[RFC 10/11] iio: Add OF support
Guenter Roeck
linux at roeck-us.net
Sat Feb 2 01:33:07 EST 2013
On Fri, Feb 01, 2013 at 12:58:02PM +0100, Lars-Peter Clausen wrote:
> 013 10:43 PM, Guenter Roeck wrote:
> > Provide bindings, new API access functions, and parse OF data
> > during initialization.
> >
>
> Hi Guenter,
>
> Thanks for taking care of this.
>
> I'd prefer to have only one iio_get_channel which handles both the dt and the
> non-dt case. Otherwise we'll soon have constructs like
>
> if (dev->of_node)
> chan = of_iio_get_channel(dev->of_node, 1);
> else
> chan = iio_get_channel(dev_name(dev), "vcc");
>
> appearing all over the place in drivers code. I'd keep the actual
> implementation pretty close to what the clk framework does. E.g. take a look at
> of_clk_get_by_name() and clk_get() in clkdev.c. And don't take a detour via the
> iio_map lookup for the devicetree case, just loop over all IIO devices and
> match by of_node. This should allow us to simplify the code quite a bit.
>
Yes, I just could not figure out how to loop over the list of iio devices. That
is why I hijacked iio_map which does provide a list.
Any hints ?
Thanks,
Guenter
> - Lars
>
> On 01/31/2
>
> > Signed-off-by: Guenter Roeck <linux at roeck-us.net>
> > ---
> > .../devicetree/bindings/iio/iio-bindings.txt | 97 ++++++++
> > drivers/iio/inkern.c | 241 ++++++++++++++++----
> > include/linux/iio/consumer.h | 8 +
> > 3 files changed, 299 insertions(+), 47 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..0f51c95
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/iio-bindings.txt
> > @@ -0,0 +1,97 @@
> > +This binding is a work-in-progress, and are based on clock bindings and
> > +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 more 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.
> > +
> > +Optional properties:
> > +io-channel-output-names:
> > + Recommended to be a list of strings of IIO output signal
> > + names indexed by the first cell in the IIO specifier.
> > + However, the meaning of io-channel-output-names is domain
> > + specific to the IIO provider, and is only provided to
> > + encourage using the same meaning for the majority of IIO
> > + providers. This format may not work for IIO providers
> > + using a complex IIO specifier format. In those cases it
> > + is recommended to omit this property and create a binding
> > + specific names property.
> > +
> > + IIO consumer nodes must never directly reference
> > + the provider's io-channel-output-names property.
> > +
> > +For example:
> > +
> > + adc: adc at 35 {
> > + compatible = "maxim,max1139";
> > + reg = <0x35>;
> > + #io-channel-cells = <1>;
> > + io-channel-output-names = "adc1", "adc2";
> > + };
> > +
> > +- this node defines a device with two named IIO outputs, the first named
> > + "adc1" and the second named "adc2". Consumer nodes always reference
> > + IIO channels by index. The names should reflect the IIO output signal
> > + names for the device.
> > +
> > +==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 c42aba6..af80a18 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"
> > @@ -26,13 +27,55 @@ struct iio_map_internal {
> > static LIST_HEAD(iio_map_list);
> > static DEFINE_MUTEX(iio_map_list_lock);
> >
> > +static struct iio_map *iio_map_of_init(struct iio_dev *idev)
> > +{
>
> To be honest I find this whole function a bit confusing. If we are using
> devicetree, we shouldn't need to register iio_map. Maybe just skip over
> io-channel-output-names for now, until we figure out if we really need this and
> what for.
