$(CONFIG_IIO_DUMMY_EVGEN) += iio_dummy_evgen.o
>  
>  obj-$(CONFIG_IIO_ST_HWMON) += iio_hwmon.o
> +obj-$(CONFIG_IIO_ST_INPUT) += iio_input.o
>  
>  obj-y += accel/
>  obj-y += adc/
> diff --git a/drivers/staging/iio/iio_input.c b/drivers/staging/iio/iio_input.c
> new file mode 100644
> index 0000000..c34b325
> --- /dev/null
> +++ b/drivers/staging/iio/iio_input.c
> @@ -0,0 +1,225 @@
> +/*
> + * The industrial I/O input client driver
> + *
> + * Copyright (c) 2011 Jonathan Cameron
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/slab.h>
> +#include <linux/module.h>
> +#include <linux/err.h>
> +#include <linux/platform_device.h>
> +#include <linux/input.h>
> +#include <linux/iio/buffer.h>
> +#include <linux/iio/consumer.h>
> +#include "iio_input.h"
> +
> +struct iio_input_state {
> +	struct iio_cb_buffer *buff;
> +	struct input_dev *idev;
> +};
> +
> +static int iio_channel_value(u8 *data,
> +			     const struct iio_chan_spec *chan,
> +			     s32 *val)
> +{
> +	u32 value = 0;
> +
> +	if (chan->scan_type.sign == 's') {
> +		switch (chan->scan_type.storagebits) {
> +		case 8:
> +			value = *(s8 *)(data);
> +			break;
> +		case 16:
> +			switch (chan->scan_type.endianness) {
> +			case IIO_CPU:
> +				value = *(s16 *)(data);
> +				break;
> +			case IIO_BE:
> +				value = be16_to_cpu(*(__be16 *)data);
> +				break;
> +			case IIO_LE:
> +				value = le16_to_cpu(*(__le16 *)data);
> +				break;
> +			}
> +			break;
> +		case 32:
> +			switch (chan->scan_type.endianness) {
> +			case IIO_CPU:
> +				value = *(s32 *)(data);
> +				break;
> +			case IIO_BE:
> +				value = be32_to_cpu(*(__be32 *)data);
> +				break;
> +			case IIO_LE:
> +				value = le32_to_cpu(*(__le32  *)data);
> +				break;
> +			}
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		*val = sign_extend32(value, chan->scan_type.storagebits);
> +	} else {
> +		switch (chan->scan_type.storagebits) {
> +		case 8:
> +			value = *(u8 *)(data);
> +			break;
> +		case 16:
> +			switch (chan->scan_type.endianness) {
> +			case IIO_CPU:
> +				value = *(u16 *)(data);
> +				break;
> +			case IIO_BE:
> +				value = be16_to_cpu(*(__be16 *)data);
> +				break;
> +			case IIO_LE:
> +				value = le16_to_cpu(*(__le16 *)data);
> +				break;
> +			}
> +			break;
> +		case 32:
> +			switch (chan->scan_type.endianness) {
> +			case IIO_CPU:
> +				value = *(u32 *)(data);
> +				break;
> +			case IIO_BE:
> +				value = be32_to_cpu(*(__be32 *)data);
> +				break;
> +			case IIO_LE:
> +				value = le32_to_cpu(*(__le32 *)data);
> +				break;
> +			}
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +		value >>= chan->scan_type.shift;
> +		value &= (1 << chan->scan_type.realbits) - 1;
> +		*val = value;
> +	}
> +
> +	return 0;
> +}
> +
> +static int iio_input_store_to(u8 *data, void *private)
> +{
> +	struct iio_input_state *st = private;
> +	struct iio_channel *channel;
> +	struct iio_input_channel_data *input_data;
> +	int offset = 0;
> +	s32 value;
> +	int ret;
> +
> +	channel = iio_channel_cb_get_channels(st->buff);
> +	while (channel->indio_dev) {
> +		input_data = channel->data;
> +		offset = ALIGN(offset,
> +			       channel->channel->scan_type.storagebits/8);
> +		ret = iio_channel_value(&data[offset],
> +					channel->channel,
> +					&value);
> +		if (ret < 0)
> +			return ret;
> +		offset += channel->channel->scan_type.storagebits/8;
> +
> +		input_report_abs(st->idev, input_data->code, value);
> +		channel++;
> +	}
> +	input_sync(st->idev);
> +
> +	return 0;
> +}
> +
> +static int __devinit iio_input_probe(struct platform_device *pdev)
> +{
> +	struct iio_input_state *st;
> +	int ret;
> +	bool registered;
> +	struct iio_channel *channel;
> +	struct iio_input_channel_data *input_data;
> +
> +	registered = false;
> +	st = kzalloc(sizeof(*st), GFP_KERNEL);
> +	if (st == NULL)
> +		return -ENOMEM;
> +	platform_set_drvdata(pdev, st);
> +	st->buff = iio_channel_get_all_cb(dev_name(&pdev->dev),
> +					  &iio_input_store_to,
> +					  st);
> +	if (IS_ERR(st->buff)) {
> +		ret = PTR_ERR(st->buff);
> +		goto error_free_state;
> +	}
> +
> +	st->idev = input_allocate_device();
> +	if (!st->idev) {
> +		ret = -ENOMEM;
> +		goto error_channels_release_all;
> +	}
> +
> +	__set_bit(EV_ABS, st->idev->evbit);
> +	channel = iio_channel_cb_get_channels(st->buff);
> +	while (channel->indio_dev) {
> +		input_data = channel->data;
> +		input_set_abs_params(st->idev, input_data->code,
> +				     input_data->min,
> +				     input_data->max,
> +				     input_data->fuzz,
> +				     input_data->flat);
> +		channel++;
> +	}
> +
> +	ret = input_register_device(st->idev);
> +	if (ret < 0)
> +		goto error_free_idev;
> +	registered = true;
> +	/* NORMALLY IN THE OPEN */
> +	ret = iio_channel_start_all_cb(st->buff);
> +	if (ret < 0)
> +		goto error_unregister_input;
> +
> +	return 0;
> +error_unregister_input:
> +	if (registered)
> +		input_unregister_device(st->idev);
> +error_free_idev:
> +	if (!registered)
> +		input_free_device(st->idev);
> +error_channels_release_all:
> +	iio_channel_release_all_cb(st->buff);
> +error_free_state:
> +	kfree(st);
> +	return ret;
> +}
> +
> +static int __devexit iio_input_remove(struct platform_device *pdev)
> +{
> +	struct iio_input_state *st = platform_get_drvdata(pdev);
> +	/* NORMALLY IN THE CLOSE */
> +	iio_channel_stop_all_cb(st->buff);
> +	input_unregister_device(st->idev);
> +	iio_channel_release_all_cb(st->buff);
> +
> +	kfree(st);
> +	return 0;
> +}
> +
> +static struct platform_driver iio_input_driver = {
> +	.driver = {
> +		.name = "iio_input_bridge",
> +		.owner = THIS_MODULE,
> +	},
> +	.probe = iio_input_probe,
> +	.remove = __devexit_p(iio_input_remove),
> +};
> +
> +module_platform_driver(iio_input_driver);
> +
> +MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
> +MODULE_DESCRIPTION("IIO input buffer driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/staging/iio/iio_input.h b/drivers/staging/iio/iio_input.h
> new file mode 100644
> index 0000000..cfd1d34
> --- /dev/null
> +++ b/drivers/staging/iio/iio_input.h
> @@ -0,0 +1,23 @@
> +/*
> + * The industrial I/O input client driver
> + *
> + * Copyright (c) 2011 Jonathan Cameron
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +/**
> + * iio_input_channel_data - description of the channel for input subsystem
> + * @code:	Absolute axis.
> + * @min:	Minimum value.
> + * @max:	Maximum value.
> + * @fuzz:	Used to filter noise from the event stream.
> + * @flat:	Values within this value will be discarded by joydev
> + *		and reported as 0 instead.
> + */
> +struct iio_input_channel_data {
> +	unsigned int code;
> +	int min, max, fuzz, flat;
> +};
> 

