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>hifive-unleashed-5.1
Guenter Roeck
Jonathan Cameron
parent
cddc1424f3
commit
17d82b47a2
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@ -0,0 +1,97 @@
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This binding is derived from clock bindings, and based on suggestions
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from Lars-Peter Clausen [1].
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Sources of IIO channels can be represented by any node in the device
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tree. Those nodes are designated as IIO providers. IIO consumer
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nodes use a phandle and IIO specifier pair to connect IIO provider
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outputs to IIO inputs. Similar to the gpio specifiers, an IIO
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specifier is an array of one or more cells identifying the IIO
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output on a device. The length of an IIO specifier is defined by the
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value of a #io-channel-cells property in the IIO provider node.
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[1] http://marc.info/?l=linux-iio&m=135902119507483&w=2
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==IIO providers==
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Required properties:
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#io-channel-cells: Number of cells in an IIO specifier; Typically 0 for nodes
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with a single IIO output and 1 for nodes with multiple
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IIO outputs.
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Example for a simple configuration with no trigger:
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adc: voltage-sensor@35 {
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compatible = "maxim,max1139";
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reg = <0x35>;
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#io-channel-cells = <1>;
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};
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Example for a configuration with trigger:
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adc@35 {
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compatible = "some-vendor,some-adc";
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reg = <0x35>;
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adc1: iio-device@0 {
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#io-channel-cells = <1>;
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/* other properties */
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};
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adc2: iio-device@1 {
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#io-channel-cells = <1>;
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/* other properties */
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};
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};
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==IIO consumers==
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Required properties:
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io-channels: List of phandle and IIO specifier pairs, one pair
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for each IIO input to the device. Note: if the
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IIO provider specifies '0' for #io-channel-cells,
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then only the phandle portion of the pair will appear.
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Optional properties:
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io-channel-names:
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List of IIO input name strings sorted in the same
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order as the io-channels property. Consumers drivers
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will use io-channel-names to match IIO input names
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with IIO specifiers.
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io-channel-ranges:
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Empty property indicating that child nodes can inherit named
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IIO channels from this node. Useful for bus nodes to provide
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and IIO channel to their children.
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For example:
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device {
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io-channels = <&adc 1>, <&ref 0>;
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io-channel-names = "vcc", "vdd";
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};
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This represents a device with two IIO inputs, named "vcc" and "vdd".
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The vcc channel is connected to output 1 of the &adc device, and the
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vdd channel is connected to output 0 of the &ref device.
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==Example==
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adc: max1139@35 {
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compatible = "maxim,max1139";
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reg = <0x35>;
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#io-channel-cells = <1>;
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};
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...
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iio_hwmon {
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compatible = "iio-hwmon";
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io-channels = <&adc 0>, <&adc 1>, <&adc 2>,
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<&adc 3>, <&adc 4>, <&adc 5>,
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<&adc 6>, <&adc 7>, <&adc 8>,
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<&adc 9>;
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};
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some_consumer {
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compatible = "some-consumer";
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io-channels = <&adc 10>, <&adc 11>;
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io-channel-names = "adc1", "adc2";
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};
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@ -18,6 +18,7 @@
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struct iio_chan_spec;
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struct iio_dev;
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extern struct device_type iio_device_type;
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int __iio_add_chan_devattr(const char *postfix,
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struct iio_chan_spec const *chan,
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@ -847,7 +847,7 @@ static void iio_dev_release(struct device *device)
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kfree(indio_dev);
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}
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static struct device_type iio_dev_type = {
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struct device_type iio_device_type = {
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.name = "iio_device",
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.release = iio_dev_release,
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};
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@ -869,7 +869,7 @@ struct iio_dev *iio_device_alloc(int sizeof_priv)
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if (dev) {
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dev->dev.groups = dev->groups;
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dev->dev.type = &iio_dev_type;
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dev->dev.type = &iio_device_type;
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dev->dev.bus = &iio_bus_type;
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device_initialize(&dev->dev);
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dev_set_drvdata(&dev->dev, (void *)dev);
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@ -960,6 +960,10 @@ int iio_device_register(struct iio_dev *indio_dev)
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{
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int ret;
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/* If the calling driver did not initialize of_node, do it here */
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if (!indio_dev->dev.of_node && indio_dev->dev.parent)
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indio_dev->dev.of_node = indio_dev->dev.parent->of_node;
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/* configure elements for the chrdev */
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indio_dev->dev.devt = MKDEV(MAJOR(iio_devt), indio_dev->id);
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@ -10,6 +10,7 @@
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#include <linux/export.h>
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#include <linux/slab.h>
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#include <linux/mutex.h>
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#include <linux/of.h>
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#include <linux/iio/iio.h>
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#include "iio_core.h"
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@ -92,6 +93,164 @@ static const struct iio_chan_spec
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return chan;
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}
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#ifdef CONFIG_OF
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static int iio_dev_node_match(struct device *dev, void *data)
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{
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return dev->of_node == data && dev->type == &iio_device_type;
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}
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static int __of_iio_channel_get(struct iio_channel *channel,
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struct device_node *np, int index)
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{
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struct device *idev;
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struct iio_dev *indio_dev;
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int err;
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struct of_phandle_args iiospec;
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err = of_parse_phandle_with_args(np, "io-channels",
