[RFC 10/11] iio: Add OF support
Lars-Peter Clausen
lars at metafoo.de
Sat Feb 2 01:59:17 EST 2013
On 02/01/2013 03:33 PM, Guenter Roeck wrote:
> 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 ?
Yes, use bus_find_device on iio_bus_type. A nice example how to use this to
lookup device by of node is of_find_i2c_device_by_node. For IIO you also need
to make sure that dev->type is iio_dev_type, since both devices and triggers
are registered on the same bus.
>
> 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