| Message ID | ff924f640feeb87819d40557f12a04e607894682.1741610847.git.mazziesaccount@gmail.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | Support ROHM BD79124 ADC | expand |
On Mon, Mar 10, 2025 at 02:55:53PM +0200, Matti Vaittinen wrote: > There are a few use-cases where child nodes with a specific name need to > be parsed. Code like: > > fwnode_for_each_child_node() > if (fwnode_name_eq()) > ... > > can be found from a various drivers/subsystems. Adding a macro for this > can simplify things a bit. > > In a few cases the data from the found nodes is later added to an array, > which is allocated based on the number of found nodes. One example of > such use is the IIO subsystem's ADC channel nodes, where the relevant > nodes are named as channel[@N]. > > Add a helpers for iterating and counting device's sub-nodes with certain > name instead, of open-coding this in every user. Almost good, I doubt we need the exported function for the device as it can be derived from the fwnode_*() API by supplying dev_fwnode(dev). Perhaps we want also this for the completeness (other comments are below): From f52dbbe97ff0cdf835eef29506e482433f0a50a9 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Date: Mon, 10 Mar 2025 16:20:35 +0200 Subject: [PATCH 1/1] device property: Split fwnode_get_child_node_count() The new helper is introduced to allow counting the child firmware nodes of their parent without requiring a device to be passed. This also makes the fwnode and device property API more symmetrical with the rest. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> --- drivers/base/property.c | 12 ++++++------ include/linux/property.h | 7 ++++++- 2 files changed, 12 insertions(+), 7 deletions(-) diff --git a/drivers/base/property.c b/drivers/base/property.c index c1392743df9c..805f75b35115 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -928,22 +928,22 @@ bool fwnode_device_is_available(const struct fwnode_handle *fwnode) EXPORT_SYMBOL_GPL(fwnode_device_is_available); /** - * device_get_child_node_count - return the number of child nodes for device - * @dev: Device to count the child nodes for + * fwnode_get_child_node_count - return the number of child nodes for a given firmware node + * @fwnode: Pointer to the parent firmware node * - * Return: the number of child nodes for a given device. + * Return: the number of child nodes for a given firmware node. */ -unsigned int device_get_child_node_count(const struct device *dev) +unsigned int fwnode_get_child_node_count(const struct fwnode_handle *fwnode) { struct fwnode_handle *child; unsigned int count = 0; - device_for_each_child_node(dev, child) + fwnode_for_each_child_node(fwnode, child) count++; return count; } -EXPORT_SYMBOL_GPL(device_get_child_node_count); +EXPORT_SYMBOL_GPL(fwnode_get_child_node_count); bool device_dma_supported(const struct device *dev) { diff --git a/include/linux/property.h b/include/linux/property.h index e214ecd241eb..bc5bfc98176b 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -208,7 +208,12 @@ DEFINE_FREE(fwnode_handle, struct fwnode_handle *, fwnode_handle_put(_T)) int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index); int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name); -unsigned int device_get_child_node_count(const struct device *dev); +unsigned int fwnode_get_child_node_count(const struct fwnode_handle *fwnode); + +static inline unsigned int device_get_child_node_count(const struct device *dev) +{ + return fwnode_get_child_node_count(dev_fwnode(dev)); +} static inline int device_property_read_u8(const struct device *dev, const char *propname, u8 *val) ... > Please note, the checkpatch.pl was not happy about the for_each...() > macros. I tried to make them to follow the existing convention. I am > open to suggestions how to improve. checkpatch is known for false-positives and/or false-negatives. ... > +/** > + * fwnode_get_named_child_node_count - number of child nodes with given name > + * @fwnode: Node which child nodes are counted. > + * @name: String to match child node name against. > + * > + * Scan child nodes and count all the nodes with a specific name. Return the You already have a return section below. Perhaps rephrase somehow? > + * number of found nodes. Potential '@number' -ending for scanned names is Not sure how this "'@foo' -ending" part is being rendered in HTML/PDF... Also kernel-doc might be not happy with the @ character followed by an immediate text as it might be misinterpreted as a reference to a parameter. > + * ignored. Eg, E.g., (because it's the phrase in Latin: exempli gratia) > + * device_get_child_node_count(dev, "channel"); Shift right to make sure it's not a text, but a code, better even to use reST approach, i.e. (note additional leading space(s) and double colon): * ignored. E.g.:: * * fwnode_get_child_node_count(dev, "channel"); // you have a copy'n'paste typo * * would match all the nodes:: * * ... * > + * would