iio: Add OF support

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>

3 files changed, 178 insertions, 2 deletions

diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
index f652e6ae5a35..05c1b74502a3 100644
--- a/drivers/iio/iio_core.h
+++ b/drivers/iio/iio_core.h
@@ -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,
diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 8848f16c547b..6d8b02785647 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -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);
 
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index b289915b8469..795d100b4c36 100644
--- a/drivers/iio/inkern.c
+++ b/drivers/iio/inkern.c
@@ -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);