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 ... > > +} > > + > > +static struct iio_channel *of_iio_channel_get(struct device_node *np, > > int index) +{ > > + struct iio_channel *channel; > > + struct device *idev; > > + struct iio_dev *indio_dev; > > + int err; > > + 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); > > + > > + idev = bus_find_device(&iio_bus_type, NULL, iiospec.np, > > + iio_dev_node_match); > > + of_node_put(iiospec.np); > > + if (idev == NULL) > > + return ERR_PTR(-EPROBE_DEFER); > > + > > + indio_dev = dev_to_iio_dev(idev); > > + > > + channel = kzalloc(sizeof(*channel), GFP_KERNEL); > > + if (channel == NULL) { > > + err = -ENOMEM; > > + goto err_no_mem; > > + } > > + > > + channel->indio_dev = indio_dev; > > + index = iiospec.args_count ? iiospec.args[0] : 0; > > What happens here with remaining phandle arguments? > > I'm not sure if such use case is needed for iio, but other subsystems give > the possibility of specifying custom xlate callback translating from a > custom specifier into channel number. (e.g. drivers/gpio/gpiolib-of.c) > I don't have a use case, and I hesitate to implement something that may never be used (and I can not really test it either). And without a use case we would not even know if the implementation makes sense or not. It should be possible to add additional functionality later if needed. Thanks, Guenter > Best regards, > Tomasz > > > + if (index >= indio_dev->num_channels) { > > + err = -EINVAL; > > + goto err_no_channel; > > + } > > + channel->channel = &indio_dev->channels[index]; > > + > > + return channel; > > + > > +err_no_channel: > > + kfree(channel); > > +err_no_mem: > > + iio_device_put(indio_dev); > > + return ERR_PTR(err); > > +} > > + > > +static struct iio_channel *of_iio_channel_get_by_name(struct > > device_node *np, + const char > *name) > > +{ > > + struct iio_channel *chan = ERR_PTR(-ENOENT); > > + > > + /* Walk up the tree of devices looking for a matching iio channel */ > > + while (np) { > > + int index = 0; > > + > > + /* > > + * For named iio channels, first look up the name in the > > + * "io-channel-names" property. If it cannot be found, the > > + * index will be an error code, and of_iio_channel_get() > > + * will fail. > > + */ > > + if (name) > > + index = of_property_match_string(np, "io-channel-names", > > + name); > > + chan = of_iio_channel_get(np, index); > > + if (!IS_ERR(chan)) > > + break; > > + else if (name && index >= 0) { > > + pr_err("ERROR: could not get IIO channel %s:%s(%i)\n", > > + np->full_name, name ? name : "", index); > > + return chan; > > + } > > + > > + /* > > + * No matching IIO channel found on this node. > > + * If the parent node has a "io-channel-ranges" property, > > + * then we can try one of its channels. > > + */ > > + np = np->parent; > > + if (np && !of_get_property(np, "io-channel-ranges", NULL)) > > + break; > > + } > > + return chan; > > +} > > + > > +static struct iio_channel *of_iio_channel_get_all(struct device *dev) > > +{ > > + struct iio_channel *chans; > > + int i, mapind, nummaps = 0; > > + int ret; > > + > > + do { > > + 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) /* no error, return NULL to search map table */ > > + return NULL; > > + > > + /* NULL terminated array to save passing size */ > > + chans = kzalloc(sizeof(*chans)*(nummaps + 1), GFP_KERNEL); > > + if (chans == NULL) { > > + ret = -ENOMEM; > > + goto error; > > + } > > + > > + /* Search for OF matches */ > > + for (mapind = 0; mapind < nummaps; mapind++) { > > + struct device *idev; > > + struct iio_dev *indio_dev; > > + 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; > > + > > + idev = bus_find_device(&iio_bus_type, NULL, iiospec.np, > > + iio_dev_node_match); > > + of_node_put(iiospec.np); > > + if (idev == NULL) { > > + ret = -EPROBE_DEFER; > > + goto error_free_chans; > > + } > > + indio_dev = dev_to_iio_dev(idev); > > + channel = iiospec.args_count ? iiospec.args[0] : 0; > > + if (channel >= indio_dev->num_channels) { > > + ret = -EINVAL; > > + goto error_free_chans; > > + } > > + chans[mapind].indio_dev = indio_dev; > > + chans[mapind].channel = &indio_dev->channels[channel]; > > + } > > + return chans; > > + > > +error_free_chans: > > + for (i = 0; i < mapind; i++) > > + iio_device_put(chans[i].indio_dev); > > + kfree(chans); > > +error: > > + return ERR_PTR(ret); > > +} > > + > > +#else /* CONFIG_OF */ > > + > > +static inline struct iio_channel * > > +of_iio_channel_get_by_name(struct device_node *np, const char *name) > > +{ > > + return ERR_PTR(-ENOENT); > > +} > > + > > +static inline struct iio_channel *of_iio_channel_get_all(struct device > > *dev) +{ > > + return NULL; > > +} > > + > > +#endif /* CONFIG_OF */ > > > > static struct iio_channel *iio_channel_get_sys(const char *name, > > const char *channel_name) > > @@ -150,7 +324,14 @@ struct iio_channel *iio_channel_get(struct device > > *dev, const char *channel_name) > > { > > const char *name = dev ? dev_name(dev) : NULL; > > + struct iio_channel *channel; > > > > + if (dev) { > > + channel = of_iio_channel_get_by_name(dev->of_node, > > + channel_name); > > + if (!IS_ERR(channel)) > > + return channel; > > + } > > return iio_channel_get_sys(name, channel_name); > > } > > EXPORT_SYMBOL_GPL(iio_channel_get); > > @@ -173,6 +354,11 @@ struct iio_channel *iio_channel_get_all(struct > > device *dev) > > > > if (dev == NULL) > > return ERR_PTR(-EINVAL); > > + > > + chans = of_iio_channel_get_all(dev); > > + if (chans) > > + return chans; > > + > > name = dev_name(dev); > > > > mutex_lock(&iio_map_list_lock); > -- 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