>
> > + struct device_node *np = idev->dev.of_node;
> > + struct iio_map *maps;
> > + u32 cells, channels = 1;
> > + int names, i, ret;
> > +
> > + ret = of_property_read_u32(np, "#io-channel-cells", &cells);
> > + if (ret < 0 || cells > 1)
> > + return ERR_PTR(-EINVAL);
> > +
> > + names = of_property_count_strings(np, "io-channel-output-names");
> > + if (names < 0)
> > + names = 0;
> > +
> > + if (channels < names)
> > + channels = names;
> > +
> > + maps = devm_kzalloc(&idev->dev, sizeof(*maps) * (channels + 1),
> > + GFP_KERNEL);
> > + if (maps == NULL)
> > + return ERR_PTR(-ENOMEM);
> > +
> > + for (i = 0; i < channels; i++) {
> > + if (i < names) {
> > + ret = of_property_read_string_index(np,
> > + "io-channel-output-names", i,
> > + &maps[i].consumer_channel);
> > + if (ret < 0)
> > + return ERR_PTR(ret);
> > + }
> > + /* Use dummy for consumer device names */
> > + maps[i].consumer_dev_name = "of";
> > + }
> > + return maps;
> > +}
> > +
> > int iio_map_array_register(struct iio_dev *indio_dev, struct iio_map *maps)
> > {
> > int i = 0, ret = 0;
> > struct iio_map_internal *mapi;
> >
> > - if (maps == NULL)
> > - return 0;
> > + if (maps == NULL) {
> > + maps = iio_map_of_init(indio_dev);
> > + if (IS_ERR(maps))
> > + return PTR_ERR(maps);
> > + if (maps == NULL)
> > + return 0;
> > + }
> >
> > mutex_lock(&iio_map_list_lock);
> > while (maps[i].consumer_dev_name != NULL) {
> > @@ -92,30 +135,14 @@ static const struct iio_chan_spec
> > return chan;
> > }
> >
> > -
> > -struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
> > +struct iio_channel *iio_channel_get_common(struct iio_map_internal *c,
> > + int index)
> > {
> > - struct iio_map_internal *c_i = NULL, *c = NULL;
> > struct iio_channel *channel;
> > int err;
> >
> > - if (name == NULL && channel_name == NULL)
> > - return ERR_PTR(-ENODEV);
> > -
> > - /* first find matching entry the channel map */
> > - mutex_lock(&iio_map_list_lock);
> > - list_for_each_entry(c_i, &iio_map_list, l) {
> > - if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
> > - (channel_name &&
> > - strcmp(channel_name, c_i->map->consumer_channel) != 0))
> > - continue;
> > - c = c_i;
> > - iio_device_get(c->indio_dev);
> > - break;
> > - }
> > - mutex_unlock(&iio_map_list_lock);
> > if (c == NULL)
> > - return ERR_PTR(-ENODEV);
> > + return ERR_PTR(-EPROBE_DEFER);
> >
> > channel = kzalloc(sizeof(*channel), GFP_KERNEL);
> > if (channel == NULL) {
> > @@ -125,7 +152,13 @@ struct iio_channel *iio_channel_get(const char *name, const char *channel_name)
> >
> > channel->indio_dev = c->indio_dev;
> >
> > - if (c->map->adc_channel_label) {
> > + if (index >= 0) {
> > + if (index >= c->indio_dev->num_channels) {
> > + err = -EINVAL;
> > + goto error_no_chan;
> > + }
> > + channel->channel = &c->indio_dev->channels[index];
> > + } else if (c->map->adc_channel_label) {
> > channel->channel =
> > iio_chan_spec_from_name(channel->indio_dev,
> > c->map->adc_channel_label);
> > @@ -144,6 +177,60 @@ error_no_mem:
> > iio_device_put(c->indio_dev);
> > return ERR_PTR(err);
> > }
> > +
> > +struct iio_channel *of_iio_channel_get(struct device_node *np, int index)
> > +{
> > + struct iio_map_internal *c_i, *c = NULL;
> > + int err, map_index;
> > + 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);
> > +
> > + map_index = iiospec.args_count ? iiospec.args[0] : 0;
> > +
> > + mutex_lock(&iio_map_list_lock);
> > + list_for_each_entry(c_i, &iio_map_list, l) {
> > + if (iiospec.np == c_i->indio_dev->dev.of_node) {
> > + c = c_i;
> > + iio_device_get(c->indio_dev);
> > + break;
> > + }
> > + }
> > + of_node_put(iiospec.np);
> > + mutex_unlock(&iio_map_list_lock);
> > + return iio_channel_get_common(c, index);
> > +}
> > +EXPORT_SYMBOL_GPL(of_iio_channel_get);
> > +
> > +struct iio_channel *iio_channel_get(const char *name,
> > + const char *channel_name)
> > +{
> > + struct iio_map_internal *c_i = NULL, *c = NULL;
> > +
> > + if (name == NULL && channel_name == NULL)
> > + return ERR_PTR(-ENODEV);
> > +
