iio: Add OF support
authorGuenter Roeck <linux@roeck-us.net>
Thu, 7 Feb 2013 17:09:00 +0000 (17:09 +0000)
committerJonathan Cameron <jic23@kernel.org>
Sat, 16 Mar 2013 10:17:59 +0000 (10:17 +0000)
Provide bindings and parse OF data during initialization.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Documentation/devicetree/bindings/iio/iio-bindings.txt [new file with mode: 0644]
drivers/iio/iio_core.h
drivers/iio/industrialio-core.c
drivers/iio/inkern.c

diff --git a/Documentation/devicetree/bindings/iio/iio-bindings.txt b/Documentation/devicetree/bindings/iio/iio-bindings.txt
new file mode 100644 (file)
index 0000000..0b447d9
--- /dev/null
@@ -0,0 +1,97 @@
+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";
+       };
index f652e6ae5a35991b20f7be95eb8c2cafa49debf4..05c1b74502a37265c86a23edaf97d4e602ead575 100644 (file)
@@ -18,6 +18,7 @@
 struct iio_chan_spec;
 struct iio_dev;
 
+extern struct device_type iio_device_type;
 
 int __iio_add_chan_devattr(const char *postfix,
                           struct iio_chan_spec const *chan,
index 8848f16c547b07a44e2de1f1834283b8f88e8fb5..6d8b027856471ff76ca19850aa719536baf5937c 100644 (file)
@@ -847,7 +847,7 @@ static void iio_dev_release(struct device *device)
        kfree(indio_dev);
 }
 
-static struct device_type iio_dev_type = {
+struct device_type iio_device_type = {
        .name = "iio_device",
        .release = iio_dev_release,
 };
@@ -869,7 +869,7 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
 
        if (dev) {
                dev->dev.groups = dev->groups;
-               dev->dev.type = &iio_dev_type;
+               dev->dev.type = &iio_device_type;
                dev->dev.bus = &iio_bus_type;
                device_initialize(&dev->dev);
                dev_set_drvdata(&dev->dev, (void *)dev);
@@ -960,6 +960,10 @@ int iio_device_register(struct iio_dev *indio_dev)
 {
        int ret;
 
+       /* If the calling driver did not initialize of_node, do it here */
+       if (!indio_dev->dev.of_node && indio_dev->dev.parent)
+               indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
+
        /* configure elements for the chrdev */
        indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
 
index b289915b8469774664ccd181cc0fa9883dda35d8..795d100b4c36fea7c82785e4f4b8545a13ff7eab 100644 (file)
@@ -10,6 +10,7 @@
 #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"
@@ -92,6 +93,164 @@ static const struct iio_chan_spec
        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)
@@ -150,7 +309,14 @@ struct iio_channel *iio_channel_get(struct device *dev,
                                    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);
@@ -173,6 +339,11 @@ struct iio_channel *iio_channel_get_all(struct device *dev)
 
        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);