Re: [PATCH 2/2] ARM: imx6q: replace clk_register_clkdev with clock DT lookup

On Wed, Aug 22, 2012 at 09:32:23AM +0100, Russell King - ARM Linux wrote:

On Tue, Aug 21, 2012 at 08:11:57AM -0500, Rob Herring wrote:

quoted

On 08/21/2012 07:27 AM, Russell King - ARM Linux wrote:

quoted

So now, you're not dealing with inventing a whole load of names for clocks
on a platform, instead what you're doing is describing _where_ the clock
comes from in the system for a particular device by device node and index
into it - just like we do for interrupts.

That is what we're doing. The names are optional for DT, but happen to
be required for struct clk now. If we don't put something in DT, then
the clock names will have to be something generic like ccm-1..ccm-185.

And that's what's wrong.  Clocks themselves should _not_ be required to
be named.

If you use purely "producer node + index" then you don't need to name a
whole bunch of clocks, and you don't need to have an array of clock names
in the DT file.  This also gets rid of the time consuming strcmp against
every clock, which has already been raised as a problem with the existing
clk_get().

Ok, if I got your point correctly, it's about amending the following
changes, and then we can get rid of that big clock-output-names list
from dts.

Regards,
Shawn

--8<---

diff --git a/arch/arm/mach-imx/clk-imx6q.c b/arch/arm/mach-imx/clk-imx6q.c
index 433c683..d52f3f4 100644
--- a/arch/arm/mach-imx/clk-imx6q.c
+++ b/arch/arm/mach-imx/clk-imx6q.c

@@ -387,7 +387,7 @@ int __init mx6q_clocks_init(void)
                        pr_err("i.MX6q clk %d: register failed with %ld\n",
                                i, PTR_ERR(clk[i]));

-       of_clk_add_provider(np, of_clk_src_onecell_get, NULL);
+       of_clk_add_provider(np, of_clk_src_onecell_get, clk);

        clk_register_clkdev(clk[gpt_ipg], "ipg", "imx-gpt.0");
        clk_register_clkdev(clk[gpt_ipg_per], "per", "imx-gpt.0");

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 06bc0b5..a010ed6 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c

@@ -1584,16 +1584,10 @@ EXPORT_SYMBOL_GPL(of_clk_src_simple_get);

 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
 {
-       const char *clk_name;
+       struct clk **clks = data;
        int idx = clkspec->args[0];
-       int ret;
-
-       ret = of_property_read_string_index(clkspec->np, "clock-output-names",
-                                           idx, &clk_name);
-       if (ret < 0)
-               return ERR_PTR(ret);

-       return __clk_lookup(clk_name);
+       return clks[idx];
 }
 EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);