[PATCH v2 4/4] iio: Add OF support
Guenter Roeck
linux at roeck-us.net
Sun Feb 3 11:59:40 EST 2013
Provide bindings and parse OF data during initialization.
Signed-off-by: Guenter Roeck <linux at roeck-us.net>
---
- Documentation update per feedback
- Dropped io-channel-output-names from the bindings document. The property is
not used in the code, and it is not entirely clear what it would be used for.
If there is a need for it, we can add it back in later on.
- Don't export OF specific API calls
- For OF support, no longer depend on iio_map
- Add #ifdef CONFIG_OF where appropriate, and ensure that the code still builds
if it is not selected.
- Change iio_channel_get to take device pointer as argument instead of device
name. Retain old API as of_iio_channel_get_sys.
- iio_channel_get now works for both OF and non-OF configurations.
.../devicetree/bindings/iio/iio-bindings.txt | 76 ++++++++
drivers/iio/inkern.c | 186 ++++++++++++++++++++
2 files changed, 262 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/iio-bindings.txt
diff --git a/Documentation/devicetree/bindings/iio/iio-bindings.txt b/Documentation/devicetree/bindings/iio/iio-bindings.txt
new file mode 100644
index 0000000..58df5f6
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/iio-bindings.txt
@@ -0,0 +1,76 @@
+This binding is a work-in-progress. It 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 clock 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.
+
+For example:
+
+ adc: adc at 35 {
+ compatible = "maxim,max1139";
+ reg = <0x35>;
+ #io-channel-cells = <1>;
+ };
+
+==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 #clock-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 at 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>, <&adc 10>, <&adc 11>;
+ io-channel-names = "vcc", "vdd", "vref", "1.2V";
+ };
diff --git a/drivers/iio/inkern.c b/drivers/iio/inkern.c
index b289915..d48f2a8 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 +93,179 @@ static const struct iio_chan_spec
return chan;
}
+#ifdef CONFIG_OF
+
+static int iio_dev_node_match(struct device *dev, void *data)
+{
+ return !strcmp(dev->type->name, "iio_device") && dev->of_node == data;
+}
+
+static struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
+{
+ struct iio_channel *channel;
+ struct device *idev;
+ struct iio_dev *indio_dev;
+ int err;
+ struct of_phandle_args iiospec;
+
+ if (index < 0)
+ return ERR_PTR(-EINVAL);
+
+ err = of_parse_phandle_with_args(np, "io-channels",
+ "#io-channel-cells",
+ index, &iiospec);
+ if (err)
+ return ERR_PTR(err);
+
+ idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
+ iio_dev_node_match);
+ of_node_put(iiospec.np);
+ if (idev == NULL)
+ return ERR_PTR(-EPROBE_DEFER);
+
+ indio_dev = dev_to_iio_dev(idev);
+
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+ if (channel == NULL) {
+ err = -ENOMEM;
+ goto err_no_mem;
+ }
+
+ channel->indio_dev = indio_dev;
+ index = iiospec.args_count ? iiospec.args[0] : 0;
+ if (index >= indio_dev->num_channels) {
+ err = -EINVAL;
+ goto err_no_channel;
+ }
+ channel->channel = &indio_dev->channels[index];
+
+ return channel;
+
+err_no_channel:
+ kfree(channel);
+err_no_mem:
+ iio_device_put(indio_dev);
+ 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 = ERR_PTR(-ENOENT);
+
+ /* 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 = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL);
+ if (chans == NULL) {
+ ret = -ENOMEM;
+ goto error;
+ }
+
+ /* Search for OF matches */
+ for (mapind = 0; mapind < nummaps; mapind++) {
+ struct device *idev;
+ struct iio_dev *indio_dev;
+ int channel;
+ struct of_phandle_args iiospec;
+
+ ret = of_parse_phandle_with_args(dev->of_node,
+ "io-channels",
+ "#io-channel-cells",
+ mapind, &iiospec);
+ if (ret)
+ goto error_free_chans;
+
+ idev = bus_find_device(&iio_bus_type, NULL, iiospec.np,
+ iio_dev_node_match);
+ of_node_put(iiospec.np);
+ if (idev == NULL) {
+ ret = -EPROBE_DEFER;
+ goto error_free_chans;
+ }
+ indio_dev = dev_to_iio_dev(idev);
+ channel = iiospec.args_count ? iiospec.args[0] : 0;
+ if (channel >= indio_dev->num_channels) {
+ ret = -EINVAL;
+ goto error_free_chans;
+ }
+ chans[mapind].indio_dev = indio_dev;
+ chans[mapind].channel = &indio_dev->channels[channel];
+ }
+ return chans;
+
+error_free_chans:
+ for (i = 0; i < mapind; i++)
+ iio_device_put(chans[i].indio_dev);
+ kfree(chans);
+error:
+ 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 ERR_PTR(-ENOENT);
+}
+
+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 +324,14 @@ 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 (!IS_ERR(channel))
+ return channel;
+ }
return iio_channel_get_sys(name, channel_name);
}
EXPORT_SYMBOL_GPL(iio_channel_get);
@@ -173,6 +354,11 @@ 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);
--
1.7.9.7
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