match all the nodes: > + * channel { }, channel@0 {}, channel@0xabba {}... > + * > + * Return: the number of child nodes with a matching name for a given device. > + */ ... > +/** > + * device_get_named_child_node_count - number of child nodes with given name > + * @dev: Device to count the child nodes for. > + * @name: String to match child node name against. > + * > + * Scan device's child nodes and find all the nodes with a specific name and > + * return the number of found nodes. Potential '@number' -ending for scanned > + * names is ignored. Eg, > + * device_get_child_node_count(dev, "channel"); > + * would match all the nodes: > + * channel { }, channel@0 {}, channel@0xabba {}... > + * > + * Return: the number of child nodes with a matching name for a given device. Similar comments as per above. > + */ ... > +#define fwnode_for_each_named_child_node(fwnode, child, name) \ > + fwnode_for_each_child_node(fwnode, child) \ One TAB too much. > + if (!fwnode_name_eq(child, name)) { } else Ditto. Note, I believe this won't get v6.15-rc1, so there will be for_each_if() available and these will become #define fwnode_for_each_named_child_node(fwnode, child, name) \ fwnode_for_each_child_node(fwnode, child) \ for_each_if(fwnode_name_eq(child, name)) and so on... ... > unsigned int device_get_child_node_count(const struct device *dev); > +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode, > + const char *name); > +unsigned int device_get_named_child_node_count(const struct device *dev, > + const char *name); I would add a blank line. unsigned int device_get_child_node_count(const struct device *dev); // here is a blank line unsigned int device_get_named_child_node_count(const struct device *dev, const char *name); unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode, const char *name); But see above the proposed additional patch that you may include in your next version. > static inline int device_property_read_u8(const struct device *dev, > const char *propname, u8 *val)
On Mon, Mar 10, 2025 at 02:55:53PM +0200, Matti Vaittinen wrote: > There are a few use-cases where child nodes with a specific name need to > be parsed. Code like: > > fwnode_for_each_child_node() > if (fwnode_name_eq()) > ... > > can be found from a various drivers/subsystems. Adding a macro for this > can simplify things a bit. > > In a few cases the data from the found nodes is later added to an array, > which is allocated based on the number of found nodes. One example of > such use is the IIO subsystem's ADC channel nodes, where the relevant > nodes are named as channel[@N]. > > Add a helpers for iterating and counting device's sub-nodes with certain > name instead, of open-coding this in every user. > Please note, the checkpatch.pl was not happy about the for_each...() > macros. I tried to make them to follow the existing convention. I am > open to suggestions how to improve. You also may update .clang-format.
Moi, On Mon, Mar 10, 2025 at 02:55:53PM +0200, Matti Vaittinen wrote: > Please note, the checkpatch.pl was not happy about the for_each...() > macros. I tried to make them to follow the existing convention. I am > open to suggestions how to improve. checkpatch.pl isn't always handling macros as well as it might. (It's just hard to parse C using regular expressions and in practice some simplifications end up being made.)
> > > + if (!fwnode_name_eq(child, name)) { } else > > Ditto. > > Note, I believe this won't get v6.15-rc1, so there will be for_each_if() > available and these will become Unless this cycle goes long (i.e. an rc8) very unlikely I'll sneak the series in now due to lack of time to soak in next. > > #define fwnode_for_each_named_child_node(fwnode, child, name) \ > fwnode_for_each_child_node(fwnode, child) \ > for_each_if(fwnode_name_eq(child, name)) > > and so on... Nice - first time I've seen this :) Jonathan
diff --git a/drivers/base/property.c b/drivers/base/property.c index c1392743df9c..335262a894f4 100644 --- a/drivers/base/property.c +++ b/drivers/base/property.c @@ -945,6 +945,60 @@ unsigned int device_get_child_node_count(const struct device *dev) } EXPORT_SYMBOL_GPL(device_get_child_node_count); +/** + * fwnode_get_named_child_node_count - number of child nodes with given name + * @fwnode: Node which child nodes are counted. + * @name: String to match child node name against. + * + * Scan child nodes and count all the nodes with a specific name. Return the + * number of found nodes. Potential '@number' -ending for scanned names is + * ignored. Eg, + * device_get_child_node_count(dev, "channel"); + * would match all the nodes: + * channel { }, channel@0 {}, channel@0xabba {}... + * + * Return: the number of child nodes with a matching name for a given device. + */ +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode, + const char *name) +{ + struct fwnode_handle *child; + unsigned int count = 