[PATCH 1/3] iio: core: Introduce debugfs support, add support for direct register access

[PATCH 1/3] iio: core: Introduce debugfs support, add support for direct register access

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Changes since V1:

debugfs:

Exclude iio debugfs code in case CONFIG_DEBUG_FS isn't enabled.
	Introduce helper function iio_get_debugfs_dentry.
	Document additions to struct iio_dev

iio_debugfs_read_reg:
	Use snprintf.
	Use a shorter fixed length.
	Introduce len instead of pointer math.

iio_debugfs_write_reg:
	Fix return value use PTR_ERR.
	sscanf scan hex, decimal and octal.
	Ensure zero terminated string.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/staging/iio/iio.h               |   27 ++++++-
 drivers/staging/iio/industrialio-core.c |  137 ++++++++++++++++++++++++++++++-
 2 files changed, 162 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/iio/iio.h b/drivers/staging/iio/iio.h
index 42a362c..baf3c45 100644
--- a/drivers/staging/iio/iio.h
+++ b/drivers/staging/iio/iio.h
@@ -269,6 +269,9 @@ struct iio_info {
 				struct iio_trigger *trig);
 	int (*update_scan_mode)(struct iio_dev *indio_dev,
 				const unsigned long *scan_mask);
+	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
+				  unsigned reg, unsigned writeval,
+				  unsigned *readval);
 };

 /**
@@ -314,7 +317,9 @@ struct iio_buffer_setup_ops {
  * @groups:		[INTERN] attribute groups
  * @groupcounter:	[INTERN] index of next attribute group
  * @flags:		[INTERN] file ops related flags including busy flag.
- **/
+ * @debugfs_dentry:	[INTERN] device specific debugfs dentry.
+ * @cached_reg_addr:	[INTERN] cached register address for debugfs reads.
+**/
 struct iio_dev {
 	int				id;

@@ -347,6 +352,10 @@ struct iio_dev {
 	int				groupcounter;

 	unsigned long			flags;
+#if defined(CONFIG_DEBUG_FS)
+	struct dentry			*debugfs_dentry;
+	unsigned			cached_reg_addr;
+#endif
 };

 /**
@@ -424,4 +433,20 @@ static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
 		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
 };

+/**
+ * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
+ * @indio_dev:		IIO device info structure for device
+ **/
+#if defined(CONFIG_DEBUG_FS)
+static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
+{
+	return indio_dev->debugfs_dentry;
+};
+#else
+static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
+{
+	return NULL;
+};
+#endif
+
 #endif /* _INDUSTRIAL_IO_H_ */
diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index e4824fe..82c9128 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -22,6 +22,7 @@
 #include <linux/cdev.h>
 #include <linux/slab.h>
 #include <linux/anon_inodes.h>
+#include <linux/debugfs.h>
 #include "iio.h"
 #include "iio_core.h"
 #include "iio_core_trigger.h"
@@ -39,6 +40,8 @@ struct bus_type iio_bus_type = {
 };
 EXPORT_SYMBOL(iio_bus_type);

+static struct dentry *iio_debugfs_dentry;
+
 static const char * const iio_data_type_name[] = {
 	[IIO_RAW] = "raw",
 	[IIO_PROCESSED] = "input",
@@ -129,6 +132,8 @@ static int __init iio_init(void)
 		goto error_unregister_bus_type;
 	}

+	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
+
 	return 0;

 error_unregister_bus_type:
@@ -142,8 +147,129 @@ static void __exit iio_exit(void)
 	if (iio_devt)
 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
 	bus_unregister(&iio_bus_type);
+	debugfs_remove_recursive(iio_debugfs_dentry);
+}
+
+#if defined(CONFIG_DEBUG_FS)
+static int iio_debugfs_open(struct inode *inode, struct file *file)
+{
+	if (inode->i_private)
+		file->private_data = inode->i_private;
+
+	return 0;
+}
+
+static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	char buf[20];
+	unsigned val = 0;
+	ssize_t len;
+	int ret;
+
+	ret = indio_dev->info->debugfs_reg_access(indio_dev,
+						  indio_dev->cached_reg_addr,
+						  0, &val);
+	if (ret)
+		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
+
+	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+
+static ssize_t iio_debugfs_write_reg(struct file *file,
+		     const char __user *userbuf, size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	unsigned reg, val;
+	char buf[80];
+	int ret;
+
+	count = min_t(size_t, count, (sizeof(buf)-1));
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	buf[count] = 0;
+
+	ret = sscanf(buf, "%i %i", &reg, &val);
+
+	switch (ret) {
+	case 1:
+		indio_dev->cached_reg_addr = reg;
+		break;
+	case 2:
+		indio_dev->cached_reg_addr = reg;
+		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
+							  val, NULL);
+		if (ret) {
+			dev_err(indio_dev->dev.parent, "%s: write failed\n",
+				__func__);
+			return ret;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static const struct file_operations iio_debugfs_reg_fops = {
+	.open = iio_debugfs_open,
+	.read = iio_debugfs_read_reg,
+	.write = iio_debugfs_write_reg,
+};
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+	debugfs_remove_recursive(indio_dev->debugfs_dentry);
 }

