Re: [PATCH 3/3] clk: keystone: Add sci-clk driver support

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On 08/12/16 23:10, Stephen Boyd wrote:
On 12/08, Tero Kristo wrote:
On 08/12/16 02:13, Stephen Boyd wrote:
On 10/21, Tero Kristo wrote:
diff --git a/drivers/clk/keystone/sci-clk.c b/drivers/clk/keystone/sci-clk.c
new file mode 100644
index 0000000..f6af5bd
--- /dev/null
+++ b/drivers/clk/keystone/sci-clk.c


+
+	handle = devm_ti_sci_get_handle(dev);
+	if (IS_ERR(handle))
+		return PTR_ERR(handle);
+
+	provider = devm_kzalloc(dev, sizeof(*provider), GFP_KERNEL);
+	if (!provider)
+		return -ENOMEM;
+
+	provider->clocks = data;
+
+	provider->sci = handle;
+	provider->ops = &handle->ops.clk_ops;
+	provider->dev = dev;
+
+	ti_sci_init_clocks(provider);

And if this fails?

Yea this is kind of controversial. ti_sci_init_clocks() can fail if
any of the clocks registered will fail. I decided to have it this
way so that at least some clocks might work in failure cause, and
you might have a booting device instead of total lock-up.

Obviously it could be done so that if any clock fails, we would
de-register all clocks at that point, but personally I think this is
a worse option.

ti_sci_init_clocks could probably be modified to continue
registering clocks when a single clock fails though. Currently it
aborts at first failure.


That sounds like a better approach if we don't care about
failures to register a clock. Returning a value from a function
and not using it isn't really a great design.

I worry that if we start returning errors from clk_hw_register()
that something will go wrong though, so really I don't know why
we want to ignore errors at all. Just for debugging a boot hang?
Can't we use early console to at least see that this driver is
failing to probe and debug that way?

Early console can be used to debug that, but it is kind of annoying to recompile most of the kernel when you suddenly need to use it.

How about modifying the ti_sci_init_clocks func to print an error for each failed clock?

If you insist on aborting the probe though if a single clock fails, I can do that also.

-Tero
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