Re: [PATCH v5] iio: Add OF support

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On Wed, Feb 20, 2013 at 06:51:08PM +0000, Jonathan Cameron wrote:
> 
> 
> Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
> 
> >On Wed, Feb 20, 2013 at 11:38:22AM -0600, Rob Herring wrote:
> >> On 02/07/2013 11:09 AM, Guenter Roeck wrote:
> >> > Provide bindings and parse OF data during initialization.
> >> > 
> >> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> >> > ---
> >> > 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].
> >> 
> >> Bindings are an ABI. It should not be a WIP. What part is a WIP?
> >> 
> >The text is copied from clock bindings. I do not claim to be better
> >than the clock subsystem is doing in respect to its bindings.
> >
> >I'll be more than happy to take this text out if it is a source of
> >contention,
> >even more so if that is what is holding up the patch. Jonathan ?
> I don't really care about the wording though can see why Rob asked!
> We will probably have other stuff to add anyway.
> 

Quite likely - for example, I did not add io-output-names since I did not
know what to do with it.

What do you want me to do ? Submit another version with the sentence deleted,
or keep it as-is ?

Thanks,
Guenter

> Jonathan
> >
> >Thanks,
> >Guenter
> >
> >> Knowing nothing about IIO, the binding seems sane.
> >> 
> >> Rob
> >> 
> >> > +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);
> >> > 
> >> 
> >> 
> 
> -- 
> Sent from my Android phone with K-9 Mail. Please excuse my brevity.
> 
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