+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	struct dentry *d;
+
+	if (indio_dev->info->debugfs_reg_access == NULL)
+		return 0;
+
+	if (IS_ERR(iio_debugfs_dentry))
+		return 0;
+
+	indio_dev->debugfs_dentry =
+		debugfs_create_dir(dev_name(&indio_dev->dev),
+				   iio_debugfs_dentry);
+	if (IS_ERR(indio_dev->debugfs_dentry))
+		return PTR_ERR(indio_dev->debugfs_dentry);
+
+	if (indio_dev->debugfs_dentry == NULL) {
+		dev_warn(indio_dev->dev.parent,
+			 "Failed to create debugfs directory\n");
+		return -EFAULT;
+	}
+
+	d = debugfs_create_file("direct_reg_access", 0644,
+				indio_dev->debugfs_dentry,
+				indio_dev, &iio_debugfs_reg_fops);
+	if (!d) {
+		iio_device_unregister_debugfs(indio_dev);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+#else
+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
 static ssize_t iio_read_channel_info(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
@@ -565,6 +691,7 @@ static void iio_dev_release(struct device *device)
 		iio_device_unregister_trigger_consumer(indio_dev);
 	iio_device_unregister_eventset(indio_dev);
 	iio_device_unregister_sysfs(indio_dev);
+	iio_device_unregister_debugfs(indio_dev);
 }

 static struct device_type iio_dev_type = {
@@ -680,11 +807,17 @@ int iio_device_register(struct iio_dev *indio_dev)
 	/* configure elements for the chrdev */
 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);

+	ret = iio_device_register_debugfs(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register debugfs interfaces\n");
+		goto error_ret;
+	}
 	ret = iio_device_register_sysfs(indio_dev);
 	if (ret) {
 		dev_err(indio_dev->dev.parent,
 			"Failed to register sysfs interfaces\n");
-		goto error_ret;
+		goto error_unreg_debugfs;
 	}
 	ret = iio_device_register_eventset(indio_dev);
 	if (ret) {
@@ -711,6 +844,8 @@ error_unreg_eventset:
 	iio_device_unregister_eventset(indio_dev);
 error_free_sysfs:
 	iio_device_unregister_sysfs(indio_dev);
+error_unreg_debugfs:
+	iio_device_unregister_debugfs(indio_dev);
 error_ret:
 	return ret;
 }
--
1.7.0.4

Re: [PATCH 1/3] iio: core: Introduce debugfs support, add support for direct register access

[Jonathan Cameron]

On 02/22/2012 12:30 PM, michael.hennerich@analog.com wrote:
> From: Michael Hennerich <michael.hennerich@analog.com>
Looks fine. One trivial formatting quirk inline and a question
about the recursive call (though I can't see it doing any harm!)