RE: [PATCH 0/4 V5] staging:iio: Add support for multiple buffers (testing required!)

[Pandruvada, Srinivas]

Hi Jonathan,

Tested hid sensor changes. They still work with this patchset.

Thanks,
Srinivas

-----Original Message-----
From: J.I. Cameron [mailto:jic23@hermes.cam.ac.uk] On Behalf Of Jonathan Ca=
meron
Sent: Saturday, October 13, 2012 2:25 AM
To: linux-iio@vger.kernel.org
Cc: Michael.Hennerich@analog.com; lars@metafoo.de; Pandruvada, Srinivas; Jo=
nathan Cameron
Subject: [PATCH 0/4 V5] staging:iio: Add support for multiple buffers (test=
ing required!)

In quick summary this is needed to do interrupt driven in kernel clients as=
 it adds the option to push to multiple 'buffer' interfaces.
Note that some of these may not actually do any buffering but rather push d=
irectly into another subsytem (the example is input).

I would like to merge at least the first 3 patches early in this cycle.
What I need is some testing across a reasonable range of devices.  Review i=
s welcome of course as well!

The complexity in this set is entirely in the changes to industrialio-buffe=
r.c concerning how we go about adding and removing client buffers.  To do t=
his we need to work out which scan mask is appropriate given the requests o=
f all the given buffers (and whether we can satisfy it).  I've been testing=
 with the max1363 driver which probably has the most complex set of availab=
le scan masks.  Thus when a new buffer is added or one is removed the whole=
 buffer set are torn down and built up again.  This may be undesirable for =
some applications but should occur only rarely.