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"#io-channel-cells",
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index, &iiospec);
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if (err)
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return err;
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idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
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iio_dev_node_match);
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of_node_put(iiospec.np);
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if (idev == NULL)
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return -EPROBE_DEFER;
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indio_dev = dev_to_iio_dev(idev);
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channel->indio_dev = indio_dev;
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index = iiospec.args_count ? iiospec.args[0] : 0;
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if (index >= indio_dev->num_channels) {
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return -EINVAL;
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goto err_put;
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}
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channel->channel = &indio_dev->channels[index];
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return 0;
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err_put:
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iio_device_put(indio_dev);
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return err;
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}
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static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
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{
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struct iio_channel *channel;
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int err;
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if (index < 0)
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return ERR_PTR(-EINVAL);
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channel = kzalloc(sizeof(*channel), GFP_KERNEL);
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if (channel == NULL)
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return ERR_PTR(-ENOMEM);
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err = __of_iio_channel_get(channel, np, index);
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if (err)
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goto err_free_channel;
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return channel;
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err_free_channel:
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kfree(channel);
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return ERR_PTR(err);
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}
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static struct iio_channel *of_iio_channel_get_by_name(struct device_node *np,
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const char *name)
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{
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struct iio_channel *chan = NULL;
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/* Walk up the tree of devices looking for a matching iio channel */
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while (np) {
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int index = 0;
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/*
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* For named iio channels, first look up the name in the
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* "io-channel-names" property. If it cannot be found, the
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* index will be an error code, and of_iio_channel_get()
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* will fail.
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*/
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if (name)
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index = of_property_match_string(np, "io-channel-names",
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name);
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chan = of_iio_channel_get(np, index);
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if (!IS_ERR(chan))
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break;
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else if (name && index >= 0) {
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pr_err("ERROR: could not get IIO channel %s:%s(%i)\n",
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np->full_name, name ? name : "", index);
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return chan;
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}
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/*
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* No matching IIO channel found on this node.
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* If the parent node has a "io-channel-ranges" property,
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* then we can try one of its channels.
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*/
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np = np->parent;
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if (np && !of_get_property(np, "io-channel-ranges", NULL))
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break;
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}
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return chan;
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}
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static struct iio_channel *of_iio_channel_get_all(struct device *dev)
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{
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struct iio_channel *chans;
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int i, mapind, nummaps = 0;
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int ret;
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do {
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ret = of_parse_phandle_with_args(dev->of_node,
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"io-channels",
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"#io-channel-cells",
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nummaps, NULL);
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if (ret < 0)
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break;
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} while (++nummaps);
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if (nummaps == 0) /* no error, return NULL to search map table */
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return NULL;
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/* NULL terminated array to save passing size */
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chans = kcalloc(nummaps + 1, sizeof(*chans), GFP_KERNEL);
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if (chans == NULL)
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return ERR_PTR(-ENOMEM);
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/* Search for OF matches */
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for (mapind = 0; mapind < nummaps; mapind++) {
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ret = __of_iio_channel_get(&chans[mapind], dev->of_node,
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mapind);
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if (ret)
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goto error_free_chans;
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}
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return chans;
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error_free_chans:
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for (i = 0; i < mapind; i++)
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iio_device_put(chans[i].indio_dev);
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kfree(chans);
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return ERR_PTR(ret);
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}
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#else /* CONFIG_OF */
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static inline struct iio_channel *
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of_iio_channel_get_by_name(struct device_node *np, const char *name)
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{
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return NULL;
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}
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static inline struct iio_channel *of_iio_channel_get_all(struct device *dev)
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{
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return NULL;
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}
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#endif /* CONFIG_OF */
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static struct iio_channel *iio_channel_get_sys(const char *name,
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const char *channel_name)
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@ -150,7 +309,14 @@ struct iio_channel *iio_channel_get(struct device *dev,
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const char *channel_name)
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{
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const char *name = dev ? dev_name(dev) : NULL;
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struct iio_channel *channel;
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if (dev) {
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channel = of_iio_channel_get_by_name(dev->of_node,
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channel_name);
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if (channel != NULL)
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return channel;
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}
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return iio_channel_get_sys(name, channel_name);
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}
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EXPORT_SYMBOL_GPL(iio_channel_get);
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@ -173,6 +339,11 @@ struct iio_channel *iio_channel_get_all(struct device *dev)
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if (dev == NULL)
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return ERR_PTR(-EINVAL);
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chans = of_iio_channel_get_all(dev);
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if (chans)
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return chans;
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name = dev_name(dev);
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mutex_lock(&iio_map_list_lock);
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