Messages in this thread | | | Date | Wed, 21 Dec 2011 07:05:40 +0100 | From | Lothar Waßmann <> | Subject | RE: [RFC PATCH v3 1/5] dt: add of_get_child_count helper function |
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Hi,
Dong Aisheng-B29396 writes: > > -----Original Message----- > > From: Marek Vasut [mailto:marek.vasut@gmail.com] > > Sent: Wednesday, December 21, 2011 3:47 AM > > To: linux-arm-kernel@lists.infradead.org > > Cc: Dong Aisheng-B29396; linux-kernel@vger.kernel.org; > > linus.walleij@stericsson.com; s.hauer@pengutronix.de; w.sang@pengutronix.de; > > rob.herring@calxeda.com; grant.likely@secretlab.ca; kernel@pengutronix.de; > > cjb@laptop.org; devicetree-discuss@lists.ozlabs.org; Guo Shawn-R65073 > > Subject: Re: [RFC PATCH v3 1/5] dt: add of_get_child_count helper function > > Importance: High > > > > > From: Dong Aisheng <dong.aisheng@linaro.org> > > > > > > Currently most code to get child count in kernel are almost same, add > > > a helper to implement this function for dt to use. > > > > > > --- > > > Changes v1->v2: > > > * change the name from of_get_child_number to of_get_child_count > > > > > > Signed-off-by: Dong Aisheng <dong.aisheng@linaro.org> > > > Cc: Grant Likely <grant.likely@secretlab.ca> > > > Cc: Rob Herring <rob.herring@calxeda.com> > > > --- > > > include/linux/of.h | 16 ++++++++++++++++ > > > 1 files changed, 16 insertions(+), 0 deletions(-) > > > > > > diff --git a/include/linux/of.h b/include/linux/of.h index > > > 4948552..d0d91a1 100644 > > > --- a/include/linux/of.h > > > +++ b/include/linux/of.h > > > @@ -189,6 +189,17 @@ extern struct device_node > > > *of_get_next_child(const struct device_node *node, for (child = > > > of_get_next_child(parent, NULL); child != NULL; \ > > > child = of_get_next_child(parent, child)) > > > > > > +static inline int of_get_child_count(const struct device_node *np) { > > > + struct device_node *child = NULL; > > > + int num = 0; > > > + > > > + while ((child = of_get_next_child(np, child))) > > > > The assignment in this condition really looks eerie, maybe just rewrite it to do > > { } while () ? Also, aren't the parenthesis unnecessary? > > > Yes, one more parenthesis. I will remove it. Thanks. > For the condition, it's a little trick but I guess for a helper function > it's ok right? And there're already many places using like this. > It's a bad habit to use an assignment as an expression. It always looks like someone used '=' instead of '=='.
You should make it clear that that's not the case like: | while ((child = of_get_next_child(np, child)) != NULL)
Lothar Waßmann -- ___________________________________________________________
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