Should I worry about "omap-mcbsp.2: alias fck already exists" or is it expected?

[NeilBrown <neilb@xxxxxxx>]

In 3.2-rc5 (and some earlier kernels) I'm getting the boot-time warning:

[    0.186828]  omap-mcbsp.2: alias fck already exists

and

[    0.188476]  omap-mcbsp.3: alias fck already exists

This happens because omap_alloc_device() contains:


	for (i = 0; i < oh_cnt; i++) {
		hwmods[i]->od = od;
		_add_hwmod_clocks_clkdev(od, hwmods[i]);
	}

so if oh_cnt is ever > 1 (which is is for mcbsp.2 and .3 in
omap_hwmod_3xxx_data.c as they both declare a '.devattr'), then
_add_hwmod_clocks_clkdev will be called twice with the one 'od', and both
calls will try to add an alias 'fsck' to that same device, and the second
will always give a warning.

Is this actually a bug, or should we silence the warning on second and
subsequent calls to omap_alloc_device()?

Like this?

Thanks,
NeilBrown

omap: don't try to register the main clock twice.

If omap_device_alloc is given 2 or more "struct omap_hwmod" it will try to
register the 'main_clk' of each of them with the same alias - "fck" - against
the same device.  This fails.
So to avoid a warning, don't even try.

Signed-off-by: NeilBrown <neilb@xxxxxxx>

diff --git a/arch/arm/plat-omap/omap_device.c b/arch/arm/plat-omap/omap_device.c
index e8d9869..11012bd 100644
--- a/arch/arm/plat-omap/omap_device.c
+++ b/arch/arm/plat-omap/omap_device.c
@@ -294,6 +294,7 @@ static void _add_clkdev(struct omap_device *od, const char *clk_alias,
  * and main clock
  * @od: struct omap_device *od
  * @oh: struct omap_hwmod *oh
+ * @sub: this is a subordinate device, so don't try to register fck
  *
  * For the main clock and every optional clock present per hwmod per
  * omap_device, this function adds an entry in the clkdev table of the
@@ -309,11 +310,12 @@ static void _add_clkdev(struct omap_device *od, const char *clk_alias,
  * No return value.
  */
 static void _add_hwmod_clocks_clkdev(struct omap_device *od,
-				     struct omap_hwmod *oh)
+				     struct omap_hwmod *oh, int sub)
 {
 	int i;
 
-	_add_clkdev(od, "fck", oh->main_clk);
+	if (!sub)
+		_add_clkdev(od, "fck", oh->main_clk);
 
 	for (i = 0; i < oh->opt_clks_cnt; i++)
 		_add_clkdev(od, oh->opt_clks[i].role, oh->opt_clks[i].clk);
@@ -576,7 +578,7 @@ static struct omap_device *omap_device_alloc(struct platform_device *pdev,
 
 	for (i = 0; i < oh_cnt; i++) {
 		hwmods[i]->od = od;
-		_add_hwmod_clocks_clkdev(od, hwmods[i]);
+		_add_hwmod_clocks_clkdev(od, hwmods[i], i);
 	}
 
 	return od;

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