Re: [PATCH v5] iio: Add OF support

Guenter Roeck
2013-02-20T16:53:30Z

On Fri, Feb 08, 2013 at 08:30:48AM +0000, Jonathan Cameron wrote:
> On 07/02/13 17:09, Guenter Roeck wrote:
> >Provide bindings and parse OF data during initialization.
> >
> >Signed-off-by: Guenter Roeck <linux@roeck-us.net>
> Looks fine to me. Will give it a few more days to see what others
> have to say.
>
Hi Jonathan,

Any further feedback on this ? If there is anything else I need to do
to get it accepted, please let me know.

Thanks,
Guenter

> Thanks Guenter
> >---
> >v5:
> >- Updated examples in bindings.
> >v4:
> >- Fixed wrong parameter to dummy of_iio_channel_get_by_name if CONFIG_OF is
> > undefined, and wrong return value.
> >- Initialize indio_dev->of_node in iio_device_register if the calling driver
> > neglected to do it.
> >v3:
> >- Cleaned up documentation (formatting, left-over clock references)
> >- Updated bindings description to permit sub-devices
> >- When searching for iio devices, use the pointer to the iio device type instead
> > of strcmp. Rename iio_dev_type to iio_device_type (to match other device
> > types) and make it global for that purpose. Check the OF node first, then the
> > device type, as the node is less likely to match.
> >- Move the common code in of_iio_channel_get and of_iio_channel_get_all to
> > __of_iio_channel_get.
> >- Return NULL from of_iio_channel_get_by_name if nothing is found, or
> > an error if there is a problem with consistency or if the provider device is
> > not yet available.
> >- In iio_channel_get, return if of_iio_channel_get_by_name() returns a channel
> > or an error, and continue otherwise.
> >v2:
> >- Rebased to iio/togreg
> >- 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
> >- Use regulator to get vref for max1363 driver.
> >
> > .../devicetree/bindings/iio/iio-bindings.txt | 97 +++++++++++
> > drivers/iio/iio_core.h | 1 +
> > drivers/iio/industrialio-core.c | 8 +-
> > drivers/iio/inkern.c | 171 ++++++++++++++++++++
> > 4 files changed, 275 insertions(+), 2 deletions(-)
> > 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..1182845
> >--- /dev/null
> >+++ b/Documentation/devicetree/bindings/iio/iio-bindings.txt
> >@@ -0,0 +1,97 @@
> >+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 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";
> >+ };
> >diff --git a/drivers/iio/iio_core.h b/drivers/iio/iio_core.h
> >index f652e6a..05c1b74 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 8848f16..6d8b027 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 b289915..795d100 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);
> >
>
>