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iio: inkern: Add of_xlate function to struct iio_info 

When #iio-cells is greater than '0', the driver could provide
a custom of_xlate function that reads the *args* and returns
the appropriate index in registered IIO channels array.

Add simple translation function, suitable for the most 1:1
mapped channels in IIO chips, and use it when driver did not
provide custom implementation.

Signed-off-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Ivan T. Ivanov 2014-10-22 18:29:43 +03:00 committed by Jonathan Cameron
parent a9bef75013
commit acd8256723
2 changed files with 36 additions and 5 deletions
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33
drivers/iio/inkern.c
View File

@ -100,6 +100,28 @@ static int iio_dev_node_match(struct device *dev, void *data)
return dev->of_node == data && dev->type == &iio_device_type;
}
/**
* __of_iio_simple_xlate - translate iiospec to the IIO channel index
* @indio_dev: pointer to the iio_dev structure
* @iiospec: IIO specifier as found in the device tree
*
* This is simple translation function, suitable for the most 1:1 mapped
* channels in IIO chips. This function performs only one sanity check:
* whether IIO index is less than num_channels (that is specified in the
* iio_dev).
*/
static int __of_iio_simple_xlate(struct iio_dev *indio_dev,
const struct of_phandle_args *iiospec)
{
if (!iiospec->args_count)
return 0;
if (iiospec->args[0] >= indio_dev->num_channels)
return -EINVAL;
return iiospec->args[0];
}
static int __of_iio_channel_get(struct iio_channel *channel,
struct device_node *np, int index)
{
@ -122,18 +144,19 @@ static int __of_iio_channel_get(struct iio_channel *channel,
indio_dev = dev_to_iio_dev(idev);
channel->indio_dev = indio_dev;
index = iiospec.args_count ? iiospec.args[0] : 0;
if (index >= indio_dev->num_channels) {
err = -EINVAL;
if (indio_dev->info->of_xlate)
index = indio_dev->info->of_xlate(indio_dev, &iiospec);
else
index = __of_iio_simple_xlate(indio_dev, &iiospec);
if (index < 0)
goto err_put;
}
channel->channel = &indio_dev->channels[index];
return 0;
err_put:
iio_device_put(indio_dev);
return err;
return index;
}
static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)

8
include/linux/iio/iio.h
View File

@ -13,6 +13,7 @@
#include <linux/device.h>
#include <linux/cdev.h>
#include <linux/iio/types.h>
#include <linux/of.h>
/* IIO TODO LIST */
/*
* Provide means of adjusting timer accuracy.
@ -326,6 +327,11 @@ struct iio_dev;
* @update_scan_mode: function to configure device and scan buffer when
* channels have changed
* @debugfs_reg_access: function to read or write register value of device
* @of_xlate: function pointer to obtain channel specifier index.
* When #iio-cells is greater than '0', the driver could
* provide a custom of_xlate function that reads the
* *args* and returns the appropriate index in registered
* IIO channels array.
**/
struct iio_info {
struct module *driver_module;
@ -385,6 +391,8 @@ struct iio_info {
int (*debugfs_reg_access)(struct iio_dev *indio_dev,
unsigned reg, unsigned writeval,
unsigned *readval);
int (*of_xlate)(struct iio_dev *indio_dev,
const struct of_phandle_args *iiospec);
};
/**