--- /dev/null
+This binding is derived from clock bindings, and based on suggestions
+from Lars-Peter Clausen [1].
+
+Sources of IIO channels can be represented by any node in the device
+tree. Those nodes are designated as IIO providers. IIO consumer
+nodes use a phandle and IIO specifier pair to connect IIO provider
+outputs to IIO inputs. Similar to the gpio specifiers, an IIO
+specifier is an array of one or more cells identifying the IIO
+output on a device. The length of an IIO specifier is defined by the
+value of a #io-channel-cells property in the IIO provider node.
+
+[1] http://marc.info/?l=linux-iio&m=135902119507483&w=2
+
+==IIO providers==
+
+Required properties:
+#io-channel-cells: Number of cells in an IIO specifier; Typically 0 for nodes
+ with a single IIO output and 1 for nodes with multiple
+ IIO outputs.
+
+Example for a simple configuration with no trigger:
+
+ adc: voltage-sensor@35 {
+ compatible = "maxim,max1139";
+ reg = <0x35>;
+ #io-channel-cells = <1>;
+ };
+
+Example for a configuration with trigger:
+
+ adc@35 {
+ compatible = "some-vendor,some-adc";
+ reg = <0x35>;
+
+ adc1: iio-device@0 {
+ #io-channel-cells = <1>;
+ /* other properties */
+ };
+ adc2: iio-device@1 {
+ #io-channel-cells = <1>;
+ /* other properties */
+ };
+ };
+
+==IIO consumers==
+
+Required properties:
+io-channels: List of phandle and IIO specifier pairs, one pair
+ for each IIO input to the device. Note: if the
+ IIO provider specifies '0' for #io-channel-cells,
+ then only the phandle portion of the pair will appear.
+
+Optional properties:
+io-channel-names:
+ List of IIO input name strings sorted in the same
+ order as the io-channels property. Consumers drivers
+ will use io-channel-names to match IIO input names
+ with IIO specifiers.
+io-channel-ranges:
+ Empty property indicating that child nodes can inherit named
+ IIO channels from this node. Useful for bus nodes to provide
+ and IIO channel to their children.
+
+For example:
+
+ device {
+ io-channels = <&adc 1>, <&ref 0>;
+ io-channel-names = "vcc", "vdd";
+ };
+
+This represents a device with two IIO inputs, named "vcc" and "vdd".
+The vcc channel is connected to output 1 of the &adc device, and the
+vdd channel is connected to output 0 of the &ref device.
+
+==Example==
+
+ adc: max1139@35 {
+ compatible = "maxim,max1139";
+ reg = <0x35>;
+ #io-channel-cells = <1>;
+ };
+
+ ...
+
+ iio_hwmon {
+ compatible = "iio-hwmon";
+ io-channels = <&adc 0>, <&adc 1>, <&adc 2>,
+ <&adc 3>, <&adc 4>, <&adc 5>,
+ <&adc 6>, <&adc 7>, <&adc 8>,
+ <&adc 9>;
+ };
+
+ some_consumer {
+ compatible = "some-consumer";
+ io-channels = <&adc 10>, <&adc 11>;
+ io-channel-names = "adc1", "adc2";
+ };
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/mutex.h>
+#include <linux/of.h>
#include <linux/iio/iio.h>
#include "iio_core.h"
return chan;
}
+#ifdef CONFIG_OF
+
+static int iio_dev_node_match(struct device *dev, void *data)
+{
+ return dev->of_node == data && dev->type == &iio_device_type;
+}
+
+static int __of_iio_channel_get(struct iio_channel *channel,
+ struct device_node *np, int index)
+{
+ struct device *idev;
+ struct iio_dev *indio_dev;
+ int err;
+ struct of_phandle_args iiospec;
+
+ err = of_parse_phandle_with_args(np, "io-channels",
+ "#io-channel-cells",
+ index, &iiospec);
+ if (err)
+ return err;
+
+ idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
+ iio_dev_node_match);
+ of_node_put(iiospec.np);
+ if (idev == NULL)
+ return -EPROBE_DEFER;
+
+ 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) {
+ return -EINVAL;
+ goto err_put;
+ }
+ channel->channel = &indio_dev->channels[index];
+
+ return 0;
+
+err_put:
+ iio_device_put(indio_dev);
+ return err;
+}
+
+static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
+{
+ struct iio_channel *channel;
+ int err;
+
+ if (index < 0)
+ return ERR_PTR(-EINVAL);
+
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+ if (channel == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ err = __of_iio_channel_get(channel, np, index);
+ if (err)
+ goto err_free_channel;
+
+ return channel;
+
+err_free_channel:
+ kfree(channel);
+ return ERR_PTR(err);
+}
+
+static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
+ const char *name)
+{
+ struct iio_channel *chan = NULL;
+
+ /* Walk up the tree of devices looking for a matching iio channel */
+ while (np) {
+ int index = 0;
+
+ /*
+ * For named iio channels, first look up the name in the
+ * "io-channel-names" property. If it cannot be found, the
+ * index will be an error code, and of_iio_channel_get()
+ * will fail.
