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@xxxxxxxxxx>
---
Changes:
- Move of_xlate function from iio_dev to iio_info structure,
where all the other callbacks are.
drivers/iio/inkern.c | 33 ++++++++++++++++++++++++++++-----
include/linux/iio/iio.h | 8 ++++++++
2 files changed, 36 insertions(+), 5 deletions(-)
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index f084610..866fe90 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -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)
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 15dc6bc..3642ce7 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -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);
};
/**
--
1.9.1
--
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