On Sun, Feb 03, 2013 at 12:29:23PM +0100, 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. > iio_dev_type is defined as static variable in industrialio-core.c, which can be loaded as module. To use it in inkern.c, I would have to move it there and make it global. I can do that, but is it worth it just to safe the strcmp ? 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
