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Message-ID: <20130220192458.GA29247@roeck-us.net>
Date: Wed, 20 Feb 2013 11:24:58 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Jonathan Cameron <jic23@...nel.org>
Cc: Rob Herring <robherring2@...il.com>, linux-iio@...r.kernel.org,
Lars-Peter Clausen <lars@...afoo.de>,
Anton Vorontsov <cbou@...l.ru>,
David Woodhouse <dwmw2@...radead.org>,
devicetree-discuss@...ts.ozlabs.org,
Tomasz Figa <tomasz.figa@...il.com>,
Rob Herring <rob.herring@...xeda.com>,
linux-kernel@...r.kernel.org, Chanwoo Choi <cw00.choi@...sung.com>,
MyungJoo Ham <myungjoo.ham@...sung.com>,
Naveen Krishna Chatradhi <ch.naveen@...sung.com>
Subject: Re: [PATCH v5] iio: Add OF support
On Wed, Feb 20, 2013 at 06:51:08PM +0000, Jonathan Cameron wrote:
>
>
> Guenter Roeck <linux@...ck-us.net> 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@...ck-us.net>
> >> > ---
> >> > 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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