From: "Heiko Stübner" <heiko@sntech.de>
To: Rob Herring <robherring2@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Pawel Moll <Pawel.Moll@arm.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"grant.likely@linaro.org" <grant.likely@linaro.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Stephen Warren <swarren@wwwdotorg.org>,
Ian Campbell <ijc+devicetree@hellion.org.uk>
Subject: [PATCH v4] of: add functions to count number of elements in a property
Date: Sat, 18 Jan 2014 13:02:08 +0100 [thread overview]
Message-ID: <5115255.DrcMbtXc1P@phil> (raw)
In-Reply-To: <CAL_JsqJ_St=OegpexzrTGXwmOYCz4YeWk_1S+R_q6NajmmPqSA@mail.gmail.com>
The need to know the number of array elements in a property is
a common pattern. To prevent duplication of open-coded implementations
add a helper static function that also centralises strict sanity
checking and DTB format details, as well as a set of wrapper functions
for u8, u16, u32 and u64.
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
changes since v3:
address more comments from Rob Herring
- export the base function and inline the type-specific wrappers
changes since v2:
address more comments from Mark Rutland
- switch to of_property_count_elems_of_size
- use full_name instead of name in error message
changes since v1:
address comments from Rob Herring and Mark Rutland:
- provide a helper and a set of wrappers for u8-u64
- get rid of extra len variable, prop->length is enough
- include node name in error message
Mark, does your Reviewed-by holds for this variant too?
drivers/of/base.c | 32 ++++++++++++++++++++++
include/linux/of.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 108 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index f807d0e..21646c0 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c
@@ -862,6 +862,38 @@ struct device_node *of_find_node_by_phandle(phandle handle)
EXPORT_SYMBOL(of_find_node_by_phandle);
/**
+ * of_property_count_elems_of_size - Count the number of elements in a property
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ * @elem_size: size of the individual element
+ *
+ * Search for a property in a device node and count the number of elements of
+ * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
+ * property does not exist or its length does not match a multiple of u16 and
+ * -ENODATA if the property does not have a value.
+ */
+int of_property_count_elems_of_size(const struct device_node *np,
+ const char *propname, int elem_size)
+{
+ struct property *prop = of_find_property(np, propname, NULL);
+
+ if (!prop)
+ return -EINVAL;
+ if (!prop->value)
+ return -ENODATA;
+
+ if (prop->length % elem_size != 0) {
+ pr_err("size of %s in node %s is not a multiple of %d\n",
+ propname, np->full_name, elem_size);
+ return -EINVAL;
+ }
+
+ return prop->length / elem_size;
+}
+EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);
+
+/**
* of_find_property_value_of_size
*
* @np: device node from which the property value is to be read.
diff --git a/include/linux/of.h b/include/linux/of.h
index 276c546..293920d 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -250,6 +250,8 @@ extern struct device_node *of_find_node_with_property(
extern struct property *of_find_property(const struct device_node *np,
const char *name,
int *lenp);
+extern int of_property_count_elems_of_size(const struct device_node *np,
+ const char *propname, int elem_size);
extern int of_property_read_u32_index(const struct device_node *np,
const char *propname,
u32 index, u32 *out_value);
@@ -426,6 +428,12 @@ static inline struct device_node *of_find_compatible_node(
return NULL;
}
+static inline int of_property_count_elems_of_size(const struct device_node *np,
+ const char *propname, int elem_size)
+{
+ return -ENOSYS;
+}
+
static inline int of_property_read_u32_index(const struct device_node *np,
const char *propname, u32 index, u32 *out_value)
{
@@ -565,6 +573,74 @@ static inline int of_node_to_nid(struct device_node *device) { return 0; }
#endif
/**
+ * of_property_count_u8_elems - Count the number of u8 elements in a property
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ *
+ * Search for a property in a device node and count the number of u8 elements
+ * in it. Returns number of elements on sucess, -EINVAL if the property does
+ * not exist or its length does not match a multiple of u8 and -ENODATA if the
+ * property does not have a value.