The example driver is for bridging to the input subsystem and still needs s=
ome work, but that can occur later in this merge cycle whereas the changes =
to the core really want to go in asap.

Changes since v3=20

Rebased and added other drivers that have occured whilst this patch series =
has been languishing in my local tree.

Changes since V2.

Improved handling of error conditions in the buffer insertion and removal c=
ode.  (suggested by Lars-Peter).  I want to take another look at these, but=
 didn't want to keep people from testing this in the meantime.

Also a number of minor fixes that came up during testing.

Thanks,

Jonathan

Jonathan Cameron (4):
  staging:iio: Add support for multiple buffers
  staging:iio:in kernel users: Add a data field for channel specific
    info.
  staging:iio: add a callback buffer for in kernel push interface
  staging:iio: Proof of concept input driver.

 drivers/iio/Kconfig                             |   6 +
 drivers/iio/Makefile                            |   1 +
 drivers/iio/accel/hid-sensor-accel-3d.c         |  15 +-
 drivers/iio/adc/ad7266.c                        |   3 +-
 drivers/iio/adc/ad7476.c                        |   2 +-
 drivers/iio/adc/ad_sigma_delta.c                |   2 +-
 drivers/iio/adc/at91_adc.c                      |   3 +-
 drivers/iio/buffer_cb.c                         | 113 +++++++
 drivers/iio/gyro/hid-sensor-gyro-3d.c           |  15 +-
 drivers/iio/industrialio-buffer.c               | 377 ++++++++++++++++----=
----
 drivers/iio/industrialio-core.c                 |   1 +
 drivers/iio/inkern.c                            |   1 +
 drivers/iio/light/adjd_s311.c                   |   3 +-
 drivers/iio/light/hid-sensor-als.c              |  15 +-
 drivers/iio/magnetometer/hid-sensor-magn-3d.c   |  15 +-
 drivers/staging/iio/Kconfig                     |  11 +
 drivers/staging/iio/Makefile                    |   1 +
 drivers/staging/iio/accel/adis16201_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16203_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16204_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16209_ring.c      |   2 +-
 drivers/staging/iio/accel/adis16240_ring.c      |   2 +-
 drivers/staging/iio/accel/lis3l02dq_ring.c      |   2 +-
 drivers/staging/iio/adc/ad7298_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7606_ring.c           |   2 +-
 drivers/staging/iio/adc/ad7887_ring.c           |   2 +-
 drivers/staging/iio/adc/ad799x_ring.c           |   2 +-
 drivers/staging/iio/adc/max1363_ring.c          |   2 +-
 drivers/staging/iio/gyro/adis16260_ring.c       |   2 +-
 drivers/staging/iio/iio_input.c                 | 225 ++++++++++++++
 drivers/staging/iio/iio_input.h                 |  23 ++
 drivers/staging/iio/iio_simple_dummy_buffer.c   |   5 +-
 drivers/staging/iio/impedance-analyzer/ad5933.c |   4 +-
 drivers/staging/iio/imu/adis16400_ring.c        |   5 +-
 drivers/staging/iio/meter/ade7758_ring.c        |   2 +-
 include/linux/iio/buffer.h                      |  24 +-
 include/linux/iio/consumer.h                    |  48 +++
 include/linux/iio/iio.h                         |   2 +
 include/linux/iio/machine.h                     |   2 +
 39 files changed, 740 insertions(+), 208 deletions(-)  create mode 100644 =
drivers/iio/buffer_cb.c  create mode 100644 drivers/staging/iio/iio_input.c=
  create mode 100644 drivers/staging/iio/iio_input.h

--
1.7.12.2

Re: [PATCH 0/4 V5] staging:iio: Add support for multiple buffers (testing required!)

[Jonathan Cameron]

