[RFC 10/11] iio: Add OF support
Lars-Peter Clausen
lars at metafoo.de
Fri Feb 1 22:58:02 EST 2013
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.
- 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);
>
[...]
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