On Tue, Mar 15, 2011 at 01:54:05AM -0600, Grant Likely wrote:
> On Mon, Mar 14, 2011 at 09:18:42PM +0800, Shawn Guo wrote:
> > With the platform clock support, the 'struct clk' should have been
> > associated with device_node->data. So the use of function
> > __of_clk_get_from_provider can be eliminated.
> >
> > Signed-off-by: Shawn Guo <shawn....@linaro.org>
> > ---
> > drivers/of/clock.c | 23 ++---------------------
> > 1 files changed, 2 insertions(+), 21 deletions(-)
> >
> > diff --git a/drivers/of/clock.c b/drivers/of/clock.c
> > index 7b5ea67..f124d0a 100644
> > --- a/drivers/of/clock.c
> > +++ b/drivers/of/clock.c
> > @@ -71,24 +71,6 @@ void of_clk_del_provider(struct device_node *np,
> > mutex_unlock(&of_clk_lock);
> > }
> >
> > -static struct clk *__of_clk_get_from_provider(struct device_node *np,
> > const char *clk_output)
> > -{
> > - struct of_clk_provider *provider;
> > - struct clk *clk = NULL;
> > -
> > - /* Check if we have such a provider in our array */
> > - mutex_lock(&of_clk_lock);
> > - list_for_each_entry(provider, &of_clk_providers, link) {
> > - if (provider->node == np)
> > - clk = provider->get(np, clk_output, provider->data);
> > - if (clk)
> > - break;
> > - }
> > - mutex_unlock(&of_clk_lock);
> > -
> > - return clk;
> > -}
> > -
> > struct clk *of_clk_get(struct device *dev, const char *id)
> > {
> > struct device_node *provnode;
> > @@ -123,9 +105,8 @@ struct clk *of_clk_get(struct device *dev, const char
> > *id)
> > __func__, prop_name, dev->of_node->full_name);
> > return NULL;
> > }
> > - clk = __of_clk_get_from_provider(provnode, prop);
> > - if (clk)
> > - dev_dbg(dev, "Using clock from %s\n", provnode->full_name);
> > +
> > + clk = provnode->data;
>
> Where is the device_node->data pointer getting set?
>
+#define ADD_CLK_LOOKUP() \
+ do { \
+ node->data = clk; \
^^^^^^^^^^^^^^^^^
+ \
+ cl->dev_id = dev_id; \
+ cl->clk = clk; \
+ clkdev_add(cl); \
+ \
+ return 0; \
+ \
+ out_kfree: \
+ kfree(cl); \
+ return ret; \
+ } while (0)
> In general the ->data pointer of struct device_node should be avoided.
> There are no strong rules about its usage which means there is a very
> real risk that another driver or subsystem will try to use it for a
> different purpose.
>
> Iterating over the whole device tree is safer, and it really isn't
> very expensive. If you really want to store the struct_clk pointer in
> the device node, then it would be better to add a struct clk * field
> to struct device_node.
>
--
Regards,
Shawn
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