> 
> Changes since V1:
> 
> debugfs:
> 
> Exclude iio debugfs code in case CONFIG_DEBUG_FS isn't enabled.
> 	Introduce helper function iio_get_debugfs_dentry.
> 	Document additions to struct iio_dev
> 
> iio_debugfs_read_reg:
> 	Use snprintf.
> 	Use a shorter fixed length.
> 	Introduce len instead of pointer math.
> 
> iio_debugfs_write_reg:
> 	Fix return value use PTR_ERR.
> 	sscanf scan hex, decimal and octal.
> 	Ensure zero terminated string.
> 
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
> ---
>  drivers/staging/iio/iio.h               |   27 ++++++-
>  drivers/staging/iio/industrialio-core.c |  137 ++++++++++++++++++++++++++++++-
>  2 files changed, 162 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/iio/iio.h b/drivers/staging/iio/iio.h
> index 42a362c..baf3c45 100644
> --- a/drivers/staging/iio/iio.h
> +++ b/drivers/staging/iio/iio.h
> @@ -269,6 +269,9 @@ struct iio_info {
>  				struct iio_trigger *trig);
>  	int (*update_scan_mode)(struct iio_dev *indio_dev,
>  				const unsigned long *scan_mask);
> +	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
> +				  unsigned reg, unsigned writeval,
> +				  unsigned *readval);
>  };
> 
>  /**
> @@ -314,7 +317,9 @@ struct iio_buffer_setup_ops {
>   * @groups:		[INTERN] attribute groups
>   * @groupcounter:	[INTERN] index of next attribute group
>   * @flags:		[INTERN] file ops related flags including busy flag.
> - **/
> + * @debugfs_dentry:	[INTERN] device specific debugfs dentry.
> + * @cached_reg_addr:	[INTERN] cached register address for debugfs reads.
> +**/
space quirk here.  Also I think the prefered option is */ if you are
going to tidy it up!
>  struct iio_dev {
>  	int				id;
> 
> @@ -347,6 +352,10 @@ struct iio_dev {
>  	int				groupcounter;
> 
>  	unsigned long			flags;
> +#if defined(CONFIG_DEBUG_FS)
> +	struct dentry			*debugfs_dentry;
> +	unsigned			cached_reg_addr;
> +#endif
>  };
> 
>  /**
> @@ -424,4 +433,20 @@ static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
>  		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
>  };
> 
> +/**
> + * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
> + * @indio_dev:		IIO device info structure for device
> + **/
> +#if defined(CONFIG_DEBUG_FS)
> +static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
> +{
> +	return indio_dev->debugfs_dentry;
> +};
> +#else
> +static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
> +{
> +	return NULL;
> +};
> +#endif
> +
>  #endif /* _INDUSTRIAL_IO_H_ */
> diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
> index e4824fe..82c9128 100644
> --- a/drivers/staging/iio/industrialio-core.c
> +++ b/drivers/staging/iio/industrialio-core.c
> @@ -22,6 +22,7 @@
>  #include <linux/cdev.h>
>  #include <linux/slab.h>
>  #include <linux/anon_inodes.h>
> +#include <linux/debugfs.h>
>  #include "iio.h"
>  #include "iio_core.h"
>  #include "iio_core_trigger.h"
> @@ -39,6 +40,8 @@ struct bus_type iio_bus_type = {
>  };
>  EXPORT_SYMBOL(iio_bus_type);
> 
> +static struct dentry *iio_debugfs_dentry;
> +
>  static const char * const iio_data_type_name[] = {
>  	[IIO_RAW] = "raw",
>  	[IIO_PROCESSED] = "input",
> @@ -129,6 +132,8 @@ static int __init iio_init(void)
>  		goto error_unregister_bus_type;
>  	}
> 
> +	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
> +
>  	return 0;
> 
>  error_unregister_bus_type:
> @@ -142,8 +147,129 @@ static void __exit iio_exit(void)
>  	if (iio_devt)
>  		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
>  	bus_unregister(&iio_bus_type);
> +	debugfs_remove_recursive(iio_debugfs_dentry);
Not sure it matters, but shouldn't we have cleared everything other than
the directory before this gets called?  If so why the recursive version?
> +}
> +
> +#if defined(CONFIG_DEBUG_FS)
> +static int iio_debugfs_open(struct inode *inode, struct file *file)
> +{
> +	if (inode->i_private)
> +		file->private_data = inode->i_private;
> +
> +	return 0;
> +}
> +
> +static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
> +			      size_t count, loff_t *ppos)
> +{
> +	struct iio_dev *indio_dev = file->private_data;
> +	char buf[20];