Thanks, I've added a tested-by tag for patch 0. The others shouldn't have any effect at
all on your drivers (or any others!)
> Hi Jonathan,
> 
> Tested hid sensor changes. They still work with this patchset.
> 
> Thanks,
> Srinivas
> 
> -----Original Message-----
> From: J.I. Cameron [mailto:jic23@hermes.cam.ac.uk] On Behalf Of Jonathan Cameron
> Sent: Saturday, October 13, 2012 2:25 AM
> To: linux-iio@vger.kernel.org
> Cc: Michael.Hennerich@analog.com; lars@metafoo.de; Pandruvada, Srinivas; Jonathan Cameron
> Subject: [PATCH 0/4 V5] staging:iio: Add support for multiple buffers (testing required!)
> 
> In quick summary this is needed to do interrupt driven in kernel clients as it adds the option to push to multiple 'buffer' interfaces.
> Note that some of these may not actually do any buffering but rather push directly into another subsytem (the example is input).
> 
> I would like to merge at least the first 3 patches early in this cycle.
> What I need is some testing across a reasonable range of devices.  Review is welcome of course as well!
> 
> The complexity in this set is entirely in the changes to industrialio-buffer.c concerning how we go about adding and removing client buffers.  To do this we need to work out which scan mask is appropriate given the requests of all the given buffers (and whether we can satisfy it).  I've been testing with the max1363 driver which probably has the most complex set of available scan masks.  Thus when a new buffer is added or one is removed the whole buffer set are torn down and built up again.  This may be undesirable for some applications but should occur only rarely.
> 
> The example driver is for bridging to the input subsystem and still needs some work, but that can occur later in this merge cycle whereas the changes to the core really want to go in asap.
> 
> Changes since v3 
> 
> Rebased and added other drivers that have occured whilst this patch series has been languishing in my local tree.
> 
> Changes since V2.
> 
> Improved handling of error conditions in the buffer insertion and removal code.  (suggested by Lars-Peter).  I want to take another look at these, but didn't want to keep people from testing this in the meantime.
> 
> Also a number of minor fixes that came up during testing.
> 
> Thanks,
> 
> Jonathan
> 
> Jonathan Cameron (4):
>   staging:iio: Add support for multiple buffers
>   staging:iio:in kernel users: Add a data field for channel specific
>     info.
>   staging:iio: add a callback buffer for in kernel push interface
>   staging:iio: Proof of concept input driver.
> 
>  drivers/iio/Kconfig                             |   6 +
>  drivers/iio/Makefile                            |   1 +
>  drivers/iio/accel/hid-sensor-accel-3d.c         |  15 +-
>  drivers/iio/adc/ad7266.c                        |   3 +-
>  drivers/iio/adc/ad7476.c                        |   2 +-
>  drivers/iio/adc/ad_sigma_delta.c                |   2 +-
>  drivers/iio/adc/at91_adc.c                      |   3 +-
>  drivers/iio/buffer_cb.c                         | 113 +++++++
>  drivers/iio/gyro/hid-sensor-gyro-3d.c           |  15 +-
>  drivers/iio/industrialio-buffer.c               | 377 ++++++++++++++++--------
>  drivers/iio/industrialio-core.c                 |   1 +
>  drivers/iio/inkern.c                            |   1 +
>  drivers/iio/light/adjd_s311.c                   |   3 +-
>  drivers/iio/light/hid-sensor-als.c              |  15 +-
>  drivers/iio/magnetometer/hid-sensor-magn-3d.c   |  15 +-
>  drivers/staging/iio/Kconfig                     |  11 +
>  drivers/staging/iio/Makefile                    |   1 +
>  drivers/staging/iio/accel/adis16201_ring.c      |   2 +-
>  drivers/staging/iio/accel/adis16203_ring.c      |   2 +-
>  drivers/staging/iio/accel/adis16204_ring.c      |   2 +-
>  drivers/staging/iio/accel/adis16209_ring.c      |   2 +-
>  drivers/staging/iio/accel/adis16240_ring.c      |   2 +-
>  drivers/staging/iio/accel/lis3l02dq_ring.c      |   2 +-
>  drivers/staging/iio/adc/ad7298_ring.c           |   2 +-
>  drivers/staging/iio/adc/ad7606_ring.c           |   2 +-
>  drivers/staging/iio/adc/ad7887_ring.c           |   2 +-
>  drivers/staging/iio/adc/ad799x_ring.c           |   2 +-
>  drivers/staging/iio/adc/max1363_ring.c          |   2 +-
>  drivers/staging/iio/gyro/adis16260_ring.c       |   2 +-
>  drivers/staging/iio/iio_input.c                 | 225 ++++++++++++++
>  drivers/staging/iio/iio_input.h                 |  23 ++
>  drivers/staging/iio/iio_simple_dummy_buffer.c   |   5 +-
>  drivers/staging/iio/impedance-analyzer/ad5933.c |   4 +-
>  drivers/staging/iio/imu/adis16400_ring.c        |   5 +-
>  drivers/staging/iio/meter/ade7758_ring.c        |   2 +-
>  include/linux/iio/buffer.h                      |  24 +-
>  include/linux/iio/consumer.h                    |  48 +++
>  include/linux/iio/iio.h                         |   2 +
>  include/linux/iio/machine.h                     |   2 +
>  39 files changed, 740 insertions(+), 208 deletions(-)  create mode 100644 drivers/iio/buffer_cb.c  create mode 100644 drivers/staging/iio/iio_input.c  create mode 100644 drivers/staging/iio/iio_input.h
> 
> --
> 1.7.12.2
>