From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas KANDAGATLA Subject: Re: [PATCH 3.6.0-rc5] dt: introduce of_get_child to get child node by name. Date: Fri, 14 Sep 2012 07:55:38 +0100 Message-ID: <5052D4EA.60108@st.com> References: <1347534640-787-1-git-send-email-srinivas.kandagatla@st.com> <505242C3.7090006@gmail.com> Reply-To: srinivas.kandagatla-qxv4g6HH51o@public.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <505242C3.7090006-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: devicetree-discuss-bounces+gldd-devicetree-discuss=m.gmane.org-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org Sender: "devicetree-discuss" To: Rob Herring Cc: bergner-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org List-Id: devicetree@vger.kernel.org On 13/09/12 21:32, Rob Herring wrote: > On 09/13/2012 06:10 AM, Srinivas KANDAGATLA wrote: >> From: Srinivas Kandagatla >> >> This patch introduces of_get_child function to get a child node by its >> name in a given parent node. >> >> Without this patch each driver code has to iterate the parent and do >> a string compare, However having of_get_child libary function would >> avoid code duplication, errors and is more convenient. >> >> Signed-off-by: Srinivas Kandagatla >> --- >> drivers/of/base.c | 27 +++++++++++++++++++++++++++ >> include/linux/of.h | 2 ++ >> 2 files changed, 29 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/of/base.c b/drivers/of/base.c >> index d4a1c9a..d4b6840 100644 >> --- a/drivers/of/base.c >> +++ b/drivers/of/base.c >> @@ -391,6 +391,33 @@ struct device_node *of_get_next_available_child(const struct device_node *node, >> EXPORT_SYMBOL(of_get_next_available_child); >> >> /** >> + * of_get_child - Find the child node by name for given parent >> + * @node: parent node >> + * @name: child name to look for. >> + * >> + * This function looks for child node for given matching name >> + * >> + * Returns a node pointer if found, with refcount incremented, use >> + * of_node_put() on it when done. >> + * else returns NULL. >> + */ >> + >> +struct device_node *of_get_child(const struct device_node *node, > of_get_child_by_name would be more consistent naming with other apis. I agree. >> + const char *name) >> +{ >> + struct device_node *child; >> + >> + read_lock(&devtree_lock); > I don't think you need the lock here. The for_each takes the lock while > finding the node. yes, you are correct. We don't need a readlock here. >> + for_each_child_of_node(node, child) >> + if (child->name && (of_node_cmp(child->name, name) == 0) >> + && of_node_get(child)) >> + break; >> + read_unlock(&devtree_lock); >> + return child; >> +} >> +EXPORT_SYMBOL(of_get_child); >> + >> +/** >> * of_find_node_by_path - Find a node matching a full OF path >> * @path: The full path to match >> * >> diff --git a/include/linux/of.h b/include/linux/of.h >> index 1b11632..510e1fe 100644 >> --- a/include/linux/of.h >> +++ b/include/linux/of.h >> @@ -192,6 +192,8 @@ extern struct device_node *of_get_next_child(const struct device_node *node, >> struct device_node *prev); >> extern struct device_node *of_get_next_available_child( >> const struct device_node *node, struct device_node *prev); >> +extern struct device_node *of_get_child(const struct device_node *node, >> + const char *name); >> >> #define for_each_child_of_node(parent, child) \ >> for (child = of_get_next_child(parent, NULL); child != NULL; \ >> > >