> +	unsigned val = 0;
> +	ssize_t len;
> +	int ret;
> +
> +	ret = indio_dev->info->debugfs_reg_access(indio_dev,
> +						  indio_dev->cached_reg_addr,
> +						  0, &val);
> +	if (ret)
> +		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
> +
> +	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
> +
> +	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
> +}
> +
> +static ssize_t iio_debugfs_write_reg(struct file *file,
> +		     const char __user *userbuf, size_t count, loff_t *ppos)
> +{
> +	struct iio_dev *indio_dev = file->private_data;
> +	unsigned reg, val;
> +	char buf[80];
> +	int ret;
> +
> +	count = min_t(size_t, count, (sizeof(buf)-1));
> +	if (copy_from_user(buf, userbuf, count))
> +		return -EFAULT;
> +
> +	buf[count] = 0;
> +
> +	ret = sscanf(buf, "%i %i", &reg, &val);
> +
> +	switch (ret) {
> +	case 1:
> +		indio_dev->cached_reg_addr = reg;
> +		break;
> +	case 2:
> +		indio_dev->cached_reg_addr = reg;
> +		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
> +							  val, NULL);
> +		if (ret) {
> +			dev_err(indio_dev->dev.parent, "%s: write failed\n",
> +				__func__);
> +			return ret;
> +		}
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return count;
> +}
> +
> +static const struct file_operations iio_debugfs_reg_fops = {
> +	.open = iio_debugfs_open,
> +	.read = iio_debugfs_read_reg,
> +	.write = iio_debugfs_write_reg,
> +};
> +
> +static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
> +{
> +	debugfs_remove_recursive(indio_dev->debugfs_dentry);
>  }
> 
> +static int iio_device_register_debugfs(struct iio_dev *indio_dev)
> +{
> +	struct dentry *d;
> +
> +	if (indio_dev->info->debugfs_reg_access == NULL)
> +		return 0;
> +
> +	if (IS_ERR(iio_debugfs_dentry))
> +		return 0;
> +
> +	indio_dev->debugfs_dentry =
> +		debugfs_create_dir(dev_name(&indio_dev->dev),
> +				   iio_debugfs_dentry);
> +	if (IS_ERR(indio_dev->debugfs_dentry))
> +		return PTR_ERR(indio_dev->debugfs_dentry);
> +
> +	if (indio_dev->debugfs_dentry == NULL) {
> +		dev_warn(indio_dev->dev.parent,
> +			 "Failed to create debugfs directory\n");
> +		return -EFAULT;
> +	}
> +
> +	d = debugfs_create_file("direct_reg_access", 0644,
> +				indio_dev->debugfs_dentry,
> +				indio_dev, &iio_debugfs_reg_fops);
> +	if (!d) {
> +		iio_device_unregister_debugfs(indio_dev);
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +#else
> +static int iio_device_register_debugfs(struct iio_dev *indio_dev)
> +{
> +	return 0;
> +}
> +
> +static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
> +{
> +}
> +#endif /* CONFIG_DEBUG_FS */
> +
>  static ssize_t iio_read_channel_info(struct device *dev,
>  				     struct device_attribute *attr,
>  				     char *buf)
> @@ -565,6 +691,7 @@ static void iio_dev_release(struct device *device)
>  		iio_device_unregister_trigger_consumer(indio_dev);
>  	iio_device_unregister_eventset(indio_dev);
>  	iio_device_unregister_sysfs(indio_dev);
> +	iio_device_unregister_debugfs(indio_dev);
>  }
> 
>  static struct device_type iio_dev_type = {
> @@ -680,11 +807,17 @@ int iio_device_register(struct iio_dev *indio_dev)
>  	/* configure elements for the chrdev */
>  	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
> 
> +	ret = iio_device_register_debugfs(indio_dev);
> +	if (ret) {
> +		dev_err(indio_dev->dev.parent,
> +			"Failed to register debugfs interfaces\n");
> +		goto error_ret;
> +	}
>  	ret = iio_device_register_sysfs(indio_dev);
>  	if (ret) {
>  		dev_err(indio_dev->dev.parent,
>  			"Failed to register sysfs interfaces\n");
> -		goto error_ret;
> +		goto error_unreg_debugfs;
>  	}
>  	ret = iio_device_register_eventset(indio_dev);
>  	if (ret) {
> @@ -711,6 +844,8 @@ error_unreg_eventset:
>  	iio_device_unregister_eventset(indio_dev);
>  error_free_sysfs:
>  	iio_device_unregister_sysfs(indio_dev);
> +error_unreg_debugfs:
> +	iio_device_unregister_debugfs(indio_dev);
>  error_ret:
>  	return ret;
>  }
> --
> 1.7.0.4
> 
> 
> --
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Re: [PATCH 1/3] iio: core: Introduce debugfs support, add support for direct register access

