On Mon, Feb 04, 2013 at 12:14:52AM +0100, Tomasz Figa wrote: > On Sunday 03 of February 2013 19:55:47 Lars-Peter Clausen wrote: > > On 02/03/2013 06:30 PM, Tomasz Figa wrote: > > > On Sunday 03 of February 2013 09:01:07 Guenter Roeck wrote: > > >> On Sun, Feb 03, 2013 at 12:52:40PM +0100, Tomasz Figa wrote: > > >>> On Sunday 03 of February 2013 12:29:23 Lars-Peter Clausen wrote: > > >>>> On 02/03/2013 03:06 AM, Guenter Roeck wrote: > > >>>>> On Sun, Feb 03, 2013 at 02:30:24AM +0100, Tomasz Figa wrote: > > >>>>>> Hi Guenter, > > >>>>>> > > >>>>>> Some comments inline. > > >>>>>> > > >>>>>> On Saturday 02 of February 2013 16:59:40 Guenter Roeck wrote: > > >>>>>>> Provide bindings and parse OF data during initialization. > > >>>>>>> > > >>>>>>> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx> > > >>>>>>> --- > > >>>>>>> - 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. > > >>>>>>> > > >>>>>>> .../devicetree/bindings/iio/iio-bindings.txt | 76 > > >>>>>>> ++++++++ > > >>>>>>> drivers/iio/inkern.c | 186 > > >>>>>>> > > >>>>>>> ++++++++++++++++++++ 2 files changed, 262 insertions(+) > > >>>>>>> > > >>>>>>> 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..58df5f6 > > >>>>>>> --- /dev/null > > >>>>>>> +++ b/Documentation/devicetree/bindings/iio/iio-bindings.txt > > >>>>>>> @@ -0,0 +1,76 @@ > > >>>>>>> +This binding is a work-in-progress. It is derived from clock > > >>>>>>> bindings, > > >>>>>>> +and based on 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 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 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. > > >>>>>>> + > > >>>>>>> +For example: > > >>>>>>> + > > >>>>>>> + adc: adc@35 { > > >>>>>>> + compatible = "maxim,max1139"; > > >>>>>>> + reg = <0x35>; > > >>>>>>> + #io-channel-cells = <1>; > > >>>>>>> + }; > > >>>>>>> + > > >>>>>>> +==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@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 b289915..d48f2a8 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 +93,179 @@ static const struct iio_chan_spec > > >>>>>>> > > >>>>>>> return chan; > > >>>>>>> > > >>>>>>> } > > >>>>>>> > > >>>>>>> +#ifdef CONFIG_OF > > >>>>>>> + > > >>>>>>> +static int iio_dev_node_match(struct device *dev, void *data) > > >>>>>>> +{ > > >>>>>>> + return !strcmp(dev->type->name, "iio_device") && dev- > >of_node > > >>> > > >>> == > > >>> > > >>>>>> data; > > >>>>>> > > >>>>>> Hmm, do you need to check type name here? One device node should > > >>>>>> rather > > >>>>>> represent only one device, making node an unique identifier. > > >>>>>> > > >>>>>> It this is meant to be a sanity check, it could be done one time > > >>>>>> after > > >>>>>> finding the device. > > >>>>> > > >>>>> Hi Tomasz, > > >>>>> > > >>>>> This is what Lars had suggested earlier: > > >>>>>> 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. > > >>>>> > > >>>>> Is it really needed, or in other words would it be sufficient to > > >>>>> check > > >>>>> if of_node and data match each other ? Your reasoning makes sense > > >>>>> to > > >>>>> me, and I had thought about it as well, but I don't really know, > > >>>>> and > > >>>>> I don't know how I could test it and guarantee correctness either. > > >>>>> I'll be happy to take the strcmp() out if someone tells me that it > > >>>>> is > > >>>>> definitely not needed ... > > >>>> > > >>>> A IIO trigger and a IIO device may have the same of_node, e.g. if > > >>>> they > > >>>> both belong to the same physical device. But you don't need to do > > >>>> the > > >>>> strcmp just compare dev->type to iio_dev_type i.e. dev->type == > > >>>> &iio_dev_type. Although it doesn't really matter in practice first > > >>>> check for the of_node then check for the type, since the of_node > > >>>> will > > >>>> only match for a few devices at most, the type will match for quite > > >>>> a > > >>>> few. > > >>> > > >>> I must disagree. > > >>> > > >>> If you have two IIO devices provided by one physical device, then in > > >>> > > >>> device tree they should be represented as follows: > > >>> phys-dev@12345678 { > > >>> > > >>> compatible = "some-physical-device"; > > >>> /* ... */ > > >>> > > >>> my_trig: iio-trigger { > > >>> > > >>> /* ... */ > > >>> > > >>> }; > > >>> > > >>> my_dev: iio-device { > > >>> > > >>> /* ... */ > > >>> > > >>> }; > > >>> > > >>> }; > > >>> > > >>> Notice that phys-dev works here as an IIO bus on which its IIO > > >>> devices > > >>> are available. This is related to the convention that single OF > > >>> device node represents single device, which would be violated > > >>> otherwise. > > >> > > >> Right now the iio device is a child of the physical device, and I am > > >> simply passing of_node on to it. guess you are saying that is not > > >> correct ? > > >> > > >> If so, what would be the correct approach ? Something like the > > >> following ? > > >> > > >> voltage-sensor@35 { > > >> > > >> compatible = "maxim,max1139"; > > >> reg = <0x35>; > > >> vcc-supply = <®_3p3v>; > > >> vref-supply = <®_3p3v>; > > >> > > >> max1139-iio: iio-device { > > >> > > >> device_type = "iio_device"; > > >> #io-channel-cells = <1>; > > >> > > >> }; > > >> > > >> }; > > >> > > >> and in the driver probe function: > > >> if (parent->of_node) > > >> > > >> iio_dev->dev.of_node = of_find_node_by_type(parent- > >of_node, > > >> > > >> "iio_device"); > > >> > > >> Another option would be to use of_find_compatible_node() and > > >> something > > >> like compatible = "iio-device"; > > >> in the iio-device node. > > > > > > A device node is defined as a node having compatible property. Other > > > nodes should be seen as helper nodes, which do not represent devices > > > (although they all have struct device_node in Linux). > > > > > > Also, AFAIK, device_type is a deprecated property used by some legacy > > > PowerPC machines and for current machines only compatible should be > > > used. > > > > > > So I guess the approach with compatible would be appropriate here. > > > > > > However for physical devices providing only a single IIO device it > > > might> > > > be better to allow simpler specification, like: > > > max1139-iio: voltage-sensor@35 { > > > > > > compatible = "maxim,max1139", "iio_device"; > > > > I don't think this makes a lot of sense. First of all iio_device an > > artificial Linux term, while the device tree should describe the > > hardware. > > Well, if you look at an iio_device as a subdevice of a physical device > then it should make a bit more sense. (See nodes of GPIO/pinctrl pin banks > or regulators of a PMIC chip.) > > > Secondly there is no generic iio driver which could match on > > a node with a "iio_device" compability string and stuff would just > > work. I mean we don't do > > > > compatible = "atmel,at91sam9260-i2c", "i2c-master"; > > > > or similar either. > > Right. We don't need the other compatible for simple devices with single > subdevice. This is implied by the driver registering a single IIO driver > using the node of physical device. > > > > reg = <0x35>; > > > vcc-supply = <®_3p3v>; > > > vref-supply = <®_3p3v>; > > > > > > device_type = "iio_device"; > > Also we don't need this device_type. Basically we don't need to specify > whether given node is an iio_device or an iio_trigger. It's up to the > driver to register the node as a device or a trigger by setting dev.of_node > field properly. > > So my suggestion would be to make the bindings as following. For single > subdevice: > > voltage-sensor@35 { > compatible = "maxim,max1139"; > reg = <0x35>; > vcc-supply = <®_3p3v>; > vref-supply = <®_3p3v>; > #io-channel-cells = <1>; > }; > > For multiple subdevices: > > voltage-sensor@35 { > compatible = "maxim,max1139"; > reg = <0x35>; > vcc-supply = <®_3p3v>; > vref-supply = <®_3p3v>; > > subdevice1 { > /* Subdevice specific data */ > #io-channel-cells = <1>; > }; > > subdevice2 { > /* Subdevice specific data */ > #io-channel-cells = <1>; > } Please provide an example how to parse that. Obviously now I can not look for "compatible" anymore. Sure, I can use of_get_child_by_name, but that means the sub-device names would have to be well defined. Or I could use of_find_node_by_name, but then I would need something like voltage-sensor@35 { compatible = "maxim,max1139"; iio-device; reg = <0x35>; vcc-supply = <®_3p3v>; vref-supply = <®_3p3v>; #io-channel-cells = <1>; }; Thanks, Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