0; + + fwnode_for_each_named_child_node(fwnode, child, name) + count++; + + return count; +} +EXPORT_SYMBOL_GPL(fwnode_get_named_child_node_count); + +/** + * device_get_named_child_node_count - number of child nodes with given name + * @dev: Device to count the child nodes for. + * @name: String to match child node name against. + * + * Scan device's child nodes and find all the nodes with a specific name and + * return the number of found nodes. Potential '@number' -ending for scanned + * names is ignored. Eg, + * device_get_child_node_count(dev, "channel"); + * would match all the nodes: + * channel { }, channel@0 {}, channel@0xabba {}... + * + * Return: the number of child nodes with a matching name for a given device. + */ +unsigned int device_get_named_child_node_count(const struct device *dev, + const char *name) +{ + struct fwnode_handle *child; + unsigned int count = 0; + + device_for_each_named_child_node(dev, child, name) + count++; + + return count; +} +EXPORT_SYMBOL_GPL(device_get_named_child_node_count); + bool device_dma_supported(const struct device *dev) { return fwnode_call_bool_op(dev_fwnode(dev), device_dma_supported); diff --git a/include/linux/property.h b/include/linux/property.h index e214ecd241eb..6dd9ae83e9a5 100644 --- a/include/linux/property.h +++ b/include/linux/property.h @@ -167,10 +167,18 @@ struct fwnode_handle *fwnode_get_next_available_child_node( for (child = fwnode_get_next_child_node(fwnode, NULL); child; \ child = fwnode_get_next_child_node(fwnode, child)) +#define fwnode_for_each_named_child_node(fwnode, child, name) \ + fwnode_for_each_child_node(fwnode, child) \ + if (!fwnode_name_eq(child, name)) { } else + #define fwnode_for_each_available_child_node(fwnode, child) \ for (child = fwnode_get_next_available_child_node(fwnode, NULL); child;\ child = fwnode_get_next_available_child_node(fwnode, child)) +#define fwnode_for_each_available_named_child_node(fwnode, child, name) \ + fwnode_for_each_available_child_node(fwnode, child) \ + if (!fwnode_name_eq(child, name)) { } else + struct fwnode_handle *device_get_next_child_node(const struct device *dev, struct fwnode_handle *child); @@ -178,11 +186,19 @@ struct fwnode_handle *device_get_next_child_node(const struct device *dev, for (child = device_get_next_child_node(dev, NULL); child; \ child = device_get_next_child_node(dev, child)) +#define device_for_each_named_child_node(dev, child, name) \ + device_for_each_child_node(dev, child) \ + if (!fwnode_name_eq(child, name)) { } else + #define device_for_each_child_node_scoped(dev, child) \ for (struct fwnode_handle *child __free(fwnode_handle) = \ device_get_next_child_node(dev, NULL); \ child; child = device_get_next_child_node(dev, child)) +#define device_for_each_named_child_node_scoped(dev, child, name) \ + device_for_each_child_node_scoped(dev, child) \ + if (!fwnode_name_eq(child, name)) { } else + struct fwnode_handle *fwnode_get_named_child_node(const struct fwnode_handle *fwnode, const char *childname); struct fwnode_handle *device_get_named_child_node(const struct device *dev, @@ -209,6 +225,10 @@ int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index); int fwnode_irq_get_byname(const struct fwnode_handle *fwnode, const char *name); unsigned int device_get_child_node_count(const struct device *dev); +unsigned int fwnode_get_named_child_node_count(const struct fwnode_handle *fwnode, + const char *name); +unsigned int device_get_named_child_node_count(const struct device *dev, + const char *name); static inline int device_property_read_u8(const struct device *dev, const char *propname, u8 *val)
There are a few use-cases where child nodes with a specific name need to be parsed. Code like: fwnode_for_each_child_node() if (fwnode_name_eq()) ... can be found from a various drivers/subsystems. Adding a macro for this can simplify things a bit. In a few cases the data from the found nodes is later added to an array, which is allocated based on the number of found nodes. One example of such use is the IIO subsystem's ADC channel nodes, where the relevant nodes are named as channel[@N]. Add a helpers for iterating and counting device's sub-nodes with certain name instead, of open-coding this in every user. Suggested-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> --- Revision history: v5 => v6: - Add helpers to also iterate through the nodes. v4 => v5: - Use given name instead of string 'channel' when counting the nodes - Add also fwnode_get_child_node_count_named() as suggested by Rob. v3 => v4: - New patch as suggested by Jonathan, see discussion in: https://lore.kernel.org/lkml/20250223161338.5c896280@jic23-huawei/ Please note, the checkpatch.pl was not happy about the for_each...() macros. I tried to make them to follow the existing convention. I am open to suggestions how to improve. --- drivers/base/property.c | 54 ++++++++++++++++++++++++++++++++++++++++ include/linux/property.h | 20 +++++++++++++++ 2 files changed, 74 insertions(+)