[Michael Hennerich]

On 02/29/2012 09:14 PM, Jonathan Cameron wrote:
> On 02/22/2012 12:30 PM, michael.hennerich@analog.com wrote:
>> From: Michael Hennerich<michael.hennerich@analog.com>
> Looks fine. One trivial formatting quirk inline and a question
> about the recursive call (though I can't see it doing any harm!)
>
>> Changes since V1:
>>
>> debugfs:
>>
>> Exclude iio debugfs code in case CONFIG_DEBUG_FS isn't enabled.
>>        Introduce helper function iio_get_debugfs_dentry.
>>        Document additions to struct iio_dev
>>
>> iio_debugfs_read_reg:
>>        Use snprintf.
>>        Use a shorter fixed length.
>>        Introduce len instead of pointer math.
>>
>> iio_debugfs_write_reg:
>>        Fix return value use PTR_ERR.
>>        sscanf scan hex, decimal and octal.
>>        Ensure zero terminated string.
>>
>> Signed-off-by: Michael Hennerich<michael.hennerich@analog.com>
> Acked-by: Jonathan Cameron<jic23@kernel.org>
>>   #endif /* _INDUSTRIAL_IO_H_ */
>> diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
>> index e4824fe..82c9128 100644
>> --- a/drivers/staging/iio/industrialio-core.c
>> +++ b/drivers/staging/iio/industrialio-core.c
>> @@ -22,6 +22,7 @@
>>   #include<linux/cdev.h>
>>   #include<linux/slab.h>
>>   #include<linux/anon_inodes.h>
>> +#include<linux/debugfs.h>
>>   #include "iio.h"
>>   #include "iio_core.h"
>>   #include "iio_core_trigger.h"
>> @@ -39,6 +40,8 @@ struct bus_type iio_bus_type = {
>>   };
>>   EXPORT_SYMBOL(iio_bus_type);
>>
>> +static struct dentry *iio_debugfs_dentry;
>> +
>>   static const char * const iio_data_type_name[] = {
>>        [IIO_RAW] = "raw",
>>        [IIO_PROCESSED] = "input",
>> @@ -129,6 +132,8 @@ static int __init iio_init(void)
>>                goto error_unregister_bus_type;
>>        }
>>
>> +     iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
>> +
>>        return 0;
>>
>>   error_unregister_bus_type:
>> @@ -142,8 +147,129 @@ static void __exit iio_exit(void)
>>        if (iio_devt)
>>                unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
>>        bus_unregister(&iio_bus_type);
>> +     debugfs_remove_recursive(iio_debugfs_dentry);
> Not sure it matters, but shouldn't we have cleared everything other than
> the directory before this gets called?  If so why the recursive version?

Hi Jonathan,

Thanks for the review.

The recursive version doesn't harm. But right you are -
debugfs_remove() is the cleaner option.
I'll fix this up before sending on to Greg.

-- 
Greetings,
Michael

--
Analog Devices GmbH      Wilhelm-Wagenfeld-Str. 6      80807 Muenchen
Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368;
Geschaeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin,
Margaret Seif

[PATCH 1/3] iio: core: Introduce debugfs support, add support for direct register access

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Changes since V1:

Exclude iio debugfs code in case CONFIG_DEBUG_FS isn't enabled.
	Introduce helper function iio_get_debugfs_dentry.
	Document additions to struct iio_dev

iio_debugfs_read_reg:
	Use snprintf.
	Use a shorter fixed length.
	Introduce len instead of pointer math.

iio_debugfs_write_reg:
	Fix return value use PT_ERR.

Changes since V2:

Use debugfs_remove.
Fix whitespace damage.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/staging/iio/iio.h               |   27 ++++++-
 drivers/staging/iio/industrialio-core.c |  137 ++++++++++++++++++++++++++++++-
 2 files changed, 162 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/iio/iio.h b/drivers/staging/iio/iio.h
index 76a3f50..e761a08 100644
--- a/drivers/staging/iio/iio.h
+++ b/drivers/staging/iio/iio.h
@@ -286,6 +286,9 @@ struct iio_info {
 				struct iio_trigger *trig);
 	int (*update_scan_mode)(struct iio_dev *indio_dev,
 				const unsigned long *scan_mask);
+	int (*debugfs_reg_access)(struct iio_dev *indio_dev,
+				  unsigned reg, unsigned writeval,
+				  unsigned *readval);
 };