+ */
+ if (name)
+ index = of_property_match_string(np, "io-channel-names",
+ name);
+ chan = of_iio_channel_get(np, index);
+ if (!IS_ERR(chan))
+ break;
+ else if (name && index >= 0) {
+ pr_err("ERROR: could not get IIO channel %s:%s(%i)\n",
+ np->full_name, name ? name : "", index);
+ return chan;
+ }
+
+ /*
+ * No matching IIO channel found on this node.
+ * If the parent node has a "io-channel-ranges" property,
+ * then we can try one of its channels.
+ */
+ np = np->parent;
+ if (np && !of_get_property(np, "io-channel-ranges", NULL))
+ break;
+ }
+ return chan;
+}
+
+static struct iio_channel *of_iio_channel_get_all(struct device *dev)
+{
+ struct iio_channel *chans;
+ int i, mapind, nummaps = 0;
+ int ret;
+
+ do {
+ ret = of_parse_phandle_with_args(dev->of_node,
+ "io-channels",
+ "#io-channel-cells",
+ nummaps, NULL);
+ if (ret < 0)
+ break;
+ } while (++nummaps);
+
+ if (nummaps == 0) /* no error, return NULL to search map table */
+ return NULL;
+
+ /* NULL terminated array to save passing size */
+ chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
+ if (chans == NULL)
+ return ERR_PTR(-ENOMEM);
+
+ /* Search for OF matches */
+ for (mapind = 0; mapind < nummaps; mapind++) {
+ ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
+ mapind);
+ if (ret)
+ goto error_free_chans;
+ }
+ return chans;
+
+error_free_chans:
+ for (i = 0; i < mapind; i++)
+ iio_device_put(chans[i].indio_dev);
+ kfree(chans);
+ return ERR_PTR(ret);
+}
+
+#else /* CONFIG_OF */
+
+static inline struct iio_channel *
+of_iio_channel_get_by_name(struct device_node *np, const char *name)
+{
+ return NULL;
+}
+
+static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
+{
+ return NULL;
+}
+
+#endif /* CONFIG_OF */
static struct iio_channel *iio_channel_get_sys(const char *name,
const char *channel_name)
const char *channel_name)
{
const char *name = dev ? dev_name(dev) : NULL;
+ struct iio_channel *channel;
+ if (dev) {
+ channel = of_iio_channel_get_by_name(dev->of_node,
+ channel_name);
+ if (channel != NULL)
+ return channel;
+ }
return iio_channel_get_sys(name, channel_name);
}
EXPORT_SYMBOL_GPL(iio_channel_get);
if (dev == NULL)
return ERR_PTR(-EINVAL);
+
+ chans = of_iio_channel_get_all(dev);
+ if (chans)
+ return chans;
+
name = dev_name(dev);
mutex_lock(&iio_map_list_lock);
projects / firefly-linux-kernel-4.4.55.git / commitdiff