+ */
+static inline int of_property_count_u8_elems(const struct device_node *np,
+ const char *propname)
+{
+ return of_property_count_elems_of_size(np, propname, sizeof(u8));
+}
+
+/**
+ * of_property_count_u16_elems - Count the number of u16 elements in a property
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ *
+ * Search for a property in a device node and count the number of u16 elements
+ * in it. Returns number of elements on sucess, -EINVAL if the property does
+ * not exist or its length does not match a multiple of u16 and -ENODATA if the
+ * property does not have a value.
+ */
+static inline int of_property_count_u16_elems(const struct device_node *np,
+ const char *propname)
+{
+ return of_property_count_elems_of_size(np, propname, sizeof(u16));
+}
+
+/**
+ * of_property_count_u32_elems - Count the number of u32 elements in a property
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ *
+ * Search for a property in a device node and count the number of u32 elements
+ * in it. Returns number of elements on sucess, -EINVAL if the property does
+ * not exist or its length does not match a multiple of u32 and -ENODATA if the
+ * property does not have a value.
+ */
+static inline int of_property_count_u32_elems(const struct device_node *np,
+ const char *propname)
+{
+ return of_property_count_elems_of_size(np, propname, sizeof(u32));
+}
+
+/**
+ * of_property_count_u64_elems - Count the number of u64 elements in a property
+ *
+ * @np: device node from which the property value is to be read.
+ * @propname: name of the property to be searched.
+ *
+ * Search for a property in a device node and count the number of u64 elements
+ * in it. Returns number of elements on sucess, -EINVAL if the property does
+ * not exist or its length does not match a multiple of u64 and -ENODATA if the
+ * property does not have a value.
+ */
+static inline int of_property_count_u64_elems(const struct device_node *np,
+ const char *propname)
+{
+ return of_property_count_elems_of_size(np, propname, sizeof(u64));
+}
+
+/**
* of_property_read_bool - Findfrom a property
* @np: device node from which the property value is to be read.
* @propname: name of the property to be searched.
--
1.7.10.4
next prev parent reply other threads:[~2014-01-18 12:02 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-15 21:40 [PATCH v6 0/6] ARM: rockchip: add smp functionality Heiko Stübner
2014-01-15 21:40 ` [PATCH v6 1/6] dt-bindings: sram: describe option to reserve parts of the memory Heiko Stübner
2014-01-16 14:36 ` Rob Herring
2014-01-15 21:41 ` [PATCH v6 2/6] misc: sram: implement mmio-sram-reserved option Heiko Stübner
2014-01-16 12:45 ` Mark Rutland
2014-01-16 18:04 ` [PATCH] of: add function to count number of u32 elements in a property Heiko Stübner
2014-01-17 14:29 ` Rob Herring
2014-01-17 14:44 ` Mark Rutland
2014-01-17 15:44 ` [PATCH v2] of: add functions to count number of " Heiko Stübner
2014-01-17 16:53 ` Mark Rutland
2014-01-17 17:27 ` [PATCH v3] " Heiko Stübner
2014-01-17 17:42 ` [PATCH v2] " Rob Herring
2014-01-18 12:02 ` Heiko Stübner [this message]
2014-01-18 15:07 ` [PATCH v4] " Rob Herring
2014-01-18 15:28 ` Heiko Stübner
[not found] ` <20140204173034.2D899C4050F@trevor.secretlab.ca>
2014-02-04 18:48 ` Heiko Stübner
[not found] ` <20140205120652.9B1A7C40A89@trevor.secretlab.ca>
2014-02-05 12:45 ` Heiko Stübner
2014-01-15 21:42 ` [PATCH v6 3/6] ARM: rockchip: add snoop-control-unit Heiko Stübner
2014-01-15 21:42 ` [PATCH v6 4/6] ARM: rockchip: add sram dt nodes and documentation Heiko Stübner
2014-01-15 21:43 ` [PATCH v6 5/6] ARM: rockchip: add power-management-unit Heiko Stübner
2014-01-15 21:43 ` [PATCH v6 6/6] ARM: rockchip: add smp bringup code Heiko Stübner
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