 /**
@@ -332,7 +335,9 @@ struct iio_buffer_setup_ops {
  * @groups:		[INTERN] attribute groups
  * @groupcounter:	[INTERN] index of next attribute group
  * @flags:		[INTERN] file ops related flags including busy flag.
- **/
+ * @debugfs_dentry:	[INTERN] device specific debugfs dentry.
+ * @cached_reg_addr:	[INTERN] cached register address for debugfs reads.
+ */
 struct iio_dev {
 	int				id;

@@ -366,6 +371,10 @@ struct iio_dev {
 	int				groupcounter;

 	unsigned long			flags;
+#if defined(CONFIG_DEBUG_FS)
+	struct dentry			*debugfs_dentry;
+	unsigned			cached_reg_addr;
+#endif
 };

 /**
@@ -443,4 +452,20 @@ static inline bool iio_buffer_enabled(struct iio_dev *indio_dev)
 		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE);
 };

+/**
+ * iio_get_debugfs_dentry() - helper function to get the debugfs_dentry
+ * @indio_dev:		IIO device info structure for device
+ **/
+#if defined(CONFIG_DEBUG_FS)
+static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
+{
+	return indio_dev->debugfs_dentry;
+};
+#else
+static inline struct dentry *iio_get_debugfs_dentry(struct iio_dev *indio_dev)
+{
+	return NULL;
+};
+#endif
+
 #endif /* _INDUSTRIAL_IO_H_ */
diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index 645bb45..7256dd6 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -22,6 +22,7 @@
 #include <linux/cdev.h>
 #include <linux/slab.h>
 #include <linux/anon_inodes.h>
+#include <linux/debugfs.h>
 #include "iio.h"
 #include "iio_core.h"
 #include "iio_core_trigger.h"
@@ -39,6 +40,8 @@ struct bus_type iio_bus_type = {
 };
 EXPORT_SYMBOL(iio_bus_type);

+static struct dentry *iio_debugfs_dentry;
+
 static const char * const iio_data_type_name[] = {
 	[IIO_RAW] = "raw",
 	[IIO_PROCESSED] = "input",
@@ -129,6 +132,8 @@ static int __init iio_init(void)
 		goto error_unregister_bus_type;
 	}

+	iio_debugfs_dentry = debugfs_create_dir("iio", NULL);
+
 	return 0;

 error_unregister_bus_type:
@@ -142,6 +147,84 @@ static void __exit iio_exit(void)
 	if (iio_devt)
 		unregister_chrdev_region(iio_devt, IIO_DEV_MAX);
 	bus_unregister(&iio_bus_type);
+	debugfs_remove(iio_debugfs_dentry);
+}
+
+#if defined(CONFIG_DEBUG_FS)
+static int iio_debugfs_open(struct inode *inode, struct file *file)
+{
+	if (inode->i_private)
+		file->private_data = inode->i_private;
+
+	return 0;
+}
+
+static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
+			      size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	char buf[20];
+	unsigned val = 0;
+	ssize_t len;
+	int ret;
+
+	ret = indio_dev->info->debugfs_reg_access(indio_dev,
+						  indio_dev->cached_reg_addr,
+						  0, &val);
+	if (ret)
+		dev_err(indio_dev->dev.parent, "%s: read failed\n", __func__);
+
+	len = snprintf(buf, sizeof(buf), "0x%X\n", val);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, len);
+}
+
+static ssize_t iio_debugfs_write_reg(struct file *file,
+		     const char __user *userbuf, size_t count, loff_t *ppos)
+{
+	struct iio_dev *indio_dev = file->private_data;
+	unsigned reg, val;
+	char buf[80];
+	int ret;
+
+	count = min_t(size_t, count, (sizeof(buf)-1));
+	if (copy_from_user(buf, userbuf, count))
+		return -EFAULT;
+
+	buf[count] = 0;
+
+	ret = sscanf(buf, "%i %i", &reg, &val);
+
+	switch (ret) {
+	case 1:
+		indio_dev->cached_reg_addr = reg;
+		break;
+	case 2:
+		indio_dev->cached_reg_addr = reg;
+		ret = indio_dev->info->debugfs_reg_access(indio_dev, reg,
+							  val, NULL);
+		if (ret) {
+			dev_err(indio_dev->dev.parent, "%s: write failed\n",
+				__func__);
+			return ret;
+		}
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return count;
+}
+
+static const struct file_operations iio_debugfs_reg_fops = {
+	.open = iio_debugfs_open,
+	.read = iio_debugfs_read_reg,
+	.write = iio_debugfs_write_reg,
+};
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+	debugfs_remove_recursive(indio_dev->debugfs_dentry);
 }

 static ssize_t iio_read_channel_ext_info(struct device *dev,
@@ -171,6 +254,49 @@ static ssize_t iio_write_channel_ext_info(struct device *dev,
 	return ext_info->write(indio_dev, this_attr->c, buf, len);
 }

