On 08/03/2011 04:50 AM, Jamie Iles wrote:
> I'm trying to work out how our cpufreq driver fits in with device tree
> bindings. We have a simple driver that just takes a struct clk and
> calls clk_set_rate() on it. Is a node in the device tree the right way
> to do this as it isn't really a physical device? I have the PLL in the
> clocks group of the DT:
Sounds generically useful...
The OF clock bindings are not really completely finalized and work on
the OF clk code is basically blocked waiting on the common struct clk
infrastructure.
>
> clocks {
> ...
>
> arm_clk: clock@11 {
> compatible = "picochip,pc3x3-pll";
> reg = <0x800a0050 0x8>;
> picoxcell,min-freq = <140000000>;
> picoxcell,max-freq = <700000000>;
> ref-clock = <&ref_clk>, "ref";
> clock-outputs = "cpu";
> };
> };
>
This describes the clock output. You still need to describe the
connection which is what the cpufreq driver should get. For that you
need something like this:
cpu@0 {
compatible = "arm,cortex-a9";
reg = <0>;
cpu-clock = <&arm_clk>, "cpu";
};
cpu@1 {
compatible = "arm,cortex-a9";
cpu-clock = <&arm_clk>, "cpu";
};
Then look for the cpu node(s) and get it's clock.
> so I could reference that. The of clk interface also requires a struct
> device for getting the clk so I guess this is needed...
I ran into that problem as well. Making of_clk_get take a struct
device_node ptr instead of struct device fixes the problem. Here's a
patch that does that.
Rob
From: Rob Herring <[email protected]>
Subject: [PATCH] of/clk: use struct device_node for of_clk_get
In order to allow clock retrieval without having a struct device,
use the OF node pointer instead for of_clk_get.
Signed-off-by: Rob Herring <[email protected]>
---
drivers/clk/clkdev.c | 3 ++-
drivers/of/clock.c | 12 +++++-------
include/linux/of_clk.h | 4 ++--
3 files changed, 9 insertions(+), 10 deletions(-)
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 9252b4f..a8f1d29 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -89,7 +89,8 @@ struct clk *clk_get(struct device *dev, const char
*con_id)
const char *dev_id = dev ? dev_name(dev) : NULL;
struct clk *clk;
- clk = of_clk_get(dev, con_id);
+ if (dev)
+ clk = of_clk_get(dev->of_node, con_id);
if (clk && __clk_get(clk))
return clk;
diff --git a/drivers/of/clock.c b/drivers/of/clock.c
index 4a6eb0a..7c90994 100644
--- a/drivers/of/clock.c
+++ b/drivers/of/clock.c
@@ -89,7 +89,7 @@ static struct clk *__of_clk_get_from_provider(struct
device_node *np, const char
return clk;
}
-struct clk *of_clk_get(struct device *dev, const char *id)
+struct clk *of_clk_get(struct device_node *node, const char *id)
{
struct device_node *provnode;
u32 provhandle;
@@ -98,12 +98,10 @@ struct clk *of_clk_get(struct device *dev, const
char *id)
char prop_name[32]; /* 32 is max size of property name */
const void *prop;
- if (!dev)
- return NULL;
- dev_dbg(dev, "Looking up %s-clock from device tree\n", id);
+ pr_debug("Looking up %s-clock from device tree\n", id);
snprintf(prop_name, 32, "%s-clock", id ? id : "bus");
- prop = of_get_property(dev->of_node, prop_name, &sz);
+ prop = of_get_property(node, prop_name, &sz);
if (!prop || sz < 4)
return NULL;
@@ -122,12 +120,12 @@ struct clk *of_clk_get(struct device *dev, const
char *id)
provnode = of_find_node_by_phandle(provhandle);
if (!provnode) {
pr_warn("%s: %s property in node %s references invalid phandle",
- __func__, prop_name, dev->of_node->full_name);
+ __func__, prop_name, 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);
+ pr_debug("Using clock from %s\n", provnode->full_name);
of_node_put(provnode);
diff --git a/include/linux/of_clk.h b/include/linux/of_clk.h
index 71a29eb..848b1c27 100644
--- a/include/linux/of_clk.h
+++ b/include/linux/of_clk.h
@@ -23,12 +23,12 @@ void of_clk_del_provider(struct device_node *np,
void *data),
void *data);
-struct clk *of_clk_get(struct device *dev, const char *id);
+struct clk *of_clk_get(struct device_node *node, const char *id);
int of_clk_fixed_parse(void);
#else
-static inline struct clk *of_clk_get(struct device *dev, const char *id)
+struct clk *of_clk_get(struct device_node *node, const char *id)
{
return NULL;
}
--
1.7.4.1
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