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. Which one is preferred ? 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