+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	struct dentry *d;
+
+	if (indio_dev->info->debugfs_reg_access == NULL)
+		return 0;
+
+	if (IS_ERR(iio_debugfs_dentry))
+		return 0;
+
+	indio_dev->debugfs_dentry =
+		debugfs_create_dir(dev_name(&indio_dev->dev),
+				   iio_debugfs_dentry);
+	if (IS_ERR(indio_dev->debugfs_dentry))
+		return PTR_ERR(indio_dev->debugfs_dentry);
+
+	if (indio_dev->debugfs_dentry == NULL) {
+		dev_warn(indio_dev->dev.parent,
+			 "Failed to create debugfs directory\n");
+		return -EFAULT;
+	}
+
+	d = debugfs_create_file("direct_reg_access", 0644,
+				indio_dev->debugfs_dentry,
+				indio_dev, &iio_debugfs_reg_fops);
+	if (!d) {
+		iio_device_unregister_debugfs(indio_dev);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+#else
+static int iio_device_register_debugfs(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static void iio_device_unregister_debugfs(struct iio_dev *indio_dev)
+{
+}
+#endif /* CONFIG_DEBUG_FS */
+
 static ssize_t iio_read_channel_info(struct device *dev,
 				     struct device_attribute *attr,
 				     char *buf)
@@ -618,6 +744,7 @@ static void iio_dev_release(struct device *device)
 		iio_device_unregister_trigger_consumer(indio_dev);
 	iio_device_unregister_eventset(indio_dev);
 	iio_device_unregister_sysfs(indio_dev);
+	iio_device_unregister_debugfs(indio_dev);
 }

 static struct device_type iio_dev_type = {
@@ -734,11 +861,17 @@ int iio_device_register(struct iio_dev *indio_dev)
 	/* configure elements for the chrdev */
 	indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);

+	ret = iio_device_register_debugfs(indio_dev);
+	if (ret) {
+		dev_err(indio_dev->dev.parent,
+			"Failed to register debugfs interfaces\n");
+		goto error_ret;
+	}
 	ret = iio_device_register_sysfs(indio_dev);
 	if (ret) {
 		dev_err(indio_dev->dev.parent,
 			"Failed to register sysfs interfaces\n");
-		goto error_ret;
+		goto error_unreg_debugfs;
 	}
 	ret = iio_device_register_eventset(indio_dev);
 	if (ret) {
@@ -765,6 +898,8 @@ error_unreg_eventset:
 	iio_device_unregister_eventset(indio_dev);
 error_free_sysfs:
 	iio_device_unregister_sysfs(indio_dev);
+error_unreg_debugfs:
+	iio_device_unregister_debugfs(indio_dev);
 error_ret:
 	return ret;
 }
--
1.7.0.4

[PATCH 2/3] iio: core: Avoid NULL pointer de-ref in case indio_dev->setup_ops are not in use

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

Drivers may not need setup_ops at all, so let the core supply
some empty ops.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/staging/iio/industrialio-core.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/staging/iio/industrialio-core.c b/drivers/staging/iio/industrialio-core.c
index 7256dd6..cc3c6dc 100644
--- a/drivers/staging/iio/industrialio-core.c
+++ b/drivers/staging/iio/industrialio-core.c
@@ -854,6 +854,8 @@ static const struct file_operations iio_buffer_fileops = {
 	.compat_ioctl = iio_ioctl,
 };

+static const struct iio_buffer_setup_ops noop_ring_setup_ops;
+
 int iio_device_register(struct iio_dev *indio_dev)
 {
 	int ret;
@@ -882,6 +884,10 @@ int iio_device_register(struct iio_dev *indio_dev)
 	if (indio_dev->modes & INDIO_BUFFER_TRIGGERED)
 		iio_device_register_trigger_consumer(indio_dev);

+	if ((indio_dev->modes & INDIO_ALL_BUFFER_MODES) &&
+		indio_dev->setup_ops == NULL)
+		indio_dev->setup_ops = &noop_ring_setup_ops;
+
 	ret = device_add(&indio_dev->dev);
 	if (ret < 0)
 		goto error_unreg_eventset;
--
1.7.0.4