> > + /* first find matching entry the channel map */
> > + mutex_lock(&iio_map_list_lock);
> > + list_for_each_entry(c_i, &iio_map_list, l) {
> > + if ((name && strcmp(name, c_i->map->consumer_dev_name) != 0) ||
> > + (channel_name && strcmp(channel_name,
> > + c_i->map->consumer_channel) != 0))
> > + continue;
> > + c = c_i;
> > + iio_device_get(c->indio_dev);
> > + break;
> > + }
> > + mutex_unlock(&iio_map_list_lock);
> > + return iio_channel_get_common(c, -1);
> > +}
> > EXPORT_SYMBOL_GPL(iio_channel_get);
> >
> > void iio_channel_release(struct iio_channel *channel)
> > @@ -159,24 +246,43 @@ struct iio_channel *iio_channel_get_all(struct device *dev)
> > struct iio_channel *chans;
> > struct iio_map_internal *c = NULL;
> > int nummaps = 0;
> > - int mapind = 0;
> > + int mapind;
> > int i, ret;
> >
> > if (dev == NULL)
> > return ERR_PTR(-EINVAL);
> > +
> > name = dev_name(dev);
> >
> > mutex_lock(&iio_map_list_lock);
> > /* first count the matching maps */
> > - list_for_each_entry(c, &iio_map_list, l)
> > - if (name && strcmp(name, c->map->consumer_dev_name) != 0)
> > - continue;
> > - else
> > - nummaps++;
> > -
> > - if (nummaps == 0) {
> > - ret = -ENODEV;
> > - goto error_ret;
> > + if (dev->of_node) {
> > + nummaps = 0;
> > + do {
> > + int ret;
> > +
> > + 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) {
> > + ret = -ENODEV;
> > + goto error_ret;
> > + }
> > + } else {
> > + list_for_each_entry(c, &iio_map_list, l)
> > + if (strcmp(name, c->map->consumer_dev_name) != 0)
> > + continue;
> > + else
> > + nummaps++;
> > + if (nummaps == 0) {
> > + ret = -EPROBE_DEFER;
> > + goto error_ret;
> > + }
> > }
> >
> > /* NULL terminated array to save passing size */
> > @@ -187,24 +293,65 @@ struct iio_channel *iio_channel_get_all(struct device *dev)
> > }
> >
> > /* for each map fill in the chans element */
> > - list_for_each_entry(c, &iio_map_list, l) {
> > - if (name && strcmp(name, c->map->consumer_dev_name) != 0)
> > - continue;
> > - chans[mapind].indio_dev = c->indio_dev;
> > - chans[mapind].data = c->map->consumer_data;
> > - chans[mapind].channel =
> > - iio_chan_spec_from_name(chans[mapind].indio_dev,
> > + if (dev->of_node) {
> > + /*
> > + * Device-tree based mapping, search for OF matches.
> > + */
> > + for (mapind = 0; mapind < nummaps; mapind++) {
> > + 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;
> > + channel = iiospec.args_count ? iiospec.args[0] : 0;
> > + ret = -EPROBE_DEFER;
> > + list_for_each_entry(c, &iio_map_list, l) {
> > + if (iiospec.np == c->indio_dev->dev.of_node) {
> > + ret = 0;
> > + break;
> > + }
> > + }
> > + if (ret)
> > + goto error_free_chans;
> > + if (channel >= c->indio_dev->num_channels) {
> > + ret = -EINVAL;
> > + goto error_free_chans;
> > + }
> > + chans[mapind].indio_dev = c->indio_dev;
> > + chans[mapind].data = c->map->consumer_data;
> > + chans[mapind].channel =
> > + &c->indio_dev->channels[channel];
> > + iio_device_get(c->indio_dev);
> > + }
> > + } else {
> > + /*
> > + * Platform data based mapping, search for consumer
> > + * device name.
> > + */
> > + mapind = 0;
> > + list_for_each_entry(c, &iio_map_list, l) {
> > + if (strcmp(name, c->map->consumer_dev_name) != 0)
> > + continue;
> > + chans[mapind].indio_dev = c->indio_dev;
> > + chans[mapind].data = c->map->consumer_data;
> > + chans[mapind].channel =
> > + iio_chan_spec_from_name(c->indio_dev,
> > c->map->adc_channel_label);
> > - if (chans[mapind].channel == NULL) {
> > - ret = -EINVAL;
> > + if (chans[mapind].channel == NULL) {
> > + ret = -EINVAL;
> > + goto error_free_chans;
> > + }
> > + iio_device_get(c->indio_dev);
> > + mapind++;
> > + }
> > + if (mapind < nummaps) {
> > + ret = -EPROBE_DEFER;
> > goto error_free_chans;
> > }
> > - iio_device_get(chans[mapind].indio_dev);
> > - mapind++;
> > - }
> > - if (mapind == 0) {
> > - ret = -ENODEV;
> > - goto error_free_chans;
> > }
> > mutex_unlock(&iio_map_list_lock);
> >
> [...]
>
>
More information about the devicetree-discuss
mailing list