[PATCH 3/3] iio: Convert platform_drivers to use module_platform_driver

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>

No functional changes.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
---
 drivers/staging/iio/adc/ad7606_par.c               |   13 +------------
 drivers/staging/iio/trigger/iio-trig-bfin-timer.c  |   12 +-----------
 drivers/staging/iio/trigger/iio-trig-gpio.c        |   12 +-----------
 .../staging/iio/trigger/iio-trig-periodic-rtc.c    |   12 +-----------
 4 files changed, 4 insertions(+), 45 deletions(-)

diff --git a/drivers/staging/iio/adc/ad7606_par.c b/drivers/staging/iio/adc/ad7606_par.c
index cff9756..bb152a8 100644
--- a/drivers/staging/iio/adc/ad7606_par.c
+++ b/drivers/staging/iio/adc/ad7606_par.c
@@ -173,18 +173,7 @@ static struct platform_driver ad7606_driver = {
 	},
 };

-static int __init ad7606_init(void)
-{
-	return platform_driver_register(&ad7606_driver);
-}
-
-static void __exit ad7606_cleanup(void)
-{
-	platform_driver_unregister(&ad7606_driver);
-}
-
-module_init(ad7606_init);
-module_exit(ad7606_cleanup);
+module_platform_driver(ad7606_driver);

 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 MODULE_DESCRIPTION("Analog Devices AD7606 ADC");
diff --git a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
index 1cbb25d..665653d 100644
--- a/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
+++ b/drivers/staging/iio/trigger/iio-trig-bfin-timer.c
@@ -232,17 +232,7 @@ static struct platform_driver iio_bfin_tmr_trigger_driver = {
 	.remove = __devexit_p(iio_bfin_tmr_trigger_remove),
 };

-static int __init iio_bfin_tmr_trig_init(void)
-{
-	return platform_driver_register(&iio_bfin_tmr_trigger_driver);
-}
-module_init(iio_bfin_tmr_trig_init);
-
-static void __exit iio_bfin_tmr_trig_exit(void)
-{
-	platform_driver_unregister(&iio_bfin_tmr_trigger_driver);
-}
-module_exit(iio_bfin_tmr_trig_exit);
+module_platform_driver(iio_bfin_tmr_trigger_driver);

 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
 MODULE_DESCRIPTION("Blackfin system timer based trigger for the iio subsystem");
diff --git a/drivers/staging/iio/trigger/iio-trig-gpio.c b/drivers/staging/iio/trigger/iio-trig-gpio.c
index f2a6559..a346594 100644
--- a/drivers/staging/iio/trigger/iio-trig-gpio.c
+++ b/drivers/staging/iio/trigger/iio-trig-gpio.c
@@ -160,17 +160,7 @@ static struct platform_driver iio_gpio_trigger_driver = {
 	},
 };

-static int __init iio_gpio_trig_init(void)
-{
-	return platform_driver_register(&iio_gpio_trigger_driver);
-}
-module_init(iio_gpio_trig_init);
-
-static void __exit iio_gpio_trig_exit(void)
-{
-	platform_driver_unregister(&iio_gpio_trigger_driver);
-}
-module_exit(iio_gpio_trig_exit);
+module_platform_driver(iio_gpio_trigger_driver);

 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
diff --git a/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c b/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c
index bd7416b..a80cf67 100644
--- a/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c
+++ b/drivers/staging/iio/trigger/iio-trig-periodic-rtc.c
@@ -195,18 +195,8 @@ static struct platform_driver iio_trig_periodic_rtc_driver = {
 	},
 };

-static int __init iio_trig_periodic_rtc_init(void)
-{
-	return platform_driver_register(&iio_trig_periodic_rtc_driver);
-}
-
-static void __exit iio_trig_periodic_rtc_exit(void)
-{
-	return platform_driver_unregister(&iio_trig_periodic_rtc_driver);
-}
+module_platform_driver(iio_trig_periodic_rtc_driver);

-module_init(iio_trig_periodic_rtc_init);
-module_exit(iio_trig_periodic_rtc_exit);
 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
 MODULE_DESCRIPTION("Periodic realtime clock  trigger for the iio subsystem");
 MODULE_LICENSE("GPL v2");
--